Influence Of Accuracy Requirement And Characteristic Quantity On Visual Working Memory Capacity Resource Allocation

As one of the key components of cognitive processing, working memory capacity limited the amount of information that can be processed simultaneously. Although the limitation of working memory capacity has been proven by numerous studies, it is the allocation mechanism of working memory capacity resources that decides the number of items that can be stored. There has been debate on this allocation mechanism, which focuses on influence of complexity on capacity, influence of the number of features on capacity and relationship between precision and capacity. In consideration of the overlap between these issues, the current studies try to isolate the influence of precision requirements and number of features through manipulation of simple stimuli. Diversity of mnemonic targets and number of features per item were controlled, and precision requirements were manipulated to investigate the influence of pure precision requirements on allocation of visual working memory capacity. The influence of number of features per item was also tested under different precision conditions.In Study1single-colored squares were used as mnemonic targets, and precision requirements were manipulated through sample-test similarity. With exclusion of the influence of test-phase difficulty, results of capacity estimates (K) and electrophysiological index (CDA) both indicated that increase of precision requirements did not lead to decrease of capacity, though precision of representation may be enhanced. In order to test whether these results can be applied to multi-feature items, bicolored squares were used in Study2. Precision requirements were manipulated through whole change and partial change, and compare of single-colored squares and bicolored squares were designed to test the effect of the number of features. The results showed that allocation of capacity for multi-feature items will not be affected by precision requirements as well, and resources which regulate precision may be increased. However, increase of the number of features led to more consumption of capacity resources, but not necessarily more consumption of control resources.In conclusion, the current studies shows that increased precision requirements will not lead to decrease of capacity either to single-feature or multi-feature items, though precision of representation may be improved. Besides, increase of the number of features will led to more consumption of capacity resources irrelevant with precision requirements. These results are more inclined to slots+resources models of visual working memory, which assumes that independent resources decide how much items can be stored and how precise the items can be represented.