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The wisdom of crowds

There are certain studies that should be replicated. Not because the findings are controversial. Rather, because the findings are so uncontroversial that you have to experience it to get how powerful the effect is.

The "craning and gawking" study1 is one of those experiments.

Researchers stood on a busy New York city street corner and stared – craned and gawked actually – up at a 6th floor window. All the while they were being unobtrusively filmed. The researchers were interested whether the size of the craning and gawking crowd would influence whether passers-by would also look up. The entire exercise lasted about 60 seconds.

As it happens, size does matter... but even small groups have a big impact. Slightly more than 40% of the passers by imitated his behavior. When 15 researchers looked up – still at nothing – about 85 % of the passers also looked up.

What is interesting about a bunch of psychologists, standing on a corner, gawking up at nothing? This experiment offers a profound demonstration of the power of social proof as a call to action.

C'mon baby, do the Macarena...

Using the behavior of crowds to shape target behavior builds on the persuasion / influence strategy of social proof. Social proof is a human decision-making shortcut. In situations where we need to act but aren't quite sure about what decision to take, we tend to look around and check out what other people in the same situation are doing. And then we use that information to shape our own behavior. Social proof turns out to be quite powerful. In fact, in some cases it is a stronger call to action than potentially saving the world.

"Easy to use " means "Processing Fluency"

Well, does this sound familiar? This interactionist view focuses on the experience of the viewer – and that's our professional expertise: "user experience".

Our authors show evidence that the user experience associated most with identifying both truth and beauty tends to be the "fluency" with which someone can process an object. Now you have some buzz words: "processing fluency". Use these buzz words over and over until your audience can process them fluently. :)

Thus, "easier" becomes "better" or "I like it" or "more beautiful". The authors present study results that support processing fluency as a reason for saying "judgments of preference, liking, and beauty are closely related."

Thus, the interaction approach allows us to say that when a viewer experiences a web page that is easy to process or understand, they get a good feeling about their experience. This good feeling contributes to calling the web page a "beautiful design". That's "interaction" experience.

Toyota Prius

Reduce. Recycle. Reuse. I do.

Have you ever noticed the "reuse your towels" cards in your hotel room? They typically show a beautiful vista with copy describing how reusing your towel will save energy, water, and, by extension, the environment. Are you convinced? Do you reuse your towels? Most people don't.

The hotel industry seemed to think that "some do" was good enough, though. Perhaps hotel executives thought they'd hit a compliance ceiling? So they continue (today!) to print the same cards with the same pictures and the same largely unpersuasive message.

Researchers Goldstein, Cialdini, and Griskevicius, however, felt that it was the hook ("Do this to save the earth.") not the sentiment ("save the earth") that was weak. They hypothesized that knowing that other people had done it would evoke greater compliance than just saving the earth.2

To test their hypothesis, Goldstein and team created two sets of request cards that contrasted the original conservationist message with a new social proof motivator message. The gist of the messages (although not the actual messages) were:

  • Original conservationist message: Reuse your towels. It will save the earth.
  • Social proof message: Reuse your towels. Everybody's doing it.

Then they worked with hotel staff to distribute the cards throughout the rooms. And then waited to see who reused their towels and who didn't.

The result was impressive. Hotel guests who saw the "Everybody's doing it" message reused their towels 26% more than those who saw the "Save the earth" message. That represents a 26% increase over the accepted industry standard.

The researchers wondered if a shared social proof appeal could be even more persuasive through similarity. So they ran the study again. This time they included a third treatment variation, which essentially conveyed, "People in exactly your situation – who stayed in the same hotel room – have reused their towels." Their hunch was that knowing that people who had stayed in the room had participated in the desired behavior would add even more social pressure to comply.

Again they were correct. Individuals exposed to the same-room-social-proof motivator message were 33% more likely to reuse their towels than individuals in the conservationist message rooms.

It seems that the closer to home (away-from-home) the social comparison is, the more effective it is.

Are you thinking what I'm thinking?

Pointing to the behavior of crowds is a powerful way to nudge people toward behaviors that they might or might not otherwise engage in. But, remember the craning and gawking experiment? It only took one or two people looking up to get others to stop. And the first few members had the biggest impact, with the largest increase in stopping and looking behavior coming with the second and third additional gawker.

And knowing that the people in your hotel room reused their towels has a bigger impact on your likelihood to reuse your towels than knowing that people in your whole hotel did.

This suggests that, that while "other people are doing it" is a strong persuasive message, "other people like you are doing it" will be even more persuasive.

I think I'd better to go sign up for twitter now...


1. Milgram, S., Bickman, L, Berkowitz L. (1969), "Note on the Drawing Power of Crowds of Different Size," Journal of Personality and Social Psychology, 13(1), 79-82.

2. Goldstein, N.J., Cialdini, R.B., Griskevicius, R.B. (2008), A Room with a Viewpoint: Using Social Norms to Motivate Environmental Conservation in Hotels, Journal of Consumer Research, Vol. 35.

Message from the CEO, Dr. Eric Schaffer — The Pragmatic Ergonomist

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Reader comments

Michael Hughes

I think this has practical application for Help writers when we are recommending a best practice. Instead of saying "We recommend a value of..." we could say "Many users set this value to..."

Wanda Lipscomb

I'm thinking the other 66% who were not motivated to reuse their towels may include some hotel-stayers like me. When I stay in a hotel with my husband or children, I don't want to reuse my towels because I don't know which ones are really mine – they are usually all white.


I don't have a study to proove this, but I am sure (by personal opinion :-) that there's a certain amount of people who will actively reject to do what "all the others are doing". It might not be significant, but it might be worth mentioning.

Patricia Oliver

I agree that the influence of social proof is powerfull. Although I haven't read the work by Goldstein, Cialdinim, and Griskevicius, my own experience at hotels triggers some questions. I have traveled quite extensively, particularly in the past 2 years. I do hang up my towels to indicate reuse and use a card to idicate that the bed linens do not need to be changed. In all but one case, housekeeping changed my towels and bed linens irrespective of the towels being hung and the card on the bed linen. Could it be possible that the results were biased to some degree by the Hawthorne Effect and Observation Effect on the housekeeping staff (including management)?

Stuart, Curriculum Corporation

BRILLIANT, just brilliant. Wonderful article.

Wendy Loreti

The gawking example is pretty simple to explain: if there are people standing around and gawking, the implied message is "We're looking at something worth looking at."

But the "save the earth" example is somewhat horrifying. I want to ask the 33% if they'd jump off a cliff if Jimmy did. This shows a complete lack of reasoning and willingness to shut off one's mind to follow some unknown "others".

While this social proof may be a reasonable reaction to something rather minimal and concrete (e.g., everyone's running away from something and screaming, so you run in the same direction), it's terrible to think that people would apply the same process to a complex idea.


Dan M

My thought is that your two examples are very qualitatively different. When people are craning their neck to look at something, how could a human being not be curious what's going on up there? With the towels, it really does seem to be an example of people acting, essentially, like sheep.


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