- Thinking Hard. The harder that your brain has to work (think) the more your pupils dilate. The harder the task, the bigger the pupils get.
- Thinking Too Hard. There is an overload point however. When you hit about 125% of your mind's capacity your pupils constrict (get smaller), indicating your overload. Likely this is where we describe someone's eyes as glazing over!
- Showing Interest. Your pupils will dilate whenever you are interested in something. Likely they will dilate at first when confronted by just about anything that is new - what's important is to see if they remain dilated... that shows ongoing interest.
- Sign of attraction. Sexual interest also involves the eyes. Both men and women's pupils expand when they are sexually interested. And... an interesting side note... men tend to show interest in naked photos of women (using pupil dilation as the measure - and no... not a big surprise here!) but women do not show the same degree of interest in naked pictures of men. This difference is hard-wired into our brains and is directly related to our past where the selection of a mate (by a female) was unconsciously based on propogation of the species, ability to feed and protect... all decisions that needed to be determined and assessed 'live' and not through photos.
- Sign of disgust. And... the converse holds true. When you are disgusted with something your pupils will constrict in size. When shown pictures of injured children, people's pupils will dilate at first because of the shock and then constrict to try to avoid or limit seeing the images.
- Maternal Instincts. Women's pupils tend to dilate when looking at babies. Live, in pictures... doesn't matter. This demonstrates their interest and also serves to help the infants bond with them. Men's pupils do not tend to dilate as much. This is more of a genetic predisposition based on times when the males were the hunters and were gone for long periods of time. Women were the caretakers and home with the children. Therefore it was more important for the infants to bond with the female since she would primarily be responsible for their care.
- Building Trust. We tend to trust people that spend more time looking at us than looking away from us. To build trust with others therefore, we need to be able to maintain a certain level of eye contact. As an internal self-defensive move, research has also shown that we unconsciously spend more time working to remember the face of someone that we distrust than those we trusted. Being memorable may therefore not always be a positive 'thing'!
And... just a note of caution to add to the mix. Someone's medication can alter their pupil size, as can the lighting of the room. Too bright a room and the pupils constrict. Too dark a room and the pupils contract which is, by the way, why romantic dinners are typically held in poorly lit rooms or by candlelight. The poor lighting makes the pupils open wide, making the other party look more interested/attracted. This can, though, lead to the wrong signals being sent! It is better to baseline for the environment you are in and watch for 'changes' from that state, based on the interactions.
Having said that though, it is typically very difficult to consciously detect changes in people's pupil sizes, although we are able to unconsciously pick up on those changes. Just another element that tends to let our 'gut' know what's going on long before we are able to consciously identify it.
(Check out our Beyond Words: Your Body Language at Work program for a more in depth study and understanding of what your body language is saying to others and how to read theirs! www.titantraining.ca)