How the Curious Mind Uses Free-Viewing Eye Movements to Maximize Scene Understanding

What humans look at and do when freely viewing a scene is not well understood. We show that free-viewing fixations resemble those of observers describing scenes but differ from those of observers counting or searching for objects. Fixations are more often directed toward people and objects whose removal most alters scene interpretation, rather than toward the most salient or meaningfully judged regions (meaning maps), or objects perceived to be grasped or gazed at. Small image changes that modify scene understanding—but not salience or meaning maps—alter fixation patterns. By instructing observers to describe scenes while fixating on objects either relevant or irrelevant to scene understanding, we demonstrate that free-viewing eye movements are functionally important for accurate scene comprehension. Thus, an important default task during free viewing for the human brain is to comprehend scenes, reflected by frequent eye movements toward people and objects that maximize accurate scene understanding.