Epilepsy patients and others with damage in a part of the brain called the amygdala fail to recognise facial emotions, though they find faces looking sideways more memorable, a new study shows.
In the new study, researchers at tthe University of Bath, in collaboration with neurosurgeons and psychologists in Warsaw, Poland, sought to examine if gaze and emotional expression — both highly self-relevant social signals — affect the recollection accuracy of perceived faces in patients with mesial temporal lobe epilepsy (MTLE).
The researchers showed a series of faces with neutral or emotional expressions to 40 patients with MTLE and 20 healthy individuals. Half of the faces were looking straight ahead, and half sideways. They found that healthy participants had better recognition of emotional faces, while epileptics couldn’t remember emotional faces any better than neutral ones — but did find pictures of people gazing away more memorable than those looking straight ahead.
The findings add to the evidence that damage to the amygdala affects facial recognition and gaze perception — which is especially important since perception and understanding the facial cues of others is essential in human societies.
People with damage to the amygdala have deficits in emotion recognition while keeping the perception of others’ eye gaze direction intact. These patients often struggle with everyday communication, particularly with understanding social signals, which causes problems in relationships with others. These social problems often lead to lower levels of life satisfaction.
“Surprisingly, we found that individuals with amygdala damage remembered faces looking to the side more than those looking towards them. This effect was independent of the emotional content of the face,” the University of Bath’s Sylwia Hyniewska said in a news release. “This was unexpected given that all research so far focusing on other populations showed either an interaction effect between emotion and gaze, or an improved memory for faces looking towards the observer.”
Hyniewska added: “We expected our patients to remember faces better when they were looking at them — presented with the direct gaze. However for some reason patients seem to remember faces looking away better. This means that the interaction between the processing of emotions and gaze is more complex than we thought, and not only emotions but also gaze should be studied further in this specific population to develop treatments improving these patients’ well-being.”
What is the amygdala?