Ageing and Feature Binding in Visual Short-Term Memory: The Role of Presentation Time.
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Older adults struggle to form associative memories for the relations between objects, and between object and context. They also struggle to remember what objects were in which locations. This suggests that ageing impairs the ability to bind different attributes within memory. However, evidence concerning age-differences in the ability of combining the features that make up these objects is less clear. A recent study (Brown & Brockmole, 2010) has suggested that older adults struggle to combine shape and colour in visual short-term memory when given longer to study objects. Therefore, the main aim of the current experiment was to further investigate this intriguing finding by systematically varying the amount of time given to younger and older adults to study memory objects for a change detection task. It was found that, taking differences in memory for shape and colour as individual features into account, older adults exhibited significantly poorer change detection accuracy for combinations of shape and colour, relative to younger adults, following both the shortest (200ms) and longest (2500ms) presentation times used in this study. The age-related binding deficit at the shortest presentation time was unexpected and is interpreted as demonstrating age-differences in the speed of encoding the more complex bound objects. The age-related binding deficit at the longest presentation time, however, is consistent with the previous study. This counterintuitive finding is interpreted with help from the wider literature on the role of attention in feature binding. It is proposed that older adults are less able to engage elaborative processes during longer stimulus exposures due to a decline in attentional resources.