Abstract
Judgments of multiple simultaneously presented stimuli can produce a variety of divided attention effects. For example, participants can detect colors in two locations as well as in one, but can recognize only one masked word at a time (White, Palmer, & Boynton, Psych Science 2018). Recent work has revealed a divided attention effect for the categorization of two simultaneously presented objects (Popovkina, Palmer, Moore, & Boynton, JoV 2021). In that study, participants saw two nameable objects followed by a mask. They were asked to judge the semantic category of one of the objects (single-task condition) or both of the objects (dual-task condition). The difference in performance (dual-task deficit) approached the large deficit expected for serial processing of only one object per trial. We asked whether this dual-task deficit can be attributed to processing the semantic meaning. If semantic processing produces the dual-task deficit, then a task with abstract objects should produce no such deficit. Alternatively, if some aspect of visual processing produces the dual-task deficit, then abstract objects should also produce the deficit. In particular, we considered the hypothesis that processing multiple interchangeable parts within an object (e.g. letters in a word) might produce the dual-task deficit. The stimulus set consisted of 210 photos of objects constructed from 3 of 7 possible parts (Duplo blocks). Participants performed a probe recognition task with single- and dual-task conditions. The task was to recognize the presented objects, and distractors consisted of objects with the same parts in a different arrangement. Preliminary results show a large dual-task deficit for judging two abstract multipart objects. These results suggest that the divided attention effect associated with multiple objects is not restricted to tasks requiring semantic processing. It is also found for tasks requiring processing of objects with multiple interchangeable parts.