Facial expressions are a powerful means for humans to communicate their feelings. Understanding their meaning allows us to recognize fundamental emotions such as joy, fear, or anger, which is essential for interacting with others. A wide-eyed look of fear, for example, can be a signal for us to distance ourselves from a situation that involves real risks; while a happy face can convey confidence and indicate that we are on the right track. Correct interpretation of the signals emitted enables us to act appropriately in different situations.
Many researchers seek to discover how facial recognition occurs and why some individuals have difficulty perceiving these signals. One technique used to assess people's ability to understand the feelings of others through their expressions is the FEEL (Facially Expressed Emotion Labeling) test, which involves presenting a photo of a face on a computer screen, followed by the same face showing one of the six emotions considered basic: joy, sadness, fear, anger, disgust, or surprise. At the end, participants must say which feeling was expressed in the image.
Through tests like this, it has been shown that although the recognition of expressions occurs almost immediately, not all feelings are perceived with the same ease. Joy, anger, and surprise are understood correctly most of the time, while disgust, sadness, and fear cause some confusion. Additionally, although viewing the entire face allows for a more effective perception of expressions, some emotions are detected almost exclusively in the upper part of the face (eyes and nose), such as fear; while others, like joy, become apparent in the lower part (mouth and sides of the face).
Indeed, studying the case of patient S.M., who had great difficulty recognizing fear on people's faces due to an amygdala injury, researcher Ralph Adolphs noticed an important difference between the patient and healthy individuals during the application of tests. While the latter oriented themselves by the expression of the frightened person's eyes, S.M. avoided looking at that region of the evaluated face, which hindered the interpretation of the emotion being expressed. Directing attention to the right place is one of the requirements for a good understanding of the emitted signals.
In addition to clinical applications, reading facial expressions has increasingly been used as a technique to assist in evaluating consumer satisfaction/ dissatisfaction during interaction with products. Quantifying a person's experience with a product solely through subjective questionnaires does not always yield reliable results, as not everyone feels comfortable revealing their true feelings. Thus, having a more natural means of evaluation is of great value. A recent study (Danner et al., 2013) showed that there is a correlation between the subjective ratings assigned by participants to samples of orange juice and their facial expressions immediately after consumption, as we will see next.
At first, in the so-called implicit experiment, consumers tasted the juice samples and assigned a score that ranged from 1 (I liked it a lot) to 9 (I didn't like it at all) and, without knowing they were being filmed, had their facial expressions analyzed by software capable of recognizing basic or neutral emotions. The results showed a correlation between the “neutral,” “anger,” and “disgust” faces and the hedonic score; however, the “happy” face was not well discriminated. In a second phase, the volunteers participated in the explicit experiment, in which they were asked to classify the samples through intentional facial expressions, and in this new situation, there was a strong correlation with the subjective evaluations, especially for the “happy” and “disgust” faces. Therefore, reading facial expressions can be an effective tool for assessing consumer interaction with products.
Maria Cristina Valzachi is a pharmaceutical biochemist graduated from the Faculty of Pharmaceutical Sciences at USP and holds a master's degree in Pharmacology from the Institute of Biomedical Sciences at USP. Currently pursuing a doctorate at the same institution, she dedicates herself to research and studies in the fields of Neurochemistry and Behavioral Pharmacology, with an emphasis on adolescence. She has a special interest in all fields related to education and the dissemination of ideas.
Contact: cris.valzachi@gmail.com
References
Danner L, Sidorkina L, Joechl M, Duerrschmid K. Make a face! Implicit and explicit measurement of facial expressions elicited by orange juices using face reading technology. Food Quality and Preference. 2013. http://dx.doi.org/10.1016/j.foodqual.2013.01.004;
Traue HC. Facial mimicry. Mente e Cérebro Magazine. How the Brain Interprets the World Collection. São Paulo; Duetto Editorial. 2012; p.12-17;
Figure: http://commons.wikimedia.org/wiki/File:Mask_Shopping_(5477910485).jpg
