C. quindiuense in a total of 122 plots of 400 m2 in forests and pastures at two sites with contrasted land use histories in Colombia and Peru. Additionally, we implemented growth models that allowed us to estimate the age of individuals at four sites. These data were combined with information collected from local land managers in order to complete our knowledge on the land use history at each site. At two sites, the presence of old individuals up to 169 years and a wide age range evidenced that, at least, a portion of current adults in pastures were spared from logging at the time of deforestation. However, at the two other sites, the absence of older adults in pastures and the narrow age range of the populations indicated that individuals came exclusively from rosette resilience. These interpretations were consistent with the land use history of sites. In consequence, the combination of the two hypotheses  explained patterns of C. quindiuense in pastures on a regional scale. Regeneration through subterranean meristems in palms is an important, yet overlooked mechanism of resilience, which occurs in a number of palm species and deserves being integrated in the conceptual framework of disturbance ecology.Wax palms are an important element of the cloud forests in the tropical Andes. Despite heavy deforestation, the density of adults seems to be similar in deforested pastures as in forests. We aimed to infer the mechanisms responsible for this apparent resilience in pastures and we tested two hypotheses to explain it: 1) adult palms survived in pastures because they were spared from logging, and 2) adults occurred in pastures through the resilience of large juvenile rosettes, which survived through subterranean meristems and later developed into adults. For this purpose, we characterized the demographic structure of  Acrocomia aculeata [Attalea spp. [Chusquea spp. (scandent bamboos), which develop long-lived dense thickets impeding secondary succession, until the occurrence of die-off following synchronized flowering events [Deforestation in the tropics has accelerated in recent years, and its progress has gained worldwide attention ,2. Alongaculeata ,11,; Attlea spp. ), or phylea spp. . Howeverlea spp. ,15, theylea spp. ,17. For g events ,19. Consg events ,21.Ceroxylon (Arecaceae), an iconic, “umbrella” taxon of the neotropical Andean forests sustaining many ecosystem services and having important positive effects on various components of the biodiversity [Ceroxylon populations are located in the vicinity of human settlements and thus confront the deleterious effects of deforestation, logging, burning, and large herbivores. Nevertheless, the adult density of Ceroxylon in deforested pastures seems to approach that of stands within adjacent forests, suggesting that the palms might be, to some extent, resilient to the effects of deforestation. However, Ceroxylon spp. are dioecious, long-lived palms, which develop a medium-sized to tall solitary stem without resprouting capacities, and with seedlings that do not tolerate the exposed conditions of open areas [In tropical forests, an interesting but understudied pattern of tree resilience has been observed in several species of the palm genus iversity ,22. SomeCeroxylon persists under the harsh environmental conditions of deforested mountain areas. For this purpose we investigated two hypotheses. First, we tested to what extent adult palms survived in pastures because they are spared from logging, having established in the formerly existing forest. Such hypothesis has been proposed recently in the case of the species C. echinulatum in Ecuador [Ceroxylon was regularly spared in pastures for various reasons, including keeping it as a construction material to be eventually used or the difficulty to cut the stems . Second, we explored the hypothesis that C. quindiuense may maintain adult populations in deforested areas through the resilience of large juvenile rosettes. This hypothesis is sustained by the fact that, once they reach the stage of large rosettes, individuals of Ceroxylon develop a subterranean meristem (underground stem), which is protected by the thick and tightly arranged enclosing leaf sheaths [We aimed at exploring the mechanisms by which  Ecuador  and has  sheaths ,24.C. quindiuense in forests and pastures at two sites with contrasting land use scenarios in Peru (recent deforestation) and Colombia (old deforestation). We examined the population structure and coupled demographic data with an estimation of the age of individuals, seeking evidence of a relationship between the history of deforestation and the age of populations. In light of the results found, we explored predictions on the long-term conservation of Ceroxylon, by comparing a series of deforestation scenarios.To achieve this goal, we studied populations of Ceroxylon  makes up a group of twelve species endemic to the tropical Andes (from Venezuela to Bolivia), where they are adapted to the relatively cold temperatures of the mountain cloud forests [Ceroxylon species are gregarious and reach high population densities, constituting a dominant structural element of the highly diverse cloud forest. For these reasons, and because they produce a high amount of fleshy fruits attractive for a large array of birds, rodents, and other mammals  Ceroxylon is considered a keystone taxon with outstanding positive impact on the functioning of the cloud forest [The genus  forests . Most ofd forest ,25. C. quindiuense is a tall, single-stemmed palm that can reach 52 m in height [th century, the areas of cloud mountain forest in Colombia are submitted to a typical slash-and-burn regime, followed by cultivation of grasses for cattle (dairy) grazing or crops such as corn, potatoes, tomatos, peas, and beans. The land is periodically burnt every 5—10 years to restart a cultivation cycle [n height . It is tn height . It formn height . It is cn height , due to on cycle . C. quindiuense at two distant sites with contrasting forest cover, in Colombia and in Peru (Quercus humboldtii (Fagaceae), Cedrela montana (Meliaceae), Weinmania rollottii (Cunnoniaceae), Hyeronima sp. (Euphorbiaceae), Billia rosea (Sapindaceae), Drymis granadensis (Winteraceae), and several species of Lauraceae and Meliaceae. Nevertheless, most of the woody components are typical of secondary forest, such as Cytharexylum subflavescens (Verbenaceae), Palicourea angustifolia (Rubiaceae), Myrsine coriacea (Primulaceae), Clethra sp. (Clethraceae), Lozania mutisiana (Lacistemataceae), Clusia sp. (Clusiaceae), Miconia lehmannii and Miconia psychrophila (Melastomataceae), and the arborescent fern Dicksonia sellowiana, among others. The understory layer is composed mainly by herbs as Lycianthes radiata (Solanaceae), Habracanthus sp. (Acanthaceae), Anthurium sp. (Araceae), Pilea spp. and Peperomia spp. (Piperaceae), Baccharis sp. and several species of Asteraceae, seedlings and sapling of shrubs and canopy trees, and in some areas, Chusquea sp. (Poaceae) [th and early 20th centuries, during the process known as Antioqueño Colonization [We studied the ecological structure of populations of  in Peru . In Colo in Peru . The forPoaceae) ,30. Extenization ,32. Nectandra sp., Ocotea sp. and Persea sp. (Lauraceae), Licania sp. , Weinmannia sp. (Cunnoniaceae), and many trees and shrubs of secondary forest like Alnus acuminata (Betulaceae), Clusia sp. (Clusiaceae), Pourouma sp. and Cecropia sp. (Urticaceae), Calyptranthes sp. (Myrtaceae), and Ficus sp. (Moraceae), as well as many shrubs and some arborescent ferns . The forest understory is composed by many herbs of Anthurium spp. (Araceae), Piper spp. and Peperomia spp. (Piperaceae), Solanaceae, Baccharis sp., and other Asteraceae, seedlings and saplings of woody species, and some woody scandent shrubs of Rubus sp. (Rosaceae) and Chusquea sp. (Poaceae) [C. quindiuense, and were therefore considered ideal settings to compare. The abiotic and biotic factors in each plot are included in In Peru, plots were established in Ocol, Department of Amazonas (06°15’46” S 77°34’06” W), between 2200 m and 2800 m. Landscape at this site consists of small areas of pasture in a dominant matrix of forest . The forPoaceae) . AccordiPoaceae) , pastureC. quindiuense distribution as in Ocol and Roncesvalles . We located plots in each habitat from random points located within patches of C. quindiuense. From each random point, we measured the distance (R) to the nearest stemmed C. quindiuense. This individual served as the proximal corner of the corresponding plot , thus totaling 122 plots and an area of 4.88 hectares. At each plot, we recorded all individuals of  in Ocol,C. quindiuense, in order to test the influence of forest structure on Ceroxylon’s demography. The area of the plots was not adjusted for slope, as many of the individuals  depend more on the area of the substrate than on the projected horizontal. Also, we wanted to follow Anthelme et al. (22) who did not adjust for slope, in order to allow other authors to make interspecific comparisons. We calculated basal areas of all trees (m2/ha), and of C. quindiuense in particular, from DBH data, in order to estimate the dominance of C. quindiuense. Differences in diameters were assessed using T-tests to compare the mean values for plots.At each plot, we measured the following variables: slope gradient (averaged from three measures taken with a Suunto PM5/1520 Clinometer); (2) the coordinates at the center of plot to ensure that the minimal distance between plots was 50 m, thus limiting the effects of autocorrelation in our sampling; (3) the diameter at breast height  of all trees with DBH > 10 cm, including C. quindiuense were obtained by counting the total number of individuals. Each individual was assessed as belonging to one of five life stages : undivided (lanceolate) leaves•Juvenile 1 (J1): divided leaves (at least 2 pinnae); length < 2 m, no stem•C. alpinum [Juvenile 2 (J2): leaf length > 2 m, no stem. These will be referred to also as “large rosettes”, compared to J1, which are smaller rosettes. This phase ranges from age 28-57 yr in  alpinum . •Juvenile 3 (J3): with stem but no evidence of reproduction, leaf scars parallel, crown erect; •Adult (A): evidence of reproduction ; crown hemispherical.C. alpinum in forest conditions, [C. alpinum), but could not be successfully sub-divided within the demographic protocol used here because the forest canopy is too closed and leaf scars are too numerous to allow detailed observations on the stem. Adult individuals were assessed as either male or female when reproductive evidence was available. The raw data were entered in Seedlings have a distinct foliar morphology and represent the germination and early development phase. Following the seedling phase, the rosette phase is long-lasting  and is C. quindiuense. A large variation in adult populations would reveal the presence of several generations of palms, thus truly resembling an adult population that established before deforestation and that had been spared form logging. In contrast, a reduced variation in the age of adult populations would increase the probability that it is represented by only one generation, likely coming from rosettes. For this purpose, at the four sites we calculated the age of 30 to 43 adults . Age estimations were based on a modified version of Corner’s model [C. alpinum [Rhopalostylis sapida, which takes 43 years to develop an aboveground stem [Sabal palmetto that takes between 30 and 60 years to complete this phase [In parallel with the demographic study, we intended to infer the relationship between the history of deforestation and the age of the remaining adult palms in pastures. Age measurement of adult palms was designed to examine age variation in adult populations of ’s model , which c’s model . The age alpinum . This esund stem , or Sabais phase .According to our model, the age of an individual is estimated as: whereN: Number of leaf scars before the first reproductionL: Distance from the first reproduction to the crown (in meters)C. alpinum by Vergara-Chaparro [Ceroxylon spp. so far, even if these were done in forests. In pastures, variation in age is expected to be more fluctuating resulting from a series of events that can be are hardly tracked in such longevous organisms . Therefore, while acknowledging these contingencies, we assumed that the duration of the rosette phase in pasture