Perceptual Decisions Bias Visual Working Memory Representations

Earlier models of VWM theorized a storage structure first comprised of a fixed number of discrete slots, then later as a set number of cognitive resources that could be allocated using attention. While both account for capacity related failure, they represent memoranda as independent. Recently, interference theories of VWM argue that memoranda in VWM have certain dependencies that can lead to memory errors beyond those of capacity limits. Interference theories acknowledge unrelated information and completing cognitive tasks create vulnerabilities leading to memory errors. This dissertation examines decision making’s influence over working memory representations. In the first two studies, participants were presented with hybrid animals (Experiment 1) or blended emotional faces (Experiment 2). Participants indicated whether an animal was a member of the group they were assigned (e.g. indicate if you see a dog) or if the face was threatening. Two images were presented, one more extreme and one less extreme than the target image, and participants were required to pick which was more like the initial target image. When animals were labeled as the target category (a dog), they were significantly more likely to select the more dog-like image. Likewise, when faces were determined to be threatening, they were significantly more likely to pick a face angrier than the initial target image. Later experiments repeated the face threat decision but provided a full lineup of images in the memory recall phase (Experiment 3) and provided category information to the participant rather than let them decide (experiment 4). The memory bias remained even with participants able to select the actual target image, with emotionally ambiguous faces having the most extreme biases. Participants given category information through audio cues again demonstrated recall bias. These findings suggest that decision making, as well as category information, influences the accuracy and precision of VWM.