The Wave- the Power of Herd Mentality During Teen Years

How is herd mentality so powerful during teen years?!
I will start this by telling you a short story. When I was a little girl, my father bought us a dog. I was the only child in our family. The dog automatically chose my dad as his leader. He went with him everywhere. He took good care of him and protected him from the adversities that he may have otherwise faced.
When my little brother was born, my father helped my mother take care of him. The dog started to feel jealous. He noticed that someone had stolen from him the attention that he had once got from my father. Therefore, he decided to take the baby’s place and started to lay down on his bed and did not get down. So we were forced to call my father from work to make him go down because he obeyed only him and no one else!
The day after, at school, we discussed in class how animals connect to people. I was bewildered by the dog's behavior and I told them about it. I really did not know what was wrong with him. The teacher told us that dogs and other animals choose one of their group to be their leader. They choose the strongest and the biggest one to be their leader and he is known after that as the "alpha".
This manifestation is called “The Herd Mentality”. The word herd in this expression means group of animals, and mentality implies a certain frame of mind. The term refers to the way a large number of creatures act in the same way at the same time.
While the term mentality applies only to humans. Herd mentality is based on fear reaction to peer pressure that makes individuals act in order to avoid feeling "left behind" from the group. Herd mentality is also sometimes known as "mob mentality".
Mob members do not like outsiders; they fight for their group and for their leaders, and they do not allow anyone from the outside to get involved in their private group affairs. They will not hesitate even to hurt him!
I believe that herd mentality fits human beings as well. Many historical events that took...