An Assessment of Spatial Context on Eye Movement During a Visual Search Task

Abstract

Contextual cueing is the implicit association of objects (or ‘cues’) in a visual scene due to repeated exposure, either spatially or semantically. These associations can aid people in detecting a specific target. The goal of this study was to investigate whether, and how, people utilize “distractors” as contextual cues during a visual target search and how spatial location of objects affects that association. Forty undergraduate participants performed a luggage-screening task in which spatial context was manipulated. First, participants were trained using 25 luggage images, each of which contained a target (i.e., knife) and a specific distractor (i.e., iPod). During the post-training session, participants screened 100 bags with a target base rate set at 50%. The bags contained either the distractor and the target (25 bags), the target only (25 bags), the distractor only (25 bags), or neither the distractor nor the target (25 bags). Participants’ fixation durations, dwell times, saccade counts, and scan paths were assessed. It was found that when the spatial context of the distractor and target were relatively close, participants appeared to encode the objects together, thereby improving search efficiency. By moving the distractor across the image from the target, eye movement patterns changed. The results suggest a higher activation threshold of the distractor when it was present adjacent to the target as compared to when it was moved farther away.