Sylvester Kenneth M, Brown Daniel G, Leonard Susan H, Merchant Emily, Hutchins Meghan
Inter-university Consortium for Political and Social Research, Institute for Social Research, University of Michigan, P.O. Box 1248, Ann Arbor, MI, 48104.
School of Natural Resources and Environment, University of Michigan, 440 Church St, Ann Arbor, MI 48109.
Reg Environ Change. 2015 Feb;15(2):301-315. doi: 10.1007/s10113-014-0628-6.
Land-use change in the U.S. Great Plains since agricultural settlement in the second half of the nineteenth century has been well documented. While aggregate historical trends are easily tracked, the decision-making of individual farmers is difficult to reconstruct. We use an agent-based model to tell the history of the settlement of the West by simulating farm-level agricultural decision making based on historical data about prices, yields, farming costs, and environmental conditions. The empirical setting for the model is the period between 1875 and 1940 in two townships in Kansas, one in the shortgrass region and the other in the mixed grass region. Annual historical data on yields and prices determine profitability of various land uses and thereby inform decision-making, in conjunction with the farmer's previous experience and randomly assigned levels of risk aversion. Results illustrating the level of agreement between model output and unique and detailed household-level records of historical land use and farm size suggest that economic behavior and natural endowments account for land change processes to some degree, but are incomplete. Discrepancies are examined to identify missing processes through model experiments, in which we adjust input and output prices, crop yields, agent memory, and risk aversion. These analyses demonstrate how agent-based modeling can be a useful laboratory for thinking about social and economic behavior in the past.
自19世纪下半叶农业定居以来，美国大平原地区的土地利用变化已有详尽记载。虽然总体历史趋势易于追踪，但个体农民的决策却难以重构。我们使用基于主体的模型，通过根据价格、产量、耕作成本和环境条件等历史数据模拟农场层面的农业决策，来讲述西部定居的历史。该模型的实证背景是1875年至1940年期间堪萨斯州的两个乡镇，一个位于短草地区，另一个位于混合草地区。产量和价格的年度历史数据与农民以前的经验以及随机设定的风险厌恶水平相结合，决定了各种土地利用方式的盈利能力，从而为决策提供依据。结果表明，模型输出与历史土地利用和农场规模的独特而详细的家庭层面记录之间的吻合程度，说明经济行为和自然禀赋在一定程度上解释了土地变化过程，但并不完整。通过模型实验来调整投入和产出价格、作物产量、主体记忆和风险厌恶，从而对差异进行研究，以识别缺失的过程。这些分析表明，基于主体的建模如何能够成为思考过去社会和经济行为的有用实验室。
