Abstract
Visual search is one of the most common behaviors in daily life. Studies of visual search, however, mainly focus on how physical properties of stimuli affect search efficiency. The current study examined the effects of immediate auditory feedback for each selection during a multiple-target visual search task. Each search display contained 32 Gabor patches, two to five of which were designated as search targets by their specific tilt angle. The subjects' task was to press a key whenever they found a target, and they heard a sound immediately after each key press. In the feedback condition, one of two different sounds was played, indicating whether the subject had reported a correct detection, i.e., was fixating a target. In the no-feedback condition, subjects always received a neutral sound, regardless of whether they had visually selected a target or a distractor. A trial was finished when subjects pressed another key to indicate that they had found all targets. We analyzed overall performance measures such as trial duration and the proportions of correct target detections and correctly completed trials. Furthermore, we analyzed pupil size as a measure of cognitive effort. Additional analyses compared pupil size and basic eye-movement variables such as fixation duration and saccade amplitude between the experimental conditions and across different types of gaze transitions. The results show that pupil dilation and search accuracy were greater when subjects were given feedback than when they only received a neutral sound. The time to complete a trial, on the other hand, was longer in the feedback condition, even though subjects detected the next target faster after receiving positive feedback as compared to a neutral sound. In summary, the present study demonstrates that immediate feedback increases cognitive effort, leading to more accurate but overall slower search, with enhancement of specific components of search behavior.
Meeting abstract presented at VSS 2014