Mere nods convey many meanings

Facial expressions can convey a world of meaning with just a mere nod or raised eyebrows, according to a new study.

A nod implies understanding, while a frown may indicate disapproval. Scientists from Max Planck’s Institute for Biological Cybernetics discovered that we are able to classify an expression much better when it moves naturally rather than when frozen in a photograph.

Scientists found out that we are able to recognise facial expressions in motion - for example, in a movie - far better than in a static photograph. The video sequence needs to be at least as long as a tenth of a second to gain this dynamic advantage.

Some expressions rely on changes in head orientation, for example, a nod or a shake of the head, others on the complex deformation of facial parts, such as wrinkling our nose to signal disgust or a frown.

In order to examine to what extent we are able to recognise - based on facial expressions - the mood of a person with whom we are interacting, scientists showed participants pictures of humans with various expressions, said a Max Planck release.

Among these were simple, emotional expressions, such as “happy” and “sad”, but also more complex ones such as agreement, confusion, or surprise, which are usually used to emphasise or modify statements in a conversation.