Long-term size-increasing adaptation of saccades in macaques

► We adapt monkeys to double off or halve their saccade size over ∼3 weeks. ► Long-term saccade adaptations (LTSA) are more persistent than short term (1 day). ► It takes fewer days to recover from LTSA than it does to finish long-term adapting. ► Size-increasing LTSA is slower than size-decreasing LTSA. ► Size-increasing and size-decreasing LTSA use distinct mechanisms.