Studies of behavioural interventions (trying to make people lead more healthy lives) consistently show small effect sizes. An effective smoking intervention would improve quit rates by four per cent1 and a successful weight loss intervention would do well to produce a sustained weight loss of more than five per cent of body weight.2
The really big gains in public health have come not from behavioural change, but from public legislation. Take a few examples:
- Forcing tobacco companies to advertise the harms of tobacco.
- Raising taxes on alcohol and tobacco.
- Seatbelt legislation.
Governments are now considering legislation, regulation or fiscal policies to reduce excessive calorie/sugar consumption. But can we really rely entirely on these measures – should we withdraw funding for research into improved behavioural interventions? I don’t think so for two principal reasons:
- There are limits to what can be achieved by public legislation. A classical example was prohibition in America in the 1930s. In the end, it did far more social harm than good. There are limits to how far we can get by coercive means. Very high taxes on tobacco can actually increase consumption by fostering a lucrative black market.3 History repeats itself. Sooner or later, we’re going to have to rely on individual motivation to provide health gains that cannot be achieved by government action alone.4
- Many interventions, although of modest effect, can still be highly cost effective. It might be true that a behaviour change can achieve only a four per cent reduction in smoking but the interventions are often relatively inexpensive, and the health effects of a four per cent reduction are impressive when compared to many clinical treatments. In short, we should not be deflected from doing what we can to promote behaviour change on the grounds that the effect sizes are of small magnitude – they are often worth having, i.e. highly cost effective5.
Of course, all this leaves open the important question of how best to achieve behaviour change. There are a large number of psychological and social theories, such as the ‘stages of change’ model6. Incidentally, these theories do not exist in competing or water tight compartments. Many have similar or overlapping elements. One of the theories receiving a lot of current attention is so-called ‘nudge’ theory7,8. I am a very strong supporter of this theory, from both philosophical and psychological points of view, as follows:
- Philosophically, this theory makes a lot of sense. It is not illiberal (unlike very high taxation or prohibitions) and recognises human autonomy. In short, it is not coercive. However, it does seek to help people promote their own long-term aims, and overcome short-term impulses. In other words, it seeks to support people when they try to maximise their long-term objectives but succumb to short-term gratification. This philosophical idea is predicated on the notion that there really is a difference between these two things – long-term objectives and short-term gains and that a person can freely choose to place limits on their future options.
- This is where modern psychological theory comes in. Traditionally, psychologists have held the view that the acid test of a person’s preferences is their expressed behaviour. If you really want to know what a person thinks about something then their behaviour is the most reliable test – a tenet of behaviourism. However, this does not conform with modern neurophysiology. For instance, it has been found that there are two circuits, one governing desire and the other governing gratification. These are only weakly linked9.
It thus seems both philosophically and psychologically entirely cogent to argue that people have two different kinds of motivation which may be in conflict – their long-term aims and desire for short-term gratification. In short, simply yielding to temptation is not tantamount to expressing an ‘overriding’ or ‘genuine’ preference. No, the brain is modular and can quite easily hold two contradictory beliefs at the same time. In fact, Homer anticipated all this, with the story of Odysseus, who had himself lashed to the mast so that he would not be able to destroy his boat in a desperate lunge to requite his desire for the sirens.
My own University of Birmingham is planning to collaborate with Professor Nick Chater’s group of behavioural psychology, at the Warwick Business School, in taking these ideas forward. We are forging links with the local authorities, both here in Birmingham and in Coventry, so that we can add to the scientific basis for behaviour change.
1. Hughes JR, Keely J, Naud S. Shape of the relapse curve and long-term abstinence among untreated smokers. Addiction.2004;99(1):29-38
2. LaFaive MD, Nesbit T. Higher Cigarette Taxes Create Lucrative, Dangerous Black Market. http://www.mackinac.org/18128 (accessed 26 April 2013).
3. Anderson JW, Konz EC, Frederich RC, Wood CL. Long-term weight-loss maintenance: a meta-analysis of US studies. The American Journal of Clinical Nutrition.2001;74(5):579-584
4. Teixeira PJ, Silva MN, Mata J, Palmeira AL, Markland D. Motivation, self-determination, and long-term weight control. Int J Behav Nutr Phys Act .2012;9(22):1-13
5. Bader P, Boisclair D, Ferrence R. Effects of Tobacco Taxation and Pricing on Smoking Behavior in High Risk Populations: A Knowledge Synthesis. Int. J. Environ. Res. Public Health.2011;(8):4118-4139
6. Prochaska JO, DiClemente CC. Stages and processes of self-change of smoking: Toward an integrative model of change. Journal of Consulting and Clinical Psychology. 1983;51(3):390-395.
7. Thaler R, Sunstein C. Nudge: Improving Decisions About Health, Wealth and Happiness. 1st ed. London. Penguin Books; 2009
8. Nick Chater. Lessons in Nudge Marketing: Wy nudges work… and why they don’t. http://portal.sliderocket.com/ACXHL/Nudge-Marketing-Event-07-07-2011 (accessed 26 April 2013).
9. Bauer M. How to Avoid the Temptations of Immediate Gratification. http://www.scientificamerican.com/article.cfm?id=how-to-avoid-the-temptations-of-immediate-gratification (accessed 23 April 2013).