Cognitive function, P3a/P3b brain potentials, and cortical thickness in aging.
Research into the biological bases of human intelligence differences is surveyed. Work on brain event-related potentials (ERPs) suggests that people with high IQ test scores: (1) show faster responses in some test conditions; (2) have ERP waveforms that can be distinguished from those of people with lower IQs; and (3) might have less variability in their ERPs. People with higher psychometric intelligence have, on average, larger brains, and possibly faster neural conduction speed. A few small functional brain-scanning studies suggest that, in healthy individuals, people who are of higher IQ have lower cerebral metabolic rates during mentally active conditions. This has led to the speculation that brighter people have more efficient brains. Despite some well-replicated findings in the search for the 'biology of human intelligence' there is a dearth of explanatory accounts to link cognitive performance differences with variance in brain mechanisms.