Alison Phillips, Iowa State University (IMAGE) Iowa State University Caption Alison Phillips says an intrinsic reward can help eliminate the deliberation over whether or not to exercise. Credit Christopher Gannon, Iowa State University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.