You can learn to interpret body language in social and professional environments, and not just law enforcement! Salesmen, Counselors, Recruiters, Agents/Editors and even parents can benefit from understanding body language. Most importantly for us, we can also use it to add "texture" and "layering" to our stories. No one explains it better than my friend Janine Driver. Check out the video clips on her Lyintamer web site. Also, keep an eye out for her upcoming book - I'm sure it will be fabulous.
We also spoke about learning styles. People tend to develop preferences for receiving information and they will be either visual, audio or kinesthetic. Keep in mind that if you are speaking to a big group, that you need to incorporate all these styles into your presentation so you can appeal to everyone. I know it's sad, but the adult attention span is 12 minutes, so you need to change up what you're doing about every ten minutes. For smaller groups or 1:1 interactions, it will benefit you to know indicators of their learning style - by watching where the eyes dart to momentarily before a person answers a question involving recall, by the words they use, and by their demeanor. Here's a link to a site with word clues, and the following is a video that talks more about demeanor:
You can also add another layer to the Visual/Audio/Kinesthetic responses, that shows indicators of recalling information or constructing information -- a great technique to use when trying to determine if someone isn't telling the whole truth or is lying.
For more resources on body language, there's no use re-inventing the wheel - I'll just refer you to Janine's site for book recommendations. However, I'll add a couple more suggestions:
This book is a 101 to get you started: The Definitive Book of Body Language.
Thank you to Christine Fairchild for recommending Anatomy of the Spirit, that expands on "leakage" depending where you self-touch. Hmm...I really should reword that sentence, but I'm laughing too hard.
Anyway, if you're interested in additional topics relating to body language, you may want to explore mirroring, micro expressions and lie detection.
.