Are Your Pupils Betraying You? The Science of Pupil Mimicry and Social Trust
"New research sheds light on how our pupils mirror each other, influencing trust and social interactions in surprising ways."
Have you ever felt an unspoken connection with someone? It might be more than just a feeling. Recent studies have revealed a fascinating phenomenon known as pupil mimicry, where our pupils unconsciously mirror the changes in the pupils of those we interact with. This subtle mirroring, it turns out, plays a significant role in how we build trust and navigate social situations.
A groundbreaking study published in the Proceedings of the National Academy of Sciences (PNAS) investigated the neural underpinnings of pupil mimicry. Researchers discovered that when individuals' pupils mimic dilation in others, it correlates with increased trust during economic games. Even more intriguing, this pupil mimicry-related trust is linked to activation in brain areas associated with 'theory of mind'—our ability to understand others' thoughts and feelings.
This discovery challenges the notion that pupil mimicry is merely a response to changes in luminance (brightness). Instead, it suggests that pupil mimicry is deeply intertwined with social cognition, influencing our perceptions and behaviors in ways we are only beginning to understand. Let's dive deeper into the science behind this captivating phenomenon and explore its implications for our daily lives.
Pupil Mimicry and Trust Decisions
A 2018 study used a multimethod approach to examine pupil mimicry and trust. It reports that pupil mimicry is regulated by the theory-of-mind network and informs trust decisions through precuneus activation. The PNAS account also names the temporo-parietal junction, superior temporal sulcus, and medial prefrontal cortex as parts of the network involved.
Decoding Pupil Mimicry: More Than Meets the Eye
While the idea of pupil mimicry may seem straightforward, its underlying mechanisms are complex and nuanced. Some researchers, like Mathôt and Naber, have questioned whether luminance differences in dilating versus constricting pupils could account for the observed effects. They argue that changes in brightness, rather than social cues, might be driving the phenomenon.
- Non-Natural Stimuli: Studies using artificial stimuli (e.g., gray pupils) yield different results compared to those using natural black pupil stimuli, suggesting that the context matters.
- Social Context Matters: The effects of pupil mimicry on social behavior, such as trust, are consistently influenced by social context, including factors like ethnicity, species, and cooperative versus competitive settings.
- Brain Network Activation: Pupil mimicry activates social brain networks that govern attention, rather than the other way around.
Pupillary Contagion Beyond Humans
A study titled “Humans’ pupillary contagion extends to cats and dogs” reports a previously unknown pupillary contagion response in humans to cats’ and dogs’ pupils. The finding extends the reported response to these two animal species. The source describes the response as newly identified but does not specify its size or how often it occurs.
Alternative Explanations for Pupil Mimicry
One study argues that previous reports of pupil mimicry may reflect differences in luminance between stimuli rather than social mimicry. A separate infant study raises associative learning as another possible explanation: infants could observe pupil dilation during arousing situations. Its authors note that infants may gain substantial social experience observing others’ pupils within their first four months. These sources therefore present alternative explanations, not a single settled account.
The Social Symphony of Pupils: Implications for Connection and Trust
In conclusion, pupil mimicry is a fascinating window into the complex interplay between our brains and social world. It highlights how subtle, often unconscious cues can significantly influence our perceptions, behaviors, and the very fabric of our social connections. By understanding the mechanisms behind pupil mimicry, we gain deeper insights into the foundations of trust and empathy, paving the way for more meaningful interactions and a more connected society.
A Network-Based Account of Trust
The report describes evidence that pupil mimicry modulates trust decisions through activation of the theory-of-mind network. It identifies the precuneus, temporo-parietal junction, superior temporal sulcus, and medial prefrontal cortex as components of that network. In this account, pupil mimicry and trust decisions are linked through activity in these regions.
Testing Pupil Mimicry in Virtual Storytelling
A September 1, 2025 paper on eye contact during virtual storytelling suggests that future studies may observe stronger effects of pupil dilation mimicry on social evaluation under conditions that produce more frequent spontaneous pupil dilation. It proposes using more engaging stories and adjusting virtual humans’ appearance or behavior as ways to create such conditions. These are suggestions for future research, not reported outcomes.