A recent study has found that we express just four primary emotions. It also revealed some remarkable evolutionary mechanisms behind our emotions.
Human beings are extraordinary creatures as we are the only species that express our emotions through our facial expressions. It is generally accepted that there are six primary emotions, as first proposed by Dr. Paul Ekman, an American psychologist and professor emeritus at the University of California.
These six emotions are universally recognised across all cultures and races and they are: happiness, sadness, fear, anger, surprise and disgust.
However, using a new technique and software, researchers from the Institute of Neuroscience and Psychology at Glasgow University are challenging this and suggest that there are in fact, only four emotions: happiness, sadness, fear/surprise, and anger/disgust.
This is because fear and surprise looked very similar, sharing the same facial expressions of raised eyebrows, as did anger and disgust, which shared a wrinkled nose.
To carry out their research, the team used new software called the Generative Face Grammar. This uses cameras to capture three-dimensional images of people’s faces. The people they used had been specifically trained to use all 42 of their facial muscles independently.
Once these images had been captured the programme could then generate expressions on a 3D model by activating any of the 42 different muscles.
Volunteers were then asked to record what emotion was being expressed by looking at the 3D model. The researchers were then able to see exactly which muscles were being activated with each emotion.
Using this method, the team could see that the muscles used for fear/surprise and anger/disgust were confused at the early stage of recognition and were only recognised as separate emotions when further muscles were activated.
The evolutionary reasons
It is thought that the reason for this is that the early signals are biologically based and could represent danger signals, whereas the later recognitions are socially based. So in the case of the fear recognition, this would be beneficial to our ancestors to signal that there was something dangerous approaching, so that is the first thing we recognise. The wide-open eyes that signify fear are our immediate response to danger. We widen our eyes to get more information in order to save ourselves.
As for disgust, the wrinkled nose that you get with this emotion is keeping us safe by stopping us eating something that has gone off or is poisonous. By wrinkling your nose, you are literally stopping something going up your nose. This is a response to a stationary threat.
The researchers believe that the four primary emotions – happiness, sadness, fear and disgust are driven by biological pressures and surprise and anger are driven by social pressures.
What the researchers say
Lead researcher Dr. Rachael Jack explained that the research showed that ‘not all facial muscles appear simultaneously during facial expressions.’ Instead, they developed over a period of time, which seems to support the premise that our facial muscles grew more defined as we moved from biological pressures to social specifics.
Dr. Jack said that the research carried out questioned the old belief that there are six complex emotions which are very different and can be easily recognised. Instead, the study suggested that indeed there are only four primary emotional expressions which over time evolved to coincide with how humans began interacting with each other. As we engaged in more complex social situations, the emotions of fear and disgust changed to surprise and anger in order for us to communicate better.
Dr. Jack explained that these four primary emotions ‘are perceptual segmented across time and follow an evolving hierarchy of signals over time’, changing as they do from biological to social signals. This would make sense, as from the moment humans started travelling across continents and began to meet other cultures, our expressions would have to change to keep up with our increasing social interactions. Biology is no longer as important; now we need to converse and understand our neighbours, whether it be fifty thousand years ago or last week.
Throughout the study, the emotions of happiness and sadness remained consistently recognisable.
The team discovered some more interesting information from the study, as when they tested subjects it was noted that populations from Eastern Asia tended to look at a person’s eye signals. In the West, the emphasis is on people’s mouths, not eyes.
This has thrown up some intriguing data so to explore it further the team intend to include different cultures in their next studies. Will different cultures show the same results or is the fact that some cultures focus on different facial aspects mean there will be differing outcomes?
Watch this space for more news!