Why humans copy others, and why that’s great for marketers

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Ed Barter, lead data scientist at Herdify

Ed Barter | 2 November 2022

I’m here today to talk about influence and the science and research that other people and I have done. These can and should affect how we think about influence and marketing – when using Herdify and when not.

I want to start with a quote, “thinking is to humans as swimming is to cats,” a quote from Daniel Kahneman, a Nobel Laureate neuroscientist.

I’m pretty sure that quote’s from a popular book he wrote called Thinking fast and slow. I must admit I haven’t actually read the book, but the quote came to me by word-of-mouth.

It’s a quote that’s shared a lot in marketing blogs as well, and what I’m going to talk about tonight is :

  • What it means
  • How we can use that, and
  • The insight it gives to govern our marketing

So, to complete the quote, “thinking is to humans as swimming is to cats; we can do it, but we’d rather not.” 

The insight that Kahneman is getting at here is that whilst we can think that we are the most sentient of animals as we have the largest brain size to body ratio, we actually like to avoid thinking as much as possible.  

There are many evolutionary reasons, but the key is that we don’t like to think very much. One of the main ways we avoid thinking is by copying people around us and copying the decisions that others have made.

So we effectively outsource our decision making to other people by letting them make our decisions for us. We then copy those decisions once they’ve already been made. 

Now collectively, when you get lots and lots of people doing that, you end up with humans behaving as herd animals. 

One study from the early 2000s showed that you could generate the success of brands like the iPhone, for example, in simulations where everyone copies at random. There’s no concept of products being better than each other and no concept of how much money they’re spending on marketing. 

You can create super-successful products just through random copying. I’m not saying that means we don’t need marketing and we shouldn’t be bothering with it, but I’m saying that it gives us some insight that there’s this powerful force that we as marketers want to be working with, rather than against. 

How do we bring that kind of thought into our campaigns? The first thing to do is to understand how influence works. There are three key kinds of factors that make influence or influence more likely to happen between two people:

  1. Being genuine
  2. “People like us”
  3. Reciprocation

But first, it’s important to understand that influence is a pull rather than a push. When I was researching at Bristol University, we researched the spread of pretty much anything! We researched the spread of opinions, the spread of products, the spread of diseases, the spread of bacteria between people. 

What we found was that when we’re talking about influencing people, we want to think about the person we want to influence rather than the person doing the influencing. 

That’s important for lots of reasons. One of the main reasons is that the connections and the relationships between people are normally not symmetric. People have done studies, for example, where they asked all the children in a high school to name their best friends. 

The study found that 80% of the links were not reciprocated – those that the children said were their best friends did not say they were their friends back. 

Being genuine

The first factor that helps to create influence is trust. A study by Neilson found that 92% of people trust their friends and family over all other advertising. 

One of the key reasons is that they don’t believe they have ulterior motives. They believe their recommendations are genuine and that lack of suspicion means they’re much more likely to take on that influence from that person. 

Being genuine is really important to humans. There are studies that show that you can get people to change their opinion by asking them to write essays giving the opposite opinion. 

Luckily for us as marketers, we hang around people we trust all the time. So, if you’re trying to get into communities and have influenced work through communities, you have a head start because we tend to only sometimes hang around with people we don’t trust. 

How to create influence using trust 


Work with influencers who genuinely support your product – creators who might already be using your products or look for longer-term relationships. Consistency builds that sense of being genuine. 


Referrals without monetary rewards allow you to be much more effective than referrals with monetary rewards. Try limited invitations, like Gmail did back in the day, or waitlist skips like Monzo, which let people jump up the waitlist by referring their friends to join.


You might think that people trust reviews, but generally, they don’t, so if you can verify your customers, that really helps. Also, have a realistic distribution of reviews, both positive and negative. Customers don’t really trust it if they’re all five-star reviews. Encourage customers to write something alongside their rating – Lots of five-star reviews without text can create suspicion.  


Encourage customers to gather the opinions of people they know because those are people they trust. Use questions such as “ask your family about our products”.  

People like us

The second factor to consider when it comes to influence is “people like us”.

In almost every hotel you stay in now, there’ll be a card somewhere in the room that says, “help us save the environment by putting your towels back on the rack instead of in the bath.” 

Now, whilst that does save the environment, it also saves the hotels money, and as a result, it’s really in their interest to motivate you to refrain from having your towels washed. 

A study found that hotels can motivate people by telling guests that other people are reusing their towels: “70% of people reuse their towels. If you want to join them, leave them on the rack. 

This was much more effective than any environmental message. Still, more than that, if you can make that message resonate with that person by including some form of identity in the description that they associate with, you can get them to reuse their towels at a higher rate. 

