By Christian Jarrett

Optimists have good reason to be optimistic – research tells us that their sunny outlook means that they are likely to live longer, healthier, happier lives compared with others who have a habit of seeing a darker future ahead. This has led positive psychologists to attempt to teach optimism, so that more people might get to benefit from its apparent positive effects. But can you really learn to see the future more brightly? By combining findings from all the relevant existing optimism intervention trials, published and unpublished, a new meta-analysis in The Journal of Positive Psychology provides us with the best answer available today. There’s reason for hope – it seems we can learn to be more optimistic. But don’t get too carried away. Many interventions only increase optimism a little bit, and probably only for a little while.

John Malouff and Nicola Schutte at the University of New England in Australia scoured the research literature and contacted psychologists in the field to try to find all published and unpublished trials that had attempted to increase people’s optimism in some way, and that had included a control group, and that had randomly allocated participants to the intervention or the control condition. They ended up with 29 studies (just one unpublished) involving collectively over three thousand participants.

Most of the studies had used an established optimism intervention known as The Best Possible Self Intervention which involves instructing participants to spend half an hour or so “Imagining yourself in the future, after everything has gone as well as it possibly could. You have worked hard and succeeded at accomplishing all the goals of your life …”. Other interventions used in the studies to induce greater optimism included things like CBT, mindfulness, self-compassion training, and also some quirky approaches like lying on a bed of nails and sensory isolation (these last two supposedly induce optimism through a relaxing experience).

Aggregating the results from all these studies revealed a small but significant increase in optimism for participants who received an intervention, as compared with control participants. Focusing on just those studies that used the Best Possible Self Intervention, this effect grew to medium in size. Shorter interventions actually seemed to be more effective than longer ones, but this is probably just because the most effective approach –Best Possible Self – is typically very short. Indeed, there is a problem with looking for patterns in aggregated results, like this study does, because different factors that seem to have an effect on outcomes can be confounded with each other, such as the nature of the intervention and the length of intervention.

Studies that measured optimism straight after the intervention was over also reported much bigger effect sizes than those that waited – suggesting that benefits fade quickly over time (though more research is needed to explore this in detail). Another result was that in-person interventions were more effective than online interventions.

The feeling you get from reading this meta-analysis is that we need more rigorous research to find out more about training optimism, and how long any benefits are likely to last. The studies included are so varied, and usually quite basic, that it’s difficult to tease out meaningful insights into why some approaches appear to work and others don’t. That said, the overall message is upbeat. Studies that achieved gains in optimism also frequently reported other benefits, for example in pain reduction and better mood. And even if it’s only possible to boost people’s optimism for a short time, this could still be a lifeline for anyone who is going through a difficult period in their life.

—Can psychological interventions increase optimism? A meta-analysis

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest