Reaction time variability and intelligence: A “worst performance” analysis of individual differences

Reaction time distributions from 303 subjects were partitioned into 16 fast-to-slow latency bands. Average latencies for the 16 bands were then correlated separately with various indices of mental ability. The slowest bands (or “worst trials”) were by far the best predictors of intelligence and working memory performance. The slowest bands also drove the individual differences in variability, and the variability/intelligence correlation. An error-based production model for worst trials was tried and abandoned.