Default beliefs guide learning under uncertainty in children and older adults

Across the lifespan, humans rely on the ability to learn from new experiences to adapt to uncertain and changing environments. Here we investigated age-related differences in the reliance on default-belief settings during learning in these environments. We collected behavioral data with a predictive-inference task in children, adolescents as well as younger and older adults. Using a Bayesian belief-updating model, we first showed that age-related learning differences might be due to a reduced ability to adjust learning according to dissociable normative factors. The results revealed a reduced consideration of uncertainty in older adults and increased perseveration in both children and older adults. Simulations indicated that interventions to reduce perseveration might lead to more similar performance levels between the age groups. In a follow-up experiment, we found that one such intervention which randomly distorted participants' initial predictions strongly reduced perseveration, but led to increased performance differences. This counter-intuitive effect resulted from an environmental control of learning in children and older adults through random information from the intervention to reduce perseveration. Across the two experiments, our findings show that age-related learning impairments can be explained with insufficient updating from a default belief. In stable environments, this results in perseverative behavior, while in the presence of random environmental information, it leads to environmental control. We formalized the emergence of these belief-updating behaviors with a model that updated beliefs only to an acceptable level of plausibility, suggesting that children and older adults are more quickly satisfied to report beliefs that reflect their default than younger adults. This model not only accounted for our own findings but might also provide a new perspective on a wide variety of previous findings in the developmental and aging literature.