Anterograde interference in multitask perceptual learning.

Learning to perform multiple tasks robustly is a crucial facet of human intelligence, yet its mechanisms remain elusive. Here, we formulated four hypotheses concerning task interactions and investigated them by analyzing training sequence effects through a continual learning framework. Forty-nine subjects learned seven tasks sequentially, each of the seven groups following a distinct sequence. Results showed that subjects learning a task later in a sequence exhibited poorer performance in six tasks (Contrast, Vernier, Face, Motion, Auditory, and N-back tasks, except for the Shape task) compared to those who learned this task earlier. Interestingly, sequence position had minimal impact on forgetting. A complementary dual-task experiment corroborated these findings. Through detailed analyses of session and block learning curves, we revealed task-specific anterograde interference, but no retrograde interference. These findings support the integrated reweighting theory and shed light on the meta-plasticity mechanism governing how human brain balances plasticity and stability.