would be equivalent to the maximum measurement obtained in forests. This, because we considered growth in pastures as being far from optimum, as in closed forests where light is scarce. The constant 4.89 is the average leaf production rate for juveniles of C. quindiuense, as counted in cultivated palms of this species and of the closely related C. ventricosum [The constant 57.3 is the maximal duration in years of the rosette phase, and the constant 11 is the number of leaves produced per year during the reproductive phase, both parameters as estimated for Chaparro . We use tricosum . FinallySince height at the first reproduction was put into the growth model, and is considered an indicator of exposure to light during growth , this fihttp://geoportal.igac.gov.co) (Colombian sites), keeping the same scale for each site (1:300000). IGAC images are included in In order to test our hypothesis that the species has been to some degree resilient to deforestation, and other forms of ecosystem degradation such as fire and herbivory, we needed to gather as much information as possible about the deforestation history and the activities that have been carried out within the sites where the palms stand. As a proxy of the history of land use of each area, we estimated the percentage of forest cover at each site by computing the total area of forested fragments with ImageJ64 software on screenshot images obtained from GoogleEarth (Peruvian site) and the Instituto Geográfico Agustín Codazzi (IGAC) . When taking into account the whole sampling, we used fixed effects models with the variable ‘habitat’ nested within the variable ‘site’ to explain variation in the number of individuals of each life stage in plots. At each site we inferred variations among habitats with two sample T-tests. Analyses were conducted in MINITAB 15  and JMP 7.0  statistical software.Palm stems were overall thinner in Ocol than in Roncesvalles . Also, they were significantly thinner in forest than in pasture . However, when all sites/habitats were compared, no difference was detected between the diameters in the forest of Roncesvalles and those in the pasture of Ocol (two-sample T tests: p > 0.05). We tested for differences in the diameters of the adults and the J3 in the forest of Roncesvalles in order to detect if the increased diameter of the adults of the forests in Roncesvalles (when compared to those of the forests of Ocol) constituted a temporal effect of that specific age class, but these were not significantly different (two-sample T test: p > 0.05). 2/ha ± 488.30 vs. 837.78 m2/ha ± 496.28; two-sample T-test: p < 0.001), and when comparing pastures of the two sites . There was no significant variation in the basal area of C. quindiuense among sites (P > 0.05). In the forest, the portion of C. quindiuense reached 11.1% of total basal area. In pastures, meanwhile, the portion of C. quindiuense was significantly higher in Roncesvalles than in Ocol .Forest plots were located at higher elevation and on steeper terrains than pasture plots , and at the same time they were located at higher elevation (p < 0.001) and on steeper terrain (p < 0.05) in Roncesvalles than in Ocol. The overall basal area of Ocol was higher than that of Roncesvalles (p < 0.001). This was true when comparing forests . In pastures, each of these life stages was observed in Ocol whereas only adults were observed in Roncesvalles. In Roncesvalles, they were equally distributed between forest and pasture . In comparison, adults were twice as many in the forest as in the pasture in Ocol .Variation in the age  of adults in Salento and Ocol was 2-3 times higher than in La Línea or Roncesvalles . Adults Ceroxylon , the prsilience  on the pC. quindiuense still exist in pastures because they have been spared from logging. There, the existence of old palms   by fewer adults within pastures than in forests, (2) by the fact that very old individuals such as those found in Salento were absent, and (3) by the local constructions observed at the site, and the information recovered during interviews.Our data in Ocol and Salento are in line with the hypothesis that, at least, a significant portion of residual adults of  compare , much ol compare . This isthe 19th ,42 and pHowever, if the “spared adult hypothesis” provides at first sight a consistent explanation for the population structure found in the pastures of Ocol and Salento, it is not sufficient to explain the structure found in the pastures of Roncesvalles and La Línea. Indeed, at these two sites age variation in adults was found particularly narrow, representing only one generation of individuals. This is not consistent with the existence of populations of spared individuals, which, as observed in Ocol and Salento, should hold a larger array of ages . At OcolCeroxylon with underground meristems is at least 28 years. This time combined with time since initial deforestation in Ocol would reach 70 years, which makes possible the presence of adults of 74 years. As well, this would better fit the age of youngest adults in Salento (98 years) than taking into account the “spared adult” hypothesis only. Demographic and age data provided in our study support the fact that the “rosette resilience” hypothesis may provide an optimized explanation on adult distribution patterns in pastures, in combination with the “spared adult” hypothesis. Following the time estimates of Vergara-Chaparro , the timC. quindiuense, with short age range and absence of adults older than 117 years, and (2) basal area of other trees in Roncesvalles’ pastures was insignificant in comparison with Ocol’s pastures. Consequently, at these two sites the “spared adult” hypothesis is rejected. Meanwhile, the absence of individuals younger than 84 years is in line with the time when massive deforestation took place at these sites, if we take into account resilience of Ceroxylon rosettes after deforestation. Subterranean stems start to develop at approximately 28 years . This assertion is supported by our data since both sites (1) displayed similar age patterns for adults of J1 phase :); takinsee also , and adusee also . This mesee also .One might ask, if rosettes are resilient to deforestation, fire, and herbivory, why are they not present in pastures in the Colombian sites, and rarely present in Ocol? The time since deforestation, accounts for this absence. In all cases studied, deforestation began at least 45 years ago, and therefore the vast majority of the persisting rosettes have by now become adults. Furthermore, no regeneration from seedlings has taken place, as this class is not resilient to grazed environments, and therefore no recruitment to J2 and J3 has taken place during this time. However, in rare, recently deforested and periodically burnt lots, rosettes were observed to grow back , and to C. quindiuense in pastures on a regional scale. In Salento and Ocol, where adults were — at least partially — spared, the height at the first reproduction occurred at 19 m  make upC. echinulatum [What predictions of long-term conservation can we raise for current adult populations surviving in pastures? A crucial requirement for their preservation is that a reforestation event occurs within the life span of residual adults. If so, the shade produced by re-colonizing species should reduce sufficiently water stress and allow seedlings and young juveniles to survive, as shown for inulatum . Neverthinulatum . Under tinulatum , but posinulatum ,54 and oinulatum . Attalea butyracea, Acrocomia aculeata, and Oenocarpus bataua, in intervened tropical ecosystems. Like Ceroxylon, populations of these species often occupy subsets of the optimal available habitat, forming dense stands not easily explained by solely climatic or edaphic variables. Their patchy distribution could possibly be attributed to differential resilience mechanisms with regard to other sympatric species, an issue that should be further addressed. The resilience mechanisms discussed here might explain the maintenance and high population density of other palm species, such as Ceroxylon to persist today amidst vast anthropogenic disturbances in the cloud forests of the Andes may have been also responsible for their survival and recolonization in the past. The long-term genetic and ecological effects of the associated demographic fluctuations deserve further research.As a final remark, we evoke uniformitarianism principles that state: “the present is the key to the past” ; mechaniDataset S1Ceroxylon quindiuense in plots at Roncevalles (Colombia) and Ocol (Peru).Demography of (XLSX)Click here for additional data file.Dataset S2Ceroxylon quindiuense in plots at Roncevalles (Colombia) and Ocol (Peru).Aggregation of (XLS)Click here for additional data file.


Subjective complexity has been found to be related to hedonic measures of preference, pleasantness and beauty, but there is no consensus about the nature of this relationship in the visual and musical domains. Moreover, the affective content of stimuli has been largely neglected so far in the study of complexity but is crucial in many everyday contexts and in aesthetic experiences. We thus propose a cross-domain approach that acknowledges the multidimensional nature of complexity and that uses a wide range of objective complexity measures combined with subjective ratings. In four experiments, we employed pictures of affective environmental scenes, representational paintings, and Romantic solo and chamber music excerpts. Stimuli were pre-selected to vary in emotional content  and complexity (low versus high number of elements). For each set of stimuli, in a between-subjects design, ratings of familiarity, complexity, pleasantness and arousal were obtained for a presentation time of 25 s from 152 participants. In line with Berlyne’s collative-motivation model, statistical analyses controlling for familiarity revealed a positive relationship between subjective complexity and arousal, and the highest correlations were observed for musical stimuli. Evidence for a mediating role of arousal in the complexity-pleasantness relationship was demonstrated in all experiments, but was only significant for females with regard to music. The direction and strength of the linear relationship between complexity and pleasantness depended on the stimulus type and gender. For environmental scenes, the root mean square contrast measures and measures of compressed file size correlated best with subjective complexity, whereas only edge detection based on phase congruency yielded equivalent results for representational paintings. Measures of compressed file size and event density also showed positive correlations with complexity and arousal in music, which is relevant for the discussion on which aspects of complexity are domain-specific and which are domain-general. New Experimental Aesthetics has been largely motivated by the question of what determines humans’ preferences for certain kinds of stimuli over others. Perceived complexity has been reliably identified as a key determinant of hedonic value . Following Cavalcante et al. [where intensities e et al. , we calchttp://www.csse.uwa.edu.au/~pk/research/matlabfns/#phasecong). Similar to the RMS contrast measures, we computed three measures of objective complexity based on edge detection by phase congruency: the mean of the M values, the standard deviation of the mean M values, and a measure β, which constitutes the product of the mean and the standard deviation of the M values.Kovesi  developeWe also calculated the entropy of the image intensity histogram of a grayscale image , anotherp-values calculated by following the sequential Bonferroni-Holm procedure [Statistical analyses were conducted in IBM SPSS Statistics version 19  or Matlab R2010b . In order to address the issue of controlling for type 1 error in multiple testing of several correlations from the same matrix, we reported adjusted rocedure . For regrocedure . All staSubjective ratings for each picture were averaged across participants prior to any further analysis. In order to ensure that participants rated each stimulus in a consistent fashion, inter-rater reliability was assessed by computing the average measure intra-class correlation coefficient (ICC) using a two-factor random effects model and type consistency ,134. We SD above or below the mean. A series of Shapiro-Wilk normality tests indicated that five variables of