Why experts on trauma and PTSD had to rethink everything they thought they knew after the terror attacks of 9/11. Then, revisiting the recommendation for how much vitamin C you need to consume. And, the science behind Sesame Street's success. Also, on today's show: the unexpected power of making a simple compliment to someone; the hoodie of the future could be made out of plastic bags. (AP Photo/Amy Sancetta, File)