Jensen's chronometric research: Neither simple nor sufficient but a good place to start

Abstract Jensen's chronometric research is an outstanding accomplishment that serves as a starting point for research into the many questions that his work has raised. His investigations of the Galtonian notion, that performance on elementary cognitive tasks (ECTs) assessing speed of information processing has significant explanatory value for broad general intelligence, have rekindled research interests in this field world-wide, after almost a century during which the idea was moribund. Two decades after Jensen began his research it is now clear that there is a reliable, moderately strong correlation between various composite reaction time (RT) variables and IQ tests, particularly those generally thought to measure fluid abilities, like Raven's Progressive matrices. Whether Jensen's version of Galton's hypothesis is true or not still remains to be settled. Powerful arguments against the reification of broad general intelligence as basic speed of information processing are that Jensen's RT task does not simply tap fundamental processes; that a number of independent kinds of speed have been identified; and that these speed factors contribute only some part, along with a number of broad, relatively orthogonal abilities, towards variance in general psychometric intelligence. However, this climate of healthy scientific debate is largely due to Jensen's initiative.