Human memory evolved subject to the constraints of nature's criterion: differential survival and reproduction. Consequently, our capacity to remember and forget is likely tuned to solving fitness-based problems, particularly those prominent in ancestral environments. Do the operating characteristics of memory continue to bear the footprint of nature's criterion? Are there mnemonic "tunings" rooted in the remnants of a stone-age brain? Work from the presenter's laboratory suggests that: (1) processing information for its survival relevance leads to superior long-term retention, better, in fact, than most known learning techniques; (2) animate (living) stimuli are remembered much better than matched inanimate (nonliving) stimuli; and (3) stimuli that have been potentially contaminated by disease are remembered especially well. Understanding how memory is used to solve adaptive problems relevant to fitness, the presenter argues, provides critical insight into how and why human memory systems formed, and why they work the way they do.