Developmental cognitive psychology is facing a recognition that complex, domain-specific cognitive skills and traits — including social cognition — emerge via interactive specialisation from simpler, more domain-general processes. Echoes of this developmental emergence can be glimpsed in the mature mind and brain in the form of correlated individual differences in non-social and social cognitive traits, and in associated neurophysiology: In Experiment 1, subjects responded to a conjunction of spatial position, orientation and colour features embedded in a field of congruent (easy) or incongruent (difficult) distractors. Event-related fMRI time series were extracted from bilateral middle frontal gyri, and congruent was subtracted from incongruent. Prolonged latencies in the resulting fMRI difference time series in left (p=0.0160) and right (p<0.0001) prefrontal cortices were associated with individual scores on the Autism Spectrum Quotient. In Experiment 2 subjects played a computer game incorporating a go/no-go task; P3 ERP amplitude in response to the no-go stimulus correlated negatively (r=-0.80, p<0.05) with scores on the ‘Reading the Mind in the Eyes’ test of facial emotion perception. Experiment 3 was a vigilance paradigm in which subjects responded as quickly as possible to all instances of a task-relevant stimulus whilst ignoring distractors; data indicate a prolonged positive ERP slow-wave response to distractors in a group of high scorers on the Autism Spectrum Quotient. In all three paradigms, then, efficiency of neurophysiological response to task-relevant versus distracting or task-irrelevant stimuli was associated with individual differences in social cognitive skills, perhaps reflecting the genesis of social cognition in domain-general cognitive control.