A new study performed by Dr. David Matsumoto and Dr. Hyi Sung Hwang demonstrated that the ability to read microexpressions, facial expressions of emotion that can appear on the face as fast as 1/2 second, can be trained.
They present two studies that prove this claim as well as evidence for the retention of the training effects. Their study is the first scientific evidence of training efficacy to read microexpressions in normal adult populations.
These findings are important because they demonstrate that not only can people be taught the ability to read emotions on the face, but also that this ability can be retained.
See the full paper and the research for both studies here.