People don't stop developing when they reach adulthood. The process of social development is something that continues throughout most people's entire lives. Once a person becomes an adult though, the influences and stimuli that affect social development change. When you are a child, your parents and school are the largest factors in social development. As an adult, the influences are much more varied.
A shift in the way that people transition from adolescence to adulthood has taken place in western industrialised countries. Teenagers are taking longer, often up to the age of 25 to explore the period of early adulthood. This results in a greater Tange of education, experiences and change before settling into adulthood. This period of emerging adulthood often includes people being exposed to risky behaviours. The way that a young person deals with and either embraces, conquers or avoids those behaviours will shape their social path after emerging from this time in their life.
The career that a young adult enters into plays a large part in determining the types of social skills he develops and the social norms that he finds acceptable. Careers affect almost every aspect of life for an adult. Largely, this is due to the income that a person earns. However, social opportunities, status, location and even political affiliation can be shaped by career choices.
The relationships that adults form play a large part in the development of personal character. A person forms friendships, business relationships and romantic partnerships. The way that a person exists within the definition of a relationship and the social circles that a relationship pulls a person toward influences how that adult will develop from a social perspective.
Age and experience play a role in social development. An older person usually has had a number of life experiences that provide a perspective and an experience that cannot be gained in any other way. As a result, people with more life experience often tend to be more tolerant as their perspective become wider. A realisation of the commonality of the basic needs of all people is the kind of realisation that some people grow into.