UC Santa Barbara

Much of what we know about visual working memory has been uncovered using simple stimuli such as colored squares, but recent studies have suggested that alternative conclusions can be drawn using more complex stimuli, such as real-world objects. A possible explanation as to why these differences exist is that objects are redundantly coded broadly across several brain regions, whereas simple stimuli like colored squares are encoded in a more limited set of regions. We hypothesize that spatial position is enhanced automatically by this redundant encoding. In our experiment, participants (N=30) were given a delayed spatial recall task in which participants remembered arrays of either real world objects or colored squares. Participants maintained the precise spatial position of 1, 2, or 6 visual stimuli over a brief 1.5s delay period. We found that participants recalled spatial positions of objects with higher precision than the colored squares. Moreover, in separate trials where participants discriminated which of two stimuli appeared at a probed location, performance was identical between stimulus conditions. Altogether, this result supports the notion that incidental features of real-world objects, such as their spatial position, can be remembered with greater precision than those of simplistic stimuli typically used in laboratory tests.