the measures of compressed file size, edge detection, RMS contrast and entropy deviated significantly from a normal distribution , after removing the outliers. Furthermore, subjective ratings of familiarity, complexity, pleasantness and arousal were generally not normally distributed when all participants were considered together , and when males  and females  were considered separately. Thus, it was decided to employ non-parametric analyses to investigate correlations between this set of variables in a first step. All relationships between the variables were visually inspected in order to ensure that the distributions of the stimuli followed a linear or monotonic function. Since further regression analyses were planned, values 2 SD above and below the mean were removed in all variables prior to these correlational analyses.An exploratory data analysis revealed that each of the variables referring to the different compression formats and other measures of objective complexity  contained several outliers that were 2 R2 = .69, F = 99.19, p < .001, y = -2.96x + .35x2 + 9.54. The pictures varied to a larger degree in terms of felt pleasantness , nearly covering the complete seven-point scale, than in arousal . Pleasant high-arousing pictures did not receive average ratings above five on the seven-point rating scale, which stood in contrast to a subset of 14 unpleasant high-arousing pictures. This finding of a smaller number of less arousing pleasant pictures can be explained by the fact that IAPS pictures with erotic scenes, generally inducing high pleasantness and arousal [Note that we decided to present three types of relationships graphically: (a) the arousal-pleasantness relationship was considered as important because it shows the distribution of stimuli in the two-dimensional emotion space, which offers insights into the representativeness of the stimulus set, and (b) the arousal-complexity and (c) pleasantness-complexity relationships were considered as most relevant for the discussion of Berlyne’s theory  in the c arousal , were ex arousal , a bias  arousal . Thus, trs = -.31), indicating that more familiar pictures were rated as less complex. This finding is in line with earlier reports of effects of familiarity on subjective complexity ratings : Unfamiliar pictures were experienced as more arousing than familiar ones. A further analysis of the difference between two Spearman rank correlation coefficients based on the Fisher r-to-z transformation [z = 1.91, p = .056, but no other gender effects were observed. The positive relationship between familiarity and pleasantness was the strongest (rs = .64), showing that familiar semantic contents of pictures was associated with a higher degree of pleasantness.Spearman’s rank-order correlations were calculated between the four subjective ratings  for all participants as well as for males and females separately  because ormation  revealedrs = .36), in other words, more complex pictures induced higher degrees of arousal (rs = -.18), although a negative association between these two variables was visually present (rs = .01), whereas the positive relationship between complexity and arousal (rs = .27) was still significant. The observed positive association between complexity and arousal is in line with Berlyne’s theory [Two further associations in relation to complexity need to be noted. First, complexity correlated moderately positively with arousal  by using the macro “MEDCURVE” for SPSS [p < .001) when both groups of participants were considered in the analysis. As expected, and in line with Berlyne’s theory, complexity was positively correlated with arousal . The dependent mediator model was calculated in a second step and explained 55% of the variance in pleasantness (p < .001). There was no significant direct effect of complexity on pleasantness , which represents how much a unit change in complexity affects pleasantness independent of its effect on arousal. With respect to the effect of arousal on pleasantness, the coefficient of the linear term was positive and significant , whereas the coefficient of the quadratic term was negative and significant . Following the suggestion of Hayes and Preacher [p = .001), which makes the pleasantness-arousal-complexity causal system a less likely candidate. Taken together, the current data suggests that arousal plays a significant role in the complexity-pleasantness relationship, supporting Berlyne’s theory [In order to gain a deeper understanding of the underlying mechanism of the complexity-pleasantness relationship, a bootstrapping approach  was usedfor SPSS . Accordifor SPSS  the instfor SPSS . All relPreacher , the sams theory ,10. Mores theory , althougrs = .53) and JPEG file size (rs = .52) were the strongest, followed by the one of PNG file size (rs = .46), whereas the one with the GIF file size was the lowest (rs = .29) among the different types of compression formats. In general, the correlations between the ZIP and 7Z versions of the respective compression formats and subjective complexity yielded very similar results and are thus not reported here. One exception concerns the ZIP version of the JPEG format, which did not correlate significantly with subjective complexity. There were no significant correlations between the different compression formats and any other type of subjective rating, and further, no indications of any significant gender differences were found. In summary, the current results suggest that the correlation between subjective complexity and the original JPEG file size is among the strongest and that further transformations may not yield better results.In order to investigate whether subjective ratings of complexity were associated with objective complexity as measured by compressed file size, a series of Spearman’s rank-order correlations was conducted. r = .36) as the one observed in the current experiment (rs = .52). Forsythe and colleagues [N = 200) presented for 5 s. In their study, JPEG file size correlated somewhat more strongly with subjective complexity (rs = .60) than in the current experiment. Forsythe et al. [rs = .55), which could not be replicated with the current set of stimuli (rs = .29).The observed positive correlations between compressed file size and subjective complexity are in line with earlier findings ,102,104.lleagues  examinede et al.  also reprs ~ .44) with subjective complexity compared to the measures based on the Canny algorithm . Therefore, the current results support the findings by Forsythe et al. [rs = .54) for a set of environmental scene photographs.e et al. , who alsIt further needs to be noted that we did not observe any significant positive correlations between participants’ self-reported familiarity with the pictures and the four measures of perimeter detection. This result is in line with Forsythe et al. , who reprs = .28), which is comparable to the correlation we detected for the raw measure of the Canny edge detection algorithm. Similar correlations were observed for the three measures of edge detection based on phase congruency . Among all applied objective complexity measures related to edge detection, subjective complexity correlated best with the mean contrast values of the RMS contrast map (rs = .59) and the α-measure of the RMS contrast values (rs = .57). These results clearly replicate those of Cavalcante et al. [r = ~ .60 between the three RMS contrast measures and subjective complexity ratings of streetscape images, revealing the potential future use of RMS contrast measures as reliable indicators of subjective complexity. It is worth noting that we also found weak, non-significant, indications for a positive association between pleasantness and the standard deviation of the mean RMS contrast values . Nevertheless, the current data suggests that correlations between objective measures of complexity and subjective ratings other than complexity are weak, and consequently, that the applicability of objectives measures of complexity to the prediction of subjective pleasantness ratings appears limited for photographs of environmental scenes.Finally, we found several positive associations between subjective complexity and objective measures of complexity, which either have not been explored yet or have only rarely been used before. The entropy of the grayscale pictures correlated weakly with subjective complexity , followed by familiarity . The RMS contrast measure accounted for around 30% of the variation in subjective complexity. A similar model considering only objective measures of complexity as predictors (p < .001), explaining approximately 28% of the variance. Similar regression analyses conducted for males and females separately revealed analogous results except that arousal was a third significant predictor in the model for females . Taken together, these results support the view that familiarity is a significant predictor of subjective complexity that cannot be ignored in any complex models, and further, that the mean RMS contrast values are the strongest predictor of subjective complexity among the current set of objective complexity measures applied to affective environmental scenes.Linear multiple regression analyses were conducted to further investigate the inter-relationships between subjective ratings and objective measures of complexity. edictors  revealedForty German-speaking students  participated in the study in return for course credit. Most of these students were enrolled in a psychology degree and none of them was pursuing an art history degree or was an arts expert. Participants did not take part in any other experiment in the current study, and they all had normal or corrected-to-normal visual acuity.prometheus, http://prometheus-bildarchiv.de, and ARTStor, http://www.artstor.org/index.shtml). These representational paintings comprised different styles from the end of the 18th to the beginning of the 20th century, including renowned artists such as Achenbach, Cezanne, Courbet, Friedrich, Gauguin, Gericault, Goya, Manet, Monet, Turner, and Van Gogh (see Supporting Information Stimulus List S2). The semantic content of the paintings was similar to the one of the IAPS pictures used in Experiment 1, depicting human beings in different situations of everyday life (excluding erotic scenes), landscapes, animals and plants. Paintings that were highly familiar and for which the semantic content could not be easily understood, as judged by the co-authors, were not included in the stimulus set. As in Experiment 1, the paintings were pre-selected, as judged by the co-authors, to fall into one of the four quadrants spanned by arousal and pleasantness. For this purpose, the range of the semantic content was matched as much as possible with the one of environmental scenes. In order to achieve sufficient variation in subjective arousal, paintings with dull colors where preferably pre-selected for the low-arousing emotion quadrants. Half of the paintings in each hedonic category (n = 24) depicted a figure-ground composition and half a complex scene. The paintings were all in landscape format and saved in the same size (1024 x 768 pixels) and resolution (72dpi) in JPEG format  as the IAPS pictures used in Experiment 1. Due to the natural preponderance of figure-ground compositions in portrait format rather than in landscape format, especially when paintings contained human faces, several paintings were cut to landscape format using Adobe Photoshop CS5 software. Other modifications concerned the presence of signatures or frames, which were removed. It was made sure that all modifications yielded natural representations of paintings without any deformations. Since we aimed to preserve the emotional contents of the paintings, we decided not to control for variations of brightness within the stimulus set. The paintings were not modified in any other way.Ninety-six high-quality digital reproductions of colored oil and acryl paintings were downloaded from two digital image libraries  and IAPS pictures  did not significantly differ in their average RGB pixel levels, t(190) = -.35, p = .726.In order to rule out that any observed differences between the results regarding paintings and IAPS pictures were due to differences in brightness, an arithmetic mean model was applied to calculate the average brightness of the 96 paintings and 96 IAPS pictures in the RGB (red-green-blue) color space