Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology


Behavioral Science



First Advisor

Charles E. Collyer


This study examined the time course of alcohol's effect on two tasks performed concurrently, and on the tradeoff between them. It was hypothesized that alcohol impairs attentional focus, as well as the accuracy and reaction time to make directional choices, and so would induce a more severe tradeoff between tasks performed concurrently.

Equipment used in the study consisted of a device used to monitor eye movements, left and right light stimuli and a breathalyzer to measure blood alcohol levels. The sample for this project consisted of 46 men and women, between the ages of 21 and 30 years old. All participants were normative drinkers, and did not have any alcohol abuse or dependence problems.

Repeated measures were used to assess alcohol effects over time. Trade-off diagrams were used to test for differences in the dual-tasks. Participants in the control condition were not expected to show any differences in reaction time or eye fixations; these results are indicative of information processing. Differences in performance in one task or both tasks were interpreted as showing that alcohol slows total information processing.

Results are based on the ascending alcohol limb; more sedating effects are known to occur on the descending alcohol limb. Trade-off results showed impairment due to alcohol on the dual tasks. However, a more severe tradeoff between the tasks under alcohol was not present. Repeated measures analysis showed that the instructional effect was always found to vary significantly with time for reaction time; however; the dose by time interaction effect was not always present. In the latter timepoints —timepoints 4 and 5— the alcohol group performed worse even with the recognition task priority.

Future work can investigate the mediation of task performance and affective response in dual task performance. Acute tolerance might have allowed the participants to perform both tasks, and the motivational instructions might have also cued their attention to one task versus the other. A future study should investigate the end of the absorption-elimination curve to assess whether these changes remain the same or change over time.



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