Abstract
Purpose: To address the controversy surrounding the organizational principle of Visual Working Memory (VWM) by critically testing object- versus location-based organization. Background: Many recent studies have claimed that VWM is ‘object-based’; that is, that it takes no more effort for a person to remember, for instance, the color, size and shape of an object than it does to just remember any single feature. However, in nearly all of these studies each object occupied a unique location. It is possible then that VWM may actually be ‘location-based’. Method: We distinguished between these two possibilities by asking observers to make judgments about two objects in one location. In the 500 msec memory phase, observers viewed two spatially superimposed Gabors, which were sufficiently different so as to segment into two objects (Blaser, et al., 2000). After a 900 msec blank delay, the two objects reappeared. Independently, the color and/or orientation of one or both of the objects potentially changed to a new value. We required observers to make same-different judgments on both dimensions; either both with respect to one of the superimposed objects (‘within’ condition) or one judgment about one object and the second about the other object (‘between’ condition). If VWM is object-based, performance in the within condition should be superior to performance in the between condition. Results: Data collection is ongoing, but results thus far are suggestive: there is no significant difference between performance in the within and between conditions, supporting location-based organization.