For decades many people have claimed one of the many benefits of meditation is that it can change how we behave toward others and make us more compassionate. But now, a new review of research suggests meditation’s role in making us nicer is, well, limited.

“The popularisation of meditation techniques, like mindfulness, despite being taught without religious beliefs, still seem to offer the hope of a better self and a better world to many,” said study author Dr Miguel Farias, from Coventry University’s Centre for Advances in Behavioural Science. “We wanted to investigate how powerful these techniques were in affecting one’s feelings and behaviours towards others.”

A research team including scientist from the UK, New Zealand and the Netherlands reviewed more than 20 studies that investigated the effect of various types of meditation (all secular meditation techniques derived from Buddhism, such as mindfulness and loving-kindness meditation) on pro-social feelings and behaviours. And while an initial comparison of people who meditated to people who did no other new, emotionally engaging activity did suggest meditation moderately bolsters feelings of compassion and empathy, further analysis found meditation plays no significant role in reducing aggression or prejudice or improving how socially-connected someone is.

The most unexpected result of this study, though, was the revelation of major methodological flaws in research that found more positive effects on compassion that hinted at a placebo effect; compassion levels in some studies only increased if the meditation teacher was also an author of the published report.

“Despite the high hopes of practitioners and past studies, our research found that methodological shortcomings greatly influenced the results we found. Most of the initial positive results disappeared when the meditation groups were compared to other groups that engaged in tasks unrelated to meditation,” Farias said. “None of this, of course, invalidates Buddhism or other religions’ claims about the moral value and eventually life-changing potential of its beliefs and practices. But our research findings are a far cry from many popular claims made by meditators and some psychologists.”

In sum, if we want meditation to make us better people, we might have to start being better people who happen to meditate. What a zen-killer.