Final answer:
The three major patterns of temperament are easy, difficult, and slow to warm up. These patterns are believed to have a biological basis, influenced by both genetics and environment.
Step-by-step explanation:
The three major patterns of temperament identified by psychologists Thomas and Chess (1977) are: easy, difficult, and slow to warm up. An easy temperament is characterized by positive emotions, adaptability to change, and the ability to regulate emotions. On the other hand, a difficult temperament includes negative emotions, a struggle with change, and difficulty in emotional regulation. Lastly, children with a slow to warm up temperament may be less reactive to stimuli and somewhat resistant to change but eventually adjust over time. These temperamental traits are considered to have a biological basis, appearing early in life, but may be influenced by environmental factors and maturation.