Blur detection is unaffected by cognitive load

• Published in: Visual cognition Vol. 22; no. 3-4; pp. 522 - 547
• Main Authors: Loschky, Lester C., Ringer, Ryan V., Johnson, Aaron P., Larson, Adam M., Neider, Mark, Kramer, Arthur F.
• Format: Journal Article
• Language: English
• Published: Hove Routledge 01.03.2014; Psychology Press; Taylor & Francis
• Subjects: Activity levels. Psychomotricity; attention; Biological and medical sciences; blur detection; cognitive load; eye movements; Fundamental and applied biological sciences. Psychology; Perception; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; retinal eccentricity; Vigilance. Attention. Sleep; Vision; Human; blur detection; Eccentricity; retinal eccentricity; Cognition; eye movements; Experimental study; Mental load; Blurred image; Eye movement; Eye; Visual system; cognitive load; Vision; Perception; attention; Visual attention
• ISSN: 1350-6285; 1464-0716
• DOI: 10.1080/13506285.2014.884203

Blur detection is affected by retinal eccentricity, but is it also affected by attentional resources? Research showing effects of selective attention on acuity and contrast sensitivity suggests that allocating attention should increase blur detection. However, research showing that blur affects selection of saccade targets suggests that blur detection may be pre-attentive. To investigate this question, we carried out experiments in which viewers detected blur in real-world scenes under varying levels of cognitive load manipulated by the N-back task. We used adaptive threshold estimation to measure blur detection thresholds at 0°, 3°, 6°, and 9° eccentricity. Participants carried out blur detection as a single task, a single task with to-be-ignored letters, or an N-back task with four levels of cognitive load (0, 1, 2, or 3-back). In Experiment 1, blur was presented gaze-contingently for occasional single eye fixations while participants viewed scenes in preparation for an easy picture recognition memory task, and the N-back stimuli were presented auditorily. The results for three participants showed a large effect of retinal eccentricity on blur thresholds, significant effects of N-back level on N-back performance, scene recognition memory, and gaze dispersion, but no effect of N-back level on blur thresholds. In Experiment 2, we replicated Experiment 1 but presented the images tachistoscopically for 200 ms (half with, half without blur), to determine whether gaze-contingent blur presentation in Experiment 1 had produced attentional capture by blur onset during a fixation, thus eliminating any effect of cognitive load on blur detection. The results with three new participants replicated those of Experiment 1, indicating that the use of gaze-contingent blur presentation could not explain the lack of effect of cognitive load on blur detection. Thus, apparently blur detection in real-world scene images is unaffected by attentional resources, as manipulated by the cognitive load produced by the N-back task.