<Li> Most of the studies supporting interference effect used slow movements that enabled movement adjustments during movement execution . </Li> <Li> According to some authors bilateral transfer may be elicited through alternate practice conditions, as a source of information can develop from both sides of the body . Despite improvements seen in these studies, interference effects would not be attributed to their improvements, and it would have been a coincidence of task characteristics and schedule of practice . </Li> <Li> The terminology of "complex skills" has not been well defined . Procedural manipulations, which vary between experiments (e.g., changing the similarity between tasks) has been cited as a contributor to skill complexity . </Li> <P> Feedback is regarded as a critical variable for skill acquisition and is broadly defined as any kind of sensory information related to a response or movement . Intrinsic feedback is response - produced--it occurs normally when a movement is made and the sources may be internal or external to the body . Typical sources of intrinsic feedback include vision, proprioception and audition . Extrinsic feedback is augmented information provided by an external source, in addition to intrinsic feedback . Extrinsic feedback is sometimes categorized as knowledge of performance or knowledge of results . </P>

What is the most common form of feedback control in humans