Asociality refers to the lack of motivation to engage in social interaction, or a preference for solitary activities. Asociality may be associated with avolition, but it can, moreover, be a manifestation of limited opportunities for social relationships. Developmental psychologists use the synonyms nonsocial, unsocial, and social uninterest. Asociality is distinct from, but not mutually exclusive to, anti-social behavior. A degree of asociality is routinely observed in introverts, while extreme asociality is observed in people with a variety of clinical conditions.

Asociality is not necessarily perceived as a totally negative trait by society, since asociality has been used as a way to express dissent from prevailing ideas. It is seen as a desirable trait in several mystical and monastic traditions, notably in Hinduism, Jainism, Roman Catholicism, Eastern Orthodoxy, Buddhism, and Sufism.

Introversion is "the state of or tendency toward being wholly or predominantly concerned with and interested in one's own mental life." Introverted persons are considered the opposite of extraverts, who seem to thrive in social settings rather than being alone. An introvert may present as an individual preferring being alone or interacting with smaller groups over interaction with larger groups, writing over speaking, having fewer but more fulfilling friendships, and needing time for reflection. While not a measurable personality trait, some popular writers have characterized introverts as people whose energy tends to expand through reflection and dwindle during interaction.

In matters of the brain, researchers have found differences in anatomy between introverted and extraverted persons. Introverted people are found to experience a higher flow of blood to the frontal lobe than extraverts, which is the part of the brain that contributes to problem-solving, memory, and preemptive thought.

Social anhedonia is found in both typical and extreme cases of asociality or personality disorders that feature social withdrawal. Social anhedonia is distinct from introversion and is frequently accompanied with alexithymia.

Many cases of social anhedonia are marked by extreme social withdrawal and the complete avoidance of social interaction. One research article studying the individual differences in social anhedonia discusses the negative aspects of this form of extreme or aberrant asociality. Some individuals with social anhedonia are at higher risk of developing schizophrenia and may have mental functioning that becomes poorer than the average.

Scientific research suggests that asocial traits in human behavior, personality, and cognition may have several useful evolutionary benefits. Traits of introversion and aloofness can protect an individual from impulsive and dangerous social situations because of reduced impulsivity and reward. Frequent voluntary seclusion stimulates creativity and can give the individual time to think, work, reflect, and see useful patterns more easily.

Research indicates the social and analytical functions of the brain function in a mutually exclusive way. With this in mind, researchers posit that people who devoted less time or interest to socialization used the analytical part of the brain more frequently and thereby were often responsible for devising hunting strategies, creating tools, and spotting useful patterns in the environment in general for both their own safety and the safety of the group.