Some original findings: comments on Fillmore and Weafer.

Abstract

Fillmore and Weafer (2004) devised a modified stop-signal paradigm by adding cues predicting whether a go or no-go target will be presented, and manipulating the correctness of the information conveyed by the cues. They found that incorrect go cues preceding no-go targets resulted in more alcohol-induced failures to inhibit in men, but not in women. This is a new finding that raises many interesting questions about the factors and processes that might account for these effects. One possible answer to these questions stemmed from the evidence that subjective stimulation during rising blood alcohol concentrations (BACs) was higher in men than in women. This raised the possibility that heightened stimulation may contribute to inhibitory failures with incorrect go cues. A regression of these inhibitory failures on stimulation ratings could assist in evaluating this idea. Since greater sedation is commonly reported when BACs decline, it would also be interesting to determine whether the gender difference in these inhibitory failures abates on the declining limb of the BAC curve. The use of cues in the present research is similar to the procedure used in learning studies to investigate ‘preparatory set’ by manipulating the temporal regularity or correctness of cues for the response to be made (Mower 1940). Such work has shown that correct cues speed reaction time (RT) whereas incorrect cues slow RT. This accords with the cue effects on RT to go targets obtained in the current experiment. The slowing effect of incorrect cues on RT is thought to reflect the extra processing time needed to switch from one response and select another (Schmidt 1988). This RT switching has been used to test response flexibility under alcohol when drinkers try to inhibit a pre-potent response and make a different one (Easdon & Vogel-Sprott 2000). That research found failures to inhibit were associated with reduced flexibility. If alcohol-impaired flexibility contributes to inhibition failures with incorrect cues for no-go targets, the RT when inhibition fails may be slower following incorrect rather than correct cues. If it contributes to gender differences, this effect should be more pronounced in male than in female social drinkers. The stop-signal paradigm presents no predictive cues, and studies using the stop-signal task have shown that alcohol reliably reduces inhibitions to stop (no-go) targets (e.g. Mulvihill, Skilling & Vogel-Sprott 1997; de Wit, Crean & Richards 2000). In contrast, the present study showed that alcohol failed to affect inhibitions when cues correctly predicted a no-go target. This is a potentially important finding because it carries safety implications, suggesting that situations providing drinkers with correct cues for appropriate behavior may counteract the disinhibiting behavioral effects of alcohol. In contrast, the adverse effect of alcohol on inhibitory control may be more intense in settings that provide no cues, or incorrect ones. The cued go/no-go paradigm used by Fillmore and Weafer seems to have more ecological validity than the stop-signal paradigm because drinking situations commonly contain unreliable or ambiguous cues for appropriate behavior. Their experiment provides provocative findings that seem to parallel observations of more pronounced disinhibited, aggressive behavior in men than in women. The study also generates many interesting questions about the underlying mechanisms and factors that might account for these gender differences in inhibitory control. Additional research with the cued go/no-go task promises to add valuable insights on the puzzle of alcohol-impaired control of inhibition.