A Systematic Review of the Literature on the Redundancy Effect

Abstract

The redundancy effect consists of greater learning for X in a blocking procedure, A+ AX+, than for Y in a discrimination procedure, BY+ CY-. These findings are new and theoretically challenging for all common error-conditioning theories which predict the opposite. Therefore, the empirical evidence of this phenomenon and its theoretical implications were reviewed through the PRISMA methodology. Eligibility of 314 articles was assessed, and 12 were included. The redundancy effect has been investigated in both animals and humans, through classical conditioning procedures and causal judgment tasks. Theoretically, modifications to traditional models such as the Rescorla-Wagner have been proposed with relative success to explain this phenomenon. It is concluded that, despite these advances, further research is required to establish with certainty the theoretical mechanism that explains this phenomenon.