The Ensemble Hypothesis of Human Cognitive Evolution

The Darwinian view is that human cognition is continuous with non-human cognition. Comparative mental abilities differ quantitatively but not qualitatively. A predominant alternative hypothesis is that language qualitatively separates human beings and other primates. The ensemble hypothesis examined here suggests that language is but one of five human capacities that produce a qualitatively unique form of cognition because of their interactions with each other. Each one taken separately has a likely precursor in non-human cognition, but taken together, their effects on cognition are not additive but interactive. The human mental ensemble proposed here includes an advanced executive attention component of working memory, a theory of mind augmenting social cognition, language, the ability to interpret information using inner speech and causal inference, and an episodic memory capable of mental time travel. Only in the evolution of Homo sapiens did these five components come together to enable non-linear changes in cognition on multiple fronts, resulting in the emergent form of cognition we experientially know and scientifically study today. Empirical evidence from behavioral studies, lesion studies, and studies involving neuroatypical populations provide tentative support for the hypothesis.