The study of personality has long been a topic of fascination for psychologists and researchers. One of the most influential perspectives in this field is the evolutionary perspective, which suggests that our personalities have been shaped by millions of years of natural selection. This perspective views personality as a set of adaptive traits and behaviors that have evolved to help individuals survive and reproduce in their environments. By analyzing individual traits and behaviors through an evolutionary lens, we can gain a deeper understanding of why certain characteristics and patterns of behavior exist and how they contribute to our overall survival and success as a species. In this way, the evolutionary perspective has greatly influenced our understanding of individual differences and has had a significant impact on the study of personality as a whole.
Evolutionary psychology is primarily interested in finding commonalities between people, or basic human psychological nature. From an evolutionary perspective, the fact that people have fundamental differences in personality traits initially presents something of a puzzle. (Note: The field of behavioral genetics is concerned with statistically partitioning differences between people into genetic and environmental sources of variance. However, understanding the concept of heritability can be tricky—heritability refers only to the differences between people, never the degree to which the traits of an individual are due to environmental or genetic factors, since traits are always a complex interweaving of both.)
Personality traits are conceptualized by evolutionary psychologists as due to normal variation around an optimum, or due to frequency-dependent selection, or facultative adaptations. Like variability in height, some personality traits may be simply reflect inter-individual variability around a general optimum. Or, personality traits may represent different genetically predisposed “behavioral morphs” — alternate behavioral strategies that depend on the frequency of competing behavioral strategies in the population. For example, if most of the population is generally trusting and gullible, the behavioral morph of being a “cheater” (or, in the extreme case, a sociopath) may be advantageous. Finally, like many other psychological adaptations, personality traits may be facultative—sensitive to typical variations in the social environment, especially during early development. For example, later born children are more likely than first borns to be rebellious, less conscientious and more open to new experiences, which may be advantageous to them given their particular niche in family structure.