The attentional boost effect facilitates visual category learning.

Increasing evidence has shown that summary visual statistics, such as the mean size or centroid of locations, can be perceived without focal attention. Here, we tested the role of attention in visual category learning - rapid learning of visual similarities among paintings of the same artist. Participants encoded paintings from two famous artists into memory while simultaneously monitoring a rapid serial visual presentation (RSVP) stream of colored squares, pressing the spacebar for target colors and making no response to distractor colors. Paintings encoded with the RSVP targets were better remembered than those encoded with the RSVP distractors, demonstrating an Attentional Boost Effect. Importantly, pairing one artist's paintings with the RSVP targets led to better visual category learning - participants were more accurate at recognizing novel paintings from this artist, relative to another artist whose paintings were presented with the RSVP distractors. Thus, visual category learning is subjected to the same constraint of attention as exemplar memory, demonstrating common mechanisms for exemplar and category learning.