Impairments in statistical learning might be a common deficit among individuals with Specific Language Impairment (SLI) and Autism Spectrum Disorder (ASD). Using meta-analysis, we examined statistical learning in SLI  and ASD  to evaluate this hypothesis. Effect sizes were examined as a function of diagnosis across multiple statistical learning tasks . Individuals with SLI showed deficits in statistical learning relative to age-matched controls. In contrast, statistical learning was intact in individuals with ASD relative to controls. Effect sizes did not vary as a function of task modality or participant age. Our findings inform debates about overlapping social-communicative difficulties in children with SLI and ASD by suggesting distinct underlying mechanisms. In line with the procedural deficit hypothesis , impaire Deficits in statistical learning have been implicated in a range of developmental disorders, such as Specific Language Impairment (SLI) and Autism Spectrum Disorder  by youth with ASD relative to youth without ASD was interpreted as evidence that atypicalities in the basal ganglia can lead to either speeding up or slowing down of performance on language tasks that depend on the procedural memory system  indicated a statistically significant impairment in statistical learning among children with SLI relative to age-matched peers, in support of The literature on statistical learning in SLI provides considerable support for Research examining statistical learning in ASD has reported mixed findings e.g., . Foti etA limitation with the approach used by To draw conclusions about putative similarities or differences in statistical learning across disorders, researchers must use the same indices of learning across populations. Therefore, the current meta-analysis expanded upon the meta-analyses by We hypothesized that based on common linguistic and non-linguistic challenges associated with SLI and ASD both disorders might share a common underlying deficit in statistical learning. The aims of the current meta-analysis were (1) to examine whether impairments in statistical learning are a shared challenge for individuals with SLI and ASD; and (2) to examine whether task modality and age moderated effect sizes. In the prior meta-analysis of performance on the SRT task in children with SLI, Understanding whether SLI and ASD share an underlying processing deficit is essential for identifying potential common neural circuits that may contribute to a range of different developmental disorders; as such, the current research is well aligned with a recent shift toward identifying common pathways that may be implicated in a range of disorders . A betteStatistical learning tasks are typically designed so that co-occurrence patterns and ordering of stimuli are based on complex sets of rules. The next section describes, in detail, the tasks represented in this meta-analysis. To be included, studies needed to have a testing phase with learning assessed by comparing performance across sequenced vs. random/control trials, using either RT or accuracy as the dependent variable. Thus, the Pursuit Rotary task, for example, was excluded from the meta-analysis because it measures time-on-target across blocks and does not have a control condition.The SRT task, introduced by The CC task is a visual search task where participants are required to locate a visual target  in a field of distractors  . Across The AGL task  involvesThe SS task examines whether participants can use transitional probabilities between non-sense syllables  to detect word boundaries in continuous speech . ParticiThe OL task  examinesIn the PCL task, participants learn which of two outcomes is predicted by combinations of four different cues . The WeaFigures 1 and 2 provide flowcharts depicting, for each meta-analysis, the main steps of the literature search and selection of studies in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines  and to include one diagnostic group of individuals identified as language impaired or ASD, in addition to a control group. As a final step, we excluded SRT studies that did not include a random block of trials. We also excluded two studies with a general language/learning disabled group that was not explicitly identified as SLI  were included. For the ASD sample, a total of 13 studies (20 comparisons) were included. All lead authors were contacted and asked to provide further statistical information and unpublished data, if available. No studies were lost due to missing data, and no additional unpublished data were identified. 2I statistic was used to determine whether the variability within the sample is due to heterogeneity between studies and not due to sampling error  program 2.0 . To examng error . Mixed-eAs mentioned, the most widely accepted method for assessing learning in the SRT task involves examining whether a difference exists between the final sequenced block and the first random block . Thus, wg as the computed effect size measure. Note that positive g values indicate that the control group in the study showed higher statistical learning compared to the diagnostic group. This approach has been used in previous meta-analyses of SRT tasks . The data extracted from primary studies to compute Hedges g were results from statistical tests, summary data presented in either tables or figures, or by contacting authors. Conversion of these data to Hedges g was undertaken using CMA 2.0  is distinct from measuring changes in RT due to practice  as a potential moderator in both the SLI and ASD data. To examine whether age moderated group differences in statistical learning, we conducted a meta-regression with age as a predictor variable. Age was entered in the analysis as the mean age for each group (Tables 1 and 2).The current meta-analysis incorporated multiple tasks as indices of statistical learning. Tasks varied in whether the stimuli were visual or auditory in nature. For this reason, we examined Figures 3 and 4 show preliminary results of possible publication bias using funnel plots for the SLI and ASD data, respectively. Funnel plots show publication bias when their individual effect sizes are distributed in an asymmetrical manner around the weighted average effect size. Egger’s test of asymmetry was not significant for either group , indicating that bias was not found in our search.Figure 5 shows a forest plot depicting effect sizes for each study and weighted averages for the SLI group. The results of the mixed-effects analysis examining statistical learning in SLI are reported in Table 3. Positive effect sizes indicate that the control group displayed higher learning compared to the SLI group. In line with g of 0.46 at the level of studies and 0.47 at the level of comparisons (p < 0.001), suggesting that participants with SLI show significant impairments in statistical learning compared to controls. A mixed-effects subgroup analysis was computed to examine whether impairments in statistical learning in SLI were moderated by task modality . This subgroup analysis was not significant Q(1) = 1.36, p = 0.24, indicating that task modality did not moderate the effect sizes.A mixed-effects meta-analysis addressed the first aim of the study, to determine whether statistical learning is impaired in SLI, by extending Figure 6. Table 4 presents the results of the mixed-effects analysis examining statistical learning in ASD, with positive effect sizes indicating higher learning in the control group relative to the ASD group. The Hedge’s g was not significant at the level of studies, g = -0.11, p = 0.30, or comparisons, g = -0.13, p = 0.22. This suggests that ASD participants did not differ significantly in learning when compared to controls, which is in line with the conclusion drawn by Q(1) = 1.25, p = 0.26.A mixed-effects analysis addressed the second aim of the study, to determine whether statistical learning is impaired in ASD. We extended Q(1) = 15.54, p < 0.001, and at the level of comparisons, Q(1) = 17.84, p < 0.001. Such between-group differences remained robust even when matching on type of task (study level: Q(1) = 8.90, p = 0.003; comparison level: Q(1) = 10.90, p = 0.001). This finding suggests that while individuals with SLI show impairments in statistical learning, this ability appears to be intact in individuals with ASD.To examine the final aim of this study, whether impairments in statistical learning are a common underlying deficit in individuals with SLI and ASD, we employed random effects models to examine overall effect size differences between groups (SLI versus ASD). Two meta-analyses were conducted to examine possible differences in statistical learning between SLI and ASD. The first analysis compared all retrieved SLI and ASD studies regardless of task, thus resulting in 14 studies (15 comparisons) for the SLI group and 13 studies (20 comparisons) for the ASD group. In the second analysis we matched the studies in both groups by task. For this analysis, we included only SRT, ASRT, AGL, SS, and PCL tasks, as those tasks were included in both SLI and ASD datasets. That is, CC and OL tasks for the ASD group were dropped from the analysis as none of our retrieved SLI studies used these tasks. This resulted in 14 studies (15 comparisons) for the SLI group and eight studies (12 comparisons) for the ASD group. Results of the first between-groups analysis showed that there was a significant difference in statistical learning between the SLI and ASD groups both at the level of studies, Figures 5 and 6. The predictor variable in the analysis was participants’ age while controlling for diagnostic group. Overall, the model was not significant; hence, age was not found to be a predictor of effect sizes, Q(1) = 0.65, R2 = 0.26, p = 0.42. Table 5 shows a summary of the coefficients of the regression model.The final meta-analysis was a multivariate meta-regression to evaluate whether participants’ ages predicted the effect sizes shown in Deficits in statistical learning have been hypothesized to be present in SLI and ASD . The proThe current meta-analyses were designed to address conflicting speculations concerning whether statistical learning is a shared impairment among individuals with SLI and ASD. Findings suggest that statistical learning is commonly impaired in SLI, but not ASD. No evidence of moderation by task modality or age was observed. While our conclusion regarding intact learning in ASD was similar to t-test). In addition, performance on different types of statistical learning tasks may develop differently with age. For instance, SRT performance tends to improve with age whereas ASRT performance tends to get worse with age  intelligence, that are likely to impact performance on a broad range of tasks. Perhaps due to claims that implicit forms of learning are robust across populations differing widely in age and intelligence  as descriptions of pictures after hearing another person use the passive-voice construction as a description of a different scene. Similarly, in a study of typically children of ages 6–8 years, Under the procedural deficit hypothesis, statistical learning is presumed to play a critical role in the mastery of rule-based aspects of language, such as grammar (morphology and syntax) and phonology. Several studies have explored the putative relationship between statistical learning and grammatical development with mixed results. In a study involving typically developing 4–6-year-olds, To date, only one study has linked individual differences in statistical learning directly to aspects of phonological processing. Using the SS task with a group of 8–12-year-olds , N = 38) as well as in an adult sample (N = 37). In a recent meta-analysis, N = 314) and age-matched controls (N = 317) and found robust evidence of a deficit in implicit learning associated with dyslexia, g = 0.45, 