All this week we're talking about incarceration in America. Yesterday we looked at juvenile justice, and whether life-without-parole sentences for teenage murder convicts violates the Eighth Amendment's ban on cruel and unusual punishment.  Today, we're talking about super-maximum-security prisons and the effects of solitary confinement. According to the United Nations, the U.S. has more inmates held in solitary confinement than any other democratic country. Last week,  we spoke with Juan Mendez, a UN special rapportuer on torture, about the UN's investigation into the treatment of Bradley Manning, the soldier accused of leaking confidential documents to Wikileaks. Manning was in solitary confinement 23 hours a day for 11 months.   States across the country have isolated difficult prisoners in Supermax prisons for decades. But new research on the effects of isolation – and the enormous cost of running supermax prisons in an economic downturn – has changed the way many states think about incarceration. Joining us is Daniel Mears, an expert on prisoner isolation and professor in the College of Criminology and Criminal Justice at Florida State University, and  Christopher Epps, commissioner of the Mississippi Department of Corrections.