It’s surprisingly difficult to introspect about your own eye movements

Eye movements have a profound influence on our conscious experience. Our vision is only high acuity at the centre, so we only see in detail those things that we shift our eyes to focus on. Also, each move of the eyes – known as a saccade – has massive consequences for visual processing in the brain because the incoming information is suppressed during the eye movement (to prevent the experience of blurring) and, on settling gaze on a new location, millions of neurons in our visual cortex must update to reflect the new slice of the visual world that they are now responsible for processing. Given all this, you'd think we'd have a good idea of where we've been pointing our eyes. In fact, as shown across three experiments published in The Quarterly Journal of Experimental Psychology, our insight into our own eye movements is virtually non-existent. 

Alasdair Clarke and his colleagues first tracked the eye movements of 32 participants as they searched for targets in detailed cartoon pictures taken from the Where's Wally books (known as Where's Waldo in the US). After completing 28 searches, the participants were shown each of the earlier pictures but now superimposed with an eye scan path that either represented their own eye movements across the picture or someone else's. Their task was to say if the scan path was their own or not. The participants found this extremely difficult, especially when comparing a memory of their own scan path with one belonging to someone who had been looking for the same target that they'd looked for themselves.

Success at this last challenge required remembering one's own eye movements for up to ten minutes. To make things easier, the researchers tracked the eye movements of dozens more participants as they looked briefly at photographs, such as a park scene, or a bedroom. Straight after each picture, the participants had to say which objects they remembered from the scene, and then they answered questions about which objects they had looked at directly in the scene.

The participants' answers suggested that they had no insight into where they had directed their gaze. If they could name an object, they generally assumed they had looked directly at it, even if they hadn't. Conversely, if they had looked at an object but hadn't named it, then the participants nearly always failed to answer correctly when asked if they had looked at that object.

The final experiment provides perhaps the most striking demonstration of our lack of insight into our eye movements. The participants' eyes were recorded as they glanced from the centre of a computer screen to successive targets that appeared in the periphery. Sometimes these targets jumped towards or away from the centre, forcing the participant to perform a corrective eye movement. Straight after glancing at each target, the participants were shown an animation that either depicted the timing and location of their eye movement(s) to the target or someone else's. The participants showed virtually no ability to distinguish their own eye movements from someone else's, even in those cases where, for example, they had made a corrective eye movement in response to the target's changed position but the animation showed no such correction, or vice versa.

We know our brains have insight at some level into our eye movements – for example, there's a phenomenon known as "inhibition of return" which is our tendency when scanning a visual scene to spend less time returning our gaze to parts of the scene that we've already focused on. But while there is information in our brains about where our eyes have been, these new experiments suggest our conscious selves are almost entirely incapable of accessing it.

"Eye movements play a pivotal role in how we view and perceive our environment by determining our primary visual input, as shaped by the strategies we deploy to search and extract information," the researchers said. "These processes rely on information that appears to be accessed by our visual, attentional and motor systems, but is unavailable to us consciously."

Of course, much of what our brains do is beyond conscious access. What seems especially remarkable in this case is that we are largely incapable of introspecting about a form of movement that we make many tens of thousands of times per day, and which has such profound consequences for our conscious experience of the world.

Further reading

—People are unable to recognize or report on their own eye movements