Origin and evolution of human cognition

Abstract

We investigate which of the higher cognitive abilities or types of intelligence characteristic of humans are found, even in preliminary form, in non-human animals, predominantly primates, or whether qualitatively different ("unique") human abilities exist. This concerns (1) tool use and fabrication, (2) problem solving, (3) gaze following, (4) mirror self-recognition, (5) imitation, (6) metacognition, (7) theory of mind, (8) consciousness, (9) prosociality, and (10) language. We found that none of these abilities can be regarded as unique to humans without precursors in non-human primates. The observed differences in cognitive functions, underlying brain mechanisms and resulting behaviors correlate best with differences in the information processing capacity as an equivalent of general intelligence based on the number of cortical neurons, packing density and axonal conduction velocity plus long-range cortical fascicles. The biggest quantitative change appears to concern the origin of syntactical language, but this was preceded by an increased mental ability to manipulate sequential events within working memory.

Keywords: Absolute and relative brain size; Cognitive abilities; Consciousness; Humans; Information processing capacity; Intelligence; Language; Primates.