Alcohol Intoxications Effects on Visual Search for Single-Feature and Conjunctive-Features Targets

• Other Authors: Donohue, Keith Francis (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Psychology
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-0699

The effect of alcohol on performance during single-feature and conjunctive-features visual search tasks was examined in 18 normal, young adult participants (nine women), using a counterbalanced, within-subjects design that examined performance under intoxicated (peak blood-alcohol concentration = 0.071 gms%) and sober (no-alcohol control) conditions. Behavioral responses, including reaction times and error rates for detection of targets were examined in the study's main analyses, as were patterns of eye-movement, including saccade velocity and amplitude, number and duration of fixations, inhibition of return, and functional field of view. The results of these analyses indicated that alcohol intoxication was not associated with increased reaction times or error rates on any searches. However, alcohol intoxication was associated with decreased numbers and increased durations of fixations on trials that involve searching for conjunctive-features targets or absent targets. Alcohol intoxication was also associated with decreased fixations on distracters during conjunctive-features searches and decreased re-fixations of search elements that they had previously visited. Finally, alcohol intoxication was associated with decreased amplitudes and velocities of saccades. In sum, these findings indicated that alcohol intoxication slowed the initiation of saccades and that this effect was most pronounced on conjunctive-features searches. The results also suggested that these delays appeared to allow participants to process more parafoveal information at each fixation than they would have when sober, thus producing more efficient processing despite reduced speed. This study provided little support for alcohol-related reductions in cognitive capacity or inhibitory control suggested by the attention allocation model (Josephs and Steele, 1990) and impaired control (Fillmore, 2003) theory, respectively, as key mechanisms underlying changes in visual search while intoxicated—at least not at the dose tested in the present study. However, there was evidence of a general slowing effect of alcohol intoxication on the initiation and velocity of eye movements, as well as alteration of their amplitudes, that appeared to enable individuals to perform visual search tasks without obvious impairment by gathering more information at each fixation and consequently reducing the number of unnecessary eye movements that they made. These results are largely consistent with those of other research that has used different oculomotor tasks to examine alcohol's effects on attention (e.g., Radach, et al., 2011). Together, this work suggests that alcohol might influence attention in visual search, not by impairing top-down, controlled processes that guide eye-movements, but rather by influencing the bottom-up, automatic processes that initiate them. === A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. === Degree Awarded: Summer Semester, 2011. === Date of Defense: May 16, 2011. === Ethanol, Fixation, Saccade, Eye-Movment, Reaction Time, Attention === Includes bibliographical references. === Alan R. Lang, Professor Directing Dissertation; Leonard LaPointe, University Representative; Michael Kaschak, Committee Member; Ralph Radach, Committee Member; Jeanette Taylor, Committee Member.