This study investigates costly punishment across human societies, analyzing data from multiple populations to understand the factors influencing individuals' willingness to punish unfair behavior. The research involved standardized experimental procedures, including the Dictator Game (DG), Ultimatum Game (UG), and Third Party Punishment Game (3PPG). Participants were tested on their willingness to reject unfair offers and punish unfair behavior, with data collected on economic and demographic variables. The study found that population-level differences in education and birth year significantly influence willingness to punish, with more educated individuals and those born later in the 20th century showing higher levels of punishment. However, these effects were largely between-group rather than within-group, suggesting that cultural and economic differences play a significant role. The study also examined the possibility that hyperfair rejections (rejections of offers greater than 50%) in the UG were due to confusion about the game. However, data from the 3PPG and post-game interviews indicated that participants understood the game and made rational decisions, suggesting that hyperfair rejections were not due to confusion. The study found that punishment in the 3PPG was less common than in the UG, and that the willingness to punish was influenced by factors such as education, birth year, and income. However, these effects were largely between-group, indicating that cultural and economic differences played a significant role. The study also found that altruism, as measured by the DG, was positively correlated with willingness to punish in the UG and 3PPG. This suggests that cultural coevolution may have played a role in the development of fairness and altruism. Overall, the study highlights the importance of cultural and economic factors in shaping human behavior, particularly in the context of punishment and fairness. The findings suggest that while individual differences in education and birth year may influence punishment, these effects are largely between-group, indicating that cultural and economic differences play a significant role in shaping human behavior.This study investigates costly punishment across human societies, analyzing data from multiple populations to understand the factors influencing individuals' willingness to punish unfair behavior. The research involved standardized experimental procedures, including the Dictator Game (DG), Ultimatum Game (UG), and Third Party Punishment Game (3PPG). Participants were tested on their willingness to reject unfair offers and punish unfair behavior, with data collected on economic and demographic variables. The study found that population-level differences in education and birth year significantly influence willingness to punish, with more educated individuals and those born later in the 20th century showing higher levels of punishment. However, these effects were largely between-group rather than within-group, suggesting that cultural and economic differences play a significant role. The study also examined the possibility that hyperfair rejections (rejections of offers greater than 50%) in the UG were due to confusion about the game. However, data from the 3PPG and post-game interviews indicated that participants understood the game and made rational decisions, suggesting that hyperfair rejections were not due to confusion. The study found that punishment in the 3PPG was less common than in the UG, and that the willingness to punish was influenced by factors such as education, birth year, and income. However, these effects were largely between-group, indicating that cultural and economic differences played a significant role. The study also found that altruism, as measured by the DG, was positively correlated with willingness to punish in the UG and 3PPG. This suggests that cultural coevolution may have played a role in the development of fairness and altruism. Overall, the study highlights the importance of cultural and economic factors in shaping human behavior, particularly in the context of punishment and fairness. The findings suggest that while individual differences in education and birth year may influence punishment, these effects are largely between-group, indicating that cultural and economic differences play a significant role in shaping human behavior.