This is the fifth post in a series which is studying the unconscious biases found in product development we see when we are designing and building products, or when trying to uncover precisely what’s wrong with our workplace today.

Prior posts in this series can be found here

Affinity Bias – a tendency to warm up to people like ourselves

Confirmation Bias – interpret/favor/recall information which confirms one’s preexisting hypotheses

Ikea effect – when the labor leads to love

Sunk cost fallacy – justification of increased investment in a decision, based on the cumulative prior “sunk cost”


Bandwagon Effect: We tend to believe something because other people believe it.

Why we care

The bandwagon effect is a form of groupthink in social psychology. The general rule is that beliefs spread among people just as fads and trends are spreading, along with the increased probability of any individual adopting it. In other words, as more people believe or do something, others are most likely to ‘hop on the bandwagon’, regardless of the evidence. (It’s known as the “Herd Mentality”.) As a result, a trend can form fast, and can also die just as fast. (Remember Pokemon Go?)


What is the Bandwagon Effect?

As more people come to believe in something, others join in, regardless of the underlying evidence. The tendency to follow the actions or beliefs of others can occur because individuals prefer to conform, or because individuals derive information from others. When individuals make rational choices based on the information they receive from others, economists have proposed that information cascades can quickly form in which people decide to follow the behavior of others. Cascades explain why behavior is fragile—people understand that they are based on very limited information.

The studies behind this herding mentality include experiments from Solomon Asch in the 1950s. (See Reference 1)

Asch had subjects participating in a number of perceptual tasks. However, only one person in the group was a subject, the rest of them were actors. In some of the tasks, the actors were all instructed to give the same wrong answer. The subject would answer last, and hearing these wrong answers would begin to feel pressured and question himself.  At the end, the subject was interviewed, providing us more insight about what happens when someone yields to a group versus when someone does not.

Asch’s results: In the tasks where the actors wouldn’t all give the same exact answer, the error rate was less than 1%. But in the tasks where all actors would give the same wrong answer, one third of all responses were incorrect, with 75% of participants giving an incorrect answer to at least one question. In Asch’s interviews with the subjects post-experiment, those who yielded to the group said they were suspicious of the answers provided, but tried to forget about it, or did not have the confidence and go against the majority. On the other hand, an independent subject who did not yield to the group, who also experienced doubt, was happy and relieved at the end of the experiment.

The bandwagon effect causes us to not stand up for our decisions. What’s more, it actually alters what we believe to be true. It makes us conform, curbing originality, and perhaps even helping us forget why we’re do what we’re doing.


“Hopping on the Bandwagon” isn’t always a bad thing

The Bandwagon Effect describes the interactions between demand and preference, and we see this when people’s preference for a product increases as the number of people buying the product increases.

Here are some of the ways marketing efforts are capitalizing on the Bandwagon Effect

  • User Reviews: We want to choose the best restaurant, but we don’t want to hear about how amazing a restaurant is from the restaurant itself. Instead, we will be much more persuaded to go to the restaurant if the claims are coming from an impartial consumer. Caution: you might be missing out on that wonderful, unknown restaurant around the corner that has no reviews yet.
  • Endorsements: The social influence is tremendous if a respected expert says something positive and unique about your product. Caution: If an endorsement does not match the product capabilities, it will likely affect sales. Also, if an endorser is portrayed in a negative manner publicly, then the endorsed product stands higher chances of being affected negatively.
  • Statistics of product use: We look for how many clients have already signed up to the service, or bought the product. If these stats are visible, this makes us feel reassured that we’re making the right choice. Caution: Depending on how important discretion is valued to a client, they may not want to see other’s names on your web page for fear that you will post theirs. The bandwagon effect continues here as well: if we are a start-up and see other start-ups as your clients we might be more likely to give it a try. If we see you are catering to a big, traditional company, we might not.
  • User testimonials: We are much more likely to be convinced of how great a product or service is if we hear about this product or service from an existing customer sharing their happy experience. Caution: If you get testimonials, give the clients a way to reach those who provided a testimonial. Sharing a long list of testimonials without being able to reach whoever provided it leads to the “so what” effect.
  • Social Media & social media plug-ins: The easier you make it for folks to like, follow, and share your content, the more likely they are to do so. Caution: Every business has to start somewhere, but having very low “share” or “follower” counts may give users the impression that your company is unpopular. Allow your social following to expand before you display your counts. Also: counting likes is a vanity metric (see Reference 2), and you know this doesn’t make your product great.

The good news: mental biases are not arbitrary, and thus can be controlled. The first step to reducing cognitive bias is to become aware and be informed, and educate yourself.

Go to that wonderful, unknown restaurant around the corner, and give it the first review!



  1. 1. For the original video of this experiment, check out
  2. 2. For the difference between vanity metrics versus actionable metrics which can be used to improve the performance of your product, here’s a clip from an interview with Eric Reis on Techcrunch: