africanamericanboys behaviormodification casestudies childdevelopment childpsychology cognitivelearning cognitivestyles curricula determination(personalitytrait)inchildren déterminationchezl'enfant earlychildhoodeducation education elementary individualizedinstruction learning learningdisabledyouth mixedabilitygroupingineducation multipleintelligences newyorktimesbestseller nyt:combined-print-and-e-book-nonfiction=2012-09-23 personalityandacademicachievement personalityandcognition personalityandmotivation personnalitéetcognition personnalitéetmotivation personnalitéetsuccèsscolaire philosophy psychologyof psychologyoflearning self-esteeminchildren sexdifferencesineducation socialaspects stressinchildren successinchildren succèschezl'enfant unitedstates