The Attentional Boost Effect: Transient increases in attention to one task enhance performance in a second task

Abstract

Recent work on event perception suggests that perceptual processing increases when events change. An important question is how such changes influence the way other information is processed, particularly during dual-task performance. In this study, participants monitored a long series of distractor items for an occasional target as they simultaneously encoded unrelated background scenes. The appearance of an occasional target could have two opposite effects on the secondary task: It could draw attention away from the second task, or, as a change in the ongoing event, it could improve secondary task performance. Results were consistent with the second possibility. Memory for scenes presented simultaneously with the targets was better than memory for scenes that preceded or followed the targets. This effect was observed when the primary detection task involved visual feature oddball detection, auditory oddball detection, and visual color-shape conjunction detection. It was eliminated when the detection task was omitted, and when it required an arbitrary response mapping. The appearance of occasional, task-relevant events appears to trigger a temporal orienting response that facilitates processing of concurrently attended information (Attentional Boost Effect).

Figure 1

Dual-task encoding design. (a) In the first part of the experiment participants were shown a long sequence of scenes and asked to memorize the scenes for a later memory test. They were also told to monitor a square that was briefly presented in the center of the scene and to press the spacebar when it was white instead of black (Experiments 1a & 1b). (b) Scenes were presented at fixed serial position relative to the target. (c) An example of the recognition memory test: Participants picked the image that was exactly the same as what they saw earlier.

Figure 2

Proportion of correctly recognized scenes in Experiments 1a (N=12; scenes lasted for 500ms each) and 1b (N=8; scenes lasted for 100ms and followed by a 400ms blank) as a function of the scene’s serial position relative to the target during encoding. Error bars represent ±1 S.E. of the mean.

Figure 3

Scene identity memory accuracy in Experiment 2 as a function of the scene’s serial position during encoding. Error bars represent ±1 S.E. of the mean.

Figure 4

Scene identity memory as a function of the serial position of the scene during single-task encoding in Experiment 3 and during dual-task encoding in Experiment 1a (replotted from Figure 2 to facilitate comparison). Serial positions are relative to the feature-oddball white square (WS or W). Error bars represent ±1 S.E. of the mean.

Figure 5

Scene identity memory accuracy in Experiment 4 as a function of the serial position of the scene during encoding. Error bars represent ±1 S.E. of the mean.

Figure 6

Scene identity memory accuracy in Experiment 5 as a function of the serial position of the scene during encoding. Error bars represent ±1 S.E. of the mean.