Still facial photographs of long-term meditators are perceived by naïve observers as less neurotic, more conscientious and more mindful than non-meditating controls.

The impact of meditation training on self-report psychological variables is well-established. Although meditation training is purported to have interpersonal impacts, whether naïve observers perceive differences associated with long- and short-term meditation training is largely unknown. The current study provided a stringent test of this possibility through observer ratings of a very thin slice of expressive behavior: still photographs. Photographs were drawn from a larger study investigating differences between long-term meditators (LTM) and meditation naïve participants (MNP) who were exposed to one of three experimental conditions. Photographs of ninety-nine targets (16 LTMs, 83 MNPs) were taken at baseline, prior to the randomization of MNPs to an eight-week mindfulness meditation course (mindfulness-based stress reduction; n = 27), an active control comparison condition (health enhancement program; n = 29), or a waitlist control group (n = 27) and again after the training period. Pre- and post-intervention photographs were then rated by 25 meditation teachers and 86 undergraduate raters on five domains theoretically linked to meditation training. Results indicated that relative to MNPs, LTMs were rated as less neurotic and more conscientious, mindful, and "comfortable in their own skin" at baseline (ds = 0.61 to 0.70, ps < .050), although not more agreeable or attractive. Results were largely unchanged when controlling for five observable confounds (age, gender, race/ethnicity, body mass index, attractiveness). No evidence was found supporting experimental effects of short-term meditation training on observer ratings. Thus, it seems that if meditation is associated with observable differences in facial behavior, effects may be limited to long-term training.