Emotions can be explained as specialized states, shaped by natural selection, that increase fitness in specific situations. The physiological, psychological, and behavioral characteristics of a specific emotion can be analyzed as possible design features that increase the ability to cope with the threats and opportunities present in the corresponding situation. This approach to understanding the evolutionary functions of emotions is illustrated by the correspondence between (a) the subtypes of fear and the different kinds of threat; (b) the attributes of happiness (...) and sadness and the changes that would be advantageous in propitious and unpropitious situations; and (c) the social emotions and the adaptive challenges of reciprocity relationships. In addition to addressing a core theoretical problem shared by evolutionary and cognitive psychology, explicit formulations of the evolutionary functions of specific emotions are of practical importance for understanding and treating emotional disorders. (shrink)

The purpose of this article is to develop a model of life history theory that incorporates environmental influences, contextual influences, and heritable variation. I argue that physically or psychologically stressful environments delay maturation and the onset of reproductive competence. The social context is also important, and here I concentrate on the opportunity for upward social mobility as a contextual influence that results in delaying reproduction and lowering fertility in the interest of increasing investment in children. I also review evidence that (...) variation in life history strategies is influenced by genetic variation as well. Finally, I show that cultural shifts in the social control of sexual behavior have had differential effects on individuals predisposed to high- versus low-investment reproductive strategies. (shrink)

In contemporary Western societies, infants in the first 3 months cry more than at any other time during their life. Although this crying is believed to function to assure nutrition, protection, and mother-infant interaction thought to be essential for later attachment, it also predisposes to complaints of excessive crying (“colic”), discontinuing breast-feeding, and, in the extreme case, child abuse. A resolution of this apparent paradox is proposed based on evidence that elements of caregiving are important determinants of some aspects of (...) early crying. It is argued that early human crying under caretaking conditions typical in Western societies is characterized by prolonged crying bouts, that it is specifically the length of crying bouts (rather than frequency or pattern) that is affected by caregiving practice, and that prolonged crying bouts are probably not characteristic with caretaking practices typical in non-Western societies and possibly in our evolutionary past. It is suggested that caregiving behaviors may recruit normal physiological functions that potentiate cry bout duration in Western caregiving contexts, but reduce it in others. Frequent, short bouts are sufficient, and probably better suited than long bouts, to promote all the positive and presumably adaptive functions claimed for infant crying. Furthermore, they may have provided a mechanism by which infants could enhance their own fitness. (shrink)