Generally, we like to think of ourselves as individuals, with habits, actions and vices all of our own design. But how much of what we do is actually influenced by the people around us?

Think about the classic pub situation. You are with your friends and say you were only out for one quick drink. Someone orders another round, and suddenly you’re having another one too. Nobody pressured you; it just felt easy to go with the flow of the group.

This is social proof at work — our tendency to look to others for clues about what is normal, acceptable or desirable.

Social proof can encourage positive behaviour, from exercising regularly to recycling, but it can also reinforce unhealthy habits, often without us noticing. When everyone around us is doing something, questioning that behaviour can feel more difficult than simply joining in.

The impact of our social network on our behaviour has been the subject of research for decades, with one of the most widely discussed examples coming from researchers Nicholas Christakis and James Fowler, who examined the connections between social relationships and obesity.

Their 2007 study, published in the New England Journal of Medicine, followed a network of 12,067 people over 32 years. The researchers found that a person’s likelihood of becoming obese was 57% higher when a friend became obese during the same period. The findings suggested that social relationships may influence behaviours and expectations around eating, physical activity and body weight.

The influence of your peers becomes particularly apparent during adolescence, when belonging and acceptance are especially important.

A 2021 systematic review and meta-analysis published in Addiction found that young people whose close friends smoked had approximately 2.5 times the odds of initiating smoking compared with those whose friends did not. Parental and sibling smoking were also associated with increased odds.

These findings highlight something fundamental about bad habits: the behaviours of people we identify with can become our reference point for what is normal/acceptable.

Psychologist Robert Cialdini and colleagues distinguish between two types of social norms: descriptive norms, which concern what people actually do, and injunctive norms, which concern what people believe is socially approved or expected.

This means, simply, that you can believe that excessive drinking is unhealthy while regularly drinking more than intended because everyone around you does.

Research into alcohol consumption illustrates how social perceptions can distort our understanding of normal behaviour, with a meta-analysis of 23 studies involving 53,825 participants finding that university students commonly overestimated both how much their peers drank and how strongly their peers approved of drinking.

This creates a self-reinforcing cycle. Individuals may drink more because they believe others are doing so, while their own behaviour contributes to an environment in which heavy drinking appears normal.

This creates a challenge for governments, educators, health organisations and brands. Raising awareness of a problem is important, but awareness alone does not necessarily motivate people to behave differently.

Technology adds a new layer, as historically, social proof largely came from the people we encountered in everyday life — family, friends, colleagues and communities. Today, digital platforms expose us to the habits of people we have never met.

Social media has changed both the scale and visibility of social influence – with platforms like Instagram, TikTok and Twitter providing us with countless examples of how other people live, consume and act. These social apps run on social approval with likes, shares and engagement proudly displayed.

This can also create an impression that certain behaviours are far more common than they actually are.

Social media apps are also blurring the distinction between social influence and commercial influence, with influencers making certain products and behaviours feel like natural parts of everyday life. An extreme example of this is the detox tea trend online, with celebrities like Kim Kardashian promoting it as a part of their daily health and body fitness routine, despite health professionals warning against it.

Social proof is no longer limited to the habits of our immediate social circle. It is increasingly shaped by highly visible, algorithmically selected examples of behaviour.

Social proof may help establish what feels normal, but breaking established habits usually requires more than information. For businesses and governments seeking to encourage positive behaviour, the opportunity is to understand the social context in which decisions are made rather than relying solely on messages directed at individuals. This is where market research comes in.

Need help on a behaviour change campaign? Square Holes have got you. 

Square Holes is a cultural insight studio.

We design mixed method explorations of people and culture beyond the category,  uncovering the patterns, tensions and shifts shaping behaviour to inform strategy, inspire innovation and enable confident decisions. Our studio model brings together the right mix of thinkers, researchers and specialists for each exploration. If you’re navigating change, entering a new market, or seeking deeper understanding of people and culture, let’s start a conversation >