Harvard psychologist Dan Gilbert, author of Stumbling on Happiness, delivered a presentation at TED about his research on the ever indefinable topic of happiness. Gilbert contends that our beliefs about what will make us happy are frequently wrong, and in this lecture he explains why with entertaining and challenging examples.
David DiSalvo is a writer and research wonk whose work appears in Scientific American Mind, True/Slant and a variety of other places. More info 
