This article examines the effects of mindfulness on brain development and the neurological effect of mindfulness on emotional regulation. The author explains the inability to switch off emotion and focus is due to the activation of one's own mental representations of present, past, and future. Mindfulness training is one way to teach people to discriminate such “simulations.” The author presents research that shows even brief laboratory training can have effects on processing emotions. Longer meditation training is associated with differences in brain structure. Finally, eight weeks’ mindfulness practice brings about changes in the way emotion is processed. Although additional research is needed, this research is a step towards the necessary neurological research which must occur in the study of mindfulness.