Uniquely human intelligence arose from expanded information capacity

Most theories of how human cognition is unique propose specific representational capacities or biases, often thought to arise through evolutionary change. In this Perspective, we argue that the evidence that supports these domain-specific theories is confounded by general information-processing differences. We argue that human uniqueness arises through genetic quantitative increases in the global capacity to process information and share it among systems such as memory, attention and learning. This change explains regularities across numerous subdomains of cognition, behavioural comparisons between species and phenomena in child development. This strict evolutionary continuity theory of human intelligence is consistent with comparative evidence about neural evolution and computational constraints of memory on the ability to represent rules, patterns and abstract generalizations. We show how these differences in the degree of information processing capacity yield differences in kind for human cognition relative to other animals. Theories of how human cognition differs from that of non-human animals often posit domain-specific advantages. In this Perspective, Cantlon and Piantadosi posit that differences in domain-general information capacity underlie uniquely human capacities.