Several lines of evidence suggest that forms of impulsivity are related to initiation of drinking in humans. Dougherty, Mathias, Tester, & Marsh (2004) used behavioral measures of impulsivity to compare social drinking women who reported early or late onset of drinking. The women were compared using the Immediate (IMT) and Delayed Memory Tasks (DMT), which are considered measures of response inhibition and passive avoidance. Women who reported early onset of drinking made more errors of commission on these tasks compared with the late-onset group. Across the sample, age at first drink was significantly negatively correlated with DMT commission errors. These results support the idea that this form of poor behavioral inhibition is associated with early onset alcohol use, even among non-problem social drinkers. Another study examined delay discounting in social drinking college students in relation to age of first alcohol use (Kollins, 2003). Students who reported earlier alcohol use also discounted delayed, hypothetical rewards more steeply than students who initiated drinking at a later age. Both of these studies suggest that more impulsive individuals, assessed by two different indices of
