How Emotions Are Made: The Secret Life of the Brain

you must show that no other explanations can account for your results.

Faces are constantly moving, and your brain relies on many different factors at once—body posture, voice, the overall situation, your lifetime of experience—to figure out which movements are meaningful and what they mean.14

As it turns out, facial EMG presents a serious challenge to the classical view of emotion. In study after study, the muscle movements do not reliably indicate when someone is angry, sad, or fearful; they don’t form predictable fingerprints for each emotion.