Banishment, public shaming in the stocks, and whipping were common punishments in the colonial period. Later, Quaker reformers conceived of imprisonment both as a punishment for crime and as a mechanism for repentance. In the late 19th and early 20th centuries, the medical model formed the basis of corrections. Parole boards were charged with monitoring progress toward rehabilitation and to timing release accordingly. The tumult and change of the 1960's brought dissatisfaction with the criminal justice system, including parole. Social science research also began to question society's ability to rehabilitate. In the 1970's, groups with varying philosophies about crime and corrections joined together to work to abolish parole and to establish a philosophy of desert. The 1980's brought further changes, with an emphasis on incapacitation to control crime. These historical developments show that the controversies surrounding parole are part of broader debates in society regarding the purposes of criminal justice and criminal sanctions.