What happens when we meditate

We picture meditation as a switching off, a making of emptiness. The brain says the opposite: when a seasoned practitioner meditates, it does not switch off, it lights up in an ordered way. Measurement shows it.

In Richard Davidson's laboratory in Madison, Tibetan monks with tens of thousands of hours of practice meditated with EEG on their heads. During compassion meditation, the electrical activity showed gamma waves - around 40 Hz - of very high amplitude and, above all, highly synchronous: distant areas of the brain oscillating together, at the same rhythm. Among the highest amplitudes ever recorded in healthy people, and larger the longer the practice (Lutz and colleagues, 2004: a few expert practitioners, in the laboratory). What this synchrony means for experience remains debated.

And perhaps it is not just a state that comes and goes. People who meditate for years have, on average, a thicker cortex in the regions of attention and of listening to the body (Lazar and colleagues, 2005: a comparison study, not proof of cause), and their attention networks work differently, more efficient at holding focus steady for long (Brefczynski-Lewis and colleagues, 2007). Studies of expert practitioners suggest that attention can be trained, at least in the laboratory.

It is again the thesis of this pillar. Consciousness is not a lamp of fixed intensity: it changes shape. Studies of monks suggest that some of its aspects, such as attention, can be trained through practice.

And the road? Here the link is simple and honest. Meditation, stripped of everything else, is attention turned on attention: noticing what your own state is, now. The sleepy driver stumbles exactly here: they feel the sleepiness, but do not notice how close sleep is. You need not be a monk. But the first messages of sleepiness - the heavy eyelid, the sliding thought, the kilometre you cannot remember - can be caught, if attention is listening. What monks train for years, the road asks in a few honest seconds: notice, and stop.