have trouble making a decision or sticking with one? sometimes i do. we're going to talk about the science of willpower. i know a lot of you remember shannon miller. 1996 gold medalist in gymnastics. today she looks like this -- and she's also a cancer survivor. she's going to tell me her story. i'm going to preview the manslaughter trial of michael jackson's doctor. first, the big headline this week of the execution of troy davis for the 1989 murder of an off-duty police officer in savannah, georgia. there were protests literally all over the world by people who say his conviction was based on unreliable eyewitness testimony. the witnesses and their memories were manipulated by the police. the man who prosecuted the case as well as the victim's family say that's not true. >> there are two troy davis cases. there is the legal case. the case in court and the public relations case. we have consistently won the case as it's been presented in

court. we have consistently lost the case as it's been presented in the public realm on tv and elsewhere. >> you know what caught my attention, the debate is happening more and more. the exact idea that there is new science. in fact the supreme court will hear a case this fall about memory and eyewitness testimony. first time they've reviewed this issue in 34 years. now enfir dysart is a psychologist. she prepared testimony to give the georgia parole board on behalf of troy davis, although in the end she was not called. she joins me from new york. thanks for joining us, good morning. >> good morning, my pleasure. >> you know, i found this whole situation fascinating, as many people did around the world. let me ask as a starting point, you know, in a situation like this where someone has witnessed or potentially witnessed a crime, what does affect their memories or their perceptions? >> yes. there are two major categories

of information that can influence a witness' reliability and their ability to provide accurate system. there's a whole host of things related to the crime itself and the witness seeing conditions, and there are factors related to the police investigation that can influence reliability. >> it's presumably a stressful situation for the witness, as well. they're witnessing something -- witnessing a crime. does that affect their memory? >> yes, it does. research shows that high degrees of stress in a situation do affect our ability to encode information and retain that information. so if any of your viewers have ever had to give a big talk or speech and have been nervous, they might realize after they've given the talk that they don't remember exactly what it is that they said. so this is an example of how memory can be affected by stress and stressful circumstances. >> i mean, if someone has witnessed a crime like that, to take it a step further, could

their memories be contaminated somehow or perceptions be contaminated through the questions they're asked? >> yes. the questions that are asked and the procedures that use r usd i case can influence reliability. if witnesses are permitted to talk with one another prior to giving a statement to police, it's possible that their memory can be influenced by what the other people say. as an example, police officers do not put multiple suspects together in a room to get them to figure out their story and get it straight. they separate them so they can get the most accurate and honest report of what happened. and so the same goes with eyewitnesses. eyewitness memory can be influenced by each other. >> and i don't know if it's possible to answer this question, but do you have some idea of how often misidentification occurs? >> we have some basic idea about

misidentification and how it occurs. we know from dna exoneration cases in the united states where individuals who were previously convicted of a crime have now been shown to be innocent of that crime through post conviction dna testing. there are 273 of those cases now in the united states. and we know that was those cases approximately 75% of them included at least one eyewitness who made a mistake and misidentified the innocent person. >> wow. fascinating stuff, jennifer dysart. obviously there's a lot to take into consideration for everybody, including their own memories on any given day. thank you very much for joining us. appreciate it. >> it's my pleasure. >> thanks a lot. >> you're welcome. in other news, there was a major two-day meeting as you may know at the united nations this week to launch a worldwide assault on so-called lifestyle illness, heart disease, lung disease, diabetes. a lot of people think the

diseases only kill in rich countries. in fact as we learned, they cause 60% of deaths worldwide. this is a trend, a bad one. here's another trend, not totally unrelated. the red cross said this week there are now more obese people in the world, 1.5 billion, than people who are malnourished, which stands at about a billion. that said, there is a deadly lack of food in east africa. we visited somalia, it is spilling over into kenya and ethiopia. a tragic situation. president obama spoke at the u.n. israel and palestinians got most of the attention, but he also called for the world to forecasts focus on -- to focus on this famine. >> we must act on this belief that freedom from want is a asia pacific basic -- is a basic human right. it's been a focus of our engagement abroad to help people feed themselves. today as drought and conflict have brought famine to the horn of africa, our conscience calls on us to act. >> i'll tell you, i can tell you from being there this summer,

