Protective effect of prior knowledge in ageing
Visual perception depends on both sensory input and prior knowledge, and the quality of these information sources changes across the lifespan. As people age, accumulated knowledge, and its influence on perception, tend to increase, while declines in low-level visual functions reduce input quality and bias perception toward prior information. Yet, the combined effects of these changes on higher-level visual perception remain unclear, partly because concurrent cognitive decline may complicate the use of stored knowledge. In this study, we examined how prior knowledge shapes visual perception in younger (<40 years) and older (>60 years) adults using ambiguous two-tone images, whose recognition depends on prior knowledge. Providing participants with the original photographs used to generate the two-tones triggered perceptual reorganisation, improving recognition in both groups. Although older adults recognised fewer two-tones overall - a pattern linked to reduced visual acuity - they showed a comparable benefit from prior knowledge when cued. These findings suggest that, despite age-related sensory decline, the ability to draw on prior knowledge remains robust in older adulthood and may help preserve perceptual function.