Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.05.327072v1?rss=1 Authors: Parrell, B. Abstract: Reinforcement learning, the ability to change motor behavior based on external reward, has been suggested to play a critical role in early stages of speech motor development and is widely used in clinical rehabilitation for speech motor disorders. However, no current evidence exists that demonstrates the capability of reinforcement to drive changes in human speech behavior. While the effects of reinforcement learning have been studied more extensively in upper limb control, speech provides a unique test of the universality of reinforcement learning across motor domains. Speech is a complex, high-dimensional motor task whose goals are unique in that they do not specify a task to be performed in the environment but ultimately must be self-generated by each speaker such that they are understood by those around them. Reinforcement learning may thus be more difficult for speech, given its high-dimensional and redundant motor system, while speech may also be particularly responsive to reinforcement given the ultimate goal is typically reliant on such feedback from our interlocutors. Across four experiments, we establish whether reinforcement learning alone is sufficient to drive changes in speech behavior and parametrically test two features known to affect reinforcement learning in reaching: how informative the reinforcement signal is as well as the availability of sensory feedback (here, auditory feedback) about the outcomes of one's motor behavior. Our results show that reinforcement learning can indeed drive changes in speech behavior and that more informative reward signals lead to greater learning. However, contrary to results from upper limb control, masking feedback about movement outcomes has no effect on speech learning. Our results suggest reinforcement learning is active in speech but may operate differently than in other motor domains. Copy rights belong to original authors. Visit the link for more info