I have mixed feelings about Derren Brown – I’ve often been intrigued, and sometimes been horrified, at the things he puts people through – but a show of his that I saw recently had me completely gripped. Taking apparently average members of the public, he took them through a series of events leading to a point where they’d have to consider pushing someone off a building, presumably to their death. If you’ve got it recorded, spoiler alert – astonishingly, 3 of the 4 people featured in the show actually did it. Of course, it was a stunt and nobody actually died – but they didn’t know that at the time.

Don’t get me wrong – they specifically screened participants to make sure they found people who were socially compliant, and then set up a complex series of events that applied more and more pressure, leading up to the point where they were asked to do something most of us would consider unthinkable. I’m not suggesting that people can be pushed to that point easily. But it made an important point: we are most socially compliant, most willing to go along with a group even against our own better judgment, when in a group of strangers.

For me as a researcher, this raised a pretty fundamental question about group composition: if group effect can lead someone (apparently) to kill someone, surely it can have some effect on what they say about their eating habits, what their kids watch on TV, their standards of household cleaning – any subject, really, where there’s a possibility they’ll be judged.

What Derren Brown did was lead people to a course of action: we all know that moderators can lead people to say or do certain things, and equally that we’d never choose to work with anyone who does – but the point about strangers is important. Traditionally, we’re taught that research groups must be made up of strangers: that people are more honest if they don’t know who they’re sharing their stories with, that their privacy is protected because they’ll never see these people again, and that people who know each other would obviously agree with each other and so give us a more limited range of opinions than we’d get from a group of strangers. But the idea that being with strangers makes us more socially compliant makes friendship groups seem a whole lot more relevant. Among adults, they’re generally used only when the subject requires a specific dynamic, but we often use them with children to provide them with both the confidence to speak their minds, and the challenge to speak the truth – often adults need just the same things.

We’ve all seen group participants posturing, knowing they don’t really live on kale and spend 12 hours a day in the gym, but unable to challenge them without causing embarrassment, discomfort or conflict. Their claimed perfection can be contagious, with others in the group either feeling they must agree, or worse still, trying to out-perfect the rest. Young first time mums, for example, often feel under so much pressure to raise their babies as perfectly as possible that groups can become a kind of competitive show & tell – not exactly helpful in uncovering what’s really going on. Yet among friends they’ll admit that perfection is pretty exhausting, and look to share experiences in a more collaborative and supportive way.

We’ve also seen people who we knew disagreed with the consensus of the group but lacked the confidence to say so: in the same new mums context, who dares be the first to suggest that they didn’t love the natural birth experience and next time might consider other options? In a group of strangers, we don’t know how they will react to us going against the grain – and for moderators, focusing in on specific individuals who we think want to disagree but dare not can simply increase the participants’ discomfort by highlighting their difference from the group’s assumed ‘norm’.

Surrounding participants with friends can help on both counts, and far from compromising the veracity of what they say, it can give us far more real, honest insight into their lives. Plus their comfort with each other puts them at ease to speak naturally, giving us the opportunity to pick up on the little things they say without even thinking – so often the most valuable insights into what’s important. At East River, we’ve been broadening our use of friendship groups to a range of subjects that could make people even mildly uncomfortable about expressing a different view, and have found we’ve developed deeper, truer and more valuable insight because of it.

So whilst there’s a place for the comfort of strangers, helping people out by giving them the support of their friends could have wider relevance than we’ve acknowledged in the past. And possibly avoid people being pushed off tall buildings.