The Maudsley Personality Inventory was given to a pool of 309 Ss from which three groups were selected along the extraversion dimension, two to represent each extreme (extravert N = 20, introvert N = 19), and an intermediate group ( N = 19). The three groups were equated for neuroticism. Ss were tested on the following measures: time-judgment, breath-holding, digit repetition, line reproduction, leg persistence, set change, kinaesthetic figural after-effect, and size constancy. Extraverts were superior in breath-holding, had a longer time span in digit repetition, showed longer leg persistence, greater variability in line reproduction, a tendency to underestimation in time judgment, but were inferior in arithmetic computation under slow set change conditions. No significant difference between extraverts and introverts was observed in the kinaesthetic figural after-effect or in size constancy.