We model the semantic recall sequences of 424 older adults aged between 69 to 103 years in the animal fluency task. Our results suggest that, under normal intellectual functioning, memory search in old age (69–84 years) is consistent with a dynamic process that switches between retrieval probes. With dementia and very old age (85–103 years), however, memory search seems to become more consistent with a static process that activates items in memory as a function of their frequency. The weight that probes have in determining the activation of items in memory seems to be an informative signature of the impact of healthy aging and dementia on memory search. Our results show that, with healthy aging and dementia, the activation of items in memory is increasingly more determined by the frequency of past experience with those items.