Pick Your Friends Carefully (they may carry viruses)

We are hugely social animals and spend much of our time around others. Our nine to five jobs, our family, choice of friends and our choice of spouse mean that we spend a lot of time in the company of the same people day in and day out. It is almost unavoidable not to be surrounded by others. But why? Aside from the way the modern world is set up, there is also some strength in an evolutionary approach that would suggest we are social because it has served us well in the past. Avoiding sabre tooth tigers, hunting and raising young are probably a little easier with social support.

This blog will discuss a side effect of being surrounded by the same people everyday. The side effect is almost Hollywood in its nature and implies that to some extent, we might be able to ‘catch’ depression or obesity from those around us. An infamous study of health and well being is known as the Framington Heart Study and the set up of this piece of research allowed the investigators to track the mental and physical health of extremely large numbers of individuals over 20-30+ year time frames. It is a gold mine for evaluating and assessing how behaviour and people change over time. Furthermore, researchers have access to similar information for spouses, friends and neighbours. Therefore, using longitudinal statistical methods it is possible to examine some quite interesting research questions.

Does your spouse or sibling gaining weight increase your chance of becoming obese? Does the happiness of those around us make us happy and optimistic people too? These questions have been addressed by Harvard researcher Nicholas Christaki & University of California’s James Fowler. The effects are interesting to say the least. For example, data appears to suggest that having a friend close to us who becomes happy greatly increases the likelihood of the level of our happiness also shooting up in the near future (as is the case with neighbours and spouses). What’s more, in one study the researchers report that having a friend that has become obese greatly increases your chances of becoming obese (an alarmingly big 50% increase). Furthermore, data is suggestive that depression may also work similarly. A now dated study from the 80’s supports this premise by showing how being assigned to a university dorm with a roommate that was mildly depressed resulted in increased depressive symptoms over several months.

The analysis is also interesting because in some of the studies we see that such social spreading of emotions or weight are dependent on gender. In that you are much more likely to be affected by a person if they are of the same gender. There is also suggestion that it isn’t simply a case of people surrounding themselves with others who are similar. (E.g. two friends happiness could be similar not because ones mood has made the other happier, but because both only tend to associate with happy people) Because the data analysis can help to control for this and track individuals over time, the researchers suggest that things like happiness or obesity can ‘spread’ through social networks, almost akin to a computer virus.

If this is really happening then how can it be explained? One such mechanism is social norms. We look out to those around us to help us define what is normal and acceptable. Therefore, if our friends around us are splitting up with husbands and wives we consider this option too. This may be particularly important when considering the possible spread of obesity. Could having friends that eat a lot result in us eating a little bit too much on a regular basis? In a study with University of Birmingham students, our laboratory has presented some results that back this idea up. Leading participants to believe that ‘previous participants’ had either eaten a lot or eaten very little during our experiment greatly influenced the amount of snack food the participants decided to eat later on in the session. A problem with this social norm idea is that it probably can’t fully account for happiness or depression. It doesn’t seem quite right that somebody may become depressed because it seems the normal thing to do.

One explanation may be quite direct; seeing someone happy is quite nice and one can’t help but smile. Yet, there is a further and perhaps more intriguing explanation. A large amount of research has shown that we have a tendency to unconsciously mimic the actions and facial expressions of others. It could be thought of as a form of social ritual and there is some suggestion that this takes place to ease social relations. Indeed, people do tend to like those that are similar to them. A study reported by Rick van Baaren and colleagues in 2004 has shown that mimicry can lead to advantages. Researchers instructed a waitress to either mimic customers and repeat their order or stay quiet. The mimicking waitresses ended up being awarded significantly more tips! In addition, we are more likely to mimic facial expressions of people we view as part of our group and similar. So, this natural inclination to mimic those around us may result in us copying their expressions and behaviours, which over time could be for the good or the worse. Fingers crossed your friends smile a lot then.

Findings concerning the impact on (effects) those around us have on us raise some interesting questions. If these results hold up then it is conceivable that previously a husband will have completely unintentionally tipped a wife into a series of depressions. If they were to become aware of this then what would they do? Is it right to cut off people that make us unhappy? Secondly there are also parallels to passive smoking. Because the habits of smokers result in adverse health effects we now see a nationwide ban on smoking in public places. Using the same logic, should we be making depressed people huddle together outside nightclubs and bars? Or have separate sections for obese people in restaurants? Both depression and obesity have been associated with a variety of illnesses and reductions in life expectancy…..

