Dave is a clinical psychologist with a specialization in clinical depression and suicidal ideation. one day he is walking home from work when he notices a group of 20 people standing and staring up at the sky. curious, he joins the group and sees a person on the roof of a 30-story building—seemingly preparing to jump. suddenly, someone in the crowd starts chanting "jump." soon the other 20 people start chanting as well—dave included. dave's behavior is likely the result of

The answer to this question is Groupthink
Groupthink refers to social phenomenon when a person within a group of people develp a tendency  to conform with the point of view of the majority of the group.
Since none of them dare to point out if the group is making a wrong decision, this will lead to irrational decision making outcome.

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.