Discrimination of speed in 5-year-olds and adults: are children up to speed?

We compared thresholds for discriminating changes in speed by 5-year-olds and adults for two reference speeds: 1.5 and 6 degrees s(-1). Both adults and 5-year-olds were more sensitive to changes from the faster than from the slower reference speed. Five-year-olds were less sensitive than adults at both reference speeds but significantly more immature at the slower (1.5 degrees s(-1)) than at the faster (6 degrees s(-1)) reference speed. The findings suggest that the mechanisms underlying speed discrimination are immature in 5-year-olds, especially those that process slower speeds.