N-Back training in middle adulthood: evidence for transfer only to structurally similar task

Understanding mechanisms and extent of training transfer to untrained tasks is one of central inquiries in cognitive training research. Since the reach of transfer remains open to debate, we aimed to investigate both near and far transfer effects resulting from updating training utilizing an n-back task. Healthy adults (N = 45, aged 49–65 years) were randomly assigned to either the training or the active control group. The study design included three measurement points (pretest, posttest, and follow-up after 6 months) and 20 training sessions distributed over 10 weeks. The comprehensive test battery included a criterion task, near-transfer tasks (one task structurally similar and one task structurally different from the trained task), and far-transfer tasks (inhibition, switching, and fluid reasoning). Training gains were observed on the trained and untrained n-back tasks only, indicating that updating training primarily improves the specific skills required to complete the trained task rather than it enhances the overall updating ability or related abilities. In line with a growing body of evidence our findings highlight the limited generalizability of updating training, indicating that future studies should focus more on identifying near-transfer mechanisms underlying the gains in process-based training.