What are psychologists doing watching dancers?  They're trying to get a better understanding of how a dancer's emotions affect the way they move.  These researchers used some sophisticated equipment - including a motion capture apparatus - to analyze exactly how people moved while they were experiencing different emotional states.  I think you'll find what they did and what they found to be quite interesting.  If you're interested in dance and psychology you'll get a glimpse of how these two fields can be combined.  That's one of the things about psychology: you can apply it to so many areas of life, including dance.