john tierney joins me from new york. ers, john, you talk about the fact that willpower is like a muscle. i think that concept is really interesting. if it is like a muscle, does this mean can you strengthen your willpower? >> yes, you can. also like a muscle it gets fatigued during the day as you go through the day using it, but then it also gets built up over time by exercises by doing things that actually strengthen your willpower. my co-author on this book did a study showing if you ask students to go home for the weekend, just practice sitting up straight for a week, work on their posture, when they came back to the lab they could do other tasks measure is their self-control much better even though that had nothing to do with posture. it is just having more self-control. >> as you said that, i sat up straighter. just so you know. i'll be putting it to use. so it is something you can strengthen but also something that fatigues. what's an example of it fatiguing then? >> well, simply resisting temptation. one of the cla

. >> john p tierney. >> mary ellen tiesi. >> william r. tieste. >> kenneth francis tietjen. >> stephen edward tighe. >> and my father. you are a star so bright, bold, now in the heavens where you belong. but your light shines out to us as if they live were in fact our own. we love you, we miss you, and we thank you. >> and my husband. their legacy lives on in our beautiful boys. your life and our love live on in my heart. until we meese again, find peace in heaven's hands. >> scott charles timmes. >> michael e. tinley. >> jennifer m. tino. >> robert frank tipaldi. >> john james tipping ii. >> david tirado. >> hector luis tirado, jr. >> michelle lee titolo. >> john j. tobin. >> richard todisco. >> vladimir tomasevic. >> stephen kevin tompsett. >> thomas tong. >> doris torres. >> luis eduardo torres. >> amy elizabeth toyen. >> and my big brother. from the pentagon, now entertaining the angels in heaven with his beautiful music, we all love and miss you terribly. god bless you and god bless america. >> and to my brother, master percussionist.