Is positive thinking having a negative effect?

Positive thinking, fantasies and daydreams are pleasant to experience; studies show this can relax us with a reduction in blood pressure, and they can also help us to work out what we want in life, or how we want to feel or act by allowing us to mentally explore possible futures.

However, only ever thinking about the positive side of behaviour change or goals has been shown to be associated with being less successful for behaviour change. For example, experiments have shown that individuals who only imagined the positive effects of behaviour change, such as losing weight actually lost less weight compared to those who imagined the barriers to achieving weight loss.

How can we avoid the pitfalls of positive imagery?

Our recent research review suggests that we can increase our chances of successful health behaviour change by imagining both the future we want to create or achieve, followed by identifying and imagining the obstacles that we would need to overcome in order to make the changes. This is a technique called mental contrasting. Our review showed that mental contrasting appears to help people to successfully change their health behaviour for up to four weeks and in some cases up to three months or even two years.

What is mental contrasting?

Mental contrasting involves three steps to help individuals generate free-flowing thoughts and images for health behaviour change:

• Defining an important future health behaviour change wish
• Identifying the best possible outcome and importantly
• Identifying and imagining an obstacle in the present reality that stands in the way of obtaining the desired future.

Using mental contrasting

To set a goal using mental contrasting, individuals should start with the wish they find most important, which should be challenging but feasible. Large, long-term goals (e.g: to get fit and feel healthy can be broken into a series of smaller wishes (e.g: to be able to complete a brisk lunchtime walk), or the individual may develop a wish based on the obstacle/barrier (e.g: to walk pain free for 30 minutes.

Timeframe

Mental contrasting is suitable for both short and long term behaviour change. Any timeframe that seems most applicable to the wish can be used although the standard instruction in most studies has been four weeks.

Enhancing mental imagery

Mental contrasting may work best for wishes that the individual values, rather than those imposed upon them by others. While some individuals may have limited power to change their environment or certain circumstances, they can use mental contrasting to work on changing their responses to challenges in the environment or circumstances. There has been a lot of recent research that has combined mental contrasting with planning, which is called mental contrasting with implementation intentions.

This involves formulating a behaviour change in the form of 'if' and 'then' plans, e.g: if an obstacle to behaviour change happens, then 'I will do an action'. In our review, we found that adding 'if-then' plans to mental contrasting was just as effective as mental contrasting, but not more so. Our plan is to carry out further studies to test this.

Imagining realistic success

We found that mental contrasting activates, rather than increases, expectations of success. This means that mental contrasting works well when you have high expectations of success. Mental contrasting also helps individuals to identify feasible and non-feasible goals.

Mental contrasting can be used as a simple health behaviour change strategy, or alongside other interventions, such as motivational interviewing, cognitive behavioural therapy, pain management services or health care services. It can help individuals to change their behaviour by focusing on the obstacles to behaviour change, as well as the positive change that they want to create.