A 1999 investigation led by Baird and Deborah Yurgelun-Todd of Harvard Medical School in Boston raised the possibility that certain characteristics of teens' brains make it difficult for them to recognize when other people are scared. They tested 12 teenagers, ages 12 to 17. A functional magnetic resonance imaging (fMRI) scanner measured changes throughout participants' brains in blood flow, which studies have indicated reflect dips and rises in neural activity. As the teens briefly viewed and identified fear in pictures of people who had intentionally tried to look scared, the researchers observed marked increases in activity of an almond-shaped inner-brain structure called the amygdala.

Neuroscientists suspect that the amygdala is important for learning to attach emotional significance to facial expressions and other stimuli. However, the results of Baird and Yurgelun-Todd indicated that there may not be a simple relationship between amygdala activity and accurate face reading.
any 8-12yo kid on the playground is intimately tuned in to fearm they turn on the whiff of it and bore in pack like. Fear has little to do with facial expression than pherenomes, body posture and practice.
thanx,
bill