According to popular belief, the ancient practice of meditation makes us all happier, shinier, more compassionate human beings. Most of those things might be true—except the compassionate part, suggests new research.

In fact, according to a new study, it almost never does.

An international team of researchers examined 20 existing studies for evidence that mindfulness and loving-kindness meditation promote less aggression, more kindness, and more pro-social behavior. Contrary to the researchers' expectations, they didn't find any.

Meditation research is biased, study finds

Meditation practices, even devoid of the religious connotations, still "seem to offer the hope of a better self and a better world to many," says a co-author of the new study, Dr. Miguel Farias, from the Centre for Advances in Behavioural Science at Coventry University in the United Kingdom.

But, he continues, "Despite the high hopes of practitioners and past studies, our research found that methodological shortcomings greatly influenced the results we found."

Specifically, it turned out that the studies that reported a rise in levels of compassion among meditators were authored by the very same meditation teacher! "This reveals that the researchers might have unintentionally biased their results," says Dr. Farias.

"Most of the initial positive results disappeared when the meditation groups were compared to other groups that engaged in tasks unrelated to meditation," the co-author adds.

So what does this mean? Should we discredit meditation altogether? Not at all, the researchers say.

"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."

Dr. Miguel Farias

"To understand the true impact of meditation on people's feelings and behavior further we first need to address the methodological weaknesses we uncovered," Dr. Farias adds, "starting with the high expectations researchers might have about the power of meditation."

So, the new analysis certainly casts some shadow over the much-hailed benefits of meditation.