95% CI , p < 0.001. These studies appear to contradict an earlier large-scale study of 422 children of ages 7–11 years  task in which 8.5-month-old infants were exposed to three-element sequences of visual images appearing in predictable spatial-temporal sequences , Our findings that individuals with ASD have intact statistical learning suggest that social-communicative deficits associated with ASD cannot be explained by an underlying deficit in statistical learning. In contrast to evidence linking individual differences in statistical learning to language development in the domains of grammar, phonology, and vocabulary, we are not aware of any studies that have demonstrated associations between implicit learning and pragmatic language development, which is the area of language development most impacted by ASD. Although statistical learning might contribute to the development of semantics—the other language domain that is most commonly impacted in ASD —via wordAlthough Atypical timing of responses may also contribute to variations in performance on statistical learning tasks among individuals with ASD. In a classical eye-blink conditioning paradigm, wherein a tone is paired with an air puff to the eye , Sears enot ASD, is associated with deficits in statistical learning, suggests that the language and communicative difficulties associated with each disorder have distinct underlying mechanisms. These results support the procedural deficit hypothesis with implications for the diagnosis and treatment of SLI, but suggest an alternative account is needed to explain the social and pragmatic difficulties associated with ASD. Core social symptoms of ASD, such as reduced joint attention and difficulty understanding others’ perspectives, likely contribute to semantic and pragmatic difficulties among individuals with ASD (The main finding of this report, that SLI, but with ASD . Howeverwith ASD , and to with ASD .Future work on statistical learning in SLI should involve longitudinal investigations of late-talking toddlers at risk for SLI to determine whether age-appropriate measures of statistical learning, such as the SS task , the AGLRO played a significant role in all aspects of this project including: Contributions to the design of the work and the acquisition, entry, analysis, and interpretation of the data, the write-up, drafting and revising the work, and submission. PB played a significant role in all aspects of this project including: Major contributions to the design of the work, data analysis and data interpretation, in addition to the write-up, revising the work, and final approval for publication. KP played major roles when it came to contributions to the design of the work and the acquisition, analysis, entry, and interpretation of the data, and write-up. KG-L played a significant role in many aspects of this project including: Contributions to the design of the work, data interpretation, in addition to the write-up, revising the work, in addition to final approval for publication. JL played a significant role in all aspects of this project including: Major contributions to the design of the work, data analysis, data entry, and data interpretation, in addition to the write-up, revising the work, and final approval for publication. All authors worked as collaborators and ensure accountability, integrity, and accuracy in the work.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


To study the course of ADHD during childhood and analyze possible personal and family predictor variables of the results.Conners' Rating Scales. The groups were compared on ADHD characteristics (symptoms of ADHD and impairment), child psychopathology, executive functioning  and parenting characteristics  at baseline.Sixty-one children with ADHD who were between 6 and 12 years old at the baseline assessment were evaluated 30 months later . Status of ADHD in follow-up was identified as persistent (met DSM-IV-TR criteria according to parents’ and teachers’ ratings), contextually persistent  and remitted ADHD . Associated psychological disorders of the three groups were analyzed in the follow-up with the At the follow-up, 55.7% of the children continued to meet the DSM-IV-TR criteria for ADHD, 29.5% showed contextual persistence, and 14.8% presented remission of the disorder. The persistent and contextually persistent ADHD groups showed more associated psychological disorders. Inattention, oppositional problems, cognitive problems and impairment at baseline distinguished the remitted ADHD children from the persistent and contextually persistent ADHD children. Moreover, the persistent groups had significantly more emotional liability and higher parental stress than the group in remission, while no differences in EF where found among the groups.ADHD children continue to present symptoms, as well as comorbid psychological problems, during adolescence and early adulthood. These findings confirm that persistence of ADHD is associated with child psychopathology, parental stress and impairment in childhood. Currently, follow-up studies show the persistence of the attention deficit hyperactivity disorder (ADHD) in the transition period from childhood to early adolescence, with a variation in the percentages ranging from 45%-55% –3, to 70In addition to its chronic nature, another worrisome issue is the high comorbidity that characterizes the course of ADHD. More than half of the children with an ADHD diagnosis continue to present other disorders, particularly behavior and anxiety disorders –14 and iThis alarming situation has stimulated research on the determinants of the course of ADHD. Genetic studies show the relationship between the DRD4 ,24, DAT1In addition to the biomarkers, the explanatory socio-ecological ADHD models highlight the contribution of environmental factors to the behavioral expression and different developmental trajectories of the disorder . The basIn recent years, another research area has involved analyzing the relationship between executive functioning (EF) and the course of ADHD, with mixed research results. A systematic review based on eighteen studies concluded that persisters and remitters did not differ on higher or lower level neurocognitive functions, although both had worse performance than controls . These fRegarding factors related to the family context, a recent review that focused on the relationship between parenting and functional impairments showed that ADHD is associated with greater stress within the family, higher rates of parental psychopathology, and conflicted parent—child relationships . Recent The research by the Biederman and Faraone group is of particular relevance in examining ADHD persistence, as they include different types of factors in their analyses. The researchers followed boys and girls with ADHD from childhood to adulthood. In adolescence (4-year follow-up) they found significant differences between the remittent and persistent groups at baseline, not only on child factors , but also on the psychosocial and family adversity of the disorder . In the In summary, many children with ADHD remain symptomatic. Understanding what characterizes this persistent ADHD group and identifying factors associated with differential developmental outcomes have important repercussions in the clinical setting. The early identification of children who are likely to have a worse course of the disorder will make it possible to perform interventions using more appropriate strategies.Hence, the present study, which is part of a longitudinal study that followed the course of children with an ADHD diagnosis, proposed two specific objectives. The first was to study the ADHD course during childhood, determining the rates of children who presented persistent, contextually persistent and remitted ADHD, and analyze possible differences among the groups on associated psychological disorders. The second objective was to compare the persistent, contextually persistent and remitted groups on baseline measures related to ADHD characteristics (ADHD symptoms and impairment), child psychopathology, executive functions  and parenting characteristics . We hypothesized that the different outcomes would be influenced by the effects of personal and family risk characteristics. Based on the proposals of a multifactorial model, we hypothesized that the persistent groups, especially if the persistence was cross-contextual, would have more severe ADHD symptoms and related child psychopathologies, greater impairments in executive functions, and worse results on parenting measures at baseline than the ADHD remitted group.In the present follow-up study, the participants were 61 children with a clinical diagnosis of combined-subtype ADHD and their families, who formed part of the sample of Spanish families from the International Multicenter ADHD Genetic Project (IMAGE) , a genetThe participants were evaluated at the beginning of the study, between 2003 and 2005 (baseline), and 30 months later, between 2006 and 2008 (follow-up). To identify the initial sample, the records from the Neuropediatric Service of La Fe Children’s Hospital were reviewed with the help of the service’s clinical psychologist, in order to identify children who had received an ADHD combined subtype diagnosis. In addition, neuro-pediatricians and pediatricians from the regions of Castellon and Valencia were contacted, as well as private specialists and psychology clinics. Through these procedures, a total of 321 possible participants were identified. Of these children, 109 were eliminated due to presenting manifestations of a possible ADHD subtype other than the combined subtype or neurological disorders (mainly epilepsy). When the 212 families were contacted, 147 agreed to participate in the study. In the individualized evaluation performed, children were excluded from the study if they presented an estimated intelligence quotient (IQ) of less than 70, suffered neurological or sensorial damage or motor impairments, or had a diagnosis of schizophrenia or generalized developmental disorder. Finally, 81 children met the strict diagnostic criteria for ADHD combined subtype (ADHD-C) from the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) , based oMoreover, these 81 children met the requirements for the IMAGE study protocol to confirm the ADHD combined subtype diagnosis using the ADHD-section of the Parental Account of Childhood Symptom (PACS), a semi-structured interview that covers ADHD related behavior in different situations . The parents have to rate the frequency or severity of their child’s hyperactivity, inattention and impulsive behaviors . A speciWechsler Intelligence Scale for children- revised (WISC-R) [At baseline, the participants were between 6 and 12 years old (mean = 8.70 ± 1.97) and had an equivalent IQ within the ranges of normality (mean IQ = 105.98 ± 16.48), estimated by the sum of the scale scores for Vocabulary and Block Design on the (WISC-R) , using t(WISC-R) .t (79) = -0.90, p = .366; hyperactivity-impulsivity: t (79) = -0.87, p = .389; DSM-total: t (79) = -0.60, p = .549) and teachers’ ratings (inattention: t (79) = 1.12, p = .266; hyperactivity-impulsivity: t (79) = -0.72, p = .476; DSM-total: t (79) = 0.37, p = .712). There were no differences in other child characteristics assessed at the study baseline either. At follow-up, participants were between 8 and 14 years old (mean = 10.98 ± 2.19). Of the total sample, 58 were boys (95.1%), and 3 were girls (4.9%). A clinical psychologist with more than 10 years of experience, under the supervision of a senior investigator, again evaluated the ADHD symptomatology. Attention was paid to the concordance between parents’ and teachers’ ratings on the DSM-IV-TR criteria for the ADHD diagnosis and information about indicators of the children’s functional impairment, which was collected in the