In neo-Pavlovian personality theory，sensory thresholds represent one means for operationalizing "sensitivity" of the nervous system or the minimum stimulus intensity required to produce cortical excitability. According to western theorists's interpretation (Eysenck，H.J,Gray,J.A.,)，this strength sensitivity
dimension means extraversion-introversion dimension. In the present study，subjects were selected on the basis of the Maudsley Personality Inventory，and categorized
as extraverted (Escore= 43.8，SD= 2.1,)，introverted (E= 16.8，SD=3.8，).
Simple reaction time method was employed，using 2 intensities of sound stimulus (500Hz)，40dB and 80dB.
Generally，extraverts were observed to have faster reaction time than introverts，but there were no significant differences between extraverts and introverts.