Summary: The initial reaction of the brain is independent of the facial emotional expression we see. It is only after the eye movement is completed that the brain shows strong responses to the emotional expression of a face.
Source: University of Gottingen
Dr Louisa Kulke from the University of Göttingen has investigated how our eyes and brain react when we see emotionally charged or neutral faces. She combined eye-tracking and electroencephalography (EEG). The result: reflex-like eye movements are independent of the expression a face shows; our attention is drawn to them just as fast. The study was published in the journal Neuroscience.
In everyday life, people are exposed to numerous stimuli, just as when walking through a town, there are people and faces, clothes and shop windows. From this onslaught of information, relevant content must be filtered and reacted to. “This shift in attention is often accompanied by a movement of the eyes,” says Kulke, a researcher in the Department of Affective Neuroscience and Psychophysiology at the University of Göttingen. In the current study, she combined two methods to investigate what happens in the brain during this attention shift: eye-tracking and EEG. With the Eye-Tracker, research volunteers sat in front of a device that records eye movements. Kulke then showed them standardised faces with different emotional expressions. At the same time, EEG measured brain waves via electrodes placed on their head.
“We investigated how quickly our test subjects look at the faces that appear on the screen in different places,” says Kulke. The result shows that quick and immediate eye movements were occurring independently of the facial expression. “We quickly look at people in our environment with the same speed, regardless of whether they look cheerful, angry or indifferent. The study also showed that the first reactions of the brain are independent of facial expression. Only later – after the eye movement is completed – do the reactions of the brain show strong responses to the emotional expression of the face.”
According to Kulke, the result is also interesting for follow-up studies. The question is whether the processing of emotions also takes place later, when the eyes do not react reflexively, but are consciously controlled using a tangible task. Kulke explains: “For example, do we process facial expressions that we see out of the corner of our eye before we move our eyes? When given the explicit goal of only looking at certain faces, such as our friendly fellow student, and ignoring others, such as our annoying neighbour, how does that affect our reactions?”
About this neuroscience research article
Source: University of Gottingen Media Contacts: Louisa Kulke – University of Gottingen Image Source: The image is credited to Louisa Kulke.
Neural Mechanisms of Overt Attention Shifts to Emotional Faces
Emotional faces draw attention and eye-movements towards them. However, the neural mechanisms of attention have mainly been investigated during fixation, which is uncommon in everyday life where people move their eyes to shift attention to faces. Therefore, the current study combined eye-tracking and Electroencephalography (EEG) to measure neural mechanisms of overt attention shifts to faces with happy, neutral and angry expressions, allowing participants to move their eyes freely towards the stimuli. Saccade latencies towards peripheral faces did not differ depending on expression and early neural response (P1) amplitudes and latencies were unaffected. However, the later occurring Early Posterior Negativity (EPN) was significantly larger for emotional than for neutral faces. This response appears after saccades towards the faces. Therefore, emotion modulations only occurred after an overt shift of gaze towards the stimulus had already been completed. Visual saliency rather than emotional content may therefore drive early saccades, while later top-down processes reflect emotion processing.