A canted smile is an asymmetrical facial expression where the mouth corners are uneven, resulting in a noticeably tilted appearance. The term “cant” refers to a slant or a tilt, distinguishing this expression from a symmetrical, balanced smile. This asymmetry is often a signifier of underlying physical or psychological factors. Unlike a full, spontaneous smile, a canted smile is characterized by an uneven pull of the facial muscles. The visual tilt of the smile frequently speaks to how an emotion is being controlled or perceived.
The Visual Characteristics of a Canted Smile
The most striking feature of a canted smile is the clear lack of parallelism between the mouth line and fixed facial features, such as the line passing through the center of the eyes. Observers may notice that one corner of the mouth is pulled significantly higher than the other, creating a diagonal rather than a horizontal line across the face. In dental contexts, this is often referred to as an occlusal cant, where the line of the teeth is tilted relative to the midline. A tilt of four degrees or more is considered noticeable to the casual observer.
The asymmetry of the expression can also affect the surrounding facial topography. The cheek on the higher side of the mouth may appear more bunched, and the nasolabial fold—the line running from the side of the nose to the corner of the mouth—may be more pronounced. This uneven muscular engagement can also lead to a differing visibility of the teeth and gums on each side of the mouth. The visual result is an unbalanced look that draws attention because the human brain seeks facial symmetry.
Psychological Interpretations of Asymmetry
The psychological significance of a canted smile lies primarily in its deviation from a genuine, symmetrical expression. A spontaneous, felt smile, known as a Duchenne smile, involves the contraction of muscles around both the mouth and the eyes, creating a balanced appearance. In contrast, the uneven nature of a canted smile often signals a non-genuine or controlled emotional state. This asymmetry can be perceived as a “chiral emotional display,” suggesting mixed or conflicting emotions.
One of the most common interpretations of a canted smile is that it conveys contempt, skepticism, or a sense of superiority, often referred to as a smirk. The asymmetry suggests a lack of full emotional commitment or a tongue-in-cheek attitude, such as in sarcasm or dry humor. An asymmetrical smile is frequently a characteristic of a “false smile,” which is an intentional effort to mask a lack of feeling or to conceal a negative emotion.
Neurological Basis and Muscle Action
The physical mechanism that creates a canted smile is rooted in the dual neurological pathways that control facial movement. Voluntary facial movements, such as intentionally posing for a photo or forcing a smile, are governed by the pyramidal tract, which originates in the primary motor cortex. This pathway is often associated with the production of asymmetrical expressions.
The extrapyramidal system, which involves subcortical structures like the limbic system, controls spontaneous and involuntary expressions of emotion. When a person experiences genuine joy, this involuntary pathway activates, resulting in a symmetrical expression that engages both sides of the face equally. The canted smile is often a product of the voluntary motor pathway overriding or partially engaging the facial muscles on one side more than the other. This uneven, conscious motor control signals a posed or non-spontaneous emotion.