interviews with the family.Thirty months later the participants were again contacted. Due to the sample loss that often occurs in longitudinal studies, the follow-up included the participation of 61 of the 81 families who had participated at baseline, that is, 75% of the original sample. The other 25% did not participate for different reasons: 9 children (11%) did not participate because of loss of their localization (changes in the family address or contact telephone), and 11 participants declined to attend to the evaluations (14%). There were no differences in baseline ADHD severity between the 61 children who continued in the follow-up and the 20 who did not participate, based on the parents’  [CRS—R:L) . This isCRS—R:L) . There aStrengths and Difficulties Questionnaire for Parents (SDQ) [ts (SDQ) . This veWISC-R Digit-Span Subtest, backward [Temporo- Spatial Retrieval Task (TSRT) [Continuous Performance Test (CPT) [Three aspects of executive functioning were assessed: verbal working memory, visuo-spatial working memory and inhibition. Verbal working memory was evaluated with the backward , where tk (TSRT) . This isst (CPT)  was selest (CPT) . On thisThe Parenting Stress Index (PSI) [ex (PSI)  is a 126Parents rate each item on a 5-point Likert scale (1 = strongly disagree to 5 strongly agree). The scores are added up to obtain a total stress score that assesses the overall magnitude of parental stress. Scores from the PSI have acceptable internal consistency (α = 0.95) and test-retest reliability (r = 0.71–0.82) . In the The Parenting Scale [ng Scale . This 30The scale has adequate reliability (0.84) and discriminates between parents of clinical and non-clinical children. It correlates with self-report measures of child behavior, marital discord and depressive symptoms, and also with observational measures of dysfunctional discipline and child behavior .At baseline, participants with a diagnosis of combined subtype ADHD were selected, and behavioral , neuropsychological  and family  measures were collected.Hospital La Fe and Ministerio de Educación y Ciencia of Spain). To make sure treatment did not mask the experimental results, all the children had their medication withdrawn 48 hours before the sessions.The follow-up evaluation took place a mean of 30 months after the initial evaluation. After giving the participants a complete description of the study, written informed consent was obtained from the parents and the children, based on the procedures approved by the clinical research ethical committee : 1) subjects with a persistent status, when both informants positively rated the presence of 6 or more criteria from the DSM-IV- TR; 2) subjects with a contextually persistent status, who met the ADHD criteria according to the ratings of one evaluator, whether parents or teachers, and had social and/or academic impairments, recorded as affirmative responses to the SDQ-Impact Supplemental questions “Do you think your child has difficulties in one or more of the following areas: emotions, concentration, behavior or being able to get on with other people?”, “Do the difficulties upset or distress your child?”, and interference in at least one of the child's everyday life areas (home life/friendships/classroom learning/leisure activities); and 3) subjects with a remission status, who did not meet criteria for the disorder according to either the parents’ or teachers’ ratings.Data analysis was conducted with the SPSS statistical package, version 19.00. To compare the groups’ associated psychological disorders in the follow-up, Multivariate Analysis of Covariance (MANCOVA) was used. Four MANCOVAs were conducted to compare the data obtained at baseline  among the subjects with remission, persistence, or a status of contextual persistence of ADHD. The age of the participants was included as a covariate to avoid interpreting the differences due to the broad age range of the participants as effects of development. Post-hoc analysis with Bonferroni correction was performed. The degrees of freedom are not the same in all the MANCOVAs, due to the lack of data from some participants on the neurocognitive tests and on the family variables. The proportion of total variance accounted for by the independent variables was calculated using the partial eta squared . Only 14.8% presented remission of the disorder at the follow-up, meeting less than six inattention and hyperactivity-impulsivity criteria according to the ratings of both parents and teachers. Finally, in the remaining 29.5%, the group with contextual persistence, there was no agreement between the parents’ and teachers’ ratings, so that only one of the evaluators determined that the diagnostic criteria were met for one of the ADHD subtypes, even though the child had a functional impairment .12,104 = 3.97, p < .001, η2p = .314). Specifically, the differences were statistically significant on all the Conners’ variables used, except Emotional Lability: Oppositional , Cognitive Problems , Anxious/shy , Social Problems  and Global Index . Bonferroni’s post hoc test revealed statistically significant differences between the remitted group and both the persistent and contextually persistent groups on Oppositional , Cognitive problems , Social Problems  and Conners’ Global Index . In these cases, the persistent and contextually persistent ADHD groups presented significantly higher scores than the remitted group. On the Anxious/shy variable, only the remitted group showed significantly lower scores than the contextually persistent group (p = .042). Finally, the persistent and contextually persistent groups presented significant differences on the Cognitive Problems variable (p = .032), as the persistent group showed greater problematicity  presented statistically significant differences in associated psychological disorders at the follow-up . In fact, 33.3% of the children in the remitted group had taken medication at some point in their lives, while in the case of the persistent and contextually persistent ADHD groups, this percentage rose to 76.5% and 77.8%, respectively. Moreover, 47.1% of the persistent ADHD group consistently took medication during the time period between baseline and follow-up, while the remaining 29.4% of the subjects had taken medication for less time. In the ADHD group with contextual persistence, the rates were 55.6% and 22.2%, respectively. In the remitted ADHD group, 11.1% took medication continuously between baseline and follow-up, and 22.2% for a shorter period of time.The three groups were also significantly different from each other in the use of pharmacological treatment  (χ2 (2) = 7.02, To study the factors that influence the persistence of ADHD, the group with a remitted status, was compared to the group with a contextually persistent and a persistent status on ADHD characteristics, child psychopathology, executive functions and parenting characteristics rated at baseline, using age as covariate.6,102 = 4.30, p = .001, η2p = .202). Specifically, statistically significant differences were found on the variables: inattention  and impairment , but not on the symptomatology of hyperactivity/impulsivity  and Impairment variables . In both cases, the remitted ADHD had better scores than the other two groups.The results of the first MANCOVA showed that overall there were statistically significant differences among the three groups on baseline ADHD characteristics . Specifically, the differences were statistically significant on Oppositional , Cognitive Problems , Emotional Lability  and the Conners Global Index , but not on Anxiety and Social Problems , Cognitive problems  and Conners’ Global Index . Moreover, the ADHD persistent group presented significantly higher scores on Emotional Lability than the remitted group (p = .028).The three groups also showed differences in child psychopathology . The same analyses were performed with the family variables of parenting stress and dysfunctional discipline style, with the results of the MANCOVA showing statistically significant differences . The posterior ANCOVAS showed differences on the total stress variable , but not on discipline style (p = .006).The MANCOVA conducted to evaluate the differences in the executive functioning variables did not show statistically significant differences (Wilks Lambda = .94, Fne style . In thisThis longitudinal study had two specific aims. The first objective consisted of providing estimates of the course of ADHD and mapping its correlates over time. The second objective was to identify risk factors at baseline associated with differential outcomes of persistence/remission, related to the psychopathology of the child, EF and parenting.Our data support the “diagnostic stability” of ADHD. Thus, at the follow-up, nearly 60% of the children continued to meet the diagnostic criteria for one of the subtypes of the disorder, while only 14.8% could be assigned the status of remitted. Moreover, when adding the contextually persistent category, the percentage rose to 85.2%, similar to the 78% found by Biederman et al  in an 11The core manifestations of ADHD changed over time, as 33.9% of the combined subtype participants moved toward the predominantly inattentive subtype. This movement is consistent with the trajectories of the symptoms from early childhood to adolescence  and withIn addition, about 50% of the participants in the persistent and contextually persistent groups took medication continuously, compared to about 10% of the remitted group. This finding suggests that at the follow-up, the greater severity of the symptomatology of the persistent and contextually persistent groups, who present significantly more oppositional problems, cognitive problems, social problems and more general problematicity, has required a prolonged administration of medication over time. In another recent study, more adolescents with persistent ADHD were treated with methylphenidate before and at that time than adolescents with non-persistent ADHD [The persistent and contextually persistent groups present a similar profile of associated psychological disorders in the follow-up. However, there are differences on the level of cognitive problems, even though both groups present more problems than the remitted group. It is necessary to further analyze what occurs with the learning disabilities at these ages, as the persistent group probably presents more severe problems in reading, writing or mathematics than the other two groups.When the differences in baseline variables among the participants who presented complete persistence, contextual persistence and remitted symptoms were analyzed, the results showed that the two groups with persistence presented a worse profile of child psychopathology variables at baseline; however, no differences were found among the three groups on any of the executive functions evaluated. Thus, the results show the influence of the psychological disorders ,6,9,61 aThe family variables were also found to have an important role in the persistence of the disorder. Our results complement the information on the stress experienced by parents of children with ADHD , indicatFurthermore, the parents of the children with remitted ADHD did not seem to apply different discipline styles from those reported by parents of children with persistent or contextually persistent ADHD. As other studies have shown, it is likely that parents of children with ADHD in our sample present more dysfunctional discipline styles than parents of children with typical development . TherefoFinally, the expectation that children with remitted symptoms would show better EF at baseline was not fulfilled. Even though EF impairments in the preschool stage seem to be a good predictor of ADHD symptomatology in the beginning school stage , our resThe limitations affecting this study must be considered. First, the