Abstract
What role do scene category expectations play in scene gist recognition? Research has shown viewers accurately identify the gist of briefly flashed scenes presented in randomized sequences suggesting it involves purely feed-forward mechanisms. We investigated if sequential expectations for scenes could influence their gist recognition. We created spatial narrative sequences of images linked along spatio-temporal routes from starting points to destinations (e.g., office, hallway, stairwell, sidewalk, parking lot). 10 scene images from each narrative were presented in an RSVP sequence, with 9 of the 10 images given 300 ms of processing time. The target image was presented for 24 ms simultaneously with an attentional alerting tone and followed by a 48 ms 1/f noise mask. Following presentation of the target and mask, the participant selected the target category from an 8-AFC array of scene category labels. Temporal position of target images within each 10 image sequence was equated and counter-balanced so participants could not guess when the target image would appear. To reduce predictability, we showed 1-3 image subsequences from each category within each narrative so targets were preceded by 0, 1, or 2 images of the same semantic category (e.g., 0, 1, or 2 offices preceded a target office). Scenes were presented in both coherent and randomized sequences to test two competing hypotheses. The "Narrative coherence" hypothesis predicted accuracy would be higher for images in coherent narrative sequences as expectations prime to-be-presented representations. Alternatively, the "Feed-forward" hypothesis predicted accuracy would not differ between coherent and randomized sequences. We found that images presented in coherent sequences were identified more accurately than targets within randomized sequences. Target images preceded by sequential exposures of the same scene category were identified more accurately than targets that were not. Further research will identify whether the facilitation is due to increased sensitivity or bias.
Meeting abstract presented at VSS 2018