Monday, July 27, 2020

To See, Your Eyes Must Move

In order to see anything, your eyes must move around. 

Painting by Magritte
In a classic scientific study back in 1976, John K. Stevens anesthetized test subjects but kept them awake. As they sat awake with their eyes open, but unable to move them, subjects found that the images quickly faded. 

Because they were unable to move their eyes across the visual field,  they couldn't re-stimulate the retina. Without constantly changing levels of stimulation, the neurons ceased delivering signals. 

The test subjects felt a strong impulse to move their eyes, and wanted to move them. It felt to them that moving their eyes would take a huge effort, and they just couldn't do it.

Another surprising result of the study was the sensation that the visual field was displaced in the direction of the anticipated jumping eye movement (or saccade) that they intended to make. 

As author Brian Dilg put it, "They were catching their own brains trying to make sense of an image that did not shift as it normally would when the eyes move."

What generates the impulse for a saccade? Vision specialist Dr. Martin Rolfs says, "When you analyze how many of our saccades are triggered by external events, you'd probably end up with very little. A part of the scene that has high contrast will probably capture your eye movements. But as soon as you have the second or third saccade, the influence of this basic visual information in the scene will become less important. Your own interests and your own task that you have at the moment will be much more influential."

This confirms an important insight for picture-makers. The observer's eye pathway does not follow passively through the composition like a ball on a track. It is driven by the viewer's own conscious and unconscious curiosity, and the artist's job is to awaken that active participation of the viewer.
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More in the book "Why You Like This Photo" by Brian Dilg.  It's a gem of a book, designed for photographers, but full of insights about visual perception that artists can also benefit from.

3 comments:

Unknown said...

Wow! this is fascinating! I used to be a little creeped out when I talked to people who would stare straight into my eyes without blinking. I noticed with a particular friend that even while she stared intently, her pupil will move slightly and rapidly... as if vibrating. I thought that was weird, but now I understand that if her pupil had been completely still she most likely would have zoned out. or stopped seeing me altogether.

I wonder if there's a way to measure the ideal amount of novelty or detail an artwork should have in order to keep the viewer interested and yet not overwhelmed. We develop a sensitivity that works as a sort of intuition to know this (some times), but I'm still curious whether there's a scientific formula that can prove of at least explain why we lose interest faster when we look at certain pictures and why others keep us engaged longer.

Mark Martel said...

Thank you!

Fhinn said...

Thanks! I also enjoyed your previous posts about eye tracking, and the Golden Ratio myth. All those posts made me rethink compositional "rules" and freed up my compositions in painting.