The 2009 TIME 100

Information about the external world streams in through our senses and is then processed and integrated by our brains into thoughts, words or deeds. And accompanying those forms of communication are facial expressions and the physical responses we call body language.

Thanks to Paul Ekman and his work on facial expression, emotion and deception, we have a better understanding of how the expressions and gestures we display on the surface are a direct reflection of what is going on in the neurocircuitry deep inside our brains.

When I experienced a severe hemorrhage in the left hemisphere of my brain in 1996, I was aphasic — incapable of understanding verbal language. But thanks to my right hemisphere, I could read the facial expressions and body language of the caregivers and medical professionals who were tending to me.

Ekman, 75, has turned the ability to read the reactions that flicker across our faces into a fine science. Through his books, including Telling Lies and Emotions Revealed, along with his role as an adviser for Lie to Me, the Fox crime series based on his work, he has brought to the general public his understanding of how we communicate with one another in the absence of words.

His research will make a tremendous contribution to the worlds of law enforcement, counterterrorism and crowd management. It also has the potential to change how we communicate with those who are aphasic. But perhaps most important, in a society in which dissemblance and evasion have become commonplace, Ekman is teaching us how to recognize the subtle signs of truth.

Taylor, a neuroanatomist, wrote My Stroke of Insight: A Brain Scientist's Personal Journey after fully recovering from her stroke and was a 2008 Time 100 honoree