gaze

gaze It is unsettling to be gazed at. Staring is a threat for monkeys and apes, and perhaps humans share some trace of this response. On the other hand, good ‘eye contact’ is recognized in most cultures as important for effective interpersonal communication, especially during dialogue. So it may be the combination of looking intently and protractedly without verbal communication that is particularly unsettling or threatening. There was a time when, in the Southern States of the US, it was a sexual offence, punishable by law, for a black man to look overly long at a white woman.

Mutual gaze is, however, one of the delights of lovers; as Shakespeare writes (Sonnet 24):Mine eyes have drawn thy shape, and thine for me
Are windows to my breast, where-through the sun
Delights to peep, to gaze therein on thee.
Francis Bacon went so far as to describe the appropriate pattern of gaze for courtship — ‘sudden glances and darting of the eye’, but not a fixed stare.

The lover's gaze may be accompanied by enlargement of the pupil (a ‘wide-eyed’ look) — a sign of activation of the sympathetic nervous system. Experimental psychologists have shown that if male subjects are shown two copies of a photograph of a girl, one modified to enlarge the pupils and the other to make them smaller, the subjects will describe the girl with the larger pupils as more attractive, even if unaware of the size of the pupils. Presumably the involuntary enlargement of the pupil acts as a signal of sexual arousal. Indeed, Southern European women are said to have put extracts of the plant Deadly Nightshade (containing the drug belladonna or atropine) into their eyes to enlarge their pupils, in order to make themselves more attractive to the opposite sex.

When we gaze directly at an object, we hold our eyes in such a position that the image of the object falls on the central, specialized region of the retina — the fovea or macula — where visual acuity and colour vision are best. If we look around a scene, thinking that our eyes are roaming smoothly, they are, in fact, making a series of step-like shifts of gaze. The line of sight or direction of gaze rests briefly on one object, before jumping to the next, as often as three or four times a second. Even when we try to fixate — to look fixedly in one direction — tiny shifts of gaze still occur. This pattern, in which the line of sight is either briefly fixed or rapidly jumping to another position (rather than slithering around), is characteristic of any situation in which the visual surroundings are stationary. This is true even if the head is moving, because as the head rotates, signals from the organ of balance (the vestibular system) trigger the powerful vestibulo-ocular reflex, which automatically causes the eyes to rotate through the same angle, in the opposite direction. So, remarkably, movement of the head does not cause a change in gaze. Only an active shift of the eye in the orbit alters the line of sight.

Perhaps because the fixity of the line of sight is so nicely maintained when the head is moving, ‘gaze’ has come to have a technical meaning for scientists who study eye and head movements. It means the ‘position of the line of sight in space’, rather than its direction relative to the head.

Even though our eyes are constantly shifting from place to place, visual perception occurs almost exclusively during the brief pauses. Very little is seen during a shift of gaze. The ability to maintain gaze can be profoundly disturbed by damage to the brain stem or hindbrain. Another, now rare, cause of difficulty in maintaining gaze is damage to the hair cells of the inner ear by high doses of particular antibiotics. Not only is hearing affected but so too is the sense of balance, because hair cells in the organ of balance in the inner ear are also destroyed. These hair cells normally detect head rotation, so the vestibulo-ocular reflex is affected and gaze becomes unstable. There is a well known account by a patient (who happened to be a physician) who suffered from this condition, which described how difficult it was to read because even small head movements shifted the line of sight unexpectedly.

Stuart J. Judge

Bibliography

Argyle, M. and and Cook, M. (1976). Gaze and mutual gaze. Cambridge University, Press.

See also autonomic nervous system; eyes; eye movements.