[1][2] The face is crucial for human identity, and damage such as scarring or developmental deformities may affect the psyche adversely.

It includes several distinct areas,[3] of which the main features are: Facial appearance is vital for human recognition and communication.

Visible variable features of the face other than shapes and proportions include color (paleness, sun tan and genetic default pigmentation), hair (length, color, loss, graying), wrinkles,[5][6] facial hair (e.g. beards), skin sagging,[6] discolorations[7] (dark spots,[6] freckles and eye circles[6]), pore-variabilities,[8] skin blemishes (pimples, scars, burn marks).

Many of these features can also vary over time due to aging,[6][5][7] skin care, nutrition,[9][10][11][12][13][14] the exposome[15] (such as harmful substances of the general environment,[11][15] workplace and cosmetics), psychological factors,[11] and behavior (such as smoking,[15] sleep,[11] physical activity and sun damage[5][7][11]).

[15] The desire of many to look young for their age and/or attractive[6] has led to the establishment of a large cosmetics industry,[5] which is largely concerned with make-up that is applied on top of the skin (topically) to temporarily change appearance but it or dermatology also develop anti-aging products (and related products and procedures) that in some cases affect underlying biology and are partly applied preventively.

[19][20][21] Another study found look-alike humans (doppelgängers) have genetic similarities, sharing genes affecting not only the face but also some phenotypes of physique and behavior.

Being able to read emotion in another's face is "the fundamental basis for empathy and the ability to interpret a person's reactions and predict the probability of ensuing behaviors".

According to Gary L. Allen, people adapted to respond more to faces during evolution as the natural result of being a social species.

[32] Furthermore, particular areas respond more to a face that is considered attractive, as seen in another study: "Facial beauty evokes a widely distributed neural network involving perceptual, decision-making and reward circuits.

In those experiments, the perceptual response across FFA and LOC remained present even when subjects were not attending explicitly to facial beauty".

[36] By extension, anything which is the forward or world-facing part of a system which has internal structure is considered its "face", like the façade of a building.