Impulsivity in adults: motor inhibition and time-interval estimation

There is a need for the development of behavioral measures of impusivity in order to elucidate the specific qualities of impulsive persons. The relationships between two behavioral measures of impulsivity and several personality inventories frequently used to assess inpulsivity were examined using 40 male Ss. The behavioral measures involved a motor-inhibition (MI) task and time-interval (TI) estimation. The personality measures included the Extraversion (E), Psychoticism (P) and Neuroticism (N) scales of the Eysenck Personality Questionnaire (EPQ), Barrat's Impulsivity Scale (BIS) and Gough's Socialization Scale (So). Significant relationships between MI scores and E, BIS and a proposed dimension of impulsivity obtained by the formation of E-P quadrants were found. In addition, performance on this task was related to So, P and E-N quadrants in the predicted directions. The consistency of these results supports the use of this task as a behavioral measure of impusivity in adults. Although personality inventory scores were not related to estimations, significant (negative) correlations were obtained between TI estimations and MI scores. The results indicate that TI estimation by itself is not an adequate measure of impulsivity, but does have implications for understanding impulsive behavior.