We investigate peer effects on crime-specific recidivism using register data for the entire Danish prison population. We find that inmates do not acquire new criminal capital in prison (no introductory peer effects). For certain types of crimes, we find that inmates strengthen their criminal capital in prison because of exposure to offenders in their field of specialization (reinforcing peer effects). Our results accord with a theory of crime-specific knowledge transmission and network building: we find reinforcing peer effects for crimes that require specific capital, planning, and networks (for example, drug crimes, theft, burglary, and fencing) and/or are more effective when committed in groups (for example, threats and vandalism). Reinforcing peer effects are especially strong because of exposure to more experienced criminals. By contrast, we find that exposure to offenders in the same specialization deters inmates from recidivism for violent offenses, including sexual offenses and robbery.

中文翻译：

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作为犯罪学校的监狱：同伴效应和监狱中的犯罪学习

我们使用整个丹麦监狱人口的注册数据来调查同伴对特定罪行的累犯的影响。我们发现囚犯在监狱中没有获得新的犯罪资本（没有介绍性的同伴效应）。对于某些类型的犯罪，我们发现囚犯会加强其在监狱中的犯罪资本，因为他们在其专业领域中暴露于犯罪者（加强同伴影响）。我们的结果符合特定犯罪知识的传播和网络建设的理论：对于需要特定资本，计划和网络（例如，毒品犯罪，盗窃，入室盗窃和击剑）的犯罪，我们发现强化的同伴效应和/或集体行动时更为有效（例如，威胁和故意破坏）。由于接触更多有经验的罪犯，加强同伴的影响尤其强烈。相比之下，