What your eyes say about your emotions

Pupil size is affected by emotions as well as by light levels. If you are angry or you see something disgusting, the pupil gets narrower, or contracts. If you look at someone you love or something delicious to eat, it expands, or dilates.

• Pupil dilation is a proven measure of interest and attraction. In one classic study, men were shown photographs of women that had been artificially retouched to make the pupils appear either larger or smaller.
• The men invariably found the women with larger pupils more attractive and friendlier than the same women with smaller pupils, though none of them were consciously aware why they made this choice.

• There is an exception to the general rule that positive feelings make the pupils dilate and negative ones make them contract — fear.
• A frightened person will often have widely-dilated pupils, because fear creates a rush of the stress hormone adrenaline, in preparation for a primitive "fight or flight" response; that response includes pupil dilation to improve visual sensitivity.

• We use pupil changes in assessing other people's emotions, though we are usually not consciously aware of the subtle differences in pupil size.
• What's more, our own pupils react in response — in one British study, volunteers who looked at pictures of sad faces with small pupils showed a corresponding reduction in their own pupil size. Such reactions may be important in the development of empathy.
• Scientists already know that when we feel in tune with someone we tend to mimic their posture and movements. It seems that body language mimicry starts with the eyes.
• The idea that our eyes reveal our character is nonsense, isn't it?
• Not necessarily, say behavioural scientists from Sweden's Örebro University and Karolinska Institute.
• They tested the personality characteristics of 428 students and matched them to their iris patterns.
• They report in the journal Biological Psychology that students who were warm, trusting and empathic had more dense iris crypts, the wavy lines that radiate out from the pupil.
• In contrast, furrows in the iris — curved lines that form around the outer edge when the pupils dilate and contract — were more numerous and extended farther in students who tested high for impulsiveness.
• During fetal growth, the researchers say, certain genes that influence the parts of the brain involved with emotion and response to rewards also affect iris patterns, suggesting a link between iris patterns and specific personality traits.