small sample size and the fact that it is composed of children with a clinical diagnosis of combined subtype ADHD may affect the generalization of the results, which cannot be extrapolated to a non-clinical sample. It is also important to note that many of our participants come basically from middle-low class families with no social marginalization; therefore, our findings may be more generalizable to the middle-class. Other limitations have to do with the broad age range of the participants, from 6 to 12 years old in the first evaluation, as well as the long follow-up period, 30 months. It is necessary to replicate the results with more specific age ranges and longer time periods that extend into late adolescence and early adulthood.The evaluation of executive functioning is another limitation of this study. Although the selection was based on the result of ad hoc reviews that point to inhibition and working memory as the executive functions most involved in ADHD, in future studies it would be advisable to include neuropsychological tasks such as the Stop Signal or the Go/No-go, in order to evaluate other basic ADHD parameters such as performance variability, or contemplate other executive functions such as planning and cognitive flexibility, in addition to using more ecological executive functioning measures.The attention deficit with hyperactivity disorder has a chronic nature. A large percentage of children with ADHD continue to present symptoms, as well as comorbid psychological problems, during adolescence and early adulthood. Therefore, understanding the personal and environmental factors that can worsen the severity of ADHD is a particularly critical issue for detecting and planning early efficacious actions that can attenuate the consequences of the disorder throughout the life cycle. For example, guidance programs for parents must go beyond a model based only on medication or behavior modification. Along with these components, parents should be offered information that: reduces their insecurity and feelings of guilt; provides them with strategies to reduce the level of stress that their children’s behavior can cause; teaches them to identify and value progress, even when limited; helps them to promote a clear distribution of responsibilities and roles; and constructs a democratic educational style that is neither coercive nor over-protective .In addition to its great relevance in the clinical setting, as it can help in designing appropriate treatment strategies to speed up remission, better knowledge about the predictors of ADHD persistence will make it possible to concentrate the scant economic resources on the cases with the greatest risk of persistence.One of the most interesting findings from the present study is that the ADHD cases that become contextually persistent have just as many associated psychological disorders as the cases with complete persistence. Related studies with adults indicate that individuals with partially-remitted ADHD showed similar substance use to those with current ADHD, whereas those in full remission were comparable to normal controls. In summary, although ADHD symptoms may remit with time, individuals who retain persisting or partial symptoms have considerable needs that must be addressed throughout their development.


Our main objective was to analyse the different contributions of relational verbal reasoning  and executive functioning to metaphor comprehension across development. We postulated that both relational reasoning and executive functioning should predict individual and developmental differences. However, executive functioning would become increasingly involved when metaphor comprehension is highly demanding, either because of the metaphors’ high difficulty (relatively novel metaphors in the absence of a context) or because of the individual’s special processing difficulties, such as low levels of reading experience or low semantic knowledge. Three groups of participants, 11-year-olds, 15-year-olds and young adults, were assessed in different relational verbal reasoning tasks—analogical and class-inclusion—and in executive functioning tasks—updating information in working memory, inhibition, and shifting. The results revealed clear progress in metaphor comprehension between ages 11 and 15 and between ages 15 and 21. However, the importance of executive function in metaphor comprehension was evident by age 15 and was restricted to updating information in working memory and cognitive inhibition. Participants seemed to use two different strategies to interpret metaphors: relational verbal reasoning and executive functioning. This was clearly shown when comparing the performance of the "more efficient" participants in metaphor interpretation with that of the "less efficient” ones. Whereas in the first case none of the executive variables or those associated with relational verbal reasoning were significantly related to metaphor comprehension, in the latter case, both groups of variables had a clear predictor effect. However, the metaphor topic would restrict the attributional process, indicating its relevant dimensions).Given that metaphor comprehension demands great abstraction and great attentional effort—and, therefore, requires high levels of control and cognitive regulation—and that such control has been linked to executive functioning, then executive functioning could be a good candidate to explain these observed developmental differences. Thus, our objective was to study the differential contribution of executive functioning across development—specifically, the executive functions of updating information in WM, inhibition, and cognitive flexibility—to metaphor interpretation in relation to analogical and class-inclusion reasoning.To our knowledge, there are few previous studies relating executive functioning to metaphor interpretation. Some authors have linked the quality of metaphor interpretation to WM capacity , 22, 37,Recently, Prat et al.  found inThis proposal accords with Johnson and Pascual-Leone’s  findingsThe main goal of the present study was to analyse the different contributions of relational verbal reasoning  and executive functioning to metaphor comprehension across development. As previously mentioned, understanding a new metaphor without a context would require not only the involvement of relational reasoning—which could also be implicated in analogical or class-inclusion reasoning—but also the involvement of attentional control processes related to executive functioning, which allows the suppression of inadequate responses, appropriate response selection, the ability to update information in WM, as well as cognitive flexibility. Thus, we proposed that both relational reasoning and executive functioning should predict individual and developmental differences in metaphor interpretation. However, executive functioning will become increasingly involved when metaphor comprehension is highly demanding, either because of the metaphors’ high difficulty (relatively novel metaphors in the absence of a context) or because of the individual’s special processing difficulties, such as low levels of reading experience or low semantic knowledge.If relational reasoning was the only factor responsible for metaphor interpretation, we would not expect developmental differences, given that most children have already acquired these abilities by approximately 11 years of age. However, executive functioning abilities continue to develop far beyond adolescence. Thus, if executive processing is responsible for metaphor interpretation, we hypothesize changes across development: when executive functioning is not yet established—that is, at the age of 11—metaphor comprehension should rely more on analogical or class-inclusion reasoning. However, when people can benefit from adequate updating of information in WM, suppression of inappropriate information, and effective shifting between literal and metaphorical meanings—that is, at the age of 15 and far beyond—they will use these attentional control resources to achieve a better interpretation.n = 39, M = 11.4, SD = 0.41), 15 years , and young adults between the ages of 21 and 25 . The children and adolescents between 11 and 15 years came from public and subsidized schools from all over Spain. None of the children had any diagnosed developmental disorders. All of the young adults had at least mid-college studies.In this study, 119 participants were divided into three age groups: 11 years  approved this study as a part of a project funded by MINECO (EDU2011-22699) on January 25, 2011. Adult participants were asked to sign a written informed consent form. Parents or guardians signed the written consent form in representation of their children.shifting or cognitive flexibility, that is, the ability to change strategies, attention, or tasks when the subject has to perform multiple tasks, operations, or mental processes; (b) updating or the ability to supervise, encode, and select information that is relevant to the task at hand, replacing old information that is no longer relevant with new information that is relevant; and (c) inhibition or the ability to inhibit dominant or preponderant information and automatic responses when they are not necessary to perform the task. Within inhibition, following the work of Friedman and Miyake [response-distractor inhibition—responsible for actively maintaining task goals in the face of interference, usually coming from external stimuli—and (2) cognitive inhibition, that is, suppression of information in WM, or the ability to inhibit in WM stimuli that are irrelevant to the goals of the task, and resistance to proactive interference, understood as the capacity to inhibit items stored in the long-term memory (LTM) that are no longer relevant for the ongoing task.The participants were evaluated using two relational verbal reasoning tasks—analogical and class-inclusion reasoning—and with the Remote Association Test (RAT), in a task of metaphor comprehension and in various tests commonly used to study executive functions : (a) shid Miyake , we alsowww.pst-net.com/eprime).The analogical reasoning test, class-inclusion test, RAT, and metaphor interpretation test were administered collectively. The order of the reasoning tests was counterbalanced, but the metaphor interpretation test was always presented last. The executive functioning tasks were also counterbalanced and individually administered, controlled by a computer. Randomization and time for stimulus presentation were controlled by E-Prime software, version 2.0 , comprehensibility , and aptness . The results showed that the metaphors used in this study were low on familiarity , fairly comprehensible  and apt . We detected two metaphors whose score on familiarity was slightly above the mean of the scale (4.2 and 4.3). To discard the effect of these different familiarity rates and as per the suggestions of one of the reviewers, we reanalysed the data excluding these two metaphors. As the results essentially did not vary, we decided to maintain them.To assess the familiarity, comprehensibility, and aptness of the various metaphors, we conducted a norming study with 43 different participants, aged 18–40 years. They rated 12 randomly ordered metaphors on three scales of familiarity, comprehensibility, and aptness. Following Blasko and Coninne [Each metaphor item is scored with a minimum of zero points and a maximum of two. The maximum possible score of each test was 24 points. Three independent judges scored the tests. Inter-rater reliability was .90, calculated by using one of the judge’s scores after a previous discussion on any disagreements until consensus was reached. Given that the literature review indicated that inter-rater reliability based upon consensus estimates should be 70% or higher  the reliThe list of items that