It's cognition, with style: rethinking the biology of intelligence

Intelligence has been attributed to a growing number of non-primate species, including birds, cephalopods, and jumping spiders. This review outlines key findings in animal intelligence, finding that there is significant support for the presence of a wide variety of intelligent capacities in these groups. Yet, how intelligence can be achieved with relatively small, non-mammalian brains remains an open question, and neuroscientific efforts have not established the relationship between brains and intelligence. Core to these research programs is the assumption that intelligence sits higher on a scale of complexity than other kinds of cognition, requiring greater neural resources. This review shows that, despite its ubiquity, there is little evidence available for this assumption, and that it does not align well with the goals of contemporary research on animal intelligence. I argue that, like other biological functions, cross-species comparisons of cognition are not usefully framed as a question of as better or worse, simpler or more complex. Cognitive differences between species are the result of differing cognitive styles, rather than gradations on a universal scale of cognition. Intelligence is the human cognitive style, and intelligent animals are those whose cognitive style bears a family resemblance to ours. This approach embraces the anthropocentrism of the concept of intelligence, while rejecting the idea that intelligence is a superior capacity. With this alternative intelligence concept in mind, investigations into animal intelligence and its neural basis could gain traction by shifting away from the search for greater absolute neural capacity in animals, instead approaching these smaller-brained species as models that reveal what is not required for intelligence.