Pay Attention

Over 60% of America is overweight or obese and the UK isn’t trailing too far behind either. Furthermore, depending on which statistics you choose to look at there are projections that near enough everybody will be obese in the not too distant future. So why is everybody so fat? The obvious answer is that energy intake (how much food you eating) and energy expenditure (how many calories you are burning) are imbalanced. Which is a shame because obesity is quite a big health problem. With it often comes heart problems, type two diabetes or even an early grave. Additionally, even if you aren’t obese, sitting next to a very large person on a long distance flight is unpleasant. Nobody is a winner when it comes to obesity. Although there are many mechanisms by which people end up over eating this blog will describe some research that suggests that a lack of attention and failing memory may be contributing to bigger waist sizes and broken scales.

A study by Wansink and colleagues (2006) helps to underline one of these ideas well. During the Superbowl the researchers invited some university students to a free Superbowl party (very kind). At the party was of course a big screen with the game on, but also free drinks and a chicken wing buffet. Participants were invited to go to the buffet as many times as they liked, pick up some wings and then return to their tables to enjoy the game and food. However, there were also some waitresses involved. Tables of participants were assigned to one of two conditions. In the first condition the waitresses would clear the plates of chicken wing bones as they mounted up. In the second condition the waitresses were instructed to leave the plates on the table. So half the participants were surrounded by evidence of the amount of food they had eaten (in the form of bones) and the other half were reliant on their memory of how much they had eaten. Why do this? The idea here was that by leaving the bones on some tables this would direct attention towards how much each individual had eaten. Whereas, constantly clearing the plates has essentially the opposite effect.

The difference this made was fairly substantial. Having the bones as a reminder of food intake resulted in these participants consuming around a third less than participants that had their tables continuously cleared. The dirty plates appeared to serve as a record of how much had been eaten and informed participants whether to over eat and go back for more. Thus, having reminders of what food we have eaten might be rather useful, as our memory for fine detail can be questionable. For example, buffet style restaurants evoke a tendency to horrendously over-eat. Although greed probably has something to do with it, a failure to recognise and register how many of those very average tasting prawn crackers you’ve already put away may also be fuelling further overeating.

Television viewing also appears to be a bit of a problem in relation to obesity. Watching TV doesn’t burn many calories but there are further problems, especially if you are eating whilst channel surfing. An ample number of studies have shown that putting a bowl of M&Ms or popcorn in front of a person watching TV is a bad idea. Watching television serves as a distraction from eating. You aren’t monitoring what you are eating and because of this intake will tend to increase dramatically. Attention is on the television screen and not to how much you’ve eaten or how hungry you are. But the effects don’t end there. Watching TV whilst eating lunch at midday may even cause a degree of over eating later on in the day. Dr Suzanne Higgs (my PhD supervisor and very nice person) devised a clever experiment underlining this point. Participants came into the lab and ate a standardised lunchtime meal. Some ate the lunch and watched TV, others ate in the absence of TV. Later on in the afternoon all participants returned and were asked to take part in a mock ‘taste test’ which would involve tasting some cookies and making ratings about them. Luckily there were a lot of cookies and participants were told that after completing the ratings they could eat as many of them as they liked. Of course, there was more to it than that. The taste test was a cover story and what the researchers were really interested in was how many of the cookies participants chose to eat.

The results indicated that participants that had eaten the lunchtime meal whilst watching TV ate significantly more cookies than those who ate in the absence of TV. Why? The likely explanation is memory. The theory being that participants who had watched TV would have paid little attention to the meal and therefore have a reduced recollection of how much they’d actually eaten at lunchtime. This in turn resulted in participants overeating later on because when making decisions about how much we should eat we are reliant on our memory of recent intake. Yet, if that memory is not particularly accurate then we end up eating more than we would normally

Paying attention to what one is eating would therefore appear to be important in both the short term (how many times have I been up to the buffet?) and perhaps more unexpectedly the long term too (how big was that cake I had at lunch?).

Application

Be mindful about what you are eating.