Abstract

Human beings have a memory adapted to primarily retain and recall information that favors their survival and reproduction. We tested whether the frequency and severity of environmental challenges influence adaptive memory, i.e., the ability to retain and recall adaptive information. Therefore, in a community of family farmers, we verified whether the salience index of snakes (as a proxy for the distribution of local knowledge and organization in the recall process) is determined by (1) relative abundance; (2) synanthropic behavior (proxies of environmental challenge frequency); (3) aposematic intensity; (4) active defense behavior; and (5) venom lethality (proxies of environmental challenge severity). To access local knowledge, we used semi-structured interviews and free lists. Ecological information about snakes, necessary for hypothesis testing, was collected from 15 herpetologists. Our results suggest that only the frequency of an environmental challenge determines a person’s ability to retain and recall adaptive information. The severity of an environmental challenge does not determine episodic memory by itself, but only amplifies the recall of information associated with frequent challenges. Therefore, an individual’s adaptive memory is fueled by the repetition of environmental challenges. Nonetheless, when the level of biological organization shifts to the population, severity is deemed evolutionarily significant. The severity of an environmental challenge, even if it leads to the death of individuals, may contribute to the evolution of the population if there are cohesive processes within the population, such as knowledge transmission, that transform it into a new “adaptive unit.”