Pattern and Adaptation in Individual Behavioral Differences

Abstract

I. ABSTRACTThe existence of individual differences in behavior is a well-documented but poorly understood phenomenon. On the one hand, individual variation could be attributable to nonadaptive evolutionary processes, such as genetic drift, or to stochastic environmental forces that act upon a single genotype to produce an array of observed behavioral phenotypes. On the other hand, behavioral differences may reflect the action of the process of natural selection on the form, degree, context, and origins of differences in behavior. The characteristics of behavioral variation in any given species may themselves represent an adaptation which increases individual success. The nonadaptive "explanation" is common, but generally untestable; it makes no specific predictions, although implicitly it suggests that many observed types will be maladaptive. The functional interpretation leads us to expect pattern in the occurrence of individual variation both between and within species such that an individual's behavior is more precisely fit for its peculiar circumstances. In this chapter, we explicitly pursue the possibility of functional and adaptive individuality. We review the reports of variation in social and foraging behavior and consider the existing explanations for this variation. We then try to develop a framework for further study which relates the appearance and controls on individuality to the life history of an organism and the dynamics of its foraging and social environments. This framework leads to some specific predictions both interspecific ally and intraspecifically. II. INTRODUCTIONIntraspecific individual variation in animal behavior has a strange status. It is a phenomenon that everyone has observed and in which most are interested. Many acknowledge or proclaim behavioral variation as "important" (e.g., Lomnicki, 1982; Davies, 1982;Armitage, 1983), but until recently, it has seldom been studied in its own right. There is a historical element to this neglect (Slater, 1981(Slater, , 1986 Davies, 1982): both ethological and behaviorist traditions ignored individual variation due to their implicitly held explanations for it. Early ethologists emphasized the importance of explaining species-typical behaviors as adaptations to the normal social and ecological environment. They focused on highly recognizable, stereotyped behavior patterns, which, in their very constancy within a species, were evidence for molding by selection. Deviations from the norm that were induced, for example, by abnormal rearing demonstrated the tight link of the behavior to the conditions under which it evolved. For many years, then, ethologists largely ignored the possibility of significant intraspecific variation in behavior or even in the environments normally experienced by different populations.Comparative psychologists, in search of more general trans-specific laws of learning and cognition, assumed that variation in their subjects' responses resulted from undetected and/or uncontrolled factors in the experimental environment. The...

Behavioral syndromes: an ecological and evolutionary overview

“…The existence of limited plasticity and behavioral correlations can cause individuals to often exhibit behavior that appears suboptimal when viewed in isolation. Finally, whereas behavioral ecology often ignores individual variation in behavior (focusing instead on shifts in average behavior in response to environmental variation [7,8]), the behavioral syndrome framework quantifies individual variation in behavior and attempts to explain the maintenance of this variation.…”

Chapter 5 Insights for Behavioral Ecology from Behavioral Syndromes

“…Although this approach is effective at determining whether a specific factor is driving behavioral differences, an important alternative view is to regard individual variation as more than mere noise. Several prominent behavioral ecologists brought attention to the importance of individual behavioral variation in the 1980s and 1990s (Arnqvist and Henriksson, 1997;Clark and Ehlinger, 1987;Huntingford, 1976b;Magurran, 1993;Riechert and Hedrick, 1993;Slater, 1981;Stamps, 1991;Wilson, 1998;. In addition, discrete, bimodal behavioral types, such as alternative strategies (producer/scrounger, hawk/dove, defect/cooperate) have long been a mainstream area of study in behavioral ecology.…”

An explanatory framework for adaptive personality differences

“…Clark & Ehlinger 1987;Digman 1990;Gosling 2001;Sih et al 2004a). Birds often differ consistently in the way they explore their environment and these differences are associated with, for example, differences in boldness and aggressiveness (Groothuis & Carere 2005).…”