Neuroendocrine mechanisms underlying behavioral stability: implications for the evolutionary origin of personality

Abstract

Personality traits are behaviors that show limited flexibility over time and across contexts, and thus understanding their origin requires an understanding of what limits behavioral flexibility. Here, I suggest that insight into the evolutionary origin of personality traits requires determining the relative importance of selection and constraint in producing limits to behavioral flexibility. Natural selection as the primary cause of limits to behavioral flexibility assumes that the default state of behavior is one of high flexibility and predicts that personality variation arises through evolution of buffering mechanisms to stabilize behavioral expression, whereas the constraint hypothesis assumes that the default state is one of limited flexibility and predicts that the neuroendocrine components that underlie personality variation are those most constrained in flexibility. Using recent work on the neurobiology of sensitive periods and maternal programming of offspring behavior, I show that some of the most stable aspects of the neuroendocrine system are structural components and maternally induced epigenetic effects. Evidence of numerous constraints to changes in structural features of the neuroendocrine system and far fewer constraints to flexibility of epigenetic systems suggests that structural constraints play a primary role in the origin of behavioral stability and that epigenetic programming may be more important in generating adaptive variation among individuals.

Understanding the evolution of personality requires the study of mechanisms behind the development and life history of personality traits

“…Thus, principles of evolutionary developmental biology (evo-devo), i.e. use of the same genetic machinery to regulate the production of different phenotypic traits at different stages in ontogeny, may fruitfully be integrated into personality research [8,9]. We urge researchers to investigate the early development of personality traits and trait changes across the lifetime from the perspective of ontogenetic mechanisms.…”

Olfactory attractants and parity affect prenatal androgens and territoriality of coyote breeding pairs

“…fecundity, longevity) [40]. Previous literature has suggested that the stability of personality traits is determined by underlying endocrine correlates and alterations to endocrine factors can induce behavioral plasticity [41]. Determining the proximate factors that affect endocrine traits may therefore help to predict accompanying changes to personality traits or vice versa.…”

Incubation temperature influences the behavioral traits of a young precocial bird

“…In our study, neither circulating corticosterone levels nor growth rates were related to any behavior, suggesting that incubation temperature is exerting an effect on behavior independently of these physiological factors. More work is needed to determine if other potential physiological correlates, such as metabolic rate (Biro & Stamps, ; Careau et al., ), other hormones (e.g., vasopressin and oxytocin, Kelly & Goodson, ; thyroid hormone, Fundaro, ; Pilhatsch et al., ; Sala‐Roca, Martí‐Carbonell, Garau, Darbra, & Balada, ), or other components of the neuroendocrine system (e.g., hormone receptors, size of brain regions, Duckworth, ; number and density of neurons, Amiel et al., ) underlie differences in behavioral traits.…”