The research examined the hypothesis that as these offenders grow older, the peer influences on their criminal decisionmaking decrease and their awareness of the legal and extralegal risks of crime increases. The participants had all been incarcerated two or more times; at least once for armed robbery, burglary, or grand theft. They completed interviews that included both forced-choice questions and ethnographic, tape-recorded interviews. The questions covered criminal behavior for three age periods: up to 17, 18-26, and 27 and older. The interviews probed for perceptions of the influence of friends and acquaintances on the assessment of the risks and benefits of crime. Results showed that youthful offenders are highly influenced by peers and pay little attention to the legal and extralegal risks of crime. As offenders age into the mid-20's and beyond, the influence of peers decreases and the deterrent effect of legal and extralegal sanctions increases. These changes reflect offenders' increasing desire to rationally assess the risks and benefits of crime. Tables, appended survey instrument, and 77 references (Author summary modified)