Why do the eye pupils dilate or contract? Is it only a response to change in illumination?
Apparently not.
It’s common knowledge that the eye pupils dilate and contract according to the light they’re exposed to. This body mechanism helps regulate the amount of light we receive, which allows us to see better in different light conditions.
Perhaps what you didn’t know is that your pupils react to visual stimulations, too – a positive or negative response represented in the eyes. Your pupils, involuntary, can dilate or constrict in their size according to whether or not you like what you see.
Let’s see if we can get a deeper look…
The Size Does Matter (sometimes…)
So what does it mean?
It can be a misleading signal, but more on that later.
Not only dilated pupils show a positive response in someone, it’s makes to look quite appealing.
Toy manufactures, understanding this, produce toys with really big eyes and pupils to draw the attention of kids, who naturally like them better. This also explains why kids (and adults) really like anime character with their excessively big eyes.
The opposite is also true, constricted eye pupils show resentment, defiance and general disliking. We also like them less. It’s really simple if you think about it – if someone seems not to like you, usually you won’t have much incentive to like him or her back.
As part of my job as juggling instructor I work with children. On the other hand, some kids, when being reprimanded, meet my gaze and I can see little defiant needles staring at me.
Attraction
So, when do our pupils grow the most?
When we’re sexually aroused of course…
According to an experiment done in pupillometry (the study of how pupil size reflects psychological condition) Heterosexual genders eye pupils were dilated in response to pictures of semi naked opposite sex. In females the pupils were affected also by pictures of babies and mothers.

OK, so our pupils dilate when we’re stimulated, but is it also going the other way around?
Are we attracted to dilated pupils?
The researchers Tombs and Silverman found that guys have a straightforward approach to this question – the bigger the eye pupils – the more attractive they found them. For females however, it’s a little more complicated: they prefer either medium or big sized pupils, and the tendency to choose bigger pupils is associated with the preference for ‘bad boy’ types of guys. Find out more here.
Advertising companies, taking advantage, often enlarge the pupils of the models on the covers of magazines to tempt us for buying it. Sex sells, and part of this sex appeal is dilated pupils.
If you think about it, it may also explain why we like dim lights in romantic places – it’s artificially dilates yours and yours date’s pupils and make you look more attractive. It’s also a great way to make all of your surroundings ‘fade to black’ and concentrate on each other.
Too Good to be True?
Thinking about these facts may make you wonder, if it’s involuntary and can accurately indicate interest and emotion, does it makes the whole ‘does he\she like me?’ thing too easy?
Ah, but of course there are some complications:
1. The biggest issue is that pupils first and foremost dilate and contract according to the lightning setting. Don’t take offense if you see your loved ones stare at you with beady eyes in a bright sunny day.
By the way, that’s why I said that this can be misleading in courtship, especially in a ‘romantic’ dimly lit place. Still, keep in mind that we like to gaze at dilated pupils so it’s not all bad.
2. You need to extremely observant to spot these changes occur, not an easy job when trying to focus on the many other aspects of communication. Besides it can be pretty hard to see the pupil size in dark eyes.
What Do We Take From Here
I don’t want you leave you with a feeling that it’s too damn hard to use. So let me remind you that while our conscious mind is busy focusing on the conversation itself, we perceive most body language signs subconsciously.
This means that you don’t need to check every moment what is the size of your date’s pupils but rather allow yourself to relax and become perceptive, knowing the signs will bring them to your mind when you see them.
I hope this post also helps to explain some intriguing scenarios from our life. Like why many poker players shade their eyes during the game – to hide the automatic dilation of their pupils when they get good cards.