Imagery modulates the pupillary response, but this does not reliably index differences in imagery vividness.

Gardner, Saurels and ArnoldJanuary 2026

Abstract
What This Study Is About
How They Studied It
What They Found
What This Might Mean
One Interesting Detail
Authors
Cite this paper

Abstract

Most people report that they can imagine seeing things in their mind’s eye. But there are large individual differences. A small proportion of people report that they can never visualise (aphantasics), and a similarly small proportion of people report that their imagined experiences are as realistic as seeing (hyperphantasics). The majority of people describe their visualisations as being moderately vivid. The ratings that inform imagery vividness analyses are subjective self-reports, but it has been suggested that imagery modulations of the pupillary response could be used as a physiological index of individual differences in imagery vividness. When we assessed this inter-relationship, we found that imagery can indeed modulate the pupillary response, with pupils becoming relatively more dilated if people imagine seeing dark, as opposed to bright scenes. However, imagery modulation of the pupillary response was not associated with individual differences in imagery vividness ratings. Overall, our data suggest that while imagery can modulate the pupillary response, this effect does not provide a reliable index of individual differences in imagery vividness ratings.

Our summary in plain words

What This Study Is About

Researchers investigated whether the way our pupils react to imagined light and dark can be used as an objective physiological test for the vividness of mental imagery (the ability to picture things in the mind). They specifically looked at whether these pupil changes could reliably identify people with aphantasia—a condition where individuals cannot create mental images at all.

How They Studied It

The study involved 52 undergraduate students who performed several tasks while an eye-tracker measured their pupil size. Participants were asked to imagine bright or dark shapes and complex scenes under different conditions. Some tasks used physical pictures as cues, while others used only written descriptions to avoid "afterimages" (the ghostly shapes you see after looking at a bright light). The researchers then compared these pupil measurements to the participants' scores on the Vividness of Visual Imagery Questionnaire (VVIQ), the standard self-report survey used to identify aphantasia.

What They Found

The researchers confirmed that the pupils do react to imagination: they dilate (get larger) when imagining dark scenes and constrict (get smaller) when imagining bright ones. However, they discovered that the strength of this pupil reaction did not match how vivid people said their imagery was. Someone who reported very vivid imagery did not necessarily have a stronger pupil response than someone with vague imagery. Crucially, the pupil response was not a reliable way to predict a person's VVIQ score or their trial-by-trial ratings of imagery intensity.

What This Might Mean

This suggests that while the "pupil test" shows that the brain is processing imagined light, it may not be a reliable "thermometer" for measuring how vivid an image feels to an individual. It highlights the ongoing difficulty in finding an objective, physical measurement for aphantasia. The results also suggest that previous studies might have been influenced by physical afterimages, which can interfere with measuring the true effect of imagination on the eyes.

One Interesting Detail

The study found that the pupil response only worked reliably when participants were given written descriptions to imagine, rather than being shown a physical picture first. When shown a physical cue, the lingering "afterimage" in the eye seemed to cancel out the effect of the imagined image.

This summary was written with AI and may contain errors. Check the original paper.

Authors

Daniel Gardner
1 paper in the library
Blake W. Saurels
6 papers in the library
Derek H. Arnold
7 papers in the library

Cite this paper

Gardner, D., Saurels, B. W., & Arnold, D. H. (2026). Imagery modulates the pupillary response, but this does not reliably index differences in imagery vividness.. Cortex. doi:10.1016/j.cortex.2025.11.018

Topics

Most-cited researchers

Recruit participants for your study

We can help you reach people across the imagery spectrum, from aphantasia to hyperphantasia.

Partner with us

Image-Free Insights

A short note from our founder, Tom Ebeyer, every other week, plus occasional news and invitations to take part in studies. Change what you get from any email.

Research Cortex

Imagery modulates the pupillary response, but this does not reliably index differences in imagery vividness.

Gardner, Saurels and ArnoldJanuary 2026

Read the paper

Abstract
What This Study Is About
How They Studied It
What They Found
What This Might Mean
One Interesting Detail
Authors
Cite this paper

Abstract

Our summary in plain words

What This Study Is About

How They Studied It

What They Found

What This Might Mean

One Interesting Detail

This summary was written with AI and may contain errors. Check the original paper.

Authors

Daniel Gardner
1 paper in the library
Blake W. Saurels
6 papers in the library
Derek H. Arnold
7 papers in the library

Cite this paper

Topics

Most-cited researchers

Recruit participants for your study

We can help you reach people across the imagery spectrum, from aphantasia to hyperphantasia.

Partner with us

More research

All research

2023

Phenomenological Studies of Visual Mental Imagery: A Review and Synthesis of Historical Datasets

Marks · Vision

Researchers synthesized historical and contemporary data to create a 16-descriptor template for visual mental imagery. This provides a normative standard to better understand individual differences in imagery vividness and clinical conditions.

2020

Screen‐time influences children's mental imagery performance

Suggate and Martzog · Developmental Science

In 266 German children aged 3 to 9, tested twice about 10 months apart, more daily screen time at the first test predicted slightly lower later accuracy on questions comparing two named objects (which is shinier, a trumpet or a violin?), after allowing for age, vocabulary, working memory and family background. Earlier task scores did not predict later screen time, and screen time did not predict answer speed. Television and interactive screens showed similar links. The authors suggest ready-made screen images give children less practice at making their own, though other factors could explain the link.

2011

Evaluating the Mind’s Eye: The Metacognition of Visual Imagery

Pearson, Rademaker and Tong · Psychological Science

Subjective vividness ratings reliably predict an image's impact on subsequent perception. This suggests that individuals have accurate metacognitive insight into the sensory strength of their mental imagery.

Image-Free Insights

A short note from our founder, Tom Ebeyer, every other week, plus occasional news and invitations to take part in studies. Change what you get from any email.