"Animal foraging and the evolution of goal-directed cognition"
One of the overarching lessons of complexity theory is that complex behaviors often emerge out of less complex local rule structures. Evolutionary theory holds that complex phenotypes evolve out of less complex phenotypes. This work presents evidence for the evolution of cognition out of simple molecular structures initially operating in the control of spatial foraging behavior. The evidence is constructed from and helps to unify observations from behavioral ecology, mathematical biology, molecular genetics, neuroscience, attention studies, and research on human goal-directed pathologies. Similarities in foraging behavior across eumetazoans (i.e., vertebrates, insects, and mollusks) suggest the early evolution of a foraging behavior called area-restricted search. Area-restricted search is characterized by initially concentrated searching around local areas of highest historical payoff, followed by more global and less focused searching as payoffs become infrequent. Mathematical models of area-restricted search show that it is optimal when resources are clumped and when only temporal information is available about resource density. I present a genetic algorithm that supports the mathematical findings and describes minimal molecular structures necessary for the evolution of area-restricted search. I show how these structures are present in existing neural pathways controlling area-restricted search and are internalized in the control of goal-directed behaviors in more recent vertebrates. Human pathologies of goal-directed behavior (e.g., ADHD, obsessive compulsive disorder, schizophrenia, drug addiction, and Parkinson’s Disease) share molecular similarities with foraging behavior, involve both motor and cognitive dysfunctions, and also appear to organize themselves along the gradient of behavior described by area-restricted search, from perseverative to interrupted. Studies of priming, memory chunking, and the prefrontal cortex provide evidence for the existence of hierarchical cognitive neighborhoods. Taken together, this work suggests that cognitive neighborhoods are the evolutionary emergent world of the foraging mind.