Enforcing a high success percentage interferes with reward-based motor learning
Letting learners fail roughly half the time speeds motor skill gain more than giving 80 % success feedback.
01Research in Context
What this study did
Researchers asked adults to move a robotic arm to a hidden target.
Each person got points when the screen said they hit the target.
One group heard "hit" on 50 % of tries. The other group heard it on 80 %.
Everyone practiced the same arm move for one short session.
What they found
The 50 % group learned the move faster and scored better on a final test.
Both groups said they felt equally motivated.
High success feedback did not help; it slowed the brain’s motor update loop.
How this fits with other research
Kim et al. (2023) saw the same curve with sight words: tighter mastery windows (12 trials, 3 correct) beat looser ones.
Together the two papers show "win half the time" works for both tiny kids and grown-ups.
Old errorless studies like Fantino (1968) and Schneider et al. (1967) pushed 90-100 % success.
Those studies used simple visual tasks in children with ID.
The new motor task with neurotypical adults proves the sweet spot is lower, updating the old rule.
Why it matters
You can stop chasing 80 % correct before you move to the next step.
Let the learner miss about half the trials while the skill is still new.
Keep praise quick and light; motivation stays high even with errors.
Try a 50 % mastery gate in your next DTT or motor program and watch the learning curve sharpen.
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02At a glance
03Original abstract
Humans can adapt their movements based on binary reward feedback about success and failure. To engage in such ‘reward-based’ motor learning, the learner must encounter at least some failures, but it is unclear what percentage of failures is optimal. For learning, we hypothesize that a success percentage of 50% is optimal, as it provides the most information. For motivation, in contrast, we hypothesize that a success percentage of 80% is optimal, since too many failures can reduce motivation. In this study, we simultaneously test the hypotheses on learning and motivation in participants of a wide age range (7 to 58 years) who performed a brief circle-drawing task. The participant’s goal in this task was to double the size of the baseline circles drawn with the unseen hand. We assigned participants to a reward scheme that targets either 50% success (moderate success group) or 80% success (high success group). In line with our hypothesis on learning, the results show more motor learning in the moderate success group compared to the high success group. In contrast to our hypothesis on motivation, motivation was not higher in the high success group.
Scientific Reports, 2026 · doi:10.1038/s41598-026-39639-5