Abstract

Tests of simple problem-solving are widely used as measures of human intelligence, and indeed, performance in these tests is widely predictive of success in all manner of laboratory and everyday activities. Beginning from this observation, now around a century old, I address the modern cognitive neuroscience of intelligent behaviour. In human brain imaging studies, a common or multiple-demand (MD) pattern of frontal and parietal activity is associated with diverse cognitive demands, and with standard problem-solving tests. In complex behaviour, goals are achieved by assembling a series of sub-tasks, creating structured mental programs, and based on behavioural studies of problem-solving, I suggest that MD cortex plays a key role in defining and controlling the parts of such programs. In agreement, physiological studies in human and monkey brain show the activity of MD cortex in dynamic construction of cognitive or attentional episodes. By these means, I suggest, the MD system provides a critical neurophysiological basis for intelligent thought and action.