It was a classic episode on the old "Candid Camera" show -- people getting on an elevator and turning backward just because everyone else did, and we all laughed.
We laughed again during the movie "Mean Girls," when an act of teenage revenge, cutting nasty Queen Bee Regina's T-shirt during gym class -- an act meant to insult her -- became a school fashion trend instead.
It turns out the joke is on us. These two examples illustrate something that we humans don't like to admit about ourselves: We follow the pack. Like birds in a flock or sheep in a pasture, we follow -- sometimes at our own peril.
But why are people so conformist? That is the question that Dr. Gregory Berns, an associate professor of psychiatry and behavioral sciences at Atlanta's Emory University, tried to answer in a recent groundbreaking experiment and paper.
"Primetime" set up its own demonstration recreating Berns' work.
We gathered a group of people together for a test of "visual perception." The actual test was simple -- to mentally rotate some 3-D shapes and compare them to see whether they were the same or different.
First, the volunteers wrote down their answers to 10 questions privately. But then they had to give the next series of answers out loud for everyone to hear.
But this test came with a twist. One of the participants, Jocelyn, was in on the experiment, with the answers in her hand. Everyone else had been told to follow her lead, except for one participant, Tony. He's the only person in the room not in the know. He was being set up to see whether he would follow the pack.
When the group gave the right answer, Tony agreed. And when everyone gave the wrong answer -- Tony still agreed.
Unwittingly, Tony had demonstrated Berns' point precisely. The group's influence on Tony profoundly altered the results: He went from 90 percent on his written test to 10 percent when he heard the others' answers.
"You know, five people are seeing it and I'm not. … I just went along with the answers," Tony said.
Tony wasn't alone. "Primetime" put seven other unsuspecting test subjects on the hot seat. Barbara, for example, got 70 percent on the written test, but her score fell to 30 percent when she listened to others' answers.
"I think I tend to do that, doubt myself when everyone else has their own opinion," Barbara said.
David and Graham, unlike the others, gave the right answers, even when the group didn't.
"I wanted to go with what I felt was the correct answer, and trust myself, and that's what I did," Graham said.
"Primetime" tried out another scenario, this time in a more social, relaxed setting. We invited a group of strangers to Jean George's Asian restaurant in lower Manhattan for a fabulous dinner -- and a surprise.
Party planner Colin Cowie and his friend, Donna D'Cruz, were in on the experiment. Their role was to exhibit outlandish behavior most people wouldn't dream of while out at dinner with a group of strangers.
Cowie and D'Cruz licked their fingers, a dinner table no-no. Cowie picked his teeth. The guests initially seemed not to take the bait -- until dessert rolled around.
D'Cruz told everyone they should pick up pieces of mango face first, using their mouth. Eventually, people who were total strangers at the beginning of the evening were passing fruit back and forth, mouth to mouth.