The role of clarity and blur in guiding visual attention in photographs.

Visual artists and photographers believe that a viewer's gaze can be guided by selective use of image clarity and blur, but there is little systematic research. In this study, participants performed several eye-tracking tasks with the same naturalistic photographs, including recognition memory for the entire photo, as well as recognition memory and personality ratings for individual people in the photos (Experiments 1-3). The results showed that fixations occurred more rapidly and frequently to a local region of clarity than to a comparable blurred region in all tasks, independent of the content of the photo in the local region, and even under instructions to look equally at both regions. However, this bias was reversed when the content of the photos was no longer task-relevant. In Experiment 4, participants located target regions defined by either clarity or blur. Fixations and manual responses were faster for blurred than for sharp targets. These findings imply that the saliency of both image clarity and image blur depends on viewers' goals. Focusing on photo content prioritizes regions of clarity whereas focusing on photo quality prioritizes attention to regions of blur.