Research by an Essex University psychologist has revealed smiling, even for a split second, makes other faces appear happier.

The study led by Dr Sebastian Korb from the Department of Psychology used a novel technique involving electrical stimulation to trigger a short uncontrollable smile.

This is the first time facial electrical stimulation has been shown to affect emotional perception.

Deriving inspiration from Charles Darwin's landmark works and using a refined version of a method developed by Duchenne de Boulogne, Dr Korb ensured participants' safety by significantly reducing electrical voltage.

Using computer technology for precision, the research team controlled the onset of smiles.

Forty-seven participants were shown digital avatars and asked to discern their emotional state.

It was found that producing a faint smile, lasting just half a second, led participants to identify happiness, contributing to our understanding of facial feedback.

Dr Korb said: “The finding that a controlled, brief and weak activation of facial muscles can literally create the illusion of happiness in an otherwise neutral or even slightly sad looking face, is ground-breaking.

“It is relevant for theoretical debates about the role of facial feedback in emotion perception and has potential for future clinical applications.”

Dr Korb added he aims to widen the study's scope and explore potential treatments for depression and expression-impairing disorders such as Parkinson’s and autism.