Adaptive Difficulty and Cognitive Gains in Multi-Domain Cognitive Training: A Randomized Active-Controlled Study

Cognitive training is widely delivered in gamified formats, but it remains unclear whether adaptive adjustment of task difficulty contributes to cognitive gains beyond participation in the same training at a fixed level of difficulty. We investigated this question using Pavlov: The Brain Is On, a functional cognitive-training game. In Experiment 1, 107 young adults were randomly assigned to 19 days of adaptive-difficulty training (ADT) or the same training maintained at low difficulty (LDT), with the same games and the same prescribed daily training time. Cognitive performance was assessed before and after training across working memory, mental rotation, attention, inductive reasoning, and response inhibition. ADT showed a suggestive advantage over LDT in the N-back response-time load effect (group × time interaction, p = 0.017, uncorrected), though this result was marginal after FDR correction (pFDR = 0.084) and should not be interpreted as confirmatory. No significant between-group differences emerged for attention, inductive reasoning, or response inhibition; mental rotation showed a similar but non-significant pattern (p = 0.076). In Experiment 2, ADT showed a greater improvement in mental rotation than recreational gaming in the full sample (pFDR = 0.045), and this estimate was unchanged after adjustment for age; no other outcome differed between groups. Because Experiment 2 was non-randomized, this finding is exploratory. These findings suggest that adaptive difficulty may be a candidate active ingredient of gamified cognitive training, particularly for working memory, but the evidence remains preliminary and requires confirmation in preregistered studies.