Poster F122, Tuesday, March 27, 8:00-10:00 am, Exhibit Hall C
Impact of Working Memory Load and Stimulus Movement on Non-symbolic Number Perception
Justin Bonny1; 1Morgan State University
Models of non-symbolic number perception, the ability to estimate the number of objects in a set (e.g., about how many students are in a classroom) without counting, suggest the process of forming a numerical representation is relatively independent of working memory. However, research studies have predominantly used static, stationary images when assessing number perception. With evidence that working memory can be recruited during the visual processing of moving scenes, it remains to be determined whether it is involved in the perception of number of dynamic, moving, objects. In the present study, modified verbal and spatial operation span tasks that simultaneously required approximate number judgments were used to assess the degree to which working memory load and stimulus movement influenced non-symbolic number judgment performance. Across participants, two approximate number arrays were either static, moving with all elements in view, or, moving with elements briefly within view (e.g., moving behind a window) while the numerical ratio difference varied. Psychophysical models revealed the slopes of response curves, plotted as a function of number ratio, were influenced by working memory and movement type. The results indicate that the precision of approximate number representations was influenced by stimulus movement and having to concurrently maintain and recall specific types of information. This suggests that working memory may be involved in the perception of number in moving, but not stationary, stimuli. This raises questions regarding how models of number perception can account for differences in representational precision when stimuli are static versus dynamic.
Topic Area: PERCEPTION & ACTION: Vision