Hypothetical purchase tasks are a widely used tool to determine the reinforcing value of commodities, especially commodities which are difficult to deliver experimentally. Amazon Mechanical Turk users (N = 375) completed two novel hypothetical purchase tasks (quantity of purchase and probability of purchase) and other measures to estimate how much an individual values the opportunity to exercise in a gym. We examined correlations between demand indices generated by each task and measures related to physical activity. In addition, we compared rates of systematic and nonsystematic responding between the two tasks. Exploratory analyses of demand indices and measures of physical activity suggest initial evidence of construct validity for each task. When accounting for an order effect, the probability of purchase task generated significantly lower rates of nonsystematic responding compared to the quantity of purchase task (2.87% vs. 14.6%, respectively). We discuss how these results may inform improved construction of future hypothetical purchase tasks and implications for using likelihood and quantity purchase tasks.

假设购买任务是一种广泛使用的工具，用于确定商品的强化价值，尤其是难以通过实验交付的商品。Amazon Mechanical Turk 用户（N= 375) 完成了两项新的假设购买任务（购买数量和购买概率）和其他衡量标准，以估计个人对在健身房锻炼的机会的重视程度。我们检查了每项任务产生的需求指数与与身体活动相关的措施之间的相关性。此外，我们比较了两项任务之间的系统和非系统响应率。对需求指数和身体活动测量的探索性分析表明，每项任务的结构有效性的初步证据。在考虑订单效应时，与购买任务的数量相比，购买任务的概率产生的非系统响应率显着降低（分别为 2.87% 和 14.6%）。