Infants' visual working memory tested with salience-mapped stimuli

University Of Massachusetts Boston, Dorchester MA

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Abstract

DESCRIPTION (provided by applicant): Visual Working Memory (VWM) underlies infants<ability to manipulate, learn from, and reason about the objects around them. The study of VWM therefore affords precious insight into object cognition and cognitive development in general. VWM is typically evaluated by the likelihood that an infant will react to a change in a to-be-remembered object;we argue that it is only legitimate to compare VWM for changes that are equally;noticeable -- or interesting -- to the infant, that is, equally salient. After all, the more salient a change, the greater the likelihood of an infant reacting to that change. To address this problem, we developed an innovative salience-mapping method that allows us to calibrate the relative salience of stimuli. We employed calibrated stimuli in what we argued was the first truly fair comparison of infants<VWM for different features and found a striking asymmetry, with better VWM for color and shape than for brightness. The broad goal of the present project is determining the origin of this asymmetry. VWM is responsible for the storage of task-relevant information, but receives information coded in an earlier memory cache: iconic memory. By the time we observe VWM responses, biases in these two stages are confounded. Applying our salience-mapping method, revised VWM tests, and a novel partial-report paradigm in the first-ever measures of infants<iconic memory, we will test for biases in the coding and storage of object features. Our salience-mapping method has applications and significance beyond memory research, in domains such as visual attention and eye movements. Since this method provides a metric by which to calibrate stimulus changes, it can equalize task difficulty, thereby allowing for a fair comparison of visual abilities between different age groups and typically versus atypically developing populations. PUBLIC HEALTH RELEVANCE: Visual Working Memory, and the system that supplies it with information, iconic memory, underlie infants<ability to manipulate, learn from, and reason about the objects around them. The study of the interaction of these memory systems therefore affords precious insight into object cognition and cognitive development in general. Moreover, our project innovates this field by providing a procedure for equating the difficulty of visual tasks between disparate groups of subjects, thereby allowing for a fair comparison of visual abilities between different age groups or typical versus clinical populations.