Cognitive evolution in major vertebrate clades: the Lack of Attentional Control hypothesis and the Cognition-Opportunities-Needs framework

Léonore Bonin, Redouan Bshary

The observed difference in relative brain size between endotherms and ectotherms raises questions about potential resulting disparities in brain function between these two groups. Until recently, no clear cognitive advantage was found in endotherms, with ectotherms occasionally even outperforming them in seemingly complex tasks. However, recent research on working memory—a core executive function—in a teleost fish species suggests that cognitive differences may lie in more fundamental processes. Here, we develop two working hypotheses that arose from this finding. First, the apparent absence of working memory in a fish, and possibly other ectotherms, may stem from their inability to voluntarily control their attentional focus. Instead, only the environment would be causing changes in that focus. In the dichotomic vision of Kahneman’s (2011) consisting of automatic System 1 and voluntary System 2, fish could only rely on System 1. We call this the Lack of Attentional Control (LAC) hypothesis. Second, to explain why smaller-brained species may nevertheless outperform larger-brained species in some cognitive tasks, we propose the Cognition – Opportunities – Needs (CON) framework, which posits that cognitive abilities and learning opportunities provide non-mutually exclusive mechanisms for meeting ecological demands. While these hypotheses require further empirical validation, they offer a comprehensive theoretical perspective on cognitive diversity and evolution across species and major vertebrate clades.