What led the majority of professional cyclists to engage in doping? Tune in as Lance Armstrong tells Neil deGrasse Tyson about how competition caused an increase in use of performance-enhancing drugs. If you like this StarTalk SoundBite, be sure to listen to the full episode "The Murky World of Doping in Sports" at https://soundcloud.com/startalk_playing-with-science/the-murky-world-of-doping-in-sports