Sandra Scarr identified four factors that explain differences in siblings. Mateo and Daniel are brothers who have very different relationships with their peers. Mateo is outgoing, well-liked, and has many friends. Daniel is more reserved, is often teased, and has few friends. Explain these differences using Scarr's ideas (they are numbered below). In your answer, provide a specific example for each factor.

1. Genetic differences
2. Differences in treatment by parents and others
3. Differences in reactions to similar experiences
4. Different choices of environments