Research examining prisoner reentry has demonstrated negative impacts of incarceration on social bonds. However, this research is limited in two ways. First, it generally examines outcomes after release, paying less attention to processes occurring in prison. Second, this work tends to examine "incarceration" as a whole, regarding prisons as homogenous. This study uses data from an experiment in which offenders were randomly assigned to incarceration at one of two prisons polarized across a number of structural characteristics that research suggests affect social bonds (a traditional prison vs. a correctional boot camp). Groups were compared with respect to commitment, belief, attachment, and in terms of changes among their relationships during incarceration. The data showed that the boot camp improved prosocial beliefs, but few differences emerged in terms of commitment and attachment. Similarly, the data showed few differences in attachment regardless of the prosocial or antisocial orientation of the inmate's friends or family. (Published Abstract)