Effects Of Spatial Distance And Memory Resolution On Visual Working Memory Consolidation

Individuals need to timely translate externally unstable visual information to internally stable visual working memory representation(VWM),to complete various kinds of high-order cognitive process in a complex environment.And the coding process which translating the representations of sensory perception to the representations of VWM is called VWM consolidation.The focus of the previous studies is generally on exploring the basic characteristics of VWM consolidation,such as the time course and the processing capacity limits of VWM consolidation,and the differences of consolidation mode between different kinds of visual information.Previous studies have generally demonstrated that individuals consolidate the same kind of visual information in a constant mode.At present,however,some studies find that the VWM consolidation may not be a relatively independent and stable cognitive processing mechanism and could be affected by other environmental factors.For example,fixing the positions of the memory items could make individuals consolidate two oriented gratings in parallel.Although these researches provide new research idea and research direction to the people,there are still some additional factors in their studies,such as controlling the threshold time unsuccessfully.Hence,the researches could not fully verify that VWM consolidation is a flexible cognitive process.Due to the fact that the understanding to VWM consolidation mechanism is still in the preliminary exploration phase,it is necessary to further explore the mechanism of VWM consolidation,to explore whether it is a relatively independent and fixed encoding process or not.The present study aims to explore whether spatial distance and memory resolution could impact on the mode of VWM consolidation,by change detection paradigm,sequential-simultaneous manipulation,and controlling the spatial distance between the memory items and controlling the similarity between memory items and probe items.The present study is composed of 4 experiments.Experiment 1 briefly presents two color patches(targets)sequentially or simultaneously within one of three levels of spatial distance(4.6°,8.5° and 11.1°).The results show that no difference is found between sequential and simultaneous presentations in 4.6° and 8.5° spatial distance conditions,while the performance for sequential presentation is better than simultaneous presentation in 11.1° spatial distance condition.These results suggest that the VWM consolidation significantly suffers the impact of spatial distance.In Experiment 2,in order to verify the reliability of the Experiment 1,presents a color target firstly and then two masked color patches appear.As a result,no difference is found in the three given spatial distance conditions,eliminating the possibility that perceptual encoding led to the results in Experiment 1.Experiment 3 replaces the experimental material with oriented gratings to explore whether consolidation for other kinds of visual information also could be affected by spatial distance.We find that the performance for sequential presentation is better than simultaneous presentation in all of three spatial distance conditions,but the performance for parallel presentation is better than the accuracy' in 4.6° spatial distance condition.The results suggest that parallel consolidation of oriented gratings into WVM is possible in this condition.Experiment 4,on the basis of the Experimental 1,investigates whether memory resolution has impact on the consolidation mode by increasing the color similarity between memory item and probe item.The results show that the performance for sequential presentation is better than simultaneous presentation in the three given spatial distance conditions.By four experiments,the present study confirms effects of spatial distance and memory resolution on visual working memory consolidation,revealing that the performance in simultaneous presentation will decrease with the increasing of spatial distance and memory resolution.According to the results,we speculate that the mode and the capacity limitation of VWM consolidation are not constant,individuals could consolidate the same kind of visual information into VWM both in sequential or limited-capacity parallel mode.And the mode of VWM consolidation might be related to the distribution of the visual spatial attention and the resources of attention which visual information could get.