Influence of age and processing stage on visual word recognition

The authors used a lexical-decision task in 3 different experiments to examine whether age differences in word recognition were consistent across processing stage. In all experiments, word frequency and length were manipulated. In Experiments 1 and 2, encoding difficulty was varied, and in Experiment 3, response selection difficulty was varied. In all 3 experiments, there were no age differences for word frequency. However, in Experiments 1 and 2, older adults showed a larger decrement for encoding. In Experiment 3, age differences were larger when response selection load increased. These results suggest that age differences in word recognition occur because older adults exhibit primarily peripheral-rather than central-processing decrements. The implications of these data for generalized and localized slowing models are discussed.