Scholars in this field usually use a strict sense of the term "verbal", meaning "of or concerned with words," and do not use "verbal communication" as a synonym for oral or spoken communication. Thus, sign languages and writing are generally understood as forms of verbal communication, as both make use of words — although like speech, both may contain paralinguistic elements and often occur alongside nonverbal messages. Nonverbal communication can occur through any sensory channel — sight, sound, smell, touch or taste. Nonverbal communication is also distinguished from unconscious communication, which may be verbal or non-verbal.
This is less commonly discussed because it seems unproblematic, refers to movement, gestures and poses intentionally made by the person: smiling, moving hands, imitating actions, and generally making movements with full or partial intention of making them and a realisation of what they communicate. It can apply to many types of soundless communication, for example, formalized gestures.
This applies to involuntary movements that may give observers cues about what one is really thinking or feeling. The ability to interpret such movements may itself be unconscious, at least for untrained observers.
Many elements of involuntary body language can easily be understood, and tested, simply by knowing about them. For example, the tendency for people to raise their eyebrows as one approaches them fact-to-face is usually indicative of esteem. If you walk down the street and encounter someone you do not know then the chances are that neither of you will raise your eyebrows. If you recognize each other, however, even if you do not greet each another, then eyebrows will likely raise and lower. Of particular interest here in a work context is that if one is not rated highly by the other person then that person will not raise their eyebrows, even though one is recognised..
It is widely believed that involuntary body language is the most accurate way into a person's subconscious. In principle, if people do not realize what they are doing or why they are doing it, it should be possible for a trained observer to understand more of what they are thinking or feeling than they intend - or even more than they realize themselves. Interrogators, customs examiners, and others who have to seek information that people do not necessarily want to give have always relied on explicit or implicit hypotheses about body language. However, this is a field that is fraught with risk of error, and it has also been plagued with plausible but superficial or just plain erroneous popular psychology: just because someone has their legs crossed toward you, it does not mean that they want to have sex with you; it could just mean that they are comfortable with you, but it could also be how they always sit regardless of where you are. Furthermore, it is not possible to tell reliably whether body language has been emitted voluntarily or involuntarily, so to rely too heavily on it is to run the risk of being bluffed.
Research conducted by Paul Ekman at the end of the 20th Century resolved an old debate about how facial expressions vary between cultures. He was interested in whether, for instance smiling, was a universal phenomenon, or whether there are cultures in which its expression varies. Ekman found that there were several fundamental sets of involuntary facial muscle movements relating to the experience of a corresponding set of emotions: grief, anger, fear, enjoyment and disgust. He also indicates that, whilst the furrowing of the eyebrows when experiencing grief is difficult to perform voluntarily, such expressions can be learnt through practice. Ekman's ideas are described and photographically illustrated in his book Emotions Revealed.
The use of video recording has led to important discoveries in the interpretation of micro-expressions, facial movements which last a few milliseconds. In particular, it is claimed that one can detect whether a person is lying by interpreting micro-expressions correctly. Oliver Sacks, in his paper The President's Speech, indicated how people who are unable to understand speech because of brain damage are nevertheless able to assess sincerity accurately. He even suggests that such abilities in interpreting human behavior may be shared by animals such as domestic dogs.
A recent empirical study of people's ability to detect whether another was lying established that some people can detect dishonesty consistently reliably. This study showed that certain convicts, American secret service agents and a Buddhist monk were better at detecting lying in others than most people, and it is postulated that this ability is learned by becoming observant of particular facial micro-expressions.
Body language is a product of both genetic and environmental influences. Blind children will smile and laugh even though they have never seen a smile. The ethologist Iraneus Eibl-Eibesfeldt claimed that a number of basic elements of body language were universal across cultures and must therefore be fixed action patterns under instinctive control. Some forms of human body language show continuities with communicative gestures of other apes, though often with changes in meaning - the human smile, for example, seems to be related to the open-mouthed threat response seen in most other primates. More refined gestures, which vary between cultures (for example the gestures to indicate "yes" and "no"), must obviously be learned or modified through learning, usually by unconscious observation of the environment.
Argyle, M. (1975). Bodily communication. New York: International Universities Press.