Multi-factorial approach in aging research

Aging affects all kinds of human functions including perception and cognition. In most perceptual studies, one paradigm is tested and it is usually found that older participants perform worse than younger participants. Implicitly, these results are taken as evidence that there is one common factor for aging. Here, we show that there is no common factor in vision. We tested 95 healthy older and 105 younger participants in 9 perceptual tasks (including visual search and contrast detection). Young participants performed better than older participants in almost all tests. However, performance in the visual perceptual tasks was mostly uncorrelated. This was also confirmed by a second study where we used “subjective tasks” (illusions, ambiguous figures, music). Hence, our results show that, contrary to cognition, there is no common cause for healthy age-related decline in visual perception.