Body and Mind Connections

Interactions between mind and body come out strongly in the surprising links between status and health. Michael Marmot's celebrated studies show that the lower you are in the pecking order, the worse your health is likely to be. You can explain away only a small part of the trend from poorer access to healthcare, or poorer food or living conditions. For Marmot, the answer lies in "the impact over how much control you have over life circumstances". The important message is that state of mind — perceived status — translates into state of body.

The effect of placebos on health delivers a similar message. Trust and belief are often seen as negative in science and the placebo effect is dismissed as a kind of "fraud" because it relies on the belief of the patient. But the real wonder is that faith can work. Placebos can stimulate the release of pain-relieving endorphins and affect neuronal firing rates in people with Parkinson's disease.

Oxytocin levels rise during orgasm and sexual arousal, as they do from touching and massage. There are defects in oxytocin receptors associated with autism. And the hormone boosts the feeling that you can trust others, which is key part of intimate relations. In a recent laboratory "investment game" many investors would trust all their money to a stranger after a puff of an oxytocin spray.

These few stories show the importance of the interplay of minds and hormonal signals, of brains and bodies.

~ALUN ANDERSON Editor-in-Chief and Publishing Director of the weekly international science magazine New Scientist Partial answer to Edge question of the year.