A recent study published in Proceedings of the National Academy of Sciences (PNAS) demonstrated that blinking acts as an information processing stage in visual perception.
Give me some background.
Blinking occurs more often than is required to maintain the corneal tear film, and is seemingly costly to perception because it interrupts the spatial information at the retina.
As a result, blinking is often assumed to be detrimental to visual processing.
I’m sensing a ‘but’ …
Yup. However, recent studies have suggested that blinking may play a more significant role in visual processing, such as:
- Eyeblinks leading to attentional benefits for object recognition after reopening the eyelids
- Eyeblinks being actively involved in the process of attentional disengagement during a cognitive behavior
Now talk about the study.
A research team from the University of Rochester performed high-resolution eye tracking on 12 volunteers and compared this data with models of blink transients and spectral analysis of visual input signals.
Translation: This allowed the researchers to understand how blinking affected what the eyes saw while open compared to when the eyelids were closed.
Findings?
Investigators found that blinking increased the power of retinal stimulation and that this effect significantly enhanced visibility, despite the time lost in exposure to the external scene.
By modulating the visual input to the retina, blinks effectively reformatted spatial information in the temporal domain.
Which led to …
This resulted in luminance signals that emphasized low-resolution information about the overall structure of the visual scene (i.e., when participants blinked, they became better at noticing big, gradually changing patterns).
Meaning…
The rapid motion of the eyelid during blinking altered the light patterns that stimulated the retina—reformatting visual information and increasing the visual input signal strength for the brain compared to when the eye was open and focused on a specific point.
Translation: Contrary to popular belief, blinks facilitate rather than disrupt visual processing—sufficiently compensating for the loss in stimulus exposure during the blink.
Anything else?
The visibility enhancement from blinking was selective for stimuli at low spatial frequencies (i.e., the general picture of a scene) and occurred during both voluntary and involuntary blinks.
Take home.
These findings suggest that, similar to eye movements, blinking acts as a step in visual processing that uses motor behavior to reformat visual information into the temporal domain.
In fact, blinking may improve visual processing and keep vision sharp by maintaining the strength of visual signals.
These results join a growing body of research that indicate visual perception is a combination of sensory input and motor activity—making vision more similar to the other senses than previously assumed.