the stories, they really stick with you. families like yours or mine are in a desperate position. this week the u.n. said 3/4 of a million people are at risk of dying in the next few months unless they find more aid. think about that, 750,000 people. if you want to help, you can go to cnn.com/impact. coming up, we were all shocked by the death of michael jackson. shocked even more when we heard that his doctor might be to blame. i'm going to break down what we know and what we don't, that's next. imagine living your life with less chronic osteoarthritis pain. imagine you, with less pain. cymbalta can help. cymbalta is a non-narcotic treatment that's fda-approved to manage chronic musculoskeletal pain. one pill a day, every day, can help reduce this pain. tell your doctor right away if your mood worsens, you have unusual changes in mood or behavior or thoughts of suicide. antidepressants can increase these in children, teens, and young adults. cymbalta is not approved for children under 18. people taking maois or thioridazine or with uncontrolled glaucoma should not take cymbalta.

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and it's why the best agents help safe drivers get a lower rate. - exactly. - oh! [ announcer ] we are insurance. ♪ we are farmers bum-pa-dum, bum-bum-bum-bum ♪ more than 2 1/2 years now since michael jackson died. his personal doctor, conrad murray, goes on trial for involuntary manslaughter. he admits to giving jackson a powerful anesthetic, one used in hospitals. he used it to help the king of pop sleep at home. he also it says wasn't the lethal amount that was found in jackson's blood. some attorneys believe the defense will argue that jackson actually killed himself. there's lots of questions about this. here's what we do know. the desperate 911 call comes from inside michael jackson's rented beverly hills mansion. just before 12:30 p.m., june 25, 2009. >> pumping his chest.

he's not responding. >> the king of pop's heart had stopped. his personal physician, dr. conrad murray, is attempting cpr. jackson's bodyguard is on with the emergency call center. >> did anybody witness what happened? >> no. just the doctor, sir. the doctor's been the only one here. >> okay. so the doctor see what happened? >> doctor, did you see what happened, sir? [ inaudible ] >> you can please -- >> we're on our way. >> cnn breaking news -- >> we're getting breaking news coming into the situation room now about michael jackson. the king of pop -- >> my brother, the legendary king of pop, michael jackson, passed away on thursday, june 25, 2009, at 2:26 p.m. >> in the midst of the shock and sorrow, the investigation comes to focus on dr. murray. the day after jackson degreeies police announce they've impounded the doctor's car from the mansion in search of medication that's could be "pertinent to the

investigation." a registered nurse tells cnn jackson had insomnia and had asked for diprivan, a powerful sedative also known as propofol. >> i said, michael, if you take that medicine, you might not wake up. >>propsfol usually administered through an iv drip in an hospital. it doesn't take too much to stop breathing. you have to monitor a patient closely. use at home is extremely unusual. propsfol a medication he uses all the time. is this it here? >> yeah. >> it looks -- like milk of mana magnesia. >> i have done all i could do. i told the truth, and i have faith the truth will prevail. >> the l.a. coroner concludes that jackson died of an overdose of propofol. according to an affidavit, dr. murray told detectives he'd been treating jackson for insomnia. he said he tried other drugs, but the pop star demanded

propofol to help him sleep. the day he died he gave him 25 milligrams. less than two hours later came the call to 911. i'll be reporting from dr. murray's trial in los angeles. that's beginning tuesday. you can also follow along on my life stream, cnn.com/sanjay, see highlights next weekend here on sgmd. next up, shannon miller. she won a lot of lifelong fans at the olympics. my heart went out to her when i heard she had cancer. she's joining us after the break. using powerful medicine and natural ingredients from around the world. he called it vicks vaporub. today, the vicks journey continues. introducing new vicks nature fusion cold & flu syrup. powerful multi-symptom medicine flavored with natural honey instead of artificial flavors and dyes. so you can feel good about what you take to feel better.

