Evolutionary psychology examines how natural selection, a theory proposed by Charles Darwin influences the development of human behavior and mental processes. Evolutionary psychology suggests that many common human behaviors — such as reactions to fear, mating strategies, and social cooperation — originated as evolutionary adaptations that increased ancestral survival and reproductive success. For example, the common fear of snakes among humans suggests that early humans who feared snakes were more likely to survive and pass this trait on to future generations. In mate selection, traits that indicate good health and fertility are favored because they increase the chances of producing healthy offspring. Human cooperative behaviors, such as teamwork and altruism, have evolved to boost both individual survival and community success. Cross-cultural research by evolutionary psychologists indicate that, despite cultural variations, basic psychological mechanisms like food preferences and mate selection are similar among humans, suggesting an evolutionary basis for many behaviors.