Biologically, an adult is a human or other organism that has reached sexual maturity. In human context, the term adult additionally has meanings associated with social and legal concepts. In contrast to a "minor", a legal adult is a person who has attained the age of A group of adult people. Historically and cross-culturally, Young adult (psychology) · Adult development · Adult (disambiguation) · Adultism. Participants were categorized by age into young adults (ages 18–35 years; n = 97), middle-aged adults (ages 36–55 years, n = ), and older adults (aged older than 55 years, n = 49). Differences in demographics, gambling variables, and ASI composite scores were compared across the groups.