About The Facial Expression EMG and Emotional Response Lab
Your face is one of the most visually expressive parts of your body. You can actually measure an emotional response by looking at how the facial muscles move, whether it is by smiling, frowning, grimacing, raising eyebrows, etc.
Facial Electromyography (fEMG) refers to an EMG technique that measures muscle activity by detecting the electrical impulses that are generated by muscle fibers in the face when they contract. It primarily focuses on two major muscle groups, the corrugator supercilli and zygomaticus major. Facial EMG has been studied to assess its basis as a tool for measuring emotional reactions to various stimuli. Studies have found that contraction of the corrugator muscle, which lowers the eyebrow and is involved in frowning, varies inversely with the activity of the zygomaticus muscle, which controls smiling. It is said these muscles groups are either associated with negative emotional stimuli and negative mood (corrugator) or positive emotional stimuli and positive mood (zygomaticus).
fEMG is emerging as a more precise and sensitive method to measure changes in facial expressions than just using visual observation of the smile or frown. Facial EMG measures minute changes in the electrical activity of facial muscles, which reflects small muscle movements. This technique has been shown to be capable of measuring facial muscle activity to even weakly evocative emotional stimuli. Even when subjects are instructed to inhibit their emotional expression, fEMG can still register the response.Facial EMG has been used to distinguish and track positive and negative emotional reactions to a stimulus as it occurs. Many of these experiments have been conducted in laboratory environments using a range of stimuli, such as: still pictures, movie clips and music pieces.
In this lab exercise, students will record and analyze facial EMGs using an iWorx A/D recorder while looking at a variety of images known to produce emotional responses. Students will be viewing still images as a slide show, but this exercise can be extended to include both video and responses when listening to music. This lab experiment is also fully customizable to add Galvanic Skin Response and both Pulse and Heart Rate to the data collection as well as to add your own images and build your own sequences. This will allow students to hypothesize and observe a wide range of parameters to support the idea that facial EMGs are a valid method for determining emotional response.