Pupils and emotions are connected through the autonomic nervous system. When we experience emotions, particularly those involving arousal or stress, our pupils tend to dilate (get larger). This is part of the "fight or flight" response, where the body prepares for action. Conversely, when we feel calm or relaxed, our pupils may constrict (get smaller).

Pupils don't just react to light. They are also influenced by the autonomic nervous system, which regulates our emotional responses.

This means that, in certain contexts, they can dilate or constrict depending on emotional activation. However, this relationship is not simple or direct.

Some recent studies suggest that certain emotional states, such as fear or sadness, are associated with greater pupil dilation, while others, such as anger, may cause constriction. Even so, these patterns are not universal or completely predictable.

In conclusion, it seems there is a relationship between our eyes and what we feel and remember. In fact, this principle is part of EMDR (Eye Movement Desensitisation and Reprocessing), about which you can learn more in this post: EMDR Therapy 

Different ways of understanding emotions

The interpretation of this data depends significantly on the theoretical model from which emotions are analysed.

On the one hand, basic emotion theory states that there are specific physiological responses for concrete emotions. From this perspective, it would make sense for pupils to reflect differentiated patterns.

On the other hand, more current approaches consider emotions to be complex constructions influenced by context, culture, and personal experience. In this case, pupillary responses would be less specific and more variable.

What do scientific studies say

Recent research has analysed how pupils react to controlled emotional stimuli.

In these studies, participants were exposed to images and sounds designed to elicit emotions such as joy, fear, sadness, or disgust, while pupillary changes were recorded.

The results show that:

• There is a certain relationship between emotion and pupillary response.
• Pupils tend to dilate in the face of intense emotions
• It is not always possible to precisely differentiate which specific emotion is being experienced

This indicates that pupils can reflect emotional activation, but do not allow for the exact “reading” of emotions.

Can we know what someone is feeling by looking at their pupils?

The short answer is no.

Although pupils provide relevant information, they are not sufficient to reliably interpret a person's emotional state. Human emotions are complex processes that depend on multiple variables:

• Personal history
• Social context
• Cognitive interpretation
• Previous values and experiences

Reducing them to a single physiological signal would be an oversimplification.

Psychological implications

This type of finding reinforces a fundamental idea in therapy: it is not enough to observe external behaviour to understand what a person is feeling.

Psychology works from an integrative vision, where emotions are understood as the result of the interaction between body, mind, and context.

That's why, in a therapeutic process, what's important isn't just what is observed, but the meaning the person gives to their experience.

Conclusion

Pupils can reflect changes related to emotional activation, but they do not allow for the precise or universal identification of emotions.

Understanding human emotions requires a broader perspective, taking into account biological, psychological, and social processes.

Ultimately, human behaviour cannot be explained solely by a physiological response: it needs to be understood within a personal history.