Haptics: the study of communication by touch

Kinesics: the study of hand, arm, body, and face movements

Vocalics: the study of paralanguage, which includes the vocal qualities that go along with verbal messages, such as pitch, volume, rate, vocal quality, and verbal fillers

Proxemics: the study of how space and distance influence communication

Territoriality: an innate drive to take up and defend spaces

Chronemics: the study of how time affects communication

Paralanguage: vocalized but not verbal part of a spoken message, such as speaking rate, volume, and pitch (see Vocalics)

Immediacy behaviors: verbal and nonverbal behaviors that lessen real or perceived physical and psychological distance between communicators and include things like smiling, nodding, making eye contact, and occasionally engaging in social, polite, or professional touch

Avoid combining touch with negative criticism; a hand on the shoulder during a critical statement can increase a person’s defensiveness and seem condescending or aggressive.

In professional and social settings, it is generally OK to touch others on the arm or shoulder. Although we touch others on the arm or shoulder with our hand, it is often too intimate to touch your hand to another person’s hand in a professional or social/casual setting

I can relate to the passage referenced in the 'Example' section. Often times when I'm talking to my brother during an argument (which happens frequently) I will put my hand on his shoulder. This makes him even more mad, but it's only a pat on the shoulder. He tried it on me once when I was frustrated during an argument, and it made me even more frustrated for some reason. Now, a sarcastic pat on the shoulder is one of my main tactics to making him mad, and is probably the most aggravating thing I can do to him during an argument. When I think of communication, I would never have thought that touching someone on the shoulder was so effective.