Category-based and location-based volitional covert attention affect memory at different timescales

Our ongoing subjective experiences, and our memories of those experiences, are shaped by our prior experiences, goals, and situational understanding. These factors influence how we allocate our attentional resources over different aspects of our ongoing experiences. These attentional shifts may happen overtly (e.g., when we change where we are looking) or covertly (e.g., without any external physical manifestation). Additionally, we may attend to what is happening at a specific spatial location (e.g., because we think something important is happening there) or we may attend to particular features irrespective of their locations (e.g., when we search for a friend's face in a crowd versus a desired item in a grocery store). We ran a covert attention experiment with two conditions that asked participants to either sustain or vary the focus of the categories and locations they were attending. Later, the participants performed a recognition memory task for attended, unattended, and novel stimuli. Participants in both conditions recognized attended stimuli more readily than unattended or novel stimuli. Participants in the "sustained attention" condition also exhibited a recognition advantage for attended-category images from the unattended location, whereas participants in the "variable attention" condition exhibited a recognition advantage for attended-location images from the unattended category. Our findings suggest that covert attention enhances memory encoding of attended stimuli, and that different aspects of partial attention affect memory encoding over different timescales.