Why does laughing feel so good? And is there any evidence to back up the adage “grin and bear it” – the suggestion that smiling might be good for your health?
The answer seems not to lie in the intellectual pleasure of cerebral humour but in the physical act of laughing. The muscular exertions appear to trigger an increase in endorphins, the feel-good brain chemicals.
Laughter is an intensely physical experience. After the brain has processed the incoming signals, it triggers the contraction of 15 muscles in the face. At the chortling stage, the voice box gets partly covered, leading to irregular breathing. And, in those all-too-rare moments of helpless laughter, our tear ducts are stimulated and our faces redden.
Researchers classify smiles as being of two types: standard smiles, where only the mouth shapes the smile, and genuine or Duchenne smiles, where the muscles around the mouth and the eyes create the smile. (The latter was named after French neurologist Guillaume Duchenne, who used electrophysiology to show how truly happy smiles also use the muscles around the eyes.)
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Charles Darwin explored the nature of smiling in his book The Expression of the Emotions. He agreed with Duchenne's view that, while smiling involves the combined contraction of face and eye muscles, "the first obeys the will, but the second is only put in play by the sweet emotions of the soul". A Duchenne smile is what we generally consider to be a "genuine" smile; smiling without contraction of the orbicularis oculi (eye) muscle is often perceived as fake and is known as non-Duchenne or deliberate smiling.
You benefit
When you are on the receiving end of a smile, you also benefit. It triggers your brain’s reward system. Functional MRI studies have shown how reward-processing regions of a mother’s brain light up in response to a simple smile from her baby. We recognise a smile at twice the distance of other facial expressions and, when we do, we automatically mimic the expression, usually within half a second. This triggers a corresponding emotion of happiness, an effect referred to as emotional contagion.
A recent review article in the Postgraduate Medical Journal suggests that when doctors smile with their patients, it may help patients to better remember the details of a consultation. There is some evidence that smiling helps clinicians build a rapport with patients, helps ease patients’ anxieties and may instil feelings of trust towards the doctor.
However, the authors caution that a false smile from a doctor can demolish any semblance of patient-clinician rapport. In an experiment, Darwin observed the ease with which people were able to identify a false smile. Some 21 out of 24 subjects recognised the false nature of a smile in a photograph, with the other three unable to make sense of the expression. So it seems our true emotions can “leak” out when we attempt to disguise them, as we are far less adept at controlling facial and bodily expressions than we are at choosing our words.
“A patient could potentially interpret a false smile, or a mismatch between affect and words, as condescension, sarcasm, disinterest, inappropriate humour, lack of empathy or even an unwanted advance,” they warn.
Better than sex
But advising trainee doctors to smile more with their patients could backfire; it could trigger a counterproductive false smile, paradoxically leading to upset for the patient.
Amazingly, a monetary value has even been placed on the smile, in a study using MRI scans to compare observing smiling faces with other pleasurable stimuli. This study reportedly found that a single smiling face had the potential to induce pleasure equivalent to being given up to £16,000 (€18,130) in cash, or eating 2,000 chocolate bars.
The researchers declared that smiling offered a better short-term high than sexual intercourse, shopping or listening to your favourite song.
Which brings a whole new perspective to the saying, “smile and the world smiles with you”.