NRSA Fellowship for Melissa Miller: Redundant Signal Effect and Alcohol Impairment of Behavioral Inhibition in ADHD and non-ADHD drinkers

Alcohol has been reliably shown to impair performance on a wide range of behaviors relevant for everyday activities. This impairment is especially pronounced in environments that require dividing attention across multiple stimuli. However, under certain circumstances, the presentation of multiple stimuli can actually facilitate performance. The “redundant signal effect” refers to the phenomenon by which individuals respond more quickly and accurately when information is presented as redundant, bimodal stimuli (e.g., visually and aurally), rather than as a single stimulus presented to either modality alone. Moreover, recent research has shown that the presence of redundant stimuli can reduce alcohol’s impairing effects on the ability to execute responses. What is not known, however, is whether the presence of redundant inhibitory signals might reduce alcohol’s impairing effects on inhibitory control. Alcohol is well-known for its “disinhibiting” effects on behavior, and studies suggest that impaired inhibition might contribute to alcohol abuse by promoting excessive, binge drinking. Therefore, it is important to determine the degree to which redundant inhibitory signals reduce the effects of alcohol on inhibitory control. Moreover, it is also important to determine the degree to which these signals might improve inhibitory control in individuals at-risk for alcohol abuse, such as those characterized by chronic deficits in the ability to inhibit behavior, such as those with attention deficit/hyperactivity disorder (ADHD). The proposed research will examine the effects of redundant inhibitory signals on inhibitory control in individuals with ADHD and a comparison group of healthy adults. Moreover, the project will determine the degree to which redundant inhibitory signals reduce the disinhibiting effects of alcohol in these two groups. Given that everyday perception is multisensory, the present study provides a unique model of drinkers’ real-world environments by assessing alcohol’s effects on inhibitory mechanisms of behavior in response to multisensory stimuli.