Why and how the brain weights contributions from a mixture of experts
It has long been suggested that human behavior reflects the contributions of multiple systems that cooperate or compete for behavioral control. Here we propose that the brain acts as a "Mixture of Experts" in which different expert systems propose strategies for action. It will be argued that the brain determines which experts should control behavior at any one moment in time by keeping track of the reliability of the predictions within each system, and by allocating control over behavior in a manner that depends on the relative reliabilities across experts. fMRI and neurostimulation studies suggest a specific contribution of the anterior prefrontal cortex in this process. Further, such a mechanism also takes into consideration the complexity of the expert, favoring simpler over more cognitively complex experts. Results from the study of different expert systems in both experiential and social learning domains hint at the possibility that this reliability-based control mechanism is domain general, exerting control over many different expert systems simultaneously in order to produce sophisticated behavior.
Additional Information© 2021 Elsevier. Received 9 June 2020, Revised 14 September 2020, Accepted 26 October 2020, Available online 11 January 2021. This work is supported by grants from the National Institutes of Mental Health (R01MH11425, R01MH121089, R21MH120805 and the NIMH Caltech Conte Center on the neurobiology of social decision-making, P50MH094258) and the National Institute on Drug Abuse (R01DA040011) to JOD. Author contributions: JOD, SL, RTN, JC, KI, CC discussed the concepts and the ideas in this manuscript. JOD wrote the manuscript. JOD, SL, RTN, JC, KI, CC edited and revised the manuscript. The authors report no declarations of interest.
Accepted Version - nihms-1665699.pdf