This paper investigates risk aversion and its relationship with incentive effects through a series of lottery choice experiments. The study compares behavior under hypothetical and real monetary incentives, revealing that risk aversion increases significantly when high payoffs are actually paid in cash, rather than being hypothetical. A hybrid "power/expo" utility function with increasing relative and decreasing absolute risk aversion effectively models the observed data patterns across a wide range of payoffs, from several dollars to several hundred dollars. The experiment involved subjects making choices between paired lotteries with varying payoffs. When payoffs were hypothetical, subjects showed relatively low risk aversion, but when payoffs were real, they became significantly more risk averse. This suggests that the context of real monetary incentives has a substantial impact on risk attitudes. The study also found that the degree of risk aversion varies with the scale of payoffs, with subjects exhibiting more risk aversion at higher stakes. The results challenge the assumption that hypothetical payoffs can accurately reflect real-world risk attitudes. Subjects facing high real payoffs were much more risk averse than those facing hypothetical payoffs, indicating that the context of real incentives significantly influences decision-making. The study also found that the effects of high payoffs on risk attitudes are not consistent with constant relative risk aversion models, suggesting the need for a more flexible utility function that accounts for both increasing relative and decreasing absolute risk aversion. The paper concludes that risk aversion is a key factor in decision-making under uncertainty, and that the context of incentives plays a crucial role in shaping risk attitudes. The hybrid utility function proposed in the study provides a more accurate model of risk behavior across a wide range of payoffs, capturing the observed patterns of risk aversion and the effects of incentive conditions on decision-making. The findings have important implications for understanding risk behavior in economic and financial contexts, and for the design of experiments that aim to measure risk attitudes.This paper investigates risk aversion and its relationship with incentive effects through a series of lottery choice experiments. The study compares behavior under hypothetical and real monetary incentives, revealing that risk aversion increases significantly when high payoffs are actually paid in cash, rather than being hypothetical. A hybrid "power/expo" utility function with increasing relative and decreasing absolute risk aversion effectively models the observed data patterns across a wide range of payoffs, from several dollars to several hundred dollars. The experiment involved subjects making choices between paired lotteries with varying payoffs. When payoffs were hypothetical, subjects showed relatively low risk aversion, but when payoffs were real, they became significantly more risk averse. This suggests that the context of real monetary incentives has a substantial impact on risk attitudes. The study also found that the degree of risk aversion varies with the scale of payoffs, with subjects exhibiting more risk aversion at higher stakes. The results challenge the assumption that hypothetical payoffs can accurately reflect real-world risk attitudes. Subjects facing high real payoffs were much more risk averse than those facing hypothetical payoffs, indicating that the context of real incentives significantly influences decision-making. The study also found that the effects of high payoffs on risk attitudes are not consistent with constant relative risk aversion models, suggesting the need for a more flexible utility function that accounts for both increasing relative and decreasing absolute risk aversion. The paper concludes that risk aversion is a key factor in decision-making under uncertainty, and that the context of incentives plays a crucial role in shaping risk attitudes. The hybrid utility function proposed in the study provides a more accurate model of risk behavior across a wide range of payoffs, capturing the observed patterns of risk aversion and the effects of incentive conditions on decision-making. The findings have important implications for understanding risk behavior in economic and financial contexts, and for the design of experiments that aim to measure risk attitudes.