There is a lot of interesting things going on in the fairly new field of behavioral economics. A while back I took a course through Coursera.org held by Dan Ariely. I truly recommend it to anyone that is even remotely interested in human behavior and motivations.
Watch a talk by him on TED here:
Are we in control of our own decisions
What makes us feel good about our work
Another interesting and rather mindblowing video is this one on the correlation between language spoken and likelihood to save money
Dolly - Marketing words 