darling of the 1996 olympic games here in atlanta. you may remember she helped the u.s. gymnastics teams to a gold medal and won two more golds for herself. today she runs and edits a health web site and has a foundation to fight childhood obesity. on top of that she has a 1-year-old son, rocco. you know, she almost lost all

this last year when she was diagnosed with ovarian cancer. first of all, i should say welcome back to atlanta. >> thank you. >> '96, obviously everyone remembers you. you see the picture behind you. how's life been? just in general over the last 15 years? >> it's been amazing. it's been a roller coaster ride. like in my gymnastics career, i enjoy every minute and try not to regret too much and keep having fun. >> obviously as an athlete, you're very aware of your body, you're aware of illnesses. had you ever been sick, you know, over the last, you know, 30 years? >> really i had not. in my gymnastics career, his a broken elbow at one point, some pulled muscles here and there. but as far as sickness, i didn't miss one day of workout. my coach always boasts about. that even if i had a minor cold or something, i didn't miss workout over a 15-year span. so i just hadn't dealt with that much sickness. >> did you have an idea when you got diagnosed, did you have any inkling beforehand that something was wrong? >> nothing, absolutely nothing.

i was in tune with my body. i was about a year out of having my son. so 12, 13 months after having him. and i was going for a regular exam. i had no symptoms of any kind. in fact, i almost put off my exam and ended up not doing that. >> what happened? did you get a call or how did this transpire? >> i called my doctor to actually reschedule my exam. and then i -- i thought about those patients and doctors that i had interviewed, and they said, don't ever put off your exam. i took the first available, which was that morning. that's when they found a seven-centimeter -- basically a baseball-sized cyst on my ovary. the worst part was i didn't know what i would wake up to after surgery. i didn't know if it was benign or it spread. that was the most difficult thing for me. it wasn't until i woke up from surgery that i found out it was a malignant germ cell tumor.

>> as someone who's been an athlete and never been sick, when they tell you that, are you thinking about your mortality? are you thinking let's get this taken care of? >> first i thought about mortality, my son. i just had him. i'm just getting to know him. he's just having a personality. i can't be gone. and then it's, wait a second, why me, why now? i've tried to live a healthy lifestyle. it's my passion, it's what i do. and now you're telling me i have cancer? so you go through that, and then when i realized i had to go through chemotherapy, it was okay. game plan. i switched into athlete mode. it was, okay, i've got a goal, nine weeks of chemo. and i got to get my game plan in place. >> did they tell you at some point, look, here's what we think will happen if you don't do chemo? here's your likelihood of survival, likelihood of having problems, and likelihood if you do get chemo? did you balance it in your head? >> they originally thought it would be solved through surgery. they came back and said it was

higher grade than they originally felt and chemo was to go. three out of four doctors say this is the way to go. gives me a 99% chance of no recurrence. i won't ever have to deal with this again. and i'm thinking while i'm looking at my son playing with his blocks, 99% with something called cancer, i can do that. >> is that the assurance still now, that -- 99%, they say, you know, you don't have to worry about this again in your life. is that what they're saying to you? >> pretty much, yeah. they're saying i'm in the 90% to 100% success rate, and certainly they're going to watch me closely over the next two years. and one of the most difficult things is i am supposed to wait a year before trying to have kids again. and that's difficult. but it's doable. i can definitely do that. >> rocco needs a sibling. >> that's right. >> you mentioned that you had no idea why you got this. and you didn't even know you had it until it was a routine exam. is there a lesson in there for other women who is there a lesson in there for other women watching regarding ovarian cancer? >> i think the lesson is for women to put their health as a

priority. we take care of everyone else. i need to be around for rocco so i need to go to the doctor. i would tell women do not delay, do not reschedule. early detection saves lives. >> i'm glad you didn't wait. i'm glad you're here. you look fantastic. >> thank you. >> i remember the hat -- i don't know if that means we're getting older. you looked great then, you look great now. >> thank you. >> you remember that as well? i'm glad to see her looking so well. shannon miller. you ever wonder why shopping is so exhausting? making decisions about what to buy and resisting all those temptations, truth is it is going to wear anybody down. science now proves it, how to avoid decision fatigue. that's up next. so who ordered the cereal that can help lower cholesterol and who ordered the yummy cereal? yummy. [ woman ] lower cholesterol. [ man 2 ] yummy.

