In my former careers I have dealt with humanitarian disasters and wars; and I was always up close and personal with the people. I have done extensive training on interviewing skills and used those skills around the globe. I began a discussion a couple of years ago about how important communications skills are in survival situations, all survival situations. People can be your greatest threat or the best opportunity for survival. In December I attended a workshop on "the neurobiology of political violence" and met Dr. David Matsumoto. He has a web site with some training tools for reading facial expressions:
Humintell
It is based on the groundbreaking work of Dr. Paul Ekman which proved that certain emotions and the accompanying facial expressions are universal to humans. If you are talking with someone, and their facial expressions display an emotion which is different from what they are telling you, you can use this. it is either a danger signal or a sign of deception. This can be very useful in survival situations of every kind. These tools are used by the Secret Service, most law enforcement agencies and many other organizations. I have found the skill handy in many situations. Dr. Matsumoto's tools are all web based and much more affordable than anything that was available before. I would highly recommend that you read Paul Ekman's books: "Telling Lies" or "Emotions Revealed" in order to understand how to use this skill properly.