Abstract
We have a remarkable ability to recognize a large number of scenes after viewing each only briefly. This ability is significantly reduced if visual attention is diverted to a superimposed letter search task during initial encoding of those scenes (DiMase, et al, OPAM 2003). How general is this impairment? In the present study, observers performed multiple object tracking (MOT) during initial encoding. This task served to both allow attentional load to be varied on different trials without changing the display and ensure that attention was broadly distributed across the scene. Additionally, prior experiments assessed scene memory after a substantial delay. The present study uses an additional, immediate (working memory) test. On each trial, observers were asked to track 0, 2, or 4 among 8 moving disks while 3 scene photographs were successively presented behind them. After five seconds, the disks stopped moving and observers indicated the ones they were asked to track. Working memory for the scenes was assessed by the immediate presentation of a single image, which was either one of the 3 scenes displayed during the trial or a completely new scene. Following the set of dual-task trials, long-term memory for the scenes was examined in a test consisting of half new pictures and half old pictures, one from each of the earlier dual-task trials. On the MOT task, observers performed better when tracking 2 items (72%) then when tracking 4 (95%). In the working memory test of scene recognition, performance decreased as MOT load increased (d' for track 0 = 2.27, track 2 = 1.69, track 4 =1.40). Long-term scene memory was poorer than working memory and was highly impaired for both load conditions (d' for track 2: 0.62, track 4: 0.61) compared to the zero track condition (d'= 1.09). These findings suggest that the ability to encode and recognize scenes in working memory and long-term memory is dependent on the degree to which visual attention is available during presentation.
This research was funded in part by a grant from NIH EY014193