The rise and fall of semantic cognition: Knowledge accumulation in later life is offset by declines in semantic control

Semantic cognition (use of acquired world knowledge to guide behaviour) is critical in everyday life. Semantic cognition is often assumed to be preserved in later life, compensating for functional declines in other cognitive domains. However, aging research rarely considers age-related effects on non-verbal knowledge or on semantic control processes that regulate how knowledge is activated and used. We addressed this by conducting the most detailed assessment of semantic cognition across the adult lifespan to date, involving 537 UK adults aged between 20 and 91. Verbal semantic knowledge increased linearly across adulthood while non-verbal knowledge reached a plateau at age 60. In contrast, controlled semantic processing showed age-related decline, particularly in the ability to inhibit task-irrelevant semantic knowledge. These results indicate that semantic cognition is not uniformly preserved in old age: though older people know more than young people, they are less able to use their knowledge flexibly in novel situations.