Submission 221
Reconciling Inconsistent Age Effects in Speed of Information Processing: The Role of Task Difficulty
SymposiumTalk-02
Presented by: Veronika Lerche
Previous research in age-related cognition has shown that older adults typically exhibit longer response times than younger adults, while their accuracy is often comparable. To better understand these differences, diffusion model analyses have been applied and have consistently revealed two key patterns: older adults tend to adopt larger threshold separations and show longer nondecision times. Findings regarding drift rate, a parameter indexing the speed of information accumulation, have been less consistent. Some studies reported higher drift rates for younger adults, whereas others found no age differences or even reversed effects. In the present research, we identified a moderating factor that may account for these inconsistencies. In Study 1, young and older participants completed three perceptual and three verbal response time tasks, each with two different levels of difficulty. As expected, we replicated the typical age-related differences in threshold separation and nondecision time. More importantly, an interaction between age and task difficulty emerged for drift rate: although younger adults generally processed information faster, this advantage was markedly reduced for more difficult stimuli. Study 2 replicated this pattern for the perceptual tasks, but not for three recognition memory tasks. These results suggest that increased task difficulty may attenuate age-related differences in information processing speed for perceptual and verbal tasks, but not for recognition memory tasks.