chin

chin In modern humans the mandibular arch is formed by fusion at the centre of two separate bones, a process complete by two years of age. The thickening of this arch at the centre forms the prominent and distinctive chin. The well-defined chin and prominent nose of humans interrupt the generally vertical profile of adult human faces and are said to be distinguishing characteristics separating modern humans from prehuman ancestors and from other primates.

Sitting at the bottom of the face, and being the most visible element of the face during speech, the chin plays numerous important physical roles and has acquired several fascinating linguistic associations. The phrase ‘to hold up by the chin’, and the nursery story's line of escaping ‘by the hairs of my chinny-chin-chin’ both express the physical prominence of the chin; one conveys the role of the chin as a support that keeps one from sinking while the other marks the chin as a protrusion one must protect. The chin-strap of a hat or helmet secures that accessory to the head, while being ‘in it up to your chin’ and ‘chin deep’ — in water or in trouble — both reflect the role of the chin as the lowest point of the face, after which all is lost. To ‘keep your chin up’ or to ‘take it on the chin’ signify a measure of psychological or physical courage or fortitude indicated by keeping one's gaze straight ahead and not flinching. Finally, the less common usages of ‘chin-wagging’ or ‘chin-chin’ refer to chat or talk, and reflect the fact that the movement of the chin is both highly visible during and a key visual cue of speech.

The chin continues to develop through adolescence and early adulthood as other facial (especially nasal and dental) structures mature. As the size of the face relative to the cranium increases, the angle of the vertical slope from forehead to chin decreases and the chin becomes more protrusive in profile. These changes have been shown to be an important part of the facial cues commonly used to identify the age of individuals. Recent work in experimental psychology suggests that the characteristic differences between adult and infant human faces, and especially the softer, less angular features — including a less prominent chin — of infants play an important role in inhibiting aggression toward infants and stimulating caregiving. As psychologist Leslie Zebrowitz put it recently, ‘A baby's face is disarming’, an observation confirmed both by experiment and by the everyday experience of adults interacting with infants.

The chin plays a very important part in these experiences, and the presence of an adult chin in an adult face when placed on an infant's body is visually disorienting, as can be observed in portrayals of the Madonna from the late Middle Ages. Cimabue's Madonna Enthroned (c.1280–90), Duccio's Maestà (c.1311), and Giotto's Madonna (c.1310) all portray the Christ child with a baby's body and an adult's face, with adult facial/cranial proportions, eye size and spacing, and nose size and prominence, and also, notably, a very adult chin. Later works, including Parmigianino's Madonna With the Long Neck (c.1535) soften the child's face, showing more features of the ‘baby face’, including a less prominent chin, and provide a less jarring visual experience.

While a babyish chin and face often elicit caregiving from adults, a ‘weak’, or relatively undeveloped chin in adults, and especially in adult males, one less angular and elongated than average, often produces less positive reactions from other adults (‘Chinless Wonder’). While it is difficult to separate the impact of the several components of a baby face in such responses, some evidence points to a prominent role for the chin. When presented with two similar faces distinguished largely by chin profile and development, the face with a typical adult chin is more likely to be associated with intelligence, physical strength, dominance, and sexual attractiveness, while the face with the more baby-like chin is frequently associated with lower levels of those features and higher levels of warmth, honesty, and agreeability. A quick glance at the profile of the traditional ‘leading man’ in cinema confirms these reactions; Clark Gable, Kirk Douglas, and other prominent stars display very prominent chins. The undeveloped, receding chin is characteristically a feature of an agreeable if immature or foolish character. In keeping with the association with babyish faces, weak chins are less common in movie villains than in more ‘innocent’ characters. Such casting and the reactions to it echo the claims of nineteenth- and twentieth-century physiognomy, that intellectual, psychological, and moral fitness can be discerned from facial (and other physical) features. As cited by Zebrowitz, the twentieth-century physiognomist, LeBarr, stated that ‘a small deficient chin stands for weakness of will and physical endurance’, while the nineteenth-century Swiss physiognomist, J. C. Lavater, categorized chins in men in a similar vein: ‘The angular chin is seldom found but in well-disposed, firm men … flatness of chin speaks of the cold and dry; smallness, fear; and roundness, with a dimple, benevolence.’

As with most facial features, there are important gender-prototypical differences in the development of the chin. Typical adult females have smaller jaws, noses, and chins, and thus eyes and cheekbones that are more prominent and appear to be larger than in typical males. The less prominent chin in females does not appear to generate the negative reactions it does in men. To judge from the psychological evidence and from experience, conventional assumptions associate attractiveness in female faces with those features most similar to the baby face. Apparently, men but not women (at least in cultures much like our own) are expected to be able to ‘take it on the chin’, and are deemed more attractive if they can.

Jeffrey M. Barker

See also face; skull.