Bandwidth Knowledge of Results Effect

The bandwidth knowledge of results effect is a finding in motor skill learning research in which providing knowledge of results, feedback about the outcome of a movement, only when a learner's error on a given attempt exceeds some pre-set tolerance range, or bandwidth, rather than delivering feedback after every single attempt regardless of how accurate it was, produces better long-term retention of the skill than a schedule that provides feedback constantly, even though the bandwidth schedule objectively gives the learner less total feedback overall. Researchers interpret the effect within the broader guidance hypothesis, documented elsewhere in this section, reasoning that a learner who receives no feedback on an attempt that was already accurate enough is thereby prompted to trust and further develop their own internal sense of whether a movement felt correct, whereas being told the outcome of every single attempt, including already-good ones, discourages that same internal error-detection process from developing as fully. The effect is one of several documented feedback-reduction techniques in motor learning, alongside the summary knowledge of results effect documented elsewhere in this section, that reliably improve retention despite reducing the sheer quantity of feedback a learner receives during practice.