Event Related Potential (ERP)


Event-Related Potentials (ERPs) are measured brain responses to particular stimuli. ERPs are measured through electroencephalography (EEG), a non-invasive procedure which measures electrical activity of the brain via the use of electrodes placed on the scalp. As the EEG reflects thousands of simultaneously ongoing brain processes, the brain response to a single stimulus or event of interest is not usually visible in the EEG recording of a single trial; to see the brain response to the stimulus, the experimenter must conduct many trials and average the results together, causing random brain activity to be averaged out and the relevant ERP to remain


The Langlois Social Development Lab is trying to find out how babies’ and adults’ brains respond to different types of faces. In our ERP studies, participants view images of faces on a computer screen while wearing an elastic cap embedded with electrodes that makes scalp recordings of brain activity. This allows us to measure brainwaves so that we can study how the brain works while it is processing the presented faces information.

researchERPWe are exploring the differential brain processing of attractive, unattractive, and averaged faces to test whether preferences for attractive faces are influenced by perceptual fluency. It is proposed that attractive and averaged faces, which are closer to the population mean, are “easier on the brain” and thus preferred. This hypothesis predicts that averaged and attractive faces should be neurocognitively processed in a highly efficient and similar manner that is distinct from the processing of low attractive faces.

Consistent with this prediction, we have found that adult college student participants are faster to categorize attractive and averaged faces than low attractive faces in a species (human vs. chimpanzee) identification task. In addition, the ERPs evoked in response to high attractive and averaged faces were nearly identical, but significantly differed from the ERPs evoked in response to the low attractive faces around 200 – 300 ms after the presentation of a face.

These findings support the notion that faces are perceived as attractive when they approximate an average facial configuration and have important implications for our understanding of the origins of facial preferences and stereotypes. Presently, we are continuing our studies with college students and extending our research methods to study attractiveness preferences in infants who are around 6 months of age.

Interested in participanting? Follow the ‘Get Involved’ page for some frequently asked questions about what to expect during your visit to the Langlois Social Development Lab.