How much of that cake should I eat? How much of that broccoli should I serve myself? Neither are highly thought provoking questions and it is for this reason that such questions are actually quite interesting. There is an explicit assumption that we eat based on hunger and our body telling us what it needs. But the story isn’t so simple. Often factors in our environment will be making us do things we probably don’t want to do. Most people like company, but at the same time most people want to maintain a fairly slender build and not overeat. This blog discusses how the two don’t always go hand in hand, very much akin to dieting and cheesecake. A wealth of research examining the psychology of eating behaviour suggests that we model how much we eat on what those around us are eating. A good example of such a study is that of Salvy et al. (2009). Here participants were invited to participate in a study that was cheekily labelled as an investigation of social interaction. Little did the participants know it was actually about food. Participants were either paired up with a friend or another participant and left at a table with a running tape recorder to discuss favoured past times. The researchers also conveniently left some bowls of snacks on the table.
The findings were pretty clear. The more one participant ate, the more the other did. Whether with a stranger or friend this finding was the same. If you eat more, so will I. Quite interestingly this was very much the case with female participants, but didn’t appear to influence males in the same way. What was going on? We don’t have the time here to go too far off topic. But previous research has actually found that males can also be prone to this social influence effect too.
Other studies have used some clever deception by getting one of the researchers to pretend to be the ‘other participant’ in the study. Therefore, the researchers can control exactly how much is being eaten by one party. Again, the more the fake participant eats the more our real participant eats. It is a striking effect. Such an effect is even observed when participants have been instructed not to eat for a day! In a study by Goldman et al. (1991), even when massively hungry if the confederate ate next to nothing our starving participants followed suit. Eating behaviour being massively driven by social cues ahead of signals coming from the depleted and hungry body.
Why such a big effect? One explanation is the need to use other’s behaviour as a guideline for what we should do. Nobody wants to come across as greedy or a bit weird. So eating similar amounts to our eating partners may in part help us out with this problem and reduce feelings of being different or an outsider. Yet, research by Roth et al. 2001 takes this social eating effect even further and shows social eating without any socialising! Here participants were left alone with a plate of cookies and asked to complete ratings concerning sensory qualities of the cookies. Before leaving the researcher told each participant to ignore a piece of paper on the table he had left there ‘by mistake’ which noted down how much previous participants had eaten. As you might expect this was either quite a lot of cookies or very few. And as you are right to guess, regardless of participant weight, hunger, gender or dieting status, the amount of cookies eaten was strongly influenced by a group of people that weren’t present and didn’t even exist.
If we all had friends that eat very little in social situations then surely we would be onto a winner? This seems like a logical explanation, but an awful lot of research suggests most of do eat quite a lot when with others. Psychologist John De Castro has done a huge amount of research tracking how the number of people present at a meal influences amount eaten. Usually this has involved participants keeping a stringent diary of their days activities, including when, what, where and whom they ate with. The general finding: the greater the number of meal companions, the greater the number of calories consumed. Individuals often eat as much as 40-50% more when eating in a group than when eating alone. Friends seem to come at a price.
So what I hear you say? Who cares if I eat a lot with my friends? You only live once. This is true. But as we all know – unhealthy eating and weight gain all come at a cost which is likely to reduce the longevity of our one shot at life. Furthermore, there is evidence that suggests that you really are what you eat (well at least in others eyes). When it comes to food we can forge some quite terrible stereotypes based on what others eat. For example, Vartanien et al. (2000) showed participants a video of a young female eating a small or large meal alone. The findings ? If participants saw the young lady eating a lot she was thought to be more manly and also messier. The latter trait is quite intriguing. One suggestion is that it is due to an association that people who eat less are more self controlled and thus tidier.
Some Thoughts
Think before you eat. What do you really want from this meal? Nourishment or social approval?
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