Evolutionary psychologists often propose that humans carry around "stone-age" brains, along with a toolkit of cognitive adaptations designed originally to solve hunter-gatherer problems. This perspective predicts that optimal cognitive performance might sometimes be induced by ancestrally-based problems, those present in ancestral environments, rather than by adaptive problems faced more commonly in modern environments. This prediction was examined in four experiments using the survival processing paradigm, in which retention is tested after participants process information in terms of its relevance to fitness-based scenarios. In each of the experiments, participants remembered information better after processing its relevance in an ancestral environment (the grasslands), compared to a modern urban environment (a city), despite the fact that all scenarios described similar fitness-relevant problems. These data suggest that our memory systems may be tuned to ancestral priorities. (Contains 4 tables and 6 figures.)