Similarity effects in visual working memory

• Published in: Psychonomic bulletin & review 2016-04, Vol.23 (2), p.476-482
• Main Authors: Jiang, Yuhong V., Lee, Hyejin J., Asaad, Anthony, Remington, Roger
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Behavioral Science and Psychology; Brief Report; Cognitive Psychology; Facial Recognition - physiology; Humans; Memory, Short-Term - physiology; Psychology; Studies; Visual task performance; Young Adult
• ISSN: 1069-9384; 1531-5320
• DOI: 10.3758/s13423-015-0905-5

Perceptual similarity is an important property of multiple stimuli. Its computation supports a wide range of cognitive functions, including reasoning, categorization, and memory recognition. It is important, therefore, to determine why previous research has found conflicting effects of inter-item similarity on visual working memory. Studies reporting a similarity advantage have used simple stimuli whose similarity varied along a featural continuum. Studies reporting a similarity disadvantage have used complex stimuli from either a single or multiple categories. To elucidate stimulus conditions for similarity effects in visual working memory, we tested memory for complex stimuli (faces) whose similarity varied along a morph continuum. Participants encoded 3 morphs generated from a single face identity in the similar condition, or 3 morphs generated from different face identities in the dissimilar condition. After a brief delay, a test face appeared at one of the encoding locations for participants to make a same/different judgment. Two experiments showed that similarity enhanced memory accuracy without changing the response criterion. These findings support previous computational models that incorporate featural variance as a component of working memory load. They delineate limitations of models that emphasize cortical resources or response decisions.