The American Psychological Association has noted: “Stress is to the human condition what tension is to the violin string: too little and the music is dull and raspy; too much and the music is shrill or the string snaps.
تذكر جمعية علم النفس الاميركية :‏ « مثلما تؤثر درجة شدّ الوتر في صوت الكمان ،‏ يؤثر التوتر في الانسان .‏