Brains, Behaviour, and Cognition: Multiple Misconceptions

Abstract

Despite abundant evidence to the contrary, non-avian reptiles are widely considered as behavioural and cognitive underachievers. The persistent myth of the sluggish, primitive, stupid reptile can be traced, at least in part, to long-standing misconceptions about reptilian brain size and organisation. Historically, reptile brains have been considered small and lacking the neural structures that support complex cognition in other vertebrates. In particular, the notion that reptiles lack a cerebral cortex has led to expectations that their behaviour and cognition should be simple and unsophisticated in comparison with birds and mammals. However, it was shown several decades ago that reptiles possess a large pallium comprising three–four distinct cortical areas and a dorsal ventricular ridge that may be functionally equivalent to parts of mammalian neocortex. In fact, forebrain organisation conforms to a common plan in birds and reptiles, which may seem surprising given the recent trend to put the cognitive achievements of birds above those of reptiles yet on a par with mammals. Moreover, the view that reptiles do not exhibit complex cognition faces a growing list of exceptions. Reptiles are capable of spatial, social, reversal, problem-solving, and many other types of learning and cognitively demanding behaviours provided that experimental designs account for some peculiarities of their biology involving their morphology, physiology, and ecology. Unlike frequent caricatures that depict reptiles as clumsy, inflexible, and instinct-driven, much reptile behaviour is precisely performed, delicate in appearance, readily modified, and contextually determined. Recent work has shown that reptiles can show elaborate communication and social systems, parental care, social learning, and play. Although such research is sparse compared to endothermic vertebrates, and the diversity among them immense, captive reptiles also benefit from enrichment, recognise their caretakers individually and form bonds with them, and are affected by early social isolation in ways similar to birds and mammals. Still, the gap between what we know and what we would like to know about reptilian behaviour and cognition is enormous.