Photo Credit: Jessica LavinOn January 20th, over two million people congregated in one place. There were no arrests, people talked to strangers with no heed of creed or religion, and there was an overwhelming sense of joy complete with outbursts of singing and dancing. When President Obama got up and spoke, all two million people went silent and his voice rang loud and clear down the course of the National Mall.

I have never experienced anything like it and as I look back I know that being on the mall will be one of the truest moments in my life. Is this what happens when over two million people focus on the present moment and meditate on positive transformation and change?

The psychology of the inauguration fascinated me; more so because my experience of mob dynamics came from working at San Quentin State Prison where I have seen the Herd Effect in human populations. I brought walkie-talkies and set an emergency plan with the three other people coming with me just in case of violence. I expected if there were problems that the psychology of the Herd Effect would come into play.

The Herd effect describes how individuals in a group can act together without planned direction. Evolutionary biologists have noted in animals fleeing a predator, individual animals will band and run in a tightly packed group to insure their own self-seeking protection. By doing so the group becomes a unified front and collective action becomes paramount over individual need.

There are numerous case studies in sociology and psychology about the Herd Effect in humans. The Los Angeles riots of 1992 exemplified how the Herd Effect often results in mob violence. The security precautions at the inauguration, complete with snipers on the top of the museums, made me all too aware that the threat of violence had not been overlooked in the massive size of the crowd.

However, the event as packed and uncomfortable as it was, remained peaceful. Without the catalyst of fear, people looked out for each other and strangers burst out in the same songs. I left feeling empowered and intuitively in tune with my surroundings and fellow Americans. Although I had prepared for the possibility violence, I left with a bigger question: is there a positive counterpart to the Herd Effect? What happens when you have a collective body in a small area experiencing something positive and uplifting? Nothing came up in my research about this type of phenomena.

I would be curious to note if there exists any case studies about the effects of joy felt by millions in one area and what the side effects were in comparison. Perhaps this day and the actions of the crowd will be fodder for further study.

Is your face giving you away? This week, QUEST met renowned psychologist Paul Ekman, who has spent his life studying how our facial muscles involuntarily reveal emotions like sadness and anger. In 1976, Dr. Ekman and his colleague Dr. Wallace Friesen published the Facial Action Coding System, or FACS, a system that comprehensively inventoried the muscles movements that create smiles, frowns and grimaces.

Each movement is categorized in Action Unit (AUs). When you puff your cheeks, it's known as AU13. The Frontalis muscle, located on the forehead, is responsible for AU1 or the "Inner Brow Raiser". Over the course of their extensive research, Ekman and Friesen determined that there are at least 19 different versions of smiles! For more information and additional resources on FACS, visit the Data Face website.

If you live in the Bay Area, you can see a special exhibit at San Francisco's Exploratorium with more of Dr. Ekman's photos. It's open through May 11.

Watch the "Emotions Revealed" TV Story online, as well as find additional links and resources.

Jenny Oh is an Associate Producer for QUEST on KQED Television.