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Abstract:
Several studies have demonstrated that the capacity of visual
working memory (VWM) is limited to approximately four objects.
Further studies have indicated that the process of encoding items
into VWM is quite slow relative to the speed of perception. In the
present study, we examined this VWM consolidation process by
presenting subjects with target arrays containing a variable number
of colored squares and then presenting an array of pattern masks
after a variable delay interval. The masks were intended to disrupt
VWM encoding, and the timing parameters were adjusted so that the
initial identification of the colored squares was not impaired by
the masks. Memory for the arrays was tested after a brief delay by
presenting either a repeat of the target array or an array that
differed from the target array in the color of a single object;
subjects then provided a same/different response. Accuracy on this
memory task varied according to both the number of items in the
array and the stimulus-to-mask interval: arrays with fewer items
appeared to be encoded into VWM more quickly than arrays with
several items. In addition, the physical similarity between the
stimulus and mask greatly influenced the effectiveness of the mask.
These results suggest that a consolidation process is necessary for
information to be stored in a durable form in VWM and that this
consolidation process appears to be limited in capacity such that
larger numbers of objects require greater amounts of encoding
time.
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