So, for example, if you know it’s a male only or a female only in the room, you can use 70% of men vs 70% of women. I think the example “70% of people who stayed in this hotel room reused their towels” is quite surprising. That’s more powerful than saying, “70% of visitors from Britain”, for example.  

So what this tells us is we associate with people on often quite odd things. Our sense of the herd or the group of people that we belong to is not static. 

As marketers, we generally associate ourselves in society with people who are like us in many different ways. We hang out with people who are more likely to have similar interests and activities as us, who are similar ages, or who have similar characteristics. People who are our friends are much more likely to have similar fitness characteristics even if they share no fitness activities. 

We also sort ourselves by behaviours like smoking, and how our cities are structured means that we end up hanging out with people of similar wealth and life stages.

I did some work when I was at the university into Bristol itself and there we found that the second most important thing that determines where people live in Bristol is affluence in the historical sense. That’s something we can use as marketers because people are hanging around people that they’re likely to copy.

How to create influence with “people like us”


You can find influencers who are already part of a community and associate with the people they might copy. A really good example of this would be gym influencers. People who go to the gym aren’t hunting out Kim Kardashian; they’re finding the person who’s the biggest guy in the gym. 

Similar to this are micro influencers because they’re much more likely to be embedded in their communities.


You can target rewards with a referral towards the person who will give the referral. So, for example, if you’ve got a customer who was there from “day one”, make sure they see new products as soon as they’re released or give them early access because they’re likely to be hanging around with people who also want early access. 

If you’ve got someone who’s always shopping at a sale, they’re likely to be hanging out with other people who also want to find those discounts, so that’s the sort of referral system that might be more effective for them.


You can go for location-based display, which is a new feature that’s about to be released in Yotpo, so you can geo-locate the user on the website and then show them reviews that are actually for the place where they’re located.

That gives a sense of camaraderie and makes them more likely to believe the review. 


You can motivate word-of-mouth within group identity, for example, saying, “talk to your neighbours about this” or “other new parents”. That works in two ways. You’re doing some of the thinking for your customers and it means people will share it with the channels where you know your product might help. 

You can also use personalised ads to motivate sharing those ads. For example, a Bristol specific ad is more likely to be shared with other people who live in Bristol. 


The final one is more abstract and that’s that reciprocation is everything. Rarely does influence happen to one person. Remember, we’re looking at this through the point of view of the person being influenced.

Those people need to be influenced multiple times. There’s a study from 2008 by Damon Centola, who did this in the US on a university campus. They were looking at a fitness referral programme by email. They found that the most effective referrer was the fourth referral. So, someone other than the person who told you about it was most likely to get you signed up. It was the fourth friend who suggested that you might want to get involved.

What this means is that as a marketer, you’ve got to build campaigns that reach people multiple times and reach people multiple times through multiple people. 

At Bristol University, we carried out some work into drone strikes. Bear with me! One way of thinking about it is that a drone strike is like a big advert for a terrorist organisation. Terrorist recruitment goes up after the US drone strikes, and what we found was that lots of little drone strikes were better recruiters for terrorist networks than one big drone strike. 

To flip that into marketing, smaller campaigns can be more effective than one big campaign because you can get people talking on multiple levels.

How to create influence using reciprocation


You can think about using influencers of overlapping communities because people are receiving those messages from multiple places. 

Two influencers with half a million followers each, and overlapping audiences, are likely to be much more effective than one with a million or even one with two million followers. 


People have lots of mutual friends. That means that if I refer someone to a programme and they’re offered a referral code, some of the people they talk to about their referral are probably the same people I’ve already spoken to. In that way, you’ll build that up to get to your magical fourth influence. 


Aggregation is key here, in terms of numbers of reviews and not an average. For example, on Google, you get the average review score. That might tell you something about quality, but it only motivates people to sign up if they’re already in the market. However, if you say over 1,000 five-star reviews, that suggests that there are lots of people who could influence you to sign up.


Target adverts to word-of-mouth areas because that becomes another impression. Your adverts in those areas are more likely to be spoken about, which means that each advert generates more impressions. Therefore your campaigns will be more effective because they will generate more secondary impressions.  

To summarise, marketers need to think about marketing to herds of people and groups rather than individuals.

I haven’t mentioned virality at all, and that’s intentional. There’s some evidence that if you spent all your money trying to go viral, your money wouldn’t be that well spent. 

Instead, by creating influence, a brand or product can be more successful – by building campaigns that pass messages between people, that are genuine, and that reach people through multiple routes from people like them.

Friends in conversation | Herdify

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Ignite your brand power: Why your offline community is the real influencer

“Social communities grow more powerfully offline, yet most marketing tactics tap into the online element. 92% of word-of-mouth – the single biggest influence on consumer buying behaviour – happens offline."

~ Ed Barter, Lead data scientist at Herdify

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