Eye contact
Eye contact is an intense nonverbal, visual connection made as one person gazes into the eyes of another. It is a highly emotional link established as two people simultaneously observe each other's eyes.
Gazing at another's eyes arouses strong emotions. Thus, eye contact rarely lasts longer than three to five seconds before one or both viewers experience a powerful urge to glance away. Breaking eye contact lowers stress levels (as measured, e.g., by breathing rate, heart rate, and sweaty palms). The size of the pupils, affected by the sympathetic nervous system, may reveal a great deal about one's emotions, convictions, and moods.
As with other primates, human beings show an extreme alertness to where others are looking. Though we consciously control where our own eyes hover and land, we feel compelled to look at objects and body parts which our primate brain finds interesting (e.g., faces, breasts, hands, and trees)--or to gaze away from what it finds distasteful. In response to feelings of shyness, submissiveness, and stranger anxiety, an inner primate voice warns us to be careful and to "watch where we look". In crowded elevators, our eyes cannot roam freely across another's faces (as they can, e.g., freely watch media faces pictured in magazines and shown on TV).
There is more direct gaze when people like each other and cooperate, while people make less eye contact when they dislike each other or disagree. In primate behavior, the unwavering gaze evolved as a sign of dominance and threat, while gaze avoidance originated as a submissive cue.
Gaze direction clearly shows others where our attention lies. Humans have developed an ability to gaze back into the eyes of our beholders in order to gauge their feelings. However, being looked at so arouses the sympathetic nervous system (fight or flight response) that we may feel compelled to glance away.
Spiritual and the biological
All human beings who are capable of sight are interested in the eyes of other people. From the moment of birth we respond to our mother's eyes as if programmed to do so. Babies instinctively smile at black geometric spots--perceiving them as "eyes" by six weeks of age. In adults, eye contact shows personal involvement and creates intimate bonds. Mutual gaze narrows the physical gap between us.
Many cultures of today and the past consider eye contact (whether prolonged or fleeting) to be a spiritual and renewing experience, while other cultures see it as intrusive and rude. The eyes have often been described as the "mirrors of the soul", and lovers often gaze into each other's eyes for extended periods of time to show and nonverbally express their love for one another.
As primates, for whom facial expressions provide key social and emotional information, we continually probe each other's eyes for positive or negative mood signs. We are acutely aware of being noticed by strangers. In waiting rooms we periodically glance up and scan for roving eyes (much as do monkeys in a cage). The popular book The Sense of Being Stared At by Rupert Sheldrake discusses how sensitive human beings are when it comes to being looked at, especially for more than a few seconds. Most if not all people have experienced the sense of being stared at least a few times during their life; the staree suddenly gets the feeling that someone is looking at them, and when they glance upwards they find that someone very close or even across a crowded room is staring them down, at which point the starer is usually startled/embarrassed and quickly looks off in another direction. This is not an uncommon experience, as almost everyone has experienced this strange but interesting phenomenon several times during his or her lifetime. This same phenomenon has been observed and can be noted by staring at strangers in stopped traffic; almost invariably the person being looked at will quickly notice that they are being 'stared down' by the stranger in one of the many cars that surround them. Once again the person somehow 'senses' that they are being stared at by another being.
Trivia and miscellaneous
Maintaining eye contact without staring (staring/gawking is considered very rude) demonstrates sincere interest in the other person. Cultural differences must be considered in determining proper eye contact. Eye contact is crucial to establishing a connection and a sense of trust between the individuals involved, and regular, friendly eye contact actively shows the other person that you are interested in him/her and what he/she has to say.
Cosmetics have been used universally throughout human history to enhance the beauty of the natural eye. Belladonna, mascara, eyeliner, eyeshadow, eye cream, colored contact lenses, and various other forms of eye enhancement have been used to draw other people's gaze to the individual's eyes who is wearing the makeup, thus (hypothetically) increasing the amount of eye contact between the people involved.
What often gives police officers away in a roomful of people is their habit of looking too intently and too carefully at others.
Most common with stutterers is the inability to maintain eye contact with the listener, which may in turn hamper the growth of personal or professional relationships.
In Japan, listeners are taught to focus on a speaker's neck in order to avoid eye contact, a holdover from Samurai days, when peasants risked decapitation by looking a samurai in the eye. In the U.S., listeners are encouraged to gaze into a speaker's eyes, though too much eye contact with someone you don't know very well is considered rude and intrusive.
On the other hand, looking directly into the others' eyes for a prolonged time can be an effective way of intimidating somebody. A good trick, if one likes to do so but cannot handle the staring oneself, that is used e.g. by military drill instructors, is to stare at a point slightly above the others eyes. Although the eye contact is now asymmetric, it may still have an intimidating effect.
The human pupil dilates if the person sees something (or someone) of interest or is aroused, thus making eye contact much more intense than it already is. Studies have shown that humans (especially females) are judged as more attractive if their pupils are wide open and more dilated than is normal.
How deep this effect lies can be seen from the following insightful experiment: Men were shown photographs of women, either the original version, or a changed one, in which the pupils have been made look larger. Although no man saw both variants, the manipulated photos were, on average, consistently judged as more attractive. Afterwards, the men were told about the result, also shown the other photos and asked whether they could identify what had been changed between the two photos. Nearly all answers were along the lines of "she looks softer", "more feminine" etc., and nobody saw (without being pointed at the fact) that the difference was the pupil size. Hence, the pupil size is registered by the brain, but processed in a layer so far from consciousness, that the emotional effect ("She is attractive.") is strongly conceived consciously but the origin (the dilated pupil) not at all. (E. H. Eckart, Scientific American 212 (1965), p. 46)
The name Belladonna (beautiful lady) comes from the fabled use of the juices of the Nightshade plant mostly by Sicilian women who would use eyedrops made from an extract of the plant in their eyes in order to enlarge their pupils and make their eyes appear more beautiful. This was done as part of their makeup preparations. The atropine content of the fluid had the effect of dilating the pupil, thus making their eyes supposedly more attractive. It had the side effect of making their vision a little blurry and making their heart rate go up ever so slightly but that was considered a little price to pay for big dilated pupils or so it seemed. In some cases gradual blindness occurred among these women through the overuse and abuse of belladonna to enhance the beauty of the eyes. Atropine, a chemical found in belladonna, is used by modern eye doctors to dilate the pupils so that they can examine the retina. Optometrists and ophthalmologists use it widely to this day for pupil dilation in eye examinations, though the dose is extremely small.
Documentary filmmaker Errol Morris invented a device called the Interrotron which allowed his interview subjects to look directly into the camera while being filmed. It allows the film's viewers to maintain eye contact with the people in Morris' films, giving what some describe as a more intimate acquaintance with them.