Final answer:
Children over 6 years old start to learn the ability to delay gratification which has been shown to have positive long-term outcomes such as higher SAT scores and better social interactions.
Step-by-step explanation:
When children reach the age of 6 years, known as the middle and late childhood stage, they exhibit significant cognitive advancements and begin to develop the ability to delay gratification. This skill is part of their emotional development and self-regulation abilities. Psychological research, such as the pioneering work by Mischel et al., highlights the development of self-regulation through the famous 'marshmallow test', where preschool children had to resist the temptation of a small, immediate reward for a larger one later. This ability to delay gratification has been linked to many positive long-term outcomes, including academic success, as evidenced by higher SAT scores, healthier social interactions, and decreased likelihood of substance abuse.