Groupthink is concept where when people of a group need to come to a consensus on a topic they tend to work towards coming up with an idea thats favored by all instead of putting actual thought into the decision. This is very counter productive becuase the point of creating groups is to combine everyones knowledge and in fact it just dumbs everyone down.
Personally ive experienced this a lot. It seems to me that when im in groups everyone seems to have much less input then if it where their actual opinion. Sometimes in group when we split the work amongst the group we can get more thoughtful input on each little bit and end up with a final product that reflects the groups combined intellect. I had more typed out but i just tryed adding a picture and it deleted this whole blog post and i had to do it over -_-