A few weeks ago I was at a friend’s house sitting chatting in his kitchen, when his 11 year old son came in and poured himself a glass of milk.

In the process of pouring it from the container some splashed out of the glass and onto the worktop.  Without hesitating he flicked his hand down by his side, this caused his slightly baggy school sweatshirt to drop down to cover half his hand.  In a deft move, he grabbed the cuff so that it now covered his palm as he extended his hand back up, and he mopped the small puddle of milk with his improvised, ever-ready cloth.

My immediate reaction was of slight disgust.  That cuff was going to smell pretty ghastly within a few hours.  Whilst I hoped his was a calculated act, the last use of a sweatshirt destined for the wash, I suspected by the casual manner of his mopping, that this was an ingrained habit, designed to avoid getting shouted at for leaving spilt milk on the counter.

A couple of days later I found myself in a similar situation.  The milk I was pouring onto my breakfast cereal had got slightly out of control and landed laterally with just enough force to break the orbit of the bowl and escape to the outer space of the kitchen table.

I caught myself flicking my wrist down and moving my sleeve-covered palm towards the milk.  Fortunately, I stopped myself and did the decent thing and fetched a cloth.  But I realised that, until I’d seen my friend’s son improvise with his sleeve, it had never occurred to me to do so.  Now, however, the concept had deposited iteself into my unconscious mind and I was going to have to consciously defeat it (or else smell of festering milk).

Researchers recently devised a clever study that explored how the negative presence of others can influence our own behaviour.

People were invited to take part in a survey that included a picture of either an overweight person, a person of appropriate weight for their height, or an everyday object (a lamp was added as a control).

After completing the survey, participants were invited to help themselves from a bowl of candy.

When people had been looking at an overweight person whilst completing the survey they took more of the sugary snacks than the people who saw the other pictures.

In a related study, people invited to do a cookie taste test ate twice as much when they’d been shown someone overweight in the lead-up to the test.

Whilst we might like to believe we’re autonomous, self-reliant agents, charting our own course through life, the evidence suggests that we’re constantly evaluating what other people are doing and referencing it when making our own decisions.  Consumer behaviour is no exception.

This study has particular implications for people involved in health or wanting to lose weight themselves: you can see why obesity can become an epidemic; once there is a sufficiently high proportion of overweight people in the population others may reference them unconsciously when making decisions about how much to eat themselves.

But it’s also an important reminder about the power of social proof: it’s also the case that our consumer behaviour is driven by the constant referencing of what other people are doing and allowing it to influence the decisions we take.  Doing what you can to ensure that potential customers see current customers choosing and enjoying your product or service is likely to reap dividends.

Source: Margaret C. Campbell and Gina S. Mohr. Seeing is Eating: How and When Activation of a Negative Stereotype Increases Stereotype-Conducive Behavior. Journal of Consumer Research, October 2011 (published online March 17, 2011) DOI:10.1086/659754