"Behavioral economist Dan Ariely, the author of Predictably Irrational, uses classic visual illusions and his own counterintuitive (and sometimes shocking) research findings to show how we're not as rational as we think when we make decisions."

http://www.ted.com/talks/dan_ariely_asks_are_we_in_control_of_our_own_decisions.html

Like other Technology, Entertainment, Design talks, this is both entertaining and informative.