 Drug self-administration procedures have been used for decades to study the effects of psychoactive substances like cocaine. These procedures involve giving animals the opportunity to choose between different doses of the drug or other rewards. This paper reviews the evolution of these procedures and their use in understanding the reinforcing effects of drugs. It also suggests that more research should be done using choice procedures to better understand how drugs affect behaviour. This article was authored by Matthew L. Banks and S. Stevens-Negas.