Storing fine detailed information in visual working memory--Evidence from event-related potentials

Abstract

Visual working memory (VWM) maintains and manipulates a limited set of visual objects being actively used in visual processing. To explore whether and how the fine detailed information is stored in VWM, four experiments have been conducted while recording the contralateral delay activity (CDA), an event-related potential difference wave that reflects the information maintenance in VWM. The type of the remembered information was manipulated by adopting simple objects and complex objects as materials. We found the amplitude of CDA was modulated by object complexity: as the set size of memory array rose from 2 to 4, the amplitude of CDA stopped increasing for maintaining complex objects with detailed information, while continued increasing for storing highly discriminable simple objects. These results suggest that VWM can store the fine detailed information; however it can not store all the fine detailed information from 4 complex objects. It implies that the capacity of VWM is not only characterized by a fixed number of objects, there is at least one stage influenced by the detailed information contained in the objects. These results are further discussed within a two-stage storing model of VWM: different types of perceptual information (highly discriminable features and fine detailed features) are maintained in VWM via two distinctive mechanisms.

Neural and Behavioral Evidence for an Online Resetting Process in Visual Working Memory

“…This is true for nonvisual information as well and we suggest that resetting is not limited to VWM. Furthermore, it is possible that well documented deficits of working memory in clinical populations such as in schizophrenia (Gold et al, 2003) are actually due to a resetting problem. Interestingly, VWM deficits sometimes coincide with flexibility problems in rule switching (Fey, 1951), which could be linked to resetting, and further work is needed to clarify this possibility.…”

“…Participants memorized the shape-parts for a change-detection task (Luck and Vogel, 1997; Zhang and Luck, 2008; Gao et al, 2009). The initial integrated movement phase conveyed a strong common-fate Gestalt cue intended to create one integrated object representation in VWM (Luria and Vogel, 2014;Balaban and Luria, 2016b), forming a link between the moving shape and a single VWM representation.…”

Saccades elicit obligatory allocation of visual working memory

“…Different models have been proposed to represent VWM, such as the distributed-resource model (Bays & Husain, 2008) and the item-limit model (Cowan & Rouder, 2009;Rouder et al, 2008;Zhang & Luck, 2008; see also Gao et al, 2009;Xu & Chun, 2009). However, since the present study focused on the control and operation processes of VWM, it provides no basis for differentiations between the storage models.…”

Lifespan age differences in working memory: A two-component framework

“…Interestingly, recent evidence nevertheless points to the influence of binding processes and topdown control on the CDA. For example, CDA amplitudes reach their asymptote for complex stimuli earlier than for simple stimuli (Gao et al, 2009; see also Luria et al, 2009). The observation that the CDA varies as a function of stimulus characteristics suggests that its amplitude may be related to the efficiency of binding features into compound objects.…”

“…However, the influence of top-down control on different WM performance markers in change detection tasks raises doubts about the fixed slot model (see above). In addition, recent studies observing effects of object complexity on CDA amplitudes (Gao et al, 2009;Luria et al, 2009) challenge this view and suggest that binding processes may critically contribute to WM performance. In line with lower behavioral performance for more complex than for simple objects (Alvarez and Cavanagh, 2004;Eng et al, 2005), the CDA reached an asymptote at a load of only two items for complex items in these studies.…”