Our pupils adjust as we imagine bright and dark scenes

December 3, 2013
eye

Conjuring up a visual image in the mind—like a sunny day or a night sky—has a corresponding effect on the size of our pupils, as if we were actually seeing the image, according to new research.

These findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that the size of our is not simply a mechanistic response, but one that also adjusts to a subjective sense of brightness.

"Visual imagery is a private and subjective experience which is not accompanied by strongly felt or visible physiological changes," explains psychological scientist and lead researcher Bruno Laeng of the University of Oslo. "It is a particularly difficult topic to research, as years of controversy about the nature of mental imagery testifies."

Along with co-author Unni Sulutvedt, also from the University of Oslo, Laeng conducted a series of experiments to see whether they could tap into subjective mental imagery by monitoring pupillary size with an eye-tracking device.

Initially, participants were asked to look at a screen while triangles of different levels of brightness appeared. When they were later asked to actively imagine those triangles, the participants' pupils varied in size according to the triangle's original brightness. When imagining brighter triangles, their pupils were smaller. But when imagining darker triangles, their pupils were larger.

In a series of additional experiments, the researchers found that participants' pupils also changed in diameter when imagining a sunny sky, a dark room, or a face in the sun compared with a face in the shade, as if in preparation for experiencing the various scenes.

The experiments further showed that these results aren't due to voluntary changes in pupil size or differences in the mental effort required to imagine scenes.

"Because humans cannot voluntarily constrict the eyes' pupils, the presence of pupillary adjustments to imaginary light presents a strong case for as a process based on brain states similar to those which arise during actual perception," says Laeng.

The researchers suggest that this work may have further applications, potentially allowing us to probe the mental experiences of animals, babies, and even patients with severe neurological disorders.

Explore further: The pupils are the windows to the mind

More information: pss.sagepub.com/content/early/ … 97613503556.abstract

Related Stories

The pupils are the windows to the mind

January 28, 2012
The eyes are the window into the soul -- or at least the mind, according to a new paper published in Perspectives on Psychological Science, a journal of the Association for Psychological Science. Measuring the diameter of ...

Looking at a photo of the sun also reduces the size of your pupils

May 27, 2013
If you look at the sun, your pupils become smaller to prevent eye damage. Researchers have now demonstrated that your pupils also become smaller if you look at an image of the sun. The research results appear to show that ...

Optical Illusion experiment shows higher brain functions involved in pupil size control

January 25, 2012
(Medical Xpress) -- We all know that our pupils contract when our eyes are exposed to increases in the brightness of light. The reason is to both protect the delicate inner workings of our eyes and to help provide for optimum ...

Questions answered with the pupils of your eyes (w/ Video)

August 5, 2013
Patients who are otherwise completely unable to communicate can answer yes or no questions within seconds with the help of a simple system—consisting of just a laptop and camera—that measures nothing but the size of their ...

Imagination can influence perception

June 16, 2011
Imagining something with our mind's eye is a task we engage in frequently, whether we're daydreaming, conjuring up the face of a childhood friend, or trying to figure out exactly where we might have parked the car. But how ...

Researchers discover how and where imagination occurs in human brains

September 16, 2013
Philosophers and scientists have long puzzled over where human imagination comes from. In other words, what makes humans able to create art, invent tools, think scientifically and perform other incredibly diverse behaviors?

Recommended for you

Study finds gene variant increases risk for depression

July 20, 2017
A University of Central Florida study has found that a gene variant, thought to be carried by nearly 25 percent of the population, increases the odds of developing depression.

In making decisions, are you an ant or a grasshopper?

July 20, 2017
In one of Aesop's famous fables, we are introduced to the grasshopper and the ant, whose decisions about how to spend their time affect their lives and future. The jovial grasshopper has a blast all summer singing and playing, ...

Study examines effects of stopping psychiatric medication

July 20, 2017
Despite numerous obstacles and severe withdrawal effects, long-term users of psychiatric drugs can stop taking them if they choose, and mental health care professionals could be more helpful to such individuals, according ...

Perceiving oneself as less physically active than peers is linked to a shorter lifespan

July 20, 2017
Would you say that you are physically more active, less active, or about equally active as other people your age?

New study suggests that reduced insurance coverage for mental health treatment increases costs for the seriously ill

July 19, 2017
Higher out-of-pocket costs for mental health care could have the unintended consequence of increasing the use of acute and involuntary mental health care among those suffering from the most debilitating disorders, a Harvard ...

Old antibiotic could form new depression treatment

July 19, 2017
An antibiotic used mostly to treat acne has been found to improve the quality of life for people with major depression, in a world-first clinical trial conducted at Deakin University.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.