in Matlab. Specifically, brightness can be thought of as the arithmetic mean μ of the red, green and blue color coordinates (μ = (R+G+B)/3). The sets of paintings . Moreover, participants reported the general level of difficulty associated with giving ratings of complexity on a seven-point Likert scale (from “very easy” to “very difficult”). Finally, participants estimated the percentage of paintings they had seen at least once before the experiment (ranging from 0% to 100%). The self-developed questionnaire on interest in arts and expertise in visual arts comprised three parts. A set of eleven questions was used to examine participants’ interest in visual arts , followed by a part in which participants had to indicate whether they are familiar with the names of a range of artists as well as to name their nationality and their associated style by free verbal responses. In the final part, participants were confronted with representations of six paintings and again had to indicate their familiarity with the paintings and to name the artist and the style.In order to be able to compare results across the two different visual stimuli sets used in this study, the procedure of Experiment 2 was generally similar to the one in Experiment 1, with the exception that the instructions for familiarity ratings were as follows: “Please rate your familiarity with the painting.” In addition, after participants had finished the experiment, they filled a self-developed one-page questionnaire relating directly to the experiment followed by a four-page questionnaire assessing general interest in arts and expertise in visual arts. These additional questionnaires extended the length of the experimental session to 90 minutes. As in Experiment 1, the original paintings in JPEG format were transformed into a set of twelve different compression formats of which the file sizes were determined. Several edge detection measures and the entropy were calculated by using the same procedures as described in Experiment 1.ps < .01). Further analyses showed that males (n = 20) and females (n = 20) did not differ in their general liking for the paintings, Mann-Whitney U = 181.5, p = .608, r = -.08, and also not in their self-reported degree of difficulty in judging the complexity of the paintings, Mann-Whitney U = 155.5, p = .214, r = -.20. Note that r refers to an effect size estimate that is derived by converting test statistics into z-scores and dividing by the square root of the number of total observations, r = z/√N ( [abs(r) for small, medium and large effect sizes are as follows: small: r = .10; medium: r = .30; large: r = .50.With regard to the questionnaire data on participants’ liking for the paintings used in the experiment and the level of difficulty of giving complexity judgments, all except one out of four Shapiro-Wilk normality tests revealed that the data was not normally distributed .n = 19, M = 6.24, SD = 1.5) and females , t(37) = 1.85, p = .072, r = .29. One male participant did not respond to all the items of the art interest questionnaire. Screening of the other parts of the questionnaire (art expertise) indicated that none of the participants was an art expert.Participants reported to have seen approximately 5-10% of the paintings prior to the experiment on average. Regarding the results of the questionnaire on the self-reported interest in visual arts, we did not observe a significant difference between males  using a two-factor random effects model and type consistency ,134. We SD from the mean and removed. A series of Shapiro-Wilk normality tests indicated that four variables deviated significantly from normality after removal of outliers . The majority of the variables of self-reported familiarity, complexity, pleasantness and arousal did not deviate significantly from a normal distribution when all participants were considered together , or when males  and females  were considered separately.Data screening of the variables of objective complexity for outliers revealed between zero and eleven outliers per variable. Outliers were defined by values ± 2 R2 = .30, F = 18.88, p < .001, y = -2.42x + .28x2 + 8.69. However, the strength of the relationship was weaker in the set of paintings than the one observed for IAPS pictures. A further comparison between the two emotion spaces indicated that the range of arousal for paintings  was smaller than the one seen for IAPS pictures . The range of pleasantness associated with the paintings  was also smaller than the one associated with IAPS pictures . Fewer paintings were regarded as highly unpleasant and high-arousing. Nevertheless, the current data suggest the presence of a negativity bias [The distribution of the paintings in the two-dimensional emotion space  was veryity bias  of emotirs = -.07), but the data revealed a significant negative association with arousal (rs = -.28) and a significant positive association with pleasantness (rs = .78). The latter correlations were of a roughly similar magnitude as the ones observed in the set of IAPS pictures. Moreover, complexity was significantly positively related with arousal (rs = .54). The non-significant negative relationship between complexity and pleasantness was weaker (rs = -.10) than in Experiment 1 (rs = -.18). In order to control for effects of familiarity, partial Spearman’s rank-order correlations (rs = .59), whereas the relationship between complexity and pleasantness did not change.elations  were perrs = .59), as was the case for IAPS pictures in Experiment 1 (rs = .27). This association between complexity and arousal was significantly stronger for paintings  when effects of familiarity were partialed out. Furthermore, we did not observe a clear linear relationship between complexity and pleasantness when males and females were analyzed separately , while it was positive in males (rs = .16). Familiarity and pleasantness were also more strongly associated in females (rs = .81) than in males (rs = .66), z = 2.19, p = .029. Moreover, the negative relationship between familiarity and arousal was stronger in females (rs = -.45) than in males (rs = -.10), z = -2.52, p = .012. Last, the direction and strength of the relationship between complexity and pleasantness (rs = .10) and females (rs = -.26) were analyzed separately, z = -2.4, p = .016. The current findings thus corroborate earlier reports of gender differences in visual art appreciation [The current data also revealed several gender differences with regard to subjective ratings , which wsantness  differedeciation ,139,140,p < .001) when both groups of participants were considered in the analysis. As expected, and in line with Berlyne’s theory and results of Experiment 1, complexity was positively correlated with arousal . In a second step, the dependent variable model was calculated and explained 59% of the variance in pleasantness (p < .001). The direct effect of complexity on pleasantness was not significant , which we also observed in Experiment 1. With respect to the effect of arousal on pleasantness, the coefficient of the linear term and the coefficient of the quadratic term were not significant. Only the effect of familiarity was highly significant (p < .001). There were no indications of any significant instantaneous indirect effects when males and females were analyzed together, which stands in clear contrast to results reported in Experiment 1. However, a further mediation model conducted without considering familiarity as a covariate revealed significant linear indirect effects of complexity through arousal on pleasantness based on data of all participants. As in Experiment 1, we tested an alternative mediation model  which could only explain around 36% of the variance, implying that the complexity-arousal-pleasantness path model may better capture the underlying perceptual and cognitive processes.As in Experiment 1, a mediation model was calculated using the macro “MEDCURVE” in SPSS  in orderc’ = .22, p = .074). We believe that a gender-wise analysis is clearly better suited to detect mediation effects since we have shown that, for example, correlations between familiarity and the respective subjective ratings differed between males and females in the current experiment. Important information would have been lost if only results based on the pooled data had been presented.By using a bootstrapping approach, instantaneous indirect effects of complexity on pleasantness through arousal were observed when males and females were analyzed separately. Interestingly, this mediation effect was only present for pictures of moderate and high complexity in both groups, suggesting that for pictures of moderate and high complexity an increase in complexity led to a decrease in pleasantness through an increase in arousal. For pictures of low complexity, no such mediation effect was found. Further, it needs to be noted that the direct effect of complexity on pleasantness was nearly significant in females  and GIF file size (rs = .47) correlated significantly with subjective complexity judgments of representational paintings (N = 148). Furthermore, the current twelve compression file sizes neither correlated with familiarity, pleasantness nor arousal, which is in agreement with the results in relation to IAPS pictures investigated in Experiment 1 (The relationships between subjective and objective complexity as measured by compressed file size were investigated by Spearman’s rank-order correlations. riment 1 . The lacrs = .37). Bearing in mind that Forsythe et al. [e et al.  did not rs = -.23), a result which clearly differs from the positive association between these measures as presented in Experiment 1 (rs ~ .29). A closer inspection of the paintings after analysis by the Canny algorithm revealed that fine features of the background, due to the individual brush strokes, were indeed largely detected, which may explain the negative association with subjective complexity. Moreover, there was no significant association between the entropy of a grayscale image and subjective complexity. Interestingly, the mean RMS contrast values correlated only weakly with subjective complexity, but positive correlations were observed for the standard deviation of the RMS contrast values (rs = .24) and the RMS contrast α-measure (rs = .25). However, the degree of these correlations was considerably smaller than the one found for IAPS pictures in Experiment 1 (rs ~ .60). The standard deviation of the mean values of edge detection based on phase congruency yielded the strongest (and only significant) correlation (rs ~ .38) among all measures. It seems that objective measures of complexity including a measure of dispersion, such as the SD measures of RMS contrast and edge detection based on phase congruency as well as the related α- and β-measures, worked better for the current set of artworks than for environmental scenes. In summary, our findings indicate that objective measures which were successful in predicting subjective complexity of environmental scenes were much less efficient for representational paintings. Inter-correlations between a representative set of objective measures of complexity can be found in the Supporting Information  with subjective complexity (ormation .rs = .37), which stands in clear contrast to the findings of Experiment 1. In addition, a negative relationship between Canny edge detection measures and subjectively reported arousal  was observed. The finding that edge detection measures correlated with arousal in paintings but not in IAPS pictures may be explicable by the fact that the correlation between subjective arousal and complexity was stronger in paintings (rs = .54) than in IAPS pictures (rs = .36). Furthermore, the data showed indications of weak correlations between subjective pleasantness and measures of Canny edge detection (rs =.26) and the standard deviation of the RMS contrast values (rs = -.28), respectively. This lends some support to the finding by Forsythe et al. [The present results not only revealed significant correlations between measures of subjective and objective complexity, but also indications of relationships between objective measures of complexity and other types of subjective ratings. The correlation between the standard deviation RMS contrast measure and arousal was significant  as well as arousal and pleasantness in the as predictors in the stepwise regression