A daytime nap reduces the attentional blink

The attentional blink (AB) is an impairment in detecting the second of two targets that appear in close temporal succession. Previous research suggests that the AB is reduced after days of practice (Maki & Padmanabhan, 1994), but not after four consecutive blocks in one session (Taatgen et al., 2009). Here we investigate the role of sleep in modulating practice-dependent changes in the AB. We used a rapid serial visual presentation (RSVP) display comprising a stream of 26 English letters presented at 12 items/s. Two of the letters were targets cued by an annulus, and the number of items between the first target (T1) and second target (T2) was varied to yield a lag of 2, 5 or 10 items. Participants reported which two letters they thought were circled, and no feedback was provided. Participants completed the task at 9am, 12pm, 3pm and 5pm for a total of four sessions in one day. At 1pm, half the participants took a polysomnographically recorded nap for 60-90min, while the other participants went about their normal day or sat in a room quietly resting. Pooling the non-napping groups, we observed a significant increase in correct T2 reporting across sessions only within the nap group, and only for lag 2. The magnitude of improvement correlated positively with proportion of light stage two sleep, and negatively with proportion of deeper slow-wave sleep. We estimated the efficacy, latency and precision of attentional selection using a mixture model that considered the serial position of non-target items mistakenly reported as T2. These analyses indicated that the improvement observed in the nap group was due to increased efficacy (probability of reporting a T2-relevant item), with no change in latency or precision. Our results suggest that sleep, particularly stage two sleep, improves temporal attention.