Abstract
Recent work has suggested that the presence of depth information can extend working memory performance beyond typical limitations (Qian et al., 2017). This benefit appears to be reliant on a strategy that involves the segmentation of items in the display by depth. What remains unclear are the temporal characteristics of such a benefit. The present study investigated how manipulating the retention interval in a change detection task would affect the benefit of depth. Participants viewed arrays of colored cubes and determined whether a single cube changed colors after one of four retention periods (i.e., 500 ms, 1000 ms, 2000 ms, 4000 ms). All arrays were presented as anaglyphs and varied by the number of items (2,4,6, or 8 items) and by the number of depth planes (1 or 2) in which the items appeared. In the multiple depth plane condition items were evenly distributed across depths. Consistent with previous research, all four retention intervals demonstrated benefits for multiple depth planes at set size 6 with an ~8% increase in task accuracy. Despite consistent patterns of performance across all retention intervals, overall accuracy varied. Participants in the 500 ms and 1000 ms retention intervals had remarkably similar performance (77% & 76% accuracy, respectively); those in the 2000 ms and 4000 ms retention conditions were less accurate (both with 71% accuracy). The present study coincides with previous research indicating that depth benefits manifest at higher working memory loads (i.e., 6 items). Additionally, these results indicate that depth benefits can be observed when holding items in memory briefly (e.g., 500 ms), or for more extended periods of time (e.g., 4,000 ms). Taken together our results suggest that although depth benefits vary with the number of items in an array, they are robust across a range of retention intervals.