In “Facial Expression Analysis” written by Dr. David Matsumoto, he states that facial expressions refer to movements of the mimetic musculature of the face.
Remember that facial behaviors are used for a variety of functions including:
– Speech illustration. For instance, people often raise their brows when being inquisitive, and lower their brows when they lower their voices.
– Conversation regulation. We provide cues to others that we are either done talking and it’s their turn, or not, through our faces (and voice).
– Emblematic Gestures. These are movements that symbolically give verbal meaning that can be conveyed by words, such as the doubtful look produced by raising the upper lip and pushing the lower lip up.
– Cognition. People often furrow their brows when concentrating or are perplexed. They also purse their lips when conducting mental searches.
– Talking and eating. We use the muscles around the mouth area for talking and eating, and especially speech articulation.
– Emotion signaling. We use the facial muscles to signal our emotional states.
– Expressive regulation. We also use the facial muscles to regulate our emotion signals.
Take a look at the video below where baby Oliver shows a wide variety of facial behaviors in 62 seconds.
[youtube]http://www.youtube.com/watch?v=Kcp6xw1qNZA[/youtube]