analysis. Familiarity was entered in a first step, although it was not significantly correlated with subjective complexity when all participants were considered together in the analysis. This procedure was chosen in order to guarantee comparability across the four experiments. The results, presented in R2 = .40) based on two significant predictors, namely arousal  and the standard deviation of the phase congruency edge detection measure . A comparison with results presented in Experiment 1 showed two main differences: First, subjective arousal was a better predictor of complexity ratings of representational paintings than the best objective measure, which was not the case for the set of IAPS pictures. Second, the mean RMS contrast values were the strongest predictor in Experiment 1, whereas the SD measure of edge detection based on phase congruency yielded the best results in the current experiment.A stepwise regression analysis was conducted in order to examine whether objective measures of complexity are better predictors of complexity than, for example, subjective arousal. As in Experiment 1, we included seven measures of objective complexity  = 11.42, p <.001, with the following predictors: familiarity , arousal , SD phase congruency  and SD RMS contrast . The final model based on the data of males also explained 41% of the variance in subjective complexity, F = 11.44, p <.001, including the following predictors: familiarity , arousal , SD phase congruency  and SD RMS contrast .Similar stepwise regression analyses were conducted for both genders separately. In general, the results were comparable to those described above, with arousal and the  Elliott , the curSD measure of phase congruency  was the strongest predictor, followed by GIF compression file size  and the SD measure of RMS contrast . Only 25% of the variance in subjective complexity could be explained, F = 7.90, p <.001. Again, the SD measure of RMS contrast was identified as a negative suppressor variable. A comparison between the current results and those presented in Experiment 1 suggest that subjective complexity in response to IAPS pictures was easier to predict by means of objective measures because the model based on one predictor  was as successful as the current model based on three predictors. In both experiments, measures based on RMS contrast values contributed as significant predictors of visual complexity, highlighting their future use in studies involving objective complexity measures.As a final step, a multiple stepwise regression model only including objective measures of complexity was employed to predict subjective complexity ratings averaged over all participants. The results  suggest Thirty-six German-speaking psychology students  participated in the experiment. Participants received course credit in return for their participation and did not take part in any other experiment in this study. All participants were enculturated in Western tonal music from their birth onwards and non-musicians, i.e., they were neither playing a musical instrument at the time of the experiment nor had they played an instrument for longer than four years in their childhood or youth. Sixteen participants had played an instrument in their past . All participants reported normal hearing.th century Romantic piano solo music repertoire and comprised composers such as Brahms, Chopin, Grieg, Mendelssohn, Schubert and Schumann (see Supporting Information Stimulus List S3). Based on the distribution of the musical excerpts in the two-dimensional emotion space reported in Experiment 1 in Marin et al. [The ninety-two musical excerpts in WAV format were taken from the stimulus set described in Marin et al. . The stin et al. , 23 stimn et al. ), and a n = 14, ranging from classical, pop, Jazz to music of foreign cultures) on a seven-point Likert scale (from “never” to “very often”). In a similar way, they reported how often they listen to music actively (without doing other activities at the same time), passively (while doing other activities at the same time) or in a live-concert setting. For each of these ratings, participants named at least one musical style to which the rating mostly referred. Furthermore, they named their least and most preferred musical style and reported on the role music plays in their daily lives . Three questions referred directly to the experiment. Participants had to indicate whether they recognized the musical style and, if so, they were asked to name it. They also reported the degree of liking for the music on a seven-point Likert scale  and the degree of difficulty of judging the complexity of the music (from “very easy” to “very difficult”).A self-developed two-page questionnaire was used to explore participants’ musical background. Participants answered questions referring to their amount of musical training and indicated how often they listen to a particular musical style  was the same for all participants. A comparison between the inter-relationships of familiarity, arousal and pleasantness with those based on data of Experiment 1 as reported in Marin et al.  revealedIn order to obtain objective measures of complexity by means of data compression, the original uncompressed audio files in WAV format were transformed into one lossless compression format  and two common lossy compression formats (MP3 and Ogg Vorbis) by using Audacity 1.3.14 software. The 16 bit FLAC files were compressed to the maximum level 8. MP3 files were created with the following settings: bit-rate mode ‒ pre-set extreme, 220-260 kbit/s; variable speed ‒ standard; and channel mode ‒ joint stereo. The quality setting for the transformation into Ogg Vorbis files was set to 8, which referred to a variable bit rate of 256 kbit/s. The file sizes of the audio files of the respective compression formats were assessed in bytes. The event density per second of each musical excerpt was analyzed by means of the MIRtoolbox  in Matlaps < .05). Mann-Whitney-U-tests indicated that males (n = 18) and females (n = 16) differed neither in their ratings of the role music played in their daily lives, U = 108.0, p = .195, r = -.22, nor in their frequency of listening to classical music, U = 108.5, p = .212, r = -.21. Regarding the questionnaire referring to the actual experiment, an independent t-test revealed that males  and females  did not significantly differ in their general liking for the piano solo music, t(34) = .16, p = .877, r = .03. With respect to the difficulty of judging the complexity of the musical excerpts, there was also no significant difference between the genders, t(34) = -.42, p = .678, r = .07 . Taken together, these results suggest that males and females had a similar musical background, especially with regard to classical music, and that both participant groups reported comparable levels of liking for the music played in the experiment and of the difficulty of judging complexity thereof. Further inspection of the musical background questionnaire indicated that only three participants had a high interest in classical music.Two female participants did not provide answers to two questions in the post-questionnaire, but their behavioral data was included in the analysis. Shapiro-Wilk normality tests showed that the data referring to participants’ musical background, i.e., the role of music in participants’ lives and the frequency of listening to classical music, was not normally distributed  using a two-factor random effects model and type consistency ,134. A hps < .122), and when males  and females  were considered separately. Shapiro-Wilk normality tests also revealed significant deviations from normality for the MP3 (p = .001) and the FLAC (p = .002) compression file sizes as well as for the measure of event density (p = .039) although several outliers were removed. It was thus decided to run non-parametric tests in order to investigate the relationships between these sets of variables.After removal of several outliers prior to the analysis, a series of Shapiro-Wilk normality tests showed that most of the data of the four subjective ratings  deviated significantly from a normal distribution when all participants were considered together  as in pleasantness . A comparison of the current results with the findings of Experiment 1 described in [rs = .75), as was the case for the respective variables in the visual domain (see Experiments 1 and 2). Familiarity did not significantly correlate with subjective complexity judgments of music (rs = .03), which stands in contrast to the negative relationship observed for IAPS pictures, but at the same time, is in line with the finding for representational paintings (rs = -.07), suggesting that familiarity and complexity may be less related in artistic stimuli if effects of gender are ignored. In contrast to the findings reported in Experiments 1 and 2, familiarity did not significantly negatively correlate with arousal (rs = -.09). This correlation was significantly different compared to the one observed with IAPS pictures, z = -2.53, p = .011.rs = .42), which was also the case for the relationship between arousal and pleasantness (rs = .28). As expected, the relationship between complexity and arousal did not change when familiarity was controlled for (rs = .82). Importantly, the underlying basis of the positive association between complexity and pleasantness in males, the only significant association observed in this series of experiments so far, is difficult to interpret. In the current experiment, the degree of complexity was not manipulated but variations in complexity were naturally present in the stimulus set under investigation. Stimuli were selected on the basis of their affective content [rs = .27), followed by the one in paintings (rs = .59), and the strongest correlation was found in the current experiment for music (rs = .83). The differences between these three correlations were significant . All together, these results support Berlyne’s hypothesis [Partial Spearman’s rank-order correlations between complexity, pleasantness and arousal were conducted to eliminate effects of familiarity . Familia content . The pos rs = .5, and thers = .42) in response to music, indicating that more complex music induced higher levels of pleasantness. This relationship was negative in females . The dependent variable model was also significant and explained 55% of the variance in pleasantness. The results showed a significant direct effect of complexity on pleasantness after controlling for arousal , which was not present in Experiments 1 and 2. The bootstrapped estimate of the indirect effect was negative and significant at the 95% confidence level, suggesting that pleasantness decreases linearly as complexity increases. Mediation models calculated for males and females separately revealed that this indirect effect was only significant in females.As a next step, we performed a mediation analysis in order to examine whether the indirect effect of complexity on pleasantness through arousal can also be detected in the musical domain. A bootstrapping approach was used to test the mediator model . First, While the results of Experiments 1 and 2 provided evidence for a complexity-arousal-pleasantness path model, which is essentially in line with the mediating role of arousal proposed by Berlyne , the currs = .65). Compared to results of Experiments 1 and 2, the current correlations between compressed file size and subjective complexity for musical stimuli were generally stronger. Interestingly, the three types of compressed file sizes correlated even slightly (non-significantly) better with reported arousal  than with subjective complexity . The results further indicated that the size of MP3 and FLAC files correlated negatively, but less strongly, with familiarity in males (rs ~ -.28). We also observed a significant negative correlation between the FLAC file size and pleasantness in females (rs = -.31). These latter findings again highlight the need to consider gender in research on musical complexity in the context of empirical aesthetics.In line with our hypothesis, the file sizes of the three types of compression format , but not those of the original WAV formats, correlated significantly positively with subjective complexity . FLAC cors = .57), supporting our hypothesis. This correlation explained about 32% of the variance in subjective complexity and thus had a