OPINION5 October 2011

The biochemistry of temptation


As consumers, we’re all familiar with that irrational urge to buy something that’s not good for us or that we don’t really need. Some blame peer pressure, others the power of marketing. But Crawford Hollingworth says biochemistry has a lot to answer for.


As Oscar Wilde wrote: “I can resist everything except temptation.” In this piece, I want to delve a little into the evidence that exists around self-control and how science is delivering some real breakthrough insights into why we find temptation so difficult to overcome.

Stress and physical exhaustion erode self-control
While levels of self-control differ among people, they can also vary within an individual depending on circumstances. Self-control is also eroded under conditions of stress or physical exhaustion. A study by Roy F. Baumeister of Florida State University found that people low in blood sugar found rational decision-making much more difficult. High stress levels reduce the brain’s access to our ‘cool’ rational system and direct activity to the ‘hot’ system. Long working hours and increasingly busy, complex lives would indicate that we have become a more stressed society in the past two decades.

Self-control reduces our blood sugar levels
Even exercising self-control reduces our glucose levels, thus making us more likely to eventually give in to temptation. The more situations we face in which we must control ourselves, the more likely we are to relinquish control at some stage. In attempting to respond to all the exhortations to lose weight, eat healthily, drink less, exercise more, stop smoking, save more and spend less, we will inevitably fail at some point. We simply don’t have the energy to keep on keeping on. For example, if people use their reserves of self-control for demands other than saving, such as giving up smoking, they are likely to find it harder to save. Researchers have found that people are more likely to choose chocolate cake over fruit when first given the task of memorising a seven-digit number as opposed to a two-digit number. Too many things challenging our brain’s willpower or our ‘cold zone’ make it more difficult for us to behave well in every circumstance. This is probably why people make use of pre-commitment devices which allow them to ‘save’ their self-control energy for other, unforeseen circumstances.

Multi-tasking reduces self-control
Researchers at the University of Minnesota have also shown that erosion of self-control relates to impulse buying. The more participants’ self-control was eroded by a range of different attention-control tasks requiring self-control such as ‘thought suppression’ or watching a video while avoiding looking at subtitles, the more likely they were to give in to buying impulse goods such as unhealthy food. The more self-control respondents have had to exercise in earlier tasks, the higher their willingness to impulse buy – or pay higher prices – in unanticipated buying situations. This also demonstrates that the part of the brain which exercises willpower in completing a task at work or activates concentration while driving is the same part that we might call on to turn down an offer of a cigarette or a glass of wine. If we’ve had a hard day at work, requiring long stretches of our attention, the chances of us giving in to a box of chocolates or a cheeky cig when we get home are much higher.

Patience is learnt, not innate
Self-control is also something that we have to learn. We are born with only the ‘hot’, impulsive, impatient side to us, the ability to want something now that, at an instinctive level, ensures that we eat when we are hungry. Our ‘cool’ rational system which allows us to be able to wait for things only develops later on in life. We have to be taught the elements of waiting and planning which are key to self-control and this has clear implications for education policies. Studies have shown that children who grasp the notion of delayed gratification are more likely to succeed later in life. For example, the number of seconds a child is able to wait for two marshmallows, as opposed to being given just one immediately, has been found to predict cognitive and social outcomes – and even SAT scores – later in life.

Having concentrated really hard on writing this article I am now going to eat cake. It’s not my fault, it’s chemistry. Just remember the words of Mick Jagger: “It’s all right letting yourself go, as long as you can get yourself back.”

Crawford Hollingworth is a founder of The Behavioural Architects