Visual Search for Transparent Overlapping Objects in Depth: Overlap Impairs Performance, but Depth does not benefit Performance

摘要

During everyday visual search tasks, such as searching for keys in a cluttered room, it is commonplace for objects to overlap one another and occur at different levels of depth. This situation stands in contrast to standard search tasks in which objects are presented on a single depth plane and do not overlap with one another. We previously examined how overlap and depth influence search performance by asking participants to search displays containing overlapping opaque polygons presented on different depth planes to one another. We found that overlap impaired search performance (increased RTs, decreased accuracy), and the presence of depth in the highly-overlapping displays decreased RTs. Here, we extend this previous work to examine search in displays containing transparent overlapping coloured polygons, again assessing whether the presence of depth aids performance, and whether overlap impairs performance. In such displays, overlap results in combinations of colours that alter the colour (but not the shape) of objects. We found that, with transparent displays, response accuracy was high a?? higher than our previous study where participants searched overlapping opaque objects. However, this increase in accuracy came at the cost of increased RTs. Finally, the presence of depth information in the displays had no effect on accuracy or speed. Overall, in displays containing opaque objects, response accuracy is negatively affected by overlap because the opaque nature of the objects removes information regarding object identities. However, in displays containing transparent objects, accuracy is negatively affected by overlap to a lesser extent, while response times are negatively affected to a greater extent. This is because information regarding object identity is available in transparent displays, but it requires more time to disambiguate each objecta??s identity from that of other objects. The delay occurs because the transparency of overlapping objects changes and obfuscates the colour of the objects.