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http://dx.doi.org/10.1037/14683-005
It is a profound truth that we know human nature through behavior. But the study of mere physiological behavior does not take us far. We are still largely ignorant of the physiological expression of human nature. The measurements of the pulse and breathing, and some obscure organs that we do not usually mention, have not thrown much light on human conduct. At best the physiological reactions are a dubious index. The same physiological reflexes may be the expression of different emotions and attitudes. And again the same emotions and attitudes may have different expressions. To get any adequate knowledge of human nature we must study it in the milieu of social relations through the variety of social responses and in the social products of language, art, and institutions. It is thus that we get an insight into the propensities, capacities, and limitations of human nature. It is thus that we come to understand the canalization of human conduct into habit and its organization into the existing patterns of behavior. (PsycINFO Database Record (c) 2016 APA, all rights reserved)