An Exploration of Failures in Visual Working Memory: A Steady-State Visual Evoked Potential Study
Peacock, Candace 2016 Exploration of Failures in Visual Working Memory - A Steady-State Visual Evoked Potential Study.pdf
AuthorPeacock, Candace E.
AdvisorBerryhill, Marian E.
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Working memory consists of three stages: encoding, maintenance, and retrieval. It has been demonstrated that working memory (WM) capacity is limited to about four items (Cowan 2001). However, there are ambiguities regarding why some items are correctly retrieved and why others are subsequently lost. Previous studies have not been able to demonstrate at which stage these items are lost because these studies only measure the processing of all items shown in a memory array. This investigation employs a novel paradigm pairing frequency tagging and a full report paradigm. This paradigm allowed us to disentangle individual items that were encoded and compare these items to the items that were actually retrieved. Two attentional models were tested in regards to encoding: the ‘graded attention’ model and the ‘all or nothing’ model. These two models describe how neural resources are allocated to items in a memory array. This study found that frequency tag amplitudes were larger for items correctly retrieved as compared to items subsequently forgotten. The data were also found to be consistent with the ‘all or nothing’ attentional model that states that attentional resources are spread to all items during encoding. The results indicate how important WM encoding is to explaining underlying mechanisms for why WM fails.