I think being different in a family is natural. If everyone in a family was the same, they might argue more because they want the same things. Having different likes helps avoid fights. So, it seems like it's part of our nature. But, our experiences also shape our personality. For example, if a brother goes through something tough that his sister doesn't, it will affect his personality.

Individuals in the same family can have different personalities because of their unique experiences. For instance, different friendships and hobbies contribute to each person's individuality. Also, the independent experiences they go through, like traveling alone or facing personal challenges, play a big part in shaping their personality.

Different personalities within the same family can stem from psychological development factors. For example, varied parenting styles can influence each child in unique ways. Also, the birth order theory suggests that a person's position in the family can impact their personality, like how firstborns often have different traits compared to younger siblings.