make up each test is shown in the Remote Association Test (RAT): This was adapted from the original test by Mednick [Bass-Complex-Sleep, the subject should infer deep. This test is commonly used to assess creative thinking, which involves relating apparently unrelated concepts, a process that, given its nature, could also be involved in metaphorical interpretation. Mednick . The tesUpdating task: We used a Spanish adaptation of the updating information in WM task [ WM task  develope WM task  and adap WM task . The tasResponse-Distractor Inhibition: We used the go/no-go task and flanker tasks.The go/no-go task was adapted from Christ, Steiner, Grange, Abrams, and White [nd White . Two expFlanker task [ker task , 48. TheCognitive inhibition: We used the updating task described above. As indexes of cognitive inhibition, we used the proportion of same-list intrusions and the proportion of previous-list intrusions, which, according to De Beni and Palladino [alladino , tap twoShifting task: This was measured with the third block of the flanker task, in which central and flanker conditions were combined so that, in some trials, participants had to switch attention from centre to flanker and vice versa. The dependent variable was the mean RT in attentional change trials.Following Friedman et al.  for updating information in WM, F = 14.05, η2 = 0.20; b) for inhibition: for response-distractor inhibition, F = 16.14, η2 = 0.22, and for the two measures of cognitive inhibition—inhibition of information in WM, F = 9.65, η2 = 0.14, and resistance to proactive interference, F = 10.33, η2 = 0.15; and c) for shifting, F = 10.58, η2 = 0.15.F  = 11.46, η2 = 0.17. In the case of metaphor interpretation, age differences were found among all age groups, F = 24.45, η2 = 0.30, and in the case of the RAT, no differences were found between 11-year-olds and 15-year-olds, but differences were found with regard to young adults for both groups. Finally, no differences among age groups were found for class inclusion.Multiple comparisons showed the same pattern for all these cases: 11-year-olds performed worse than 15-year-olds and young adults, but no differences were found between 15-year-olds and young adults. The same pattern was also found in analogical reasoning, p < .05) to metaphor interpretation were analogical reasoning (r = .44), class inclusion (r = .32) and remote associations (r = .29), and there was no significant correlation with measures of executive functioning. At age 15, the significant relationship between metaphor comprehension and analogies (r = .47) and class inclusion (r = .51) remained, but we also observed significant correlations with some measures of executive functioning: updating in all the experimental conditions (r = .36), with the highest correlation occurring in the high cognitive demand condition (r = .40), suppression of information in WM in high suppression conditions (r = -.37), and resistance to proactive interference in conditions of low inhibitory demand (r = -.42).To analyse the relationship between the different variables and metaphor interpretation, Pearson correlations were computed for each age group see . The patr = .37), updating in all experimental conditions (r = .37), and resistance to proactive interference in low suppression conditions (r = -.34) were maintained.In the case of young adults, the significant correlation of metaphor comprehension/ interpretation with class inclusion disappeared, but correlations with analogical reasoning , with analogical reasoning being the variable with more weight at this age, although only marginally significant .The independent variables (IVs) used were analogies, remote associations, and class inclusion because they were the only ones showing significant correlations with metaphor comprehension see . A totalAnalysis of the variance communality see  showed tp < .001). The variable with the highest weight in the regression was resistance to proactive interference , followed by suppression of information in WM  and class inclusion .The IVs used were analogies, class inclusion, resistance to proactive interference, and suppression of information in WM because they showed significant correlations with metaphor interpretation see . UpdatinAnalysis of the variance communality revealed that the unique contribution of resistance to proactive interference explained the highest percentage of variance (27.95%), followed by the unique contribution of suppression of information in WM (17.49%), both processes related to cognitive inhibition. The unique contributions of the two variables related to cognitive inhibition—resistance to proactive interference and suppression of information in WM—were higher than their interaction with analogical or class-inclusion reasoning see .On the other hand, the unique contributions of the variables related to relational verbal reasoning—class-inclusion and analogical reasoning—were much lower  than their common contribution: the interaction between class inclusion and analogies explained 17.87% of the total variance. Therefore, conjointly, the two relational verbal reasoning variables explained as much variance as suppression of information in WM by itself, but the interaction between the variables of cognitive inhibition and relational verbal reasoning greatly suppressed the effect found.p < .02). The variable with the greatest weight in the regression was analogical reasoning , followed by updating information in WM  and resistance to proactive interference   see . TherefoAnalysis of the variance communality revealed that analogical reasoning made a unique contribution of 28.52%; the interaction between resistance to proactive interference and updating made a contribution of 16.80%, whereas the unique contribution of updating was 16.41%.t was performed between the two groups of participants in the variables that made significant contributions to metaphor interpretation. The results showed that the less efficient group of metaphor processors also obtained poorer scores in updating information in WM, analogical reasoning, and class inclusion . However, the difference in cognitive inhibition fell short of the standard levels of significance (p < .08).Analysis by age revealed that at age 11, executive functioning did not significantly influence performance of metaphor interpretation. However, it did affect the 15-year-old and young adults groups, especially with regard to the variables related to updating information in WM and cognitive inhibition. Moreover, there were no significant differences in any of the variables of executive functioning between 15-year-olds and young adults, but there were differences in metaphor interpretation. A possible interpretation of this result is that the difference between 15-year-olds and young adults did not reflect the possible individual differences in metaphor processing efficiency. That is, some young adults may have poorer metaphor comprehension than some 15-year-old adolescents. To verify this possibility, a new analysis was performed by dividing the 15-year-olds and young adults not by age, but by good or poor metaphor comprehension. Participants who scored above the median in metaphor interpretation (58.3%) were assigned to the efficient group, and those who scored below the median were assigned to the less efficient group. According to this division, 32 participants (twenty-one 15-year-olds and eleven young adults) were assigned to the "less efficient metaphor processors" group, and 35 (twelve 15-year-olds and twenty-three young adults) to the “efficient metaphor processors” group. To verify that the group division performance actually reflected differential efficiency in metaphor processing, Student’s r = .61), and negative and significant correlations were observed between metaphor interpretation and suppression of information in WM (r = -.55) and resistance to proactive interference (r = -.41). The correlations with class inclusion (r = .53) and analogical reasoning were also significant (r = .38). However, there was no significant correlation with any of the variables in the group of efficient processors in metaphor interpretation.As r = -.55), resistance to proactive interference under low suppression condition (r = -.41), overall updating (r = .61), class inclusion (r = .53), and analogical reasoning (r = .38)  see . Howeverion r = ., and anap < .001). The only variable whose weight was close to significance in the regression was class inclusion . The communality analysis revealed that the highest percentage of variance explained corresponded to the interaction between updating and cognitive inhibition (29.8%), the two variables associated with executive functioning  and executive functioning across development. We postulated that both relational reasoning and executive functioning should predict individual and developmental differences in metaphor interpretation. However, executive functioning will play a supplementary role, especially when metaphor comprehension is highly demanding, either because of the high difficulty of the metaphors (relatively novel metaphors in the absence of a context) or because of the individual’s special processing difficulties, such as low levels of reading experience or low semantic knowledge. Thus, we hypothesized that if relational reasoning was the only factor responsible for metaphor interpretation, developmental differences would not be expected because most children have already acquired these abilities by approximately 11 years of age. However, as executive functioning abilities continue to develop during adolescence and far beyond adolescence, if executive functioning is responsible for metaphor interpretation, we hypothesized changes across development. Thus, when executive functioning is not yet established—that is, at the age of 11—metaphor comprehension should rely more on analogical or class-inclusion reasoning. However, when people can benefit from an adequate updating of information in WM, suppression of inappropriate information, and effective shifting between literal and metaphorical meanings—that is, at the age of 15 and far beyond—they will use these executive resources to better interpret metaphorical sentences.As expected, our results showed that metaphor interpretation improves across development, as has been shown by other developmental studies , 21, 54.young adults, the studied variables made a lower contribution to metaphor interpretation. Relevant variables—updating information in WM, resistance to proactive interference, and analogical reasoning—explained 25.6% of the variance. The analysis of the variance communality revealed that analogical reasoning made the greatest contribution to the explained variance (28.52%), with executive functioning variables having a much lower weight: the interaction between resistance to proactive interference and updating contributed 16.80%, and the unique contribution of updating was 16.41%. It seems that we again found—as in the case of 15-year-olds—two alternative strategies because the unique effect of analogy decreased when it interacted with the executive functioning variables, whereas the executive functioning variables benefitted from the interaction with other processes.Moreover, also as expected, the analysis of the contribution of the different variables to metaphor interpretation varied with age. At age 11, only variables related to relational verbal reasoning were predictive of metaphor interpretation: the variable that accounted for the greatest amount of the explained variance was the unique effect of analogical reasoning (37.5%), but when unique and common effects of analogical reasoning were summed, the explained variance reached 88% of the total variance explained. At the age of 15, relational verbal reasoning measures—analogical and class-inclusion reasoning—were also