Visual Search Versus Memory in a Paired Associate Task

The Digit Symbol Substitution Test (DSST) has been used to study various effects, like aging and fatigue. Multiple cognitive and perceptual processes, like associative memory and visual search, are prominently utilized in the DSST. Understanding how these processes contribute to execution of tasks like the DSST is important to human factors research, as moderators like age and fatigue may differentially affect these processes. This study investigates performance on variants of the DSST that emphasize either visual search or associative memory with experimentation and computational cognitive modeling. While there are similarities in performance across task variants, the observed data suggests that, when visual search is possible, people appear to not utilize memory to the extent they would if relying on memory alone. The modeling suggests that behavior differences in the DSST variants results partly from procedural (i.e. strategic) choices and partly from the demands of the tasks.