Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Arts and Sciences



First Advisor

Dr. Craig R. Rush


Heightened attentional bias towards cocaine-related stimuli relative to neutral stimuli is a characteristic observed in cocaine-use disorders. Response time is an indirect measure of attention and research has failed to consistently demonstrate evidence of clinical relevance. Eye tracking presents a novel tool for directly measuring attentional allocation. The aim of this dissertation was to assess the sensitivity, reliability, and specificity of attentional bias through fixation and response time during the visual probe task.

In the visual probe task, substance-related and matched neutral images were presented side-by-side on a computer screen. Eye-tracking technology measured time spent fixating on each image. A probe then replaced one image and time to respond was measured. Attentional bias was defined as the difference between neutral and substance-related images for fixation time and response time. A programmatic series of experiments was conducted using the visual probe task to demonstrate the sensitivity, reliability, and specificity of attentional bias as measured by fixation time during the visual probe task.

Cocaine users displayed a robust and reliable cocaine cue attentional bias as measured by fixation time. Non-cocaine-using controls did not display a cocaine cue attentional bias. Fixation time was specific to substance use history. Individuals dependent on both cocaine and alcohol displayed an attentional bias to both substances, whereas individuals dependent on cocaine only displayed an attentional bias towards cocaine, but not alcohol. Fixation time also correlated with craving and deprivation. Cigarette cue attentional bias correlated positively with self-reported cigarette craving. Response time was a less sensitive measure of attentional bias, displayed low reliability, and did not correlate with substance use severity.

Unlike response time, eye tracking applied to the visual probe task is a sensitive, reliable, and specific measure of attentional bias in cocaine users. Importantly, fixation time during the visual probe task is sensitive to clinically relevant differences in substance abuse. This outcome is consistent with incentive motivational hypotheses, proposing that reward-paired cues obtain incentive salience. These findings provide future directions for attentional bias research, such as applying eye tracking to treatment-related outcomes.

Included in

Psychology Commons