Como os humanos constroem tradições médicas? O papel do ambiente e da história de vida na memória e na transmissão cultural

Abstract

This thesis is part of the effort to understand how human memory evolved to fix information about diseases and how this information emerges in human groups through the process of cultural transmission. Human beings have a memory adapted for survival that presents plasticity, fixing information about different types of threats that may originate from ancestral or recent environments, although this idea is controversial. In this sense, we do not know which factors are responsible for modulating this plasticity in memory, allowing some information to receive better recall than others. Evidences suggest that environmental factors, such as the regularity of attacks by threats and factors related to human life history, such as previous experience with threats, may be responsible for this modulation. However, we do not know whether regularity guides information that will be better remembered, nor whether it is associated with diseases that are more regular in the current environment or with diseases that have been more regular throughout human evolutionary history. Furthermore, we do not know whether diseases that first emerged in ancestral environments can also guide recall, so we controlled whether this factor would influence memory. On the other hand, just investigating which factors guide a better fixation of information in memory without evaluating whether these same factors guide the dissemination of information about diseases in human groups can lead us to a simplistic view of human behavior in relation to these threats in the real world. Thus, we also investigated whether factors such as regularity, ancestry and previous experience with diseases would be behind the dissemination of information in human groups. Therefore, we investigated whether greater regularity, previous experience and ancestry of the disease act as learning biases leading to a biased diffusion of information. To test our claims, we created a model with different types of diseases as stimuli to be remembered and transmitted. To test whether the greater regularity of diseases over evolutionary time influences the recall and transmission of information, we grouped diseases into diseases of high regularity (acute) and low regularity (chronic). To test whether disease regularity in the current environment affects recall and information sharing, we grouped acute and chronic diseases into high- and low-incidence illnesses in the Brazilian adult population. To investigate the effect of previous experience with the disease, we evaluated its effects on memory and information diffusion. To investigate the effect of diseases that originated in ancestral environments, we grouped acute and chronic diseases into ancestral and modern. Our results showed that more regular diseases over evolutionary time (acute) and previous experience with diseases improved recalled information, while more regular diseases in the current environment (high incidence), and ancestors were less remembered. In addition, we observed that the greater regularity of diseases over evolutionary time (acute) acted as a content bias in cultural transmission, guiding the more reliable transmission of information. Another content bias was also observed for ancestral diseases. However, diseases from previous experiences and high incidence did not support our assumptions about possible context biases in cultural transmission, not influencing the accuracy of the transmitted information. In summary, we argue that the best recall and the most reliable transmission of information about diseases occurred due to the greater regularity of these diseases throughout the evolutionary history of our species, which exerted greater selective pressure on human cognition.