comparable strength to the ones observed for the correlations between the FLAC and MP3 compressed file sizes and subjective complexity. Event density also correlated positively with arousal (rs = .42). The data further revealed a weak positive association between pleasantness and event density in males (rs = .25). Taken together, these results are similar to those of Experiment 2, in which we also found indications that subjective ratings of paintings other than complexity weakly correlated with measures of edge detection and compressed file size. Specifically, the positive relationship between edge detection measures and arousal in the set of paintings and the one between compressed file size, event density and arousal in the set of piano solo music may be due to the stronger relationship between subjective complexity and arousal in visual and musical artistic stimuli compared to IAPS pictures. There was also a significant positive correlation between event density and subjective complexity  = 59.21, p < .001. Arousal was the strongest predictor , followed by pleasantness  and the FLAC file size . It is notable that arousal was the strongest predictor in the model, which was also the case in the model predicting subjective complexity of representational art in Experiment 2, but not in the model predicting subjective complexity ratings of IAPS pictures in Experiment 1. However, this pattern of results changed when males and females were analyzed separately. Familiarity was again entered in a first step. The model based on data from the male group was significant with an adjusted R2 of .79, F = 55.41, p < .001, revealing the following significant predictors: arousal , event density , MP3 file size (β = .17p = .022) and pleasantness . The regression analysis based on data of the female group was similar, indicating a significant model with an adjusted R2 of .74, F = 42.03, p < .001, and the following predictors: arousal , event density , MP3 file size (β = .19p = .002) and pleasantness . The finding that the type and order of the predictors are the same when both genders are analyzed separately and different when a model is fitted to the averaged data is worth noting. One possible explanation may relate to the different directions of the correlations between complexity and familiarity in males and females , event density  and MP3 file size  were significant predictors, explaining approximately 60% of the variance in subjective complexity, F = 43.12, p < .001. These results did not differ between males and females. In comparison to recent models of musical complexity based on objective measures [A stepwise regression model predicting subjective complexity only by means of objective measures of complexity  showed tmeasures ,115, theForty German-speaking psychology students  participated in the experiment in return for course credits. These participants did not take part in any other experiment in this study. All participants were enculturated in Western tonal music from their birth onwards and were non-musicians, i.e., they were neither playing a musical instrument at the time of the experiment nor had they played an instrument for longer than four years in their childhood or youth. Twenty-one participants had played an instrument in their past . All participants reported normal hearing.In this experiment, the aim was to manipulate musical complexity by the number of musical instruments present in an auditory scene, that is, one instrument (piano solo music) vs. three instruments (piano trios). This approach made a meaningful comparison with Experiments 1 and 2, in which visual complexity was manipulated in a similar vein, possible. Thus, 40 piano trio excerpts (see Supporting Information Stimulus List S4) were pre-selected by the first author, a trained musicologist, from the Romantic music repertoire to fall into one of the four emotion quadrants defined by the dimensions of arousal and pleasantness . The firIn general, the experimental procedure was identical to the one described in Experiment 3, except for that participants were tested in pairs separated by a wall in a quiet room. Each participant was wearing Sennheiser (HD 380 pro) headphones. Furthermore, the piano solo music and piano trio excerpts were blocked according to their position in the arousal-pleasantness space. All trials (10 piano solo music excerpts and 10 piano Trió excerpts) were randomized within the four blocks, which were also randomized across participants. After the experiment, participants completed the questionnaire and were debriefed and dismissed. The experimental session lasted approximately 80 minutes on average. The 40 piano trio excerpts in WAV format were also transformed into MP3, Ogg Vorbis and FLAC files. The file size and event density of each musical excerpt were determined as described in Experiment 3.ps < .140). Similarly, the distributions of the variables regarding the general liking of the music presented in the experiment and the difficulty of giving complexity ratings were not normally distributed . Mann–Whitney U-tests indicated that males (n = 20) and females (n = 20) differed neither in their ratings of the role music plays in their daily lives, U = 200.0, p = 1.00, r =.00, nor in their frequency of listening to classical music, U = 192.5, p = .836, r = -.03. Moreover, males and females liked the musical stimuli to a similar extent, U = 171.5, p = .423, r = -.13, and they also reported a similar degree of difficulty of judging the complexity of the musical excerpts, U = 188.5, p = .750, r = -.05.A series of Shapiro-Wilk normality tests indicated that the data referring to participants’ musical background, i.e., the role of music in participants’ lives and the frequency of listening to classical music, was largely not normally distributed when the data was considered separately for males and females  using a two-factor random effects model and type consistency ,134. A hSD above or below the mean, Shapiro-Wilk normality tests showed that most of the subjective ratings with regard to the musical excerpts, with the exception of those of familiarity, were not normally distributed when both genders were considered together , and when males  and females  were analyzed separately. Deviations from normality were also observed for the Ogg Vorbis compressed file size (p < .001), therefore it was decided to conduct non-parametric correlation analyses as in Experiments 1-3. A comparison between the distributions of musical excerpts in the arousal-pleasantness space in Experiment 3  were indeed rated as more complex than piano solo excerpts , t(78) = -4.34, p < .001, r = .44.Here, complexity was manipulated by mixing piano solo excerpts with piano trios on the grounds that these have a greater number of melodic parts than the piano solo excerpts used in Experiment 3. However, adding additional melodic parts does more than simply add extra complexity to a piece of music. It may also add timbral streaming, harmonic richness and complexity, and greater expressive scope. It thus remains possible that these factors were responsible for any differences found between Experiments 3 and 4, rather than differences in subjective complexity per se. A comparison between the subjective complexity ratings of the original 40 piano solo and 40 piano trio excerpts revealed that piano trio excerpts (rs = .84). The findings further indicated significant positive correlations between familiarity and pleasantness in all three groups. Furthermore, the pattern of correlations between arousal and pleasantness was similar in direction as in Experiment 3. Specifically, the current results showed that arousal and pleasantness were negatively associated in females (rs = -.29) but positively in males (rs = .22), yielding a slightly negative correlation on average. Another notable finding concerns the positive relationship between complexity and pleasantness in males (rs = .22) and a concurrent negative relationship in females (rs = -.24) compared to results presented in Experiment 3. In a similar vein, there were clear indications for a negative correlation between familiarity and complexity in males and females, which was not the case for females in Experiment 3.The inter-relationships between the four subjective variables  were gen females , whereasrs = .41), whereas this relationship remained negative but not significant in females (rs = -.14). The relationship between arousal and pleasantness got stronger only for males (rs = .35) but not for females (rs = -.23) when familiarity was considered in the analysis. The association between complexity and arousal also remained unchanged in all analyses after controlling for familiarity effects. In summary, it can be concluded that familiarity plays an indispensable role in the investigation of the inter-relationships between complexity, arousal and pleasantness. Most importantly, it seems that the relationship between complexity and pleasantness cannot be meaningfully discussed without considering gender. Future studies may investigate the underlying reasons of these gender effects and whether they hold true for other musical styles.Partial Spearman’s rank-order correlations controlling for effects of familiarity were computed in a next step , and thea = .76, p < .001). The dependent variable model was also significant and explained 54% of the variance in pleasantness. Furthermore, the results showed a significant direct effect of complexity on pleasantness after controlling for arousal , which we did not find in Experiments 1 and 2. The bootstrapped estimate of the indirect effect was negative and significant at the 95% confidence level, suggesting that pleasantness decreases linearly as complexity increases through its effect on arousal. As in Experiment 3, mediation models calculated for males and females separately revealed that this indirect effect was only significant in females, although both groups had similar musical listening backgrounds. We consider the replication of the results of Experiment 3, with partially different musical stimuli and a new sample of participants, to be a noteworthy finding. First, the observed gender effects with regard to the mediation effect seem to be robust when different styles of Romantic music are used as stimulus material. Second, the co-occurrence of significant direct and indirect effects may be a particularity of the musical domain because direct effects were not present in the current two experiments involving visual stimuli. Future studies employing different types of visual and musical stimuli under a common experimental framework may thus reveal whether the current findings can be generalized.As in Experiments 1-3, a mediation analysis based on a bootstrapping approach  was perfrs = .43), when piano trios and piano solo music were combined in one stimulus set. As in Experiment 3, the highest correlation was observed for the compression size based on the FLAC format (rs = .78), explaining around 60% of the variance in the data. Bearing in mind that Streich’s model of musical complexity [The Spearman’s rank-order correlations between subjective and objective complexity as measured by compressed file size  revealedmplexity  reached rs = .34), an association which was already weakly present in all groups in Experiment 3. A summary of the inter-relationships between the objective measures of musical complexity applied to piano solo and piano trio excerpts is shown in Moreover, as observed in Experiment 3, the compressed file size measures and event density did not correlate solely with subjective complexity. The strength of the relationships between compressed file size and arousal were similar for the two data sets, whereas event density did not significantly correlate with arousal in Experiment 4. Interestingly, indications for a negative correlation between familiarity and the MP3 and FLAC file sizes were present in Experiments 3 and 4. In contrast to these findings, familiarity and event density correlated positively with each other in both experiments. In addition, the current data revealed negative correlations between pleasantness and the three types of compression file size in females, which was also present in Experiment 3. In Experiment 4, we further observed a significant positive correlation between event density and pleasantness in males (p = .048). The final model after four steps  = 62.52, p < .001) revealed three other significant predictors, namely arousal , event density  and MP3 file size . Separate regression analyses computed for both genders showed very similar results. The model for males, adjusted R2 = .74, F = 42.61, p < .001, yielded the following four predictors: familiarity , arousal , event density  and MP3 file size . The pattern of results only changed minimally for females because MP3 file size did not significantly explain variance in subjective complexity. The model, adjusted R2 = .77, F = 69.58, p < .001, was based on the following predictors: familiarity , arousal , and event density . Importantly, a similar pattern of results was observed in Experiment 3 when the groups of males and females were analyzed separately, with the exception that pleasantness did not emerge as a significant predictor of subjective complexity in the current models. Finally, a model of subjective complexity solely based on objective complexity measures was built  = 44.77, p < .001, comprised three predictors: FLAC file size , MP3 file size  and event density . A comparison with results of Experiment 3 , followed by representational paintings (rs = .59) and music (rs = .84). In the present study, environmental scenes and representational paintings were matched for semantic contents and for average brightness; therefore, it can be argued that the differences in strength of this relationship may not only refer to the type of modality but also to the degree of artistic quality and motivational relevance. In other words, for artworks we observed a stronger relationship between complexity and arousal. Future studies may examine this hypothesis by comparing different types of visual and auditory stimuli varying in their artistic quality.In all four experiments, the current data provided convincing evidence for a positive association between subjective complexity and arousal, which is in line with Berlyne’s collative-motivation model ,10. Whenrs = .42; piano solo music combined with piano trios: rs = .41) but not in females. It needs to be seen whether this result holds for different musical styles. These findings may suggest that there is no common trend for the relationship between complexity and pleasantness in the current framework of the present cross-domain study, although this was clearly the case for the relationship between complexity and arousal. Further experiments may explore whether these findings are due to the specific emotion model on which the selection of stimuli was based [Based on recent findings by Nadal et al. in the visual domain , that esas based , or whetOur results also shed light on the question of whether the complexity-pleasantness relationship is mediated by arousal as proposed by Berlyne ,10. By aIf one considers adopting an affective approach to the study of complexity, including the concept of arousal, there are several issues that warrant attention: Arousal presumably may not form a uniform concept as described in Berlyne’s psychobiological model; instead, current behavioral and neuroscientific findings suggest that there may be different forms of affective arousal with related multiple underlying brain mechanisms. For example, energy arousal has been differentiated from tension arousal . In lineMeasures based on compressed file size and edge detection algorithms have recently been applied to the study of visual complexity ,102,104.rs = .53) and JPEG (rs = .52) compression file sizes yielded the strongest correlations with subjective complexity ratings of environmental scenes. In contrast to Forsythe et al. [rs = .29). The moderate correlation between JPEG compression size and subjective complexity was also reported by Cavalcante et al. [Specifically, the findings obtained in the present study showed that compressed file size only correlated positively with subjective complexity judgments of photographs of environmental scenes but not with complexity judgments of representational paintings. TIFF , followed by perimeter detection (rs ~ .45) and the standard deviation of the RMS contrast measure (rs = .43). The mean and beta phase congruency measures worked reasonably well with a correlation of rs ~ .35. The pattern of results looks somewhat different for representational paintings. The standard deviation of the phase congruency measure performed best (rs = .38), followed by the beta measure of phase congruency (rs = .30), and the alpha and standard deviation of the RMS contrast measures (rs ~ .25). Taken together, these results suggest that the correlation strength between edge detection measures and subjective complexity is stronger for photographs of environmental scenes than for paintings. This finding is in line with Forsythe et al. [rs = .54) than for representational paintings (rs = .37) with respect to perimeter detection. In the present study, perimeter detection did not yield correlations as strong as those reported by Forsythe et al. [In a similar vein, disparities between environmental scenes and representational paintings were noted when comparing the performance of a set of edge detection measures to predict subjective complexity. For environmental scenes, the mean and alpha RMS contrast measures yielded the strongest correlations , and the beta phase congruency measure worked similarly well for environmental scenes (rs = .36). Further research may elucidate why these new measures of RMS contrast and phase congruency work better to predict subjective complexity for representational stimuli than previously used measures of edge detection.Furthermore, the current results replicate and extend those by Cavalcante et al. , who foungruency ,153 provrs = -.23). Canny edge detection is particularly sensitive to fine lines in an image; therefore, lines associated with brush strokes in a background of a simple figure-ground composition are detected, yielding a negative correlation with subjective complexity judgments. For environmental scenes, this correlation was positive and together with the correlation for the entropy measure it was among the weakest when the whole set of edge detection measures was considered. This stands in contrast to earlier studies which reported moderate positive correlations between subjective complexity and the Canny algorithm for different types of stimulus sets other than environmental scenes [It is interesting to note that we observed a negative correlation between the Canny edge detection measure and subjective complexity for representational paintings,  when complexity is manipulated by the number of elements present in a visual scene. We also demonstrated that compressed file size and event density are useful predictors of subjective musical complexity in two sets of musical stimuli. Furthermore, we found instances of weak correlations between measures of objective complexity with familiarity pleasantness and arousal ratings, and these correlations seem partly to depend on gender and stimulus type. In summary, these findings are consistent with the view that only a cross-domain approach may lead to the development of a general theory about the relationship between emotion and complexity that incorporates aesthetic quality in its framework.Figure S1Relationships between pleasantness, arousal and complexity, analyzed for males and females, in a set of IAPS pictures.Low numbers refer to low ratings of pleasantness, arousal and complexity, respectively. A) Relationship between pleasantness and arousal for females. B) Relationship between complexity and arousal for females. C) Relationship between complexity and pleasantness for females. D) Relationship between pleasantness and arousal for males. E) Relationship between complexity and arousal for males. F) Relationship between complexity and pleasantness for males.(TIF)Click here for additional data file.Figure S2Relationships between pleasantness, arousal and complexity, analyzed for males and females, in a set of representational paintings.Low numbers refer to low ratings of pleasantness, arousal and complexity, respectively. A) Relationship between pleasantness and arousal for females. B) Relationship between complexity and arousal for females. C) Relationship between complexity and pleasantness for females. D) Relationship between pleasantness and arousal for males. E) Relationship between complexity and arousal for males. F) Relationship between complexity and pleasantness for males.(TIF)Click here for additional data file.Figure S3Relationships between pleasantness, arousal and complexity, analyzed for males and females, in a set of piano solo music excerpts.Low numbers refer to low ratings of pleasantness, arousal and complexity, respectively. A) Relationship between pleasantness and arousal for females. B) Relationship between complexity and arousal for females. C) Relationship between complexity and pleasantness for females. D) Relationship between pleasantness and arousal for males. E) Relationship between complexity and arousal for males. F) Relationship between complexity and pleasantness for males.(TIF)Click here for additional data file.Figure S4Relationships between pleasantness, arousal and complexity, analyzed for males and females, in a set of piano solo and piano trio excerpts.Low numbers refer to low ratings of pleasantness, arousal and complexity, respectively. A) Relationship between pleasantness and arousal for females. B) Relationship between complexity and arousal for females. C) Relationship between complexity and pleasantness for females. D) Relationship between pleasantness and arousal for males. E) Relationship between complexity and arousal for males. F) Relationship between complexity and pleasantness for males.(TIF)Click here for additional data file.Table S1N = 96).Partial Spearman’s rank-order correlations between ratings of complexity, pleasantness and arousal, controlling for effects of familiarity, in response to IAPS pictures (Delete this.(PDF)Click here for additional data file.Table S2N = 96).Spearman’s rank-order correlations between a representative set of measures of objective complexity applied to a set of IAPS pictures ((PDF)Click here for additional data file.Table S3N = 72).Summary of linear stepwise regression analysis for seven variables of objective complexity predicting subjective complexity ratings of IAPS pictures ((PDF)Click here for additional data file.Table S4N = 96).Partial Spearman’s rank-order correlations, controlling for effects of familiarity, between ratings of complexity, pleasantness and arousal in response to representational paintings ((PDF)Click here for additional data file.Table S5N =96).Spearman’s rank-order correlations between a representative set of measures of objective complexity applied to a set of representational paintings ((PDF)Click here for additional data file.Table S6N = 64).Summary of linear stepwise regression analysis for seven variables of objective complexity predicting subjective complexity ratings of representational paintings ((PDF)Click here for additional data file.Table S7N = 92).Partial Spearman’s rank-order correlations controlling for effects of familiarity, between ratings of complexity, pleasantness and arousal in response to piano solo music ((PDF)Click here for additional data file.Table S8N = 92) and to a set of piano solo music excerpts combined with piano trio excerpts (N = 80).Spearman’s rank-order correlations between four measures of objective complexity applied to a set of piano solo excerpts ((PDF)Click here for additional data file.Table S9N = 79).Summary of linear stepwise regression analysis for four variables of objective complexity predicting subjective complexity of piano solo music ((PDF)Click here for additional data file.Table S10N = 80).Partial Spearman’s rank-order correlations, controlling for effects of familiarity, between ratings of complexity, pleasantness and arousal in response to piano solo and piano trio excerpts ((PDF)Click here for additional data file.Table S11N = 67).Summary of linear stepwise regression analysis for four variables of objective complexity predicting subjective complexity ratings of piano solo and piano trio excerpts ((PDF)Click here for additional data file.Stimulus List S1List of 96 IAPS pictures.(PDF)Click here for additional data file.Stimulus List S2List of 96 representational paintings.(PDF)Click here for additional data file.Stimulus List S3List of 92 Romantic piano solo music excerpts.(PDF)Click here for additional data file.Stimulus List S4List of 40 Romantic piano chamber music excerpts.(PDF)Click here for additional data file.


