From simple, invariant behaviour to complex social populations

The prevailing perspective on ecological interactions' influence on fitness and ecosystem dynamics has traditionally favoured competition over cooperation, likely influenced by Darwin's theory of natural selection. However, the origin of life was probably shaped only by cooperation, giving rise to the emergence of sociality and the sharing of public information for resource acquisition. Over time, intricate forms of social organization have evolved, yet invariant, simple behaviours —social copying and conspecific attraction— remain shared among all social animals, spanning from Archaea to primates. This talk centers on how these two basic behavioural processes may elucidate certain emergent features within complex social populations, including instances of cultural punctuated evolution. Simple behaviour holds the capacity to generate features of complexity, such as feedback mechanisms, self-organization, and non-equilibrium states, as well as functional attributes like adaptation and memory. Social copying and conspecific attraction prove remarkably effective for information gathering and decision-making, particularly in scenarios involving perturbations such as invasions and warfare. Crucially, decisions concerning public information not only impact individual fitness prospects but also exert significant influence on complex population dynamics. Examples are the emergence of non-linear responses, exemplified by phenomena like transients and tipping points within populations and metapopulations. This becomes particularly evident when considering the interplay between philopatry and dispersal in social animals, including humans.