caressing

Physical intimacy is sensual proximity or touching. It is an act or reaction, such as an expression of feelings (including close friendship, platonic love, romantic love or sexual attraction), between people. Examples of physical intimacy include being inside someone's personal space, holding hands, hugging, kissing, caressing and sexual activity. Physical intimacy can often convey the real meaning or intention of an interaction in a way that accompanying speech cannot do. Physical intimacy can be exchanged between any people but as it is often used to communicate positive and intimate feelings, it most often occurs in people who have a preexisting relationship, whether familial, platonic or romantic, with romantic relationships having increased physical intimacy. Several forms of romantic touch have been noted including holding hands, hugging, kissing, cuddling, as well as caressing and massaging. Physical affection is highly correlated with overall relationship and partner satisfaction.

It is possible to be physically intimate with someone without actually touching them; however, a certain proximity is necessary. For instance, a sustained eye contact is considered a form of physical intimacy, analogous to touching. When a person enters someone else's personal space for the purpose of being intimate, it is physical intimacy, regardless of the lack of actual physical contact.

Most people partake in physical intimacy, which is a natural part of interpersonal relationships and human sexuality, and research has shown it has health benefits. A hug or touch can result in the release of the hormone oxytocin and in a reduction in stress hormones.

Due to the important role that language-based communication plays in humans, the role of touch is often downplayed; however, there is ample evidence that physical touch still plays an important role in everyday human relationships. While humans often communicate verbally, they also participate in close contact. Physical touch has emotional and social connotations that often far outweigh anything that can be expressed via language.

Inducements towards physical intimacy can come from various sources. During colder seasons, humans as well as other animals seek physical intimacy with one another as a means to apportion thermoregulation. Some forms of physical touch among monkeys and apes serve multiple functions, including cleaning, treatment of a lice influx or infection and social grooming.

Some forms of physical intimacy may be received negatively. This attitude is especially marked amongst those with haphephobia. One study has shown that there is generally a higher level of physical intimacy allowed between immediate family members than between second-degree relatives. Intimacy norms are usually more negative near erogenous zones. Some jurisdictions may specify this as referring to the genitals, buttocks and female breasts.

Development

Physical affection and intimacy appear to have a profoundly important role during infancy and childhood. The skin is the largest sensory organ and is the first to develop. Humans experience touch as early as fetal development, when the fetus begins receiving sensory information from coming in contact with the mothers’ abdominal wall. In infancy, babies receive significant amounts of touch through being held, cuddled, and breastfed. In addition to necessary functions like breastfeeding, touch is also used to soothe and calm babies or with skin-to-skin contact called "kangaroo care". Vision and auditory senses are limited in infancy and babies are introduced to their world primarily through touch and are able to distinguish between temperature and texture.

Decreased amounts of affectionate touch from caregivers (i.e. for infants in institutional settings or infants with depressed mothers) is related to cognitive and neurodevelopmental delays. These delays appear to persist for years and sometimes whole lifetimes. Studies suggest that if depressed mothers give their infants massages, it benefits both the baby and themselves, increasing growth and development for the babies and leading to increased sensitivity and responsivity of the mothers. There are also biologically beneficial effects of infant massage, with premature infants displaying lower cortisol levels after being held by their mothers. During the holding period, the mothers' cortisol levels also decreased.

Personal space

Most people value their personal space and feel discomfort, anger or anxiety when somebody encroaches on their personal space without consent. Entering somebody's personal space is normally an indication of familiarity and intimacy. However, in modern society, especially in crowded urban communities, it is at times difficult to maintain personal space, for example, in a crowded train, elevator or street. Many people find the physical proximity within crowded spaces to be psychologically disturbing and uncomfortable. In an impersonal crowded situation, eye contact tends to be avoided. Even in a crowded place, preserving personal space is important. Non-consensual intimate and sexual contact, such as frotteurism and groping, are unacceptable.

On the other hand, most people occasionally desire physical proximity to others, and will at times welcome a familiar and trusted person into their personal space. When a partner or friend is not available at such a time, some people satisfy this need for human contact in a crowded venue, such as a bar, nightclub, rock concert, street festival, etc.

Display of affection

People who are on a familiar basis may enter into each other's personal space to make physical contact. These can be indicators of affection and trust. The manner in which people display affection is generally different in a public context to a private one. In private, people in an intimate relationship or who are familiar with each other may be at ease with physical contact and displays of affection, which may involve:
* cuddling,
* caressing (e.g. head, hands, arms, back and waist),
* tickling