Introduction. Endocrine therapy (ET) is an integral part of breast cancer (BC) treatment with surgical resection remaining the cornerstone of curative treatment. The objective of this study is to compare the survival of elderly postmenopausal women with hormone receptor-positive early-stage BC treated with ET alone, without radiation or chemotherapy, versus ET plus surgery. Materials and Methods. This is a retrospective study based on a prospective database. The medical records of postmenopausal BC patients referred to the surgical oncology service of two hospitals during an 8-year period were reviewed. All patients were to receive ET for a minimum of four months before undergoing any surgery. Results. Fifty-one patients were included and divided in two groups, ET alone and ET plus surgery. At last follow-up in exclusive ET patients (n = 28), 39% had stable disease or complete response, 22% had progressive disease, of which 18% died of breast cancer, and 39% died of other causes. In surgical patients (n = 23), 78% were disease-free, 9% died of recurrent breast cancer, and 13% died of other causes. Conclusions. These results suggest that surgical resection is beneficial in this group and should be considered, even for patients previously deemed ineligible for surgery. Breast cancer (BC) is the most common cancer in North American women. Elderly postmenopausal women are defined as postmenopausal women over the age of 65, or postmenopausal women with comorbidities that render them ineligible for chemotherapy. Elderly postmenopausal women with early-stage BC represent a particular subset of patients because the majority of their tumors are hormone receptor positive (HR+). Blockage of hormone receptor activation with endocrine therapy (ET) reduces cancer cell division and improves disease control. For this reason, ET is an integral part of standard treatment for postmenopausal women with HR+ BC at any stage. ET is used after mastectomy to prevent recurrence, and is also the only therapeutic option in selected stage IV patients. When locally advanced, ET can be used to reduce unresectable disease to a resectable form. As well, it is now often used prior to surgery in early-stage BC to reduce the extent of surgical resection and thus potentially avoid general anesthesia. For many years, tamoxifen was the only ET agent available but studies in the metastatic setting ATAC, BIG1-98) confirmed the superiority of aromatase inhibitors over tamoxifen in improving disease-free survival -98 confi. FurtherThe therapeutic challenge for the surgeon is to determine the likelihood of achieving complete response, disease stability, or palliation with available therapies, and to decide whether surgery is indicated. A decision is made according to the clinical and pathological characteristics of the disease, the patient's preferences, the presence of any comorbid conditions, and estimated survival. For example, postmenopausal patients with comorbid conditions may be considered unsafe for surgery, while others may refuse surgery because of concerns regarding perioperative morbidity and mortality, or the need for hospitalization. In such cases, ET represents the only treatment option. To our knowledge, no study has yet evaluated ET alone in elderly postmenopausal women with HR+ early BC. ET alone is not widely used in postmenopausal early-stage BC women since it is recognized that a complete clinical response is unlikely. For this reason, most clinicians believe that the cornerstone of curative treatment remains surgical resection followed by adjuvant treatment. However, as discussed above, not all elderly postmenopausal women with HR+ BC will receive surgery. Therefore we devised a study to compare the outcome for elderly postmenopausal women with HR+ early-stage BC treated with ET alone, without radiation therapy or chemotherapy, with that of those treated with ET and breast surgery to determine if surgery could be avoided without affecting survival. Medical records collected in a prospective database of elderly postmenopausal BC patients referred to the surgical oncology clinics of one teaching hospital and one community hospital during an 8-year period  were reviewed. The diagnosis of BC was confirmed by breast biopsy and the date of diagnosis was taken as the date of biopsy. Elderly postmenopausal women with palpable HR+ (estrogen and/or progesterone receptor expression >10%) tumors, without evidence of metastasis at diagnosis, and who were scheduled to receive at least four months of ET upfront, were included in the study. The reasons to elect for upfront ET were locally advanced disease, the presence of any comorbid condition, and/or the patient's preference. The ET agents used were anastrozole, letrozole, and tamoxifen. Decisions regarding subsequent surgery were taken either at day 0 or after four months of ET using the same criteria. Patients were evaluated every month during the initial four months and every two to three months afterwards. In the case of tumor progression during the initial four months, patients underwent surgery or a change of ET agent. In the case of a partial response, a decision was made based on comorbid conditions and/or patient's preference. When possible, surgery was performed when the maximum best response was attained. In accordance with the above criteria, two arms were formed. The study arm was composed of elderly postmenopausal early-stage BC women treated with ET alone, without radiation therapy or chemotherapy. The control arm was composed of elderly postmenopausal early-stage BC women treated with ET and surgery, without chemotherapy. All patients underwent breast conserving surgery. Survival was calculated from the date of diagnosis until death. Two patients in the study arm were lost to followup (at 2.6 and 7.1 months) and were included in the intent-to-treat analysis. Response to treatment was evaluated according to RECIST criteria by measuring the tumor with a caliper. Complete response was defined as disappearance of the tumor on physical examination. Partial response was defined as at least a 30% decrease in the diameter of the lesion, progression as at least a 20% increase in the diameter of the lesion, and stable disease as any tumor size in between. Development of metastasis was considered as progressive disease. Initial response was defined as the response observed at four months, or before if surgery was performed because of progressive nonmetastatic disease.t test was used for continuous data while Fisher's exact test was used for all categorical data except the initial tumor's response, which was compared between the two groups with the chi-square test for trend. Log rank test was used to compare survival curves (Kaplan–Meier) between patients who underwent surgery and those who did not. We considered the differences to be significant at P ≤ 0.05. Statistical analyses were performed using Prism 4.0 . Demographic and oncologic characteristics were compared between patients who had surgery and those who underwent ET alone. Student's P = 0.3145). Patient characteristics are summarized in Fifty-one patients were included in the study. The study group  was composed of 28 women , and the control group (ET plus surgery) of 23 women . There was no significant age difference between the two groups (P = 0.8781). The median interval between diagnosis and best response was 7.4 months  in the study group, and 3.2 months  in the control group. ET in the study arm and control groups consisted of tamoxifen , and aromatase inhibitors . Results of initial response (0 to 4 months) to ET are summarized in The median interval between diagnosis and surgery in the control group was 6.2 months . The median duration of followup was 28.4 months  in the study group, and 63.8 months  in the control group. n = 1, 4%), cardiac failure , and undetermined or not specified . Ten patients (36%) refused surgery at the beginning for personal reasons and remained in the study group, half of which (50%) where still alive at the last follow-up visit. Of these patients, four (14%) had stable disease, two (7%) had progressive disease, of which one (4%) died from recurrent breast cancer 28 months after diagnosis, and four (14%) died from causes unrelated to their cancer. These causes were uterine bleeding  and advanced cognitive disorders . Two patients (7%) were initially deemed unfit for surgery because of Parkinson's disease  and contralateral breast cancer . Finally, 11 (39%) died from a cause unrelated to their cancer . These causes were pneumonia , mesenteric ischemia , cardiac failure , Parkinson's disease , infectious colitis , and undetermined or not specified . At last follow-up visit, in the study group , 11 patients (39%) had a stable disease or complete clinical response. Six (22%) had a progressive disease, of which five (18%) died of breast cancer . Breast cancer causes of death were distant metastatic disease , and recurrent breast cancer . Finally, three patients (13%) died from a cause unrelated to their cancer . These causes were a fall , and undetermined or not specified . At the last follow-up visit, in the control group (ET plus surgery), 18 patients (78%) were disease-free, two (9%) died of recurrent breast cancer . Breast cancer causes of death were distant metastatic disease (P = 0.0003). Survival curves are shown in At five years, the overall survival for the study group was 18%, and for the control group, 52%. The median survival for the study group was 28 months, and for the control group, 64 months. There was a statistically significant difference in survival between both groups  had significant longer survival than patients in the study group . A larger proportion of patients in the study group died of comorbid conditions rather than of breast cancer. However, in comparison with the control group, there was still a greater proportion of patients in the study group who died of breast cancer (18% versus 9%). For this reason, we think that surgery is clearly indicated in most cases, even when comorbid conditions are present. Still, the use of ET prior to surgery until the best maximal response has been reached merits consideration. The IMPACT trial looked at the effects of neoadjuvant anastrozole, tamoxifen, or a combination of both in postmenopausal HR+ patients with a palpable BC. It concluded that anastrozole is as effective and well tolerated as tamoxifen in these patients . It founWe think that the difference in mortality observed between the study and control groups is due to a selection bias, because patients in the study group had more often severe comorbid conditions and did not receive surgery. On the other hand, patients who had surgery were in better general physical condition. The choice of ET did not appear to play a role.Randomization of patients could not be performed due to several reasons. First, it is a retrospective study. Second, the decision to operate or not was taken at day 0 or after four months, and was dependent on several factors, including comorbid conditions and patient's preference. For our statistics, use of the multivariable Cox proportional hazards model was considered, but our statistician found it was not feasible.In this study, the complete response rate was higher in the study group. This can be explained by a longer duration of endocrine treatment, while patients in the control group underwent surgery at some point dictated by a progression of breast cancer or by partial response to the endocrine therapy. A downside to prolonged endocrine treatment is that a proportion of patients may stop responding and eventually progress. On the other hand, continuing treatment beyond the planned four months could have incremental benefits in reducing tumor size and allowing surgery for previously inoperable tumors. This could explain why surgery was performed as late as 337 days after diagnosis. Despite some limitations , this study supports the use of upfront ET in most clinical situations in elderly postmenopausal women with HR+ early-stage BC. Appropriate surgery should be performed when the best maximal response has been reached because it reduces BC mortality, even in high-risk patients. At this point, prospective studies should be undertaken.