related to metaphor interpretation. Moreover, different measures of executive functions also made a significant contribution, but only variables related to updating information in WM and to cognitive inhibition—all the measures of updating, inhibition of information in WM, and resistance to proactive interference—so that, conjointly, relational verbal reasoning and executive functioning explained 52.6% of the variance. The analysis of variance communality showed that the variable that accounted for the greatest amount of the explained variance was resistance to proactive interference (27.95%), followed by the unique contribution of suppression of information in WM (17.49%), a percentage of variance similar to that explained by the interaction between analogical and class-inclusion reasoning, which explained 17.87%. Taking into account that the effects are not additive—because the interaction between the variables of cognitive inhibition and relational verbal reasoning considerably suppressed the effect of the unique contribution of resistance to proactive interference—this seemed to indicate that the 15-year-old adolescents use two different alternative strategies to interpret metaphors: either they resolved metaphors using mechanisms of cognitive inhibition, especially resistance to proactive interference, or they did so through analogical and class-inclusion reasoning. We referred to two alternative mechanisms because the interaction of the effects of both inhibitory and reasoning processes suppressed the unique effect attributed to them. Finally, in Therefore, analysis by age could be showing that, given that updating information in WM and cognitive inhibition—both related to executive functioning—are both still developing until late adolescence (and some processes related to inhibition even far beyond that stage) , 56, at Importantly, our results also corroborated those found by other studies that have not received much attention, such as those of Johnson and Pascual-Leone , who alsLast but not least, the results of the analysis of the more efficient metaphor processors revealed that not one of the variables considered in this study influenced metaphor comprehension, whereas in the case of less efficient processors, the opposite occurred. There was a significant correlation between metaphor interpretation and updating information in WM, cognitive inhibition (suppression of information in WM and resistance to proactive interference), and relational verbal reasoning measures . All these variables explained 47% of the variance. The analysis of variance communality showed that the interaction between updating and cognitive inhibition explained the greatest proportion (29.8%), and the unique contribution of class inclusion was 14.68%. These results again showed—as in the case of the 15-year-olds and the young adults—the use of two alternative strategies to understand metaphors: either executive control processes or the well-consolidated (since age 11) class-inclusion reasoning were used.This kind of behavioural dissociation between more and less efficient processors was also observed by Prat et al.  at a neuTherefore, to process metaphors that require high levels of processing—such as the relatively new metaphors in the absence of context used in this study—demanded from the less efficient processors not only the intervention of relational reasoning but also the supplementary aid of executive functioning, especially cognitive inhibition and updating information in WM. These results also supported those that have previously linked metaphor comprehension to the intervention of inhibitory processes –11, 37. Finally, our results stepped away from the traditional debate over whether analogical or class-inclusion reasoning have more influence on metaphor interpretation. What we have found is that both types of relational verbal reasoning were acceptable strategies to address metaphorical interpretation, but their differential effectiveness depended on the level of development, task difficulty, and, therefore, on the individuals' knowledge of the world to which the metaphor refers.These results reflect metaphor interpretations of low familiarity items. Thus, it would be desirable to consider different types of metaphors with and without context for future research to more fully address the contribution of executive functioning under different tasks’ demands.S1 Appendix(DOCX)Click here for additional data file.


N = 71 experts as the most important cause of international ability differences. Genes were rated as the second most relevant factor but also had the highest variability in ratings. Culture, health, wealth, modernization, and politics were the next most important factors, whereas other factors such as geography, climate, test bias, and sampling error were less important. The paper concludes with a discussion of limitations of the survey .Following Snyderman and Rothman , 1988, w Cognitive ability is understood as the ability to think (intelligence), the disposition of knowledge (the store of true and relevant knowledge), and the intelligent use of this knowledge. The current study focuses on international differences in cognitive ability, based on test scores from different countries. International differences in cognitive ability have been estimated using student assessment studies  points, whereas South Korean pupils achieved 587 SAS points. If SAS points are converted to IQ points, the Yemeni would have an IQ of 56 and the Koreans would have an IQ of 113, a difference of 11 years of schoolingSDs in IQ. Such a large range has raised questions about the validity, measurement, and causes of the differences  in Finland  may differ from public appraisals such as those reported in Gottfredson's  “MainstrThirty years ago, Snyderman and Rothman , 1988 suTo examine expert opinions, we created a new questionnaire (“Expert Questionnaire on Cognitive Ability”). The questionnaire was partly based on the one developed by Snyderman and Rothman , 1988, bThe first general question was, “On causes of cross-national differences, what do you think are the reasons for large differences in cognitive ability and intelligence studies ?” This and subsequent questions were followed by the statement, “To address this question, please rate the factors below in importance .” There were 15 factors, each rated on a scale from 0 to 100 in 5% steps, with “no answer” also possible. 0% would suggest that the factor explains 0% of international differences and is unimportant; 100% would suggest that the factor explains all of the differences and is highly important. The 15 factors were culture , genes, educational quantity, educational quality, wealth, health, geography, climate, politics, modernization, sampling error, test knowledge, discrimination, test bias, and migration.- Finland: “One of the countries with the highest scores on international assessments  is Finland. Why do you think this is the case?”- East Asia: “The region with the highest scores on international assessments is East-Asia . Why do you think this is the case?”- sub-Saharan Africa: “The region with the lowest scores on international assessments is sub-Saharan Africa . Why do you think this is the case?”- Southern Europe (compared to North-Western-Middle Europe): “Results in Southern Europe  are lower than results in North-Western-Middle Europe . Why?”- Arabian-Muslim world (compared to North-Western-Middle Europe): “Results in the Arabian-Muslim world  are lower than results in North-Western-Middle Europe . Why?”- Latin America (compared to North America): “Results in Latin America  are lower than results in USA or Canada. Why?”- Israel (compared to North-Western-Middle Europe): “Results in Israel are lower than results in North-Western-Middle Europe. Why?”- Jews in the Western world: “Results of Jews in the Western world are at the top. Why?”- Roma: “Results of Roma (gypsies) in Europe are comparatively low. Why?”- Muslim immigrants: “Results of immigrants from the Middle East (Arabian and Muslim countries) in the Western world are not at the top. Why?”To obtain additional information, the same questions were asked for the following scientifically or politically important countries and groups:Each country or group was rated on the same 15 factors used to evaluate general cross-national differences, using the same scales (0–100), questions, and instructions. In addition, comments could be given for each factor being rated.Intelligence, Cognitive Psychology, Contemporary Educational Psychology, New Ideas in Psychology, and Learning and Individual Differences. Notice of the study was also emailed to members of the International Society for Intelligence Research (ISIR), and posted to the web site for the International Society for the Study of Individual Differences (ISSID). ISIR and ISSID support intelligence research and host professional conferences with intelligence researchers. Finally, the study was announced at the 2013 ISIR conference in Melbourne, Australia. A total of 1345 people received an email invitation. An expert was defined as a person who had published on cognitive ability or who had attended intelligence conferences and presented research. Compared to Snyderman and Rothman , our selection criteria were based more on publications in specific scientific journals and less on membership in scientific organizations. In addition, we used email and a web-based survey rather than traditional mail and paper-pencil surveys.Notice of the study was emailed to experts who published articles on or after 2010 in journals on intelligence, cognitive abilities, and student achievement. The journals included We received a total of 265 responses from May 2013 to March 2014, at which time the survey was closed. The response rate was 20% of all invitations. The present article focused on cross-national differences and concerned questions toward the end of the survey. These questions were answered by 71 respondents. By comparison, there were 1020 invitations and 661 participants (65%) in the Snyderman and Rothman study.SD = 14.87, median = 47 years). Respondents were mainly from the United States (38%), Germany (17%), Scandinavia (9%), the UK and Ireland (8%), Spain (7%), Canada (6%), and Australia/New Zealand (6%). The rest were from Latin America, Austria, Switzerland, Italy, Russia, The Netherlands, Greece, Portugal, and China. Around 20% had at least some self-rated Jewish heritage. The religious background of the respondents' families was about one third Catholic, one third Protestant, and one third with no affiliation. About 6% of respondents were Jewish (religion), and 62% professed no religious affiliation.Respondents were 83% male and 17% female, and had a mean age of 49 years (Participants worked in the fields of psychology (80%), education (8%), biology (5%), economics (3%), sociology (2%), and physical anthropology (2%). 