Hobbies And Interests
Smile!
The smile when used by humans is usually interpreted as meaning happiness, affection or contentment. However, animal researchers believe that in non-human primates the smile, or at least the smile in which the teeth are held together, is a gesture of submission. By revealing the teeth and showing that they are closed, the animal communicates the fact that it has no desire to bite and thus shows its peaceful intention. The human smile probably originated in this behavior. Indeed, depending on how you choose to look at it, you could regard the human smile itself as a gesture of submission, showing acceptance of another person or idea.
Showing Teeth and Agonistic Displays
While the tooth-closed smile is a sign of submission, most primates reveal parted teeth as a threat. In baboons this takes the form of a yawn-like gesture, while in apes the expression is more like a human smile. Humans, especially babies and children, will also bare their parted teeth when frightened or angry, though this is more rare in adults. Species such as marmosets and tamarins have fewer muscles to control the face and so show aggression by turning their backs and showing their genitals from the rear. While humans don't generally resort to such extreme measures, they do turn their backs to show a person that they are excluded, and the practice of "mooning," or displaying the naked buttocks, is often used to show disrespect and scorn. Interestingly, both apes and humans engage in smirking, in which the teeth are concealed, in both case showing contempt and a lack of recognition of the other's status. It may be that when a primate smirks, it is gesturing with its mouth but concealing the teeth. This makes the gesture ambiguous between the closed- and open-mouthed smile, concealing the intentions and putting the receiver on edge.
Grooming
Most non-human primates engage in social grooming of one another's fur. Grooming induces pleasurable sensations by causing the release of endorphins. Though it is a social, reciprocal behavior, the question of who grooms whom, and how much, is tightly tied up with the politics and power play of the group. Adults will also compete for the opportunity to groom infants. We can see this predilection for non-sexual touching still present in humans. The sensation of having the scalp rubbed is pleasurable, and running the fingers through another person's hair is seen as a sign of affection. However, picking nits from the receiver's hair and eating them rarely receives a similarly affectionate response.
Tone of Voice
Early studies on non-verbal communication seemed to show that the majority of our communication is non-verbal and that body language and tone communicate far more than the verbal part of the message. While this information is now disputed, it is certainly still the case that the tone of voice people adopt has a significant bearing on how they are perceived. Louder and deeper tones, especially among males, represent assertion of status, and wild, higher pitches represent anger. This can certainly be recorded among other primates, which, though they have particular "words" or patterns of call to represent specific predators or food types, do much of their communicating through the volume and pitch of their voices. However, the distinct way in which certain patterns of pitch and tone influence behavior differ between humans and non-humans. Humans use rising tones to show approval, staccato to inhibit behavior and lengthened tones to soothe. This is particularly noticeable in the way humans speak to infants. These patterns do not have the same effect on non-humans. Researchers have suggested that this is why non-humans do not respond to human music, while music composed using sound patterns derived from recording of monkey calls has a noticeable effect on their behavior.