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making good decisions. it is what we all dwoont, right? but sometimes it is hard. in fact, mental effort actually can take a physical toll. what's even more fascinating about that statement is that this entire process can now be measured in the lab. i learned this from a new book by john tyranny called "willpower." john tierney joins me from new york. so for starters, 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 classic experiments roy did was they brought these college students in to a lab and on the table there there was a dish of radishes and there was a dish of freshly baked chocolate chip cookies that you could smell. some of the students were in the radish condition, they were not allowed to eat the cookies, they could only eat the radishes. researchers looked at them through one-way mirror. they were hungry, they'd also skipped a meal so they had to resist some of those chocolate

chip cookies. they were able to resist but afterwards they were tested for self-control. they were given these math puzzles to work with that couldn't be solved and the test was how long would they work at it. the kids who didn't have to use their willpower, who could eat the cookies, could work on the puzzle for about 20 minutes. but the ones who were just staring at the cookies and could only eat the radishes, they gave up after eight minutes. that's a huge difference but experimental standards. when you use willpower to resist a temptation, also when you use it to make a decision, simply making decisions draws on that same source of mental energy. so during the day by the time you've made a lot of decisions during the day, by the time you've resisted eating dessert at lunch, you've recertificated snapping back at your boss, you made a decision about where to go to dinner, by the end of the day you're suffering from this condition, ego depletion. that is you have less willpower so you are less able to resist temptations and also less able

to make good decisions at that point. >> that's fascinating. let me ask you about the chocolate chip/radish experiment. if i ate the chocolate chip cookies, i did not have to expend my willpower or resist that temptation and i can -- as you say, maybe work at these puzzles better. could there be other explanations as to why that is? the chocolate chip cookies providing more energy or just the sugar? could that have fueled some of that? >> the willpower is fueled by glucose in the blood stream so there is a factor certainly that food plays a factor. >> do you do things differently in your own life as a result of all this? >> i've got something on my computer that keeps track of which websites i visit and which programs i use so it tells me at the end of the day, at the end of the week it sends me an e-mail how many hours were you spending productively on stuff you want to be doing like writing and how much time were you spending surfing tmz, say? and so just knowing that that's

there helps you avoid it. it is a way of outsourcing self-control to someone else. now some people can do it. i didn't do it but can you set it up so it will send e-mails of your work habits to your boss or to your spouse, to a friend that you designate. that's a way of outsourcing self-control beyond yourself and it is a way of conserving willpower that you have. >> i can almost assure you thatly never buy that gadget that's going to tell my wife and my boss -- let me ask you really quickly. you have a son, i have three young children. is this something that you can teach? >> yes, it's definitely something that kids need to learn from their parents. the way they learn it is by giving given clear goals and by being given quick reinforcement, either rewards for achieving goals and punishments for not achieving them. it doesn't have to be strict punishment but it is important that it be consistent and that it happen quickly. and it takes a lot of self-control and willpower for parents to do that. it is much easier to let your kids get away with something, if they leave a mess it is often

easier to clean it up rather than bring them back to the kitchen to say clean it up. that's why parents with good self-control tend to have kids with good self-control. some of that may be genetic but it is also in a fact where a home where parents enforce rules and kids learn to acquire the self-discipline. that turns out to be the most important predictor. it is even more important -- it is even better than iq at predicting school performance. self-control is that important. it predicts success in virtually every area of life. >> the book is called "willpower, rediscovering the greatest human strength." john tierney, that was both informative and very, very helpful. thanks for joining us. >> thank you. thanks. that wraps things up for "sgmd" this morning. i'm headed to los angeles to cover the conrad murry trial that's going to get under way on tuesday. follow along on my life stream cnn.com/sanjay. of course see highlights next weekend right here on "sgmd." time now for a check of your top stories with my pal mr. t.j. holmes.