87% had a Ph.D. All were scientists . Sixty seven percent were tenured faculty, 24% non-tenured faculty, and 6% students. Other participants (about 3%) were not categorized or worked in non-academic research institutes.h-indexes . The published papers had passed peer review, a requirement for inclusion in Scopus h-index counts. The counts substantiate the high quantity and quality of research published by respondents.The majority of respondents did research on the “nature of intelligence/cognitive abilities.” The percentage of respondents that studied group differences in ability and related topics was 55% for “group differences”; 33% for “consequences for economics, society, and culture”; 26% for “bias in ability tests”; 25% for “cross-cultural comparisons”; and 25% for “FLynn effect.” Respondents published an average of 47 papers (median = 20 papers), and reported high One limitation of the study can be seen in the small sample and low response rates. The sample consisted of 71 respondents, which is small compared to Snyderman and Rothman's sample of 661 respondents (of 1020 invitations). In addition, self-selection of experts could have biased the results.We attempted to increase response rates by using an Internet survey, emailing invitations (and reminders), and announcing the survey at intelligence conferences. Despite these measures, response rates were still low. The low response rates may be attributed to the length of the survey (which took about 40–90 min to complete), self-censorship, or fear of addressing a controversial subject (despite assurances of anonymity). The low response rates may also reflect a paucity of experts on intelligence and international differences in cognitive ability. There may be 20–50 scientists who study international differences in intelligence. Based on this estimate, the number of respondents (71 people) may exceed the number of scientists who study the topic! Because the aim of the survey was to obtain expert opinions on the research questions, our view is that participation of people with only tangential knowledge of the subject matter could distort answers more than low response rates attributable to self-selection by experts.One researcher suggested in an email that only politically biased researchers would respond to the questionnaire, especially given its length. In contrast to the speculation, three researchers sometimes labeled as “conservative” in Internet articles and Wikipedia refused to participate due to lack of expertise, survey length, or disapproval of opinion surveys as a way of finding truth. Based on several comments of researchers with diverse political backgrounds we have no hint of biased participation or refusal of participation.The Internet based survey was created with the free software LimeSurvey. Invitees received an invitation email with instructions on how to obtain a participation code, which could not be linked to the respondents' identities. Participants were told, “All questionnaires will be anonymously treated. No individual results will be published or given to other persons or the media. Results will be presented in an anonymous manner.” Only people who received a participation code could participate. After 2 weeks, invitees who had not responded automatically received a reminder email.Experts could assign a percentage to all 15 factors (causes) for each question. Logically, the percentages across all factors should sum to 100%. However, experts did not always rate all factors, and their ratings did not always sum to 100%. To address variation in percentages across participants (and questions), we analyzed only responses from experts who rated at least 5 of 15 factors or whose ratings summed to at least 75%. The sum of the ratings of 5 factors usually explained more than the half of the international differences. In addition, we replaced missing ratings with 0%, and standardized the sum of the ratings (within each question) to 100%. Replacing missing values with a score of 0% was based on the assumption that experts who did not rate a factor judged that factor as having no influence on ability differences.The adjustments corrected for biases across raters and questions. For example, the average sum of items  for the first global question  was 440%. With the corrections, the average sum of items for the first global question  was 100%. Without the corrections, the average sum of items for each question would deviate from 100%, and would prevent comparisons across questions.SD = 23.85; all other factors, SD < 10), indicating disagreement about the importance of genetic influences. Only 5 of 71 experts (7%) who responded to the genetic item thought that genes had no influence. If non-responses to the genetic item are converted to 0% , 13% of experts doubted any genetic influence. The frequency of zero-percentage-ratings was larger for genes than for culture or education (about 1%), but experts who believed that genes had no influence were a minority: Around 90% of experts believed that genes had at least some influence on cross-national differences in cognitive ability.Seventy-one experts rated possible causes of cross-national differences in cognitive ability based on psychometric IQs and student assessment studies . Genes were rated as the most important cause 17%), followed by educational quality (11.44%), health (10.88%), and educational quantity (10.20%)  included wealth, culture, and modernization (7–9%). Methodological bias factors  were rated as less important .Finnish miracle refers to the top student test results in Finland , a finding confirmed by psychometric IQs and Piagetian tasks . Similar to other countries and regions, sub-Saharan Africa had low ratings for discrimination and methodological problems .s Lemos, . Similars Lemos, . Factorss Lemos, . Measures Lemos, . In the Southern Europe attains low student test results compared to Central, West, and Northern Europe, and to North America and Australia/New ZealandArab-Muslim countries have low student test results and psychometric IQs, and also low levels of educational and scientific achievements, compared to other regions and countries  Arab Fund for Economic Social Development, Latin America lags behind other regions in student assessment results, a finding that has been attributed to culture .Roma  are the lowest scoring long-term natives in Europe  generally show low student test results and psychometric IQs, which are a third to one standard deviation lower than other groups , followed by educational quality (14.69%), culture (13.71%), and educational quantity . In addition, compared to cross-country comparisons, single countries showed higher ratings for genes (19.72 vs. 16.99%), educational quantity (13.60 vs. 10.20%), and educational quality (14.69 vs. 11.44%). In contrast, single countries showed lower ratings for wealth, health, modernization, and test bias , suggesting that general cross-country comparisons reflect global impressions that may not hold for single countries.There were few entries in the comment sections. Two experts noted that the results for Israel depended on a mix of ethnicities and climate, without detailed explanation. Other experts noted that strong discrimination may be a cause of Jewish high intelligence, and that the causes of international ability differences are interconnected. Another expert stressed that Finns have the “fastest simple visual reaction times of any contemporary Western population,” and referred to a publication.Experts on cognitive ability rated possible causes of international differences in student assessment and psychometric IQ test results. Ratings were obtained for cross-national differences and single countries using a percentage scale ranging from 0 to 100% (higher percentages = more important). The expert survey revealed important results: Methodological factors  were weakly rated , as was discrimination . In contrast, educational factors  and genes were strongly rated. The low ratings for methodological factors suggest that international assessments were perceived to be valid indicators of cognitive ability and cross-country patterns.educational factors together  as the most important cause of international differences in cognitive ability . Weaker ratings were given for environmental factors such as health , wealth , modernization , and politics . The sum of all these environmental factors explained more than half of the international ability differences .Experts rated the two genetic-evolutionary factor was the single most important cause of international differences in cognitive ability : Experts attributed about one-sixth to one-fifth of international ability differences to genes. While the rated impact of genes was remarkable, it was still well below the rated impact of environmental factors (around 50%). In addition, disagreement among experts (based on SDs in ratings) was much higher for genes than for environmental factors. Other factors such as geographic and climate differences were rated as negligible influences on international ability differences. Immigration was rated as important only for Israel.The relative importance of environmental factors does not mean that genetic factors were seen as irrelevant. Based on expert opinions, the While both camps, the nature as well as the nurture camp, are supported by the results of the expert survey, the scientifically more interesting result is the support for genetic explanations. Because environmental theories are rarely questioned in research, their corroboration by an expert survey is not astonishing. More important is the support for the frequently hotly disputed genetic explanations. Assuming that the survey is representative of expert opinions, genetic factors should receive more attention in future research and public debates. To fairly consider different hypotheses, future research should incorporate procedures  that reduce zeitgeist or political pressures that may bias responses on controversial issues , they were in a good position to provide informed opinions of ability differences. Thus, although response rates were low, the responses were likely to reflect the opinions of people who had expertise on the topic being evaluated.This finally leads to some limitations of the presented study: The main limitation can be seen in the low response rate (20%). Although low response rates can produce unreliable results, low response rates are less problematic in the current study, which was designed to solicit A related limitation is self-selection. Only a small number of experts responded to the invitation, and the responses of these experts may be unrepresentative and biased. Such problems are common to surveys, but might be less relevant in the current study, which was designed to attract experts in a narrow domain.  The experts who completed the survey reported that they had expertise in intelligence and group differences. This suggests that the experts had self-selected into the survey based on relevant expertise, which should increase the validity of opinions. Based on our experience, we suggest that future surveys more carefully preselect who is invited to participate. In the current study, our aim was to recruit a broad sample of experts, including experts who might be reluctant to respond for various reasons, but not to exclude anybody who perceives him- or herself as an expert. In retrospect, our recruitment procedure was probably too broad, yielding many invitations but few responses, which lowered response rates.A third limitation concerned the measurement of factors that cause international ability differences. Different factors were measured with different numbers of items. Education was measured with two items, environmental factors with 11 items, and genetics with one item. To better estimate the importance of nature and nurture, a single binary question could be added to future surveys . In addition, the survey did not assess indirect influences. Additionally, genetic effects can be included in the rated environmental aspects health, wealth, institutional features and migration or in non-rated aspects of personality Dawkins, . FinallyFurther research is needed to identify the facets of the factors that contributed to expert opinions. The facets may include different aspects of educational quality  or different types of genes .opinion instrument and a possible indicator of truth. As an opinion instrument, the survey would be biased if the selection of experts were biased. In the current study, experts were selected if they had published on intelligence or attended an intelligence conference, increasing the likelihood that the experts had an informed opinion. The other aspect of an expert survey—that it is an indicator of truth—cannot be answered by this study. A single empirical study can contradict expert opinion, and the results of the current survey must be validated in future empirical research.It should be noted that an expert survey is both an the interdependence of factors. Factors related to cognitive ability may influence each other in complex ways. For example, culture may influence education, genes, health, and cognitive ability, which in turn may influence wealth and economic development (e.g., Rindermann et al., Finally, the expert survey did not address All three authors developed the study concept. DB programmed the web-based questionnaire and carried out the survey. DB and HR performed the data analysis. DB drafted an initial version of the manuscript. HR and TC provided revisions. All authors approved the final version of the manuscript for submission.