The relationship of behavioral inhibition to executive functions in young adults.

Barkley's hybrid model of executive functions (EFs) predicts that individuals with deficient inhibitory control should show impairment of EFs. Thirty-eight nonreferred young adults were administered tests of EFs and four laboratory measures of inhibitory control: Stop Signal (SS), Go No-Go, Competing Motor Program (CMP), and Stroop Color-Word tests. Behavioral ratings of impulsivity were collected using the Barratt Impulsivity Scale-11 (BIS-11). CMP and SS accounted for a significant proportion of variance in measures of EFs beyond that accounted for by IQ. Additionally, increased impulsivity, as measured by the BIS-11, was associated with poorer performance on some tests of EFs. These findings provide partial support for Barkley's theory in that effective executive functioning is associated with sufficient inhibitory control.