What would imaginary ancestors do? Thought experiments and intuitive plausibility in human cognitive evolution

Abstract The reconstruction of the evolutionary history of human cognition is a complex, interdisciplinary science. Human evolutionary theorists generally use a wide variety of evidential sources to construct hypotheses for the emergence of novel cognitive capacities in the hominin lineage. But sometimes, they take certain associations among cognitive capacities to be intuitively plausible—so much so that they accept and include them in their hypotheses. I argue that when they make these plausibility judgments, they are actually attempting (explicitly or implicitly) to reason from the perspective of an ancestral hominin. They reason about whether some inference would be easy, natural, or obvious for a hominin with only a hypothesized set of ancestral capacities. When they do this, they invoke their intuitive sense of ease or obviousness as evidence for the association among cognitive capacities. But such intuitions are systematically misleading, because they are influenced by the very cognitive capacity whose evolution the theorist seeks to explain. Intuitions that stem from the evolved capacity in question thus make some associations among cognitive capacities appear artificially plausible. I analyze examples of this kind of reasoning from three recent hypotheses for human cognitive evolution. I argue that this is a particularly pervasive challenge for evolutionary theorists. Even though they are typically highly attuned to similar errors, theorists should expect to keep contending with this challenge, even in our best approaches to human cognitive evolution.