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Objective: The feasibility of a high-frequency real-time monitoring approach to psychotherapy is outlined and tested for patients' compliance to evaluate its integration to everyday practice. Criteria concern the ecological momentary assessment, the assessment of therapy-related cognitions and emotions, equidistant time sampling, real-time nonlinear time series analysis, continuous participative process control by client and therapist, and the application of idiographic (person-specific) surveys.Methods: The process-outcome monitoring is technically realized by an internet-based device for data collection and data analysis, the Synergetic Navigation System. Its feasibility is documented by a compliance study on 151 clients treated in an inpatient and a day-treatment clinic.Results: We found high compliance rates  amongst the respondents, independent of the severity of symptoms or the degree of impairment. Compared to other diagnoses, the compliance rate was lower in the group diagnosed with personality disorders.Conclusion: The results support the feasibility of high-frequency monitoring in routine psychotherapy settings. Daily collection of psychological surveys allows for the assessment of highly resolved, equidistant time series data which gives insight into the nonlinear qualities of therapeutic change processes . Outcome monitoring and feedback on therapeutic progress has become popular and has been adopted by many mental health providers all over the world  developed by Lambert and colleagues . Only regular and frequent assessments through (process-) questionnaires allow for meaningful application of time series analysis methods in the frequency domain  and the frequency of the measurement (sampling rate): Imagine a completely dark room, with a disk at the center, spinning continuously at one speed. The disk has a dot painted on it and the only source of light to determine the dot's position is a stroboscopic light. Depending on how frequently the light flickers, the dot's position, and thus the rotational speed of the disk, appears to be very different. If the light matches the disk's rotation frequency exactly, the disk appears to be static; however, depending on the frequency of the flickering light, the disk and dot can just as well appear to be moving quickly, slowly, forwards, backwards, or completely erratically. So even for a regularly and continuously spinning dot, a non-standardized and infrequent detection method can only yield invalid results. Going one step further, imagine we tried to estimate the behavior of a dot painted on a chaotically moving double pendulum. In that case, not only the measurement frequency is irregular, but also the dynamic of the phenomenon under investigation is unknown/chaotically. The only way to give a rough estimate of the true behavior of the double pendulum in that imagined dark room would be to install a very rapidly flickering stroboscope and it needs to do so very regularly. In analogy to this phenomenon, if a psychological process is in any form nonlinear or susceptible to sudden changes, the only way to detect—and feedback—theses changes is via frequent and regular measurement. Only then intra-personal identification of processes can be achieved and put to direct use in psychotherapy. In consequence, there should be just as much emphasis placed on standardizing the frequency of measurement as there is currently on standardizing the instruments used for measurement .When aiming at (a) a complete recording of therapies (not only as an irregular event sampling), (b) frequent and (c) continuous measurements, and (d) considering practicalities of data collection, daily measurements appear to be a good and achievable way. The present paper therefore reports on results from daily administration of a process questionnaire.Most therapy feedback applications utilize linear models of psychological change. However, there are accumulating findings supporting nonlinearity and chaoticity of psychotherapy and change dynamics  are more likely to be an artifact of infrequent/irregular data collection and widely used linear assumptions, than of the actual linearity of the researched phenomena. In other words, daily measurements using an appropriate survey  followed the same expected trajectory and the dynamics could be controlled by the input , it would be a safe bet to recommend invariant manuals. However, the more the courses of psychopathology and recovery deviate from linear input-output mechanisms and from planned routes, the more we need immediate support by feedback systems that provide information at short time delays to the ongoing process. Time series analysis tools offer just that, by reporting on nonlinear features of processes such as varying complexity, critical fluctuations, time-dependent synchronization of signals, and other precursors of pattern transitions . SNS is a web-based generic system that allows for the implementation of various questionnaires at any chosen interval. The response options to the items combine Likert-type scales and visual analog scales. Data can be entered using web-compatible devices including PCs, notebooks, tablets, or smartphones, which permits maximal spatial and temporal flexibility for entering data. Data privacy protection and data security are guaranteed by https-pages, anonymized usernames, passwords, and security technology at the level of online banking transactions. Alongside an administrative mode and client documentation, a range of outcome and process questionnaires can be selected. The raw data results can be visualized by time series graphs. These time series can be submitted to several analyses, e.g., Dynamic Complexity ]. The Therapy Process Questionnaire is filled in daily, normally in the evening hours. Its welcoming text specifically asks to report on all aspects covered in the TPQ as experienced at the current day. Clients were free to access the questionnaires via internet through private devices or make use of the clinic's infrastructure. The introduction to the TPQ items and the use of SNS is made by the responsible psychotherapist at the very beginning of the hospital stay. All clients sign an informed consent, introducing real-time monitoring as a routine part of the clinics practice as well as the willingness for allowing the data to be used for empirical purposes. Application of the SNS to patients and the usage of the retrieved data has been approved by the ethical committee of the Paracelsus Medical University.This feasibility study was realized at the Department of Inpatient Psychotherapy and at the Department of Psychosomatics/Day-Treatment Center, Christian Doppler University Clinic, Salzburg, Austria. The sample includes the cohort of 159 clients which were released after treatment in 2013 .The mean compliance of the sample was 78.3% . 66.4% of all clients realized a compliance rate of 80% or more, 49.3% realized a compliance rate of 90% or more, and 25 clients (16.4%) had a compliance rate of 100%. Figure p < 0.004).The mean time series length of the 115 clients of the Department of Inpatient Psychotherapy was 73.4 measurement points (= days) (SD 31.5), the mean time series length of the 37 clients of the psychosomatic day-treatment center was 47.9 (SD 10.0). The complete sample had on average 10.1% missing values within the time series  . 81.6% of all clients had less than 20% missing data, 73.7% of all clients had less than 10% missing data, and 74 clients (48.7%) had no missing data (0%). Figure r = −0.081 (p = 0.325), DASS anxiety scale: r = −0.035 (p = 0.668), DASS stress scale: r = −0.069 (p = 0.403), ISR total score: r = −0.073 (p = 0.380). This corresponds to a real null correlation between symptom/problem intensity or burden of disease with the monitoring compliance.Symptom or problem severity was defined by the DASS subscales  and the ISR total score at admission to psychotherapy. The Pearson correlation coefficients of the compliance rate with these scales are as follows: DASS depression scale: F = 5.37, df = 2, p = 0.006). Multiple comparisons (Scheffé Test) indicate significant differences between the compliance rates of F30 (83.2%) and F60 (66.1%) (p = 0.010), F40 (81.1%) to F60 (66.1%) (p = 0.027), but not between F30 and F40 (p = 0.920). Evidently, the compliance rate of the clients diagnosed with personality disorders (F60) was significantly lower than the compliance rate of the other categories . A comparison of the diagnosis categories with % missing data . Multiple comparisons (Scheffé Test) indicate that the difference between the percentage of missing data of F30 (6.9%) and F60 (16.3%) scarcely misses the 5%-significance level (p = 0.051), differences between F40 (8.6%) and F60 (16.3%) (p = 0.136), or between F30 to F40 (p = 0.882) are far from being significant.For testing the differences between the compliance rates of the frequent diagnosis categories of this sample [F30: mood (affective) disorders; F40: neurotic, stress-related, and somatoform disorders; F60: disorders of adult personality and behavior; see Tables r = + 0.231) indicates that there is no fatigue, resistance, or reactance effect with increasing duration of the monitoring (as a negative correlation would have suggested).The results illustrate the feasibility of a highly resolved real-time monitoring procedure on psychotherapy processes in an inpatient and a day-treatment setting. A large proportion of the clients revealed high compliance rates and low rates of missing data, resulting in time series of high frequency, low missing rates, and equidistant measurements. Application of the questionnaires was accomplished using an internet-based device (SNS) with a process questionnaire of 42 items  make evidence for nonlinear processes and self-organization in every single case (Schiepek et al., The consequences for psychotherapy research are manifold: highly resolved real-time monitoring can define a standard for the investigation of dynamic phenomena like drop-outs and its precursors, sudden changes or sudden losses, crisis-repair sequences, phase-transition-like phenomena, dosis-to-effect shapes, or sustainable and long-term outcomes. Even the outcome may be evaluated not only by pre-post differences in outcome measures, but by changing dynamic patterns of cognitions and emotions [e.g., changes in the rapid cycling of mood or affective instability in Borderline Personality Disorders (compare Figure One additional future application and improvement of feedback procedures are idiographic approaches to individual item selection and case formulation (Schiepek, GSch and BA contributed to data gathering, text, study design, and data analysis. GSt contributed significant to data analysis and study design. EB, MG, and WA contributed significantly to data gathering and study design. All authors added corrections and proofread the paper.Paracelsus Medical University, Salzburg, Austria. Award number: R-14/02/058-AAS.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.