Blur Detection is Unaffected by Cognitive Load.
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 theN-back task. We used adaptive threshold estimation to measure blur detection thresholds at 0&deg;, 3&deg;, 6&deg;, and 9&deg; 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 theN-back stimuli were presented auditorily. The results for three participants showed a large effect of retinal eccentricity on blur thresholds, significant effects ofN-back level onN-back performance, scene recognition memory, and gaze dispersion, but no effect ofN-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 theN-back task.
Department of Psychological Sciences, Kansas State University, Manhattan, KS, USA.
Lester C
LC
Loschky
Department of Psychological Sciences, Kansas State University, Manhattan, KS, USA.
Ryan V
RV
Ringer
Department of Psychology, Concordia University, Montreal, Quebec, Canada.
Aaron P
AP
Johnson
Department of Psychology, University of Findlay, Findlay, OH, USA.
Adam M
AM
Larson
Department of Psychology, University of Central Florida, Orlando, FL, USA.
Mark
M
Neider
Department of Psychology and the Beckman Institute, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
Arthur F
AF
Kramer
attention; blur detection; cognitive load; eye movements; retinal eccentricity