Performance
A careful review distinguishes durable effects of meditation from inflated short-term claims.
The real payoff of a mental practice isn't the pleasant state felt during a session, which ends when the session ends. It is the lasting change in how a person behaves in ordinary life. Benefits that vanish once you stop practising are a different and lesser thing than ones that stay.
The benefits most widely advertised in the press and in marketing are not necessarily those best backed by sound science. Some heavily promoted claims have little scientific merit. Popularity calls for a hard-nosed check of which effects actually hold up.
Meditation was designed to free people from ordinary mind states, not to relax them or make them more productive. The health and work benefits now used to sell it were historically incidental side effects. The authors still report some of those effects, such as an analysis of 47 studies finding meditation as effective as medication for depression, anxiety and pain, without the side effects.
The authors hypothesise that what remains after one practice session becomes the calmer starting point for the next. In their phrase, 'the after is the before for the next during.' Gains build on each other over time because each session begins where the last one left off.
Every form of meditation, whether watching the breath, picturing an image or repeating a phrase, retrains habits of attention. A little practice briefly sharpens focus, for example by shortening the moment after noticing one thing when the mind misses the next. Long-term practice brings lasting improvement and lets people re-focus with little effort.
The authors report that effects scale with practice. Beginners get modest, short-lived gains. Long-term practitioners show durable changes, and those with intensive lifetime practice show markedly different brain activity and pain responses. A light, accessible practice for many people and an intensive one for a dedicated few are distinct paths with different results.
The authors report that about 30 hours of training reduced activation in the brain's alarm center, the amygdala. Long-term practice strengthened the links between that alarm center and the planning regions behind the forehead that can regulate it. In experienced practitioners this showed up as little dread before pain and very fast recovery afterward.
Understanding someone's pain, sharing their feeling, and concern that moves you to act are three separate capacities. Only the third leads to action to reduce suffering. The authors report that as little as eight hours of practice wishing others well can increase it.
The self-focused mind-wandering of the brain's resting state is often unpleasant. Once you see your mind as a set of processes rather than getting swept away by its thoughts, that chatter loses its grip. The authors report that early on, other brain circuits learn to restrain it, and with longer practice its activity itself declines.