Learning where to direct gaze during change detection

Abstract

Where do observers direct their attention in complex scenes? Previous work on the cognitive control of fixation patterns in natural environments suggests that subjects must learn where to direct attention and gaze. We examined this question in the context of a change blindness paradigm, where some objects were more likely to undergo a change in orientation than others. The experiments revealed that observers are capable of learning the frequency with which objects undergo a change, and that this learning is manifested in the distribution of gaze among objects in the scene, as well as in the reaction time for detecting visual changes, and the frequency of localizing changing objects. However, observers were much less sensitive to the conditional probability of a second feature, border color, predicting a change in orientation. We conclude that striking demonstrations of change blindness may reflect not only the constraints of attention and working memory, but also what observers have learnt about what information to attend and select for storage during the task of change detection. Such exploitation of the frequency of change suggests that gaze allocation is sensitive to the probabilistic structure of the environment.

Learning cue validity through performance feedback

“…In the Droll et al (2007) study, observers' bias in behavior emerged despite not alerting participants to the presence of an underlying statistical structure. In the present study, subjects were informed that some cues were more likely to contain the target than others, but were not informed about the possible values or distribution of cue validity and thus had to learn this structure on their own.…”

“…Performance improvements throughout the course of a single experimental session have been shown when this structure includes the probable spatial position of a target (Geng & Behrmann, 2005), or repeated spatial configurations (Chun & Jiang, 1998), and these performance improvements may be facilitated by biases in the distribution of gaze (Peterson & Kramer, 2001;Walthew & Gilchrist, 2006). Observers are also capable of learning the probability that certain objects may undergo a change, and distribute their saccadic and perceptual decisions towards objects likely to be the target for a correct response (Droll et al, 2007).…”

“…Previous visual tasks have demonstrated learning using supervised feedback (Droll, Gigone, & Hayhoe, 2007), reinforcement (Seitz, Nanez, Holloway, Tsushima, & Watanabe, 2006), or only passive exposure (Fiser & Aslin, 2001). The learning of scene statistics may also be facilitated by visual attention, suggesting that learning scene structure is sensitive to top-down signals and attentional control (Jiang & Leung, 2005).…”

“…In the final half of the experiment, overall percent correct for perceptual decisions was nearly identical with supervised or reinforcement feedback, and both were higher than unsupervised feedback ( Figure 2B). This is important because it shows that for a visual search task, reinforcement may be sufficient for learning to transpire, and supervised learning is not always necessary (Droll et al, 2007). As exploratory actions in a new task or environment are usually rewarded only following success, and supervised learning may not be available, it is often critical that reinforcement be sufficient for learning to occur (Sprague et al, in press).…”

“…Observers also learn the probable spatial location of a target, evidenced by increased saccadic accuracy and decreased reaction times (Geng & Behrmann, 2002Walthew & Gilchrist, 2006). Learning may also include non-spatial properties of a scene, such as the probability that an object will undergo a change, and this learning is manifest in the distribution of both saccades and perceptual decisions (Droll, Gigone, & Hayhoe, 2007).…”