According to some theorists (e.g. Anderson 2001), information processing speed forms the basis of individual differences in IQ.
My understanding is that information processing time (as measured by reaction time) is pretty standard across humans, and pretty close the physical limits of neurons.
It is true that reaction time correlates with IQ, but that is a bit misleading. Average reaction time correlates with IQ, but every person’s best case reaction time is about the same. It seems that the the correlation with between average RT and IQ is mediated by better vigilance. That is, people with higher IQs are able to score better on RT tasks because they are able to maintain their attention on the task (and therefore maintain an RT closer to their best), for longer periods.
My understanding is that information processing time (as measured by reaction time) is pretty standard across humans, and pretty close the physical limits of neurons.
It is true that reaction time correlates with IQ, but that is a bit misleading. Average reaction time correlates with IQ, but every person’s best case reaction time is about the same. It seems that the the correlation with between average RT and IQ is mediated by better vigilance. That is, people with higher IQs are able to score better on RT tasks because they are able to maintain their attention on the task (and therefore maintain an RT closer to their best), for longer periods.
My citation is chapter 3 (?) of this textbook.