1. Romeo and Juliet's developing brains may have caused them to be overly attached to one another, making it difficult for them to think through the consequences of their actions.
2. Romeo and Juliet's developing brains may have caused them to be more impulsive, due to their lack of experience and understanding of the world, which led to them taking drastic measures like eloping and taking their own lives.
3. Romeo and Juliet's developing brains may have caused them to idealize their relationship, leading to an unrealistic perspective on how things could turn out, and causing them to disregard potential dangers or consequences.