Temperament is each person's unique way of thinking, behaving, and reacting to other people and situations. Although every person is different, basic patterns of temperament exist, such as being shy and withdrawn or outgoing and eager to try new things.
Temperament often affects a person's:
Temperament is greatly shaped and affected by a person's life experiences and environment. For example, a shy child who is hugged and praised often will develop self-confidence. This helps him or her respond in a positive way to new situations.
Temperament may change over time as a person ages.
WebMD Medical Reference from Healthwise