Name: Cody A. Mashburn

Ph.D. Dissertation Defense Meeting

Date: Thursday, July 18th, 2024

Time: 3:00pm EST

Location: https://gatech.zoom.us/j/95844708582

Dissertation Chair/Advisor:

Dr. Randall Engle—School of Psychology, Georgia Institute of Technology

Dissertation Committee Members:

Dr. Rick Thomas—School of Psychology, Georgia Institute of Technology

Dr. Mark Wheeler—School of Psychology, Georgia Institute of Technology

Dr. Scott Moffat—School of Psychology, Georgia Institute of Technology

Dr. Andrew Conway—Department of Psychology, New Mexico State University

Title: Explaining individual differences in the rate of focusing attention: Dissociating attention control from drift rates

Abstract: The top-down control of attention and the speed of information processing are two competing explanations of individual differences in higher-order cognitive abilities, such as working memory capacity and fluid intelligence. However, the relationship between attention control and processing speed remains unclear. While some studies show that the two constructs are related but distinct (e.g., Burgoyne et al., 2023), others contend that the two constructs are virtually indistinguishable (Löffler et al., 2024). The present study adds to this discussion by comparing attention control and processing speed as measured by drift rates from the Ratcliff (1978) drift-diffusion model for predicting working memory capacity, fluid intelligence, and selective attention dynamics in two flanker tasks. Results indicate that individual differences in attention control and drift rates are statistically distinct. Additionally, only individual differences in attention control uniquely predicts individual differences in working memory capacity and fluid intelligence. Finally, attention control and drift rates are sensitive to different processing stages underlying flanker performance, with attention control being more strongly related to the rate of selectively focusing attention and drift rate being more strongly related to perceptual decision making. These results affirm that attention control tasks measure processes related to the focusing of attention that are dissociable from individual differences in differences in drift rate. They also indicate that processes related to selective attention are more broadly related to individual differences in cognitive abilities than individual differences in perceptual decision making processes.