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Pupils enlarge when the brain's working memory is focused on a task

Working memory plays a pivotal role in our day-to-day functions. It’s an essential brain skill that helps us manage and process information while engaging in activities, without losing focus.

For instance, working memory allows us to remember to buy more dishwasher soap while we’re busy loading the dishwasher and to keep track of other future necessities.

Researchers have long understood the significant variability in working memory across individuals but have struggled to pinpoint the reasons behind these differences.

Taking an innovative approach to studying this dilemma, researchers at the University of Texas at Arlington, including Matthew Robinson and Lauren Garner, conducted an experiment that examined whether pupil dilation could be a reliable indicator of working memory capacity.

Understanding pupil dilation and working memory

In a recent study, it was discovered that pupil size could tell us more than just how much light is entering the eye.

Typically, pupils dilate in low-light conditions to improve vision. However, this study revealed that pupils also dilate in response to cognitive tasks requiring concentration.

The study involved 179 undergraduate students who underwent a series of working memory tests. While they attempted these tasks, an eye-tracker, similar to devices used during routine eye exams, continuously measured their pupil dilation. The findings were quite revealing.

“We found that people who more intensely and consistently paid attention, as evidenced by greater pupil dilation, performed better on memory tasks,” explained Robinson.

“The highest-performing participants not only had larger overall pupil dilations but were also more discerning about the information they needed to remember,” he added.

How pupil dilation correlates to performance

The correlation between pupil size and task performance could have broader implications.

For instance, Matthew Robison noted that, “The lowest performers on the tasks showed less pupil dilation. For the highest-performing participants, their pupil dilations were both larger overall and the individuals were more discerning about the information they were asked to recall.”

This research highlights a fascinating aspect of how our bodies respond to mental exertion and could lead to more personalized approaches in educational and professional settings to enhance cognitive performance.

The study, published in the peer-reviewed journal Attention, Perception & Psychophysics, provides valuable insights into the physiological underpinnings of working memory.

“This is exciting research because it adds another valuable piece of the puzzle to our understanding of why working memory varies between individuals,” Robison concluded.

Exploring the intricacies of working memory

Working memory enables us to hold and manipulate information in our minds for short periods, allowing us to perform complex tasks, solve problems, and make decisions. Without working memory, we would struggle to navigate the world around us effectively.


The phonological loop

This component handles auditory information, such as speech and sound.

The visuospatial sketchpad

This component processes visual and spatial information, such as images and locations.

The central executive

This component acts as a control center, allocating attention and coordinating the activities of the other components.

The episodic buffer

This component integrates information from the other components and long-term memory, creating a unified representation.


Working memory has a limited capacity, typically allowing us to hold and manipulate between three and seven items at a time. This capacity varies among individuals and can be influenced by factors such as age, training, and cognitive impairments.

Researchers have developed various tests and tasks to measure working memory capacity, such as the n-back task and the complex span task.

Importance in everyday life

Working memory plays a vital role in numerous everyday activities, such as:

  • Following instructions and directions
  • Engaging in conversations and maintaining the flow of dialogue
  • Reading comprehension and language processing
  • Performing mental calculations and problem-solving
  • Multitasking and switching between different tasks

Deficits in working memory can lead to difficulties in these areas, impacting an individual’s academic performance, work efficiency, and social interactions.

Enhancement strategies

While working memory capacity is largely determined by genetic factors, research suggests that certain strategies and interventions can help improve its efficiency:

  • Chunking: Grouping information into meaningful units to reduce the number of items to be remembered.
  • Rehearsal: Repeating information mentally or aloud to maintain it in working memory.
  • Visualization: Creating mental images or diagrams to represent information visually.
  • Mindfulness and meditation: Practicing mindfulness and meditation techniques to improve focus and attention.
  • Cognitive training: Engaging in targeted exercises and activities designed to challenge and strengthen working memory

By understanding the intricacies of working memory and employing these strategies, individuals can optimize their cognitive performance and enhance their ability to navigate the demands of daily life.

Pupil dilation, working memory, and future implications

In summary, this study has revealed a fascinating connection between pupil dilation and working memory performance. By measuring participants’ pupils during cognitive tasks, the researchers discovered that individuals with greater pupil dilation and sensitivity consistently outperformed those with less dilation.

This finding enhances our understanding of the factors influencing working memory variation and paves the way for future research into the neural mechanisms underlying this critical cognitive skill.

As scientists continue to explore the complexities of the brain’s executive functions, studies like this one bring us closer to developing targeted interventions and strategies to support individuals struggling with working memory, ultimately unlocking the full potential of the human mind.

The full study was published in the journal Attention Perception & Psychophysics


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