Human Vision and Eye Movement Laboratory, Department of Medicine (Neurology), University of British Columbia, Vancouver, British Columbia, Canada.
PLoS One. 2012;7(4):e33460. doi: 10.1371/journal.pone.0033460. Epub 2012 Apr 6.
There are few clinical tools that assess decision-making under risk. Tests that characterize sensitivity and bias in decisions between prospects varying in magnitude and probability of gain may provide insights in conditions with anomalous reward-related behaviour.
We designed a simple test of how subjects integrate information about the magnitude and the probability of reward, which can determine discriminative thresholds and choice bias in decisions under risk.
DESIGN/METHODS: Twenty subjects were required to choose between two explicitly described prospects, one with higher probability but lower magnitude of reward than the other, with the difference in expected value between the two prospects varying from 3 to 23%.
Subjects showed a mean threshold sensitivity of 43% difference in expected value. Regarding choice bias, there was a 'risk premium' of 38%, indicating a tendency to choose higher probability over higher reward. An analysis using prospect theory showed that this risk premium is the predicted outcome of hypothesized non-linearities in the subjective perception of reward value and probability.
This simple test provides a robust measure of discriminative value thresholds and biases in decisions under risk. Prospect theory can also make predictions about decisions when subjective perception of reward or probability is anomalous, as may occur in populations with dopaminergic or striatal dysfunction, such as Parkinson's disease and schizophrenia.
评估风险下决策的临床工具较少。评估在收益幅度和概率不同的前景之间进行决策的敏感性和偏差的测试，可以为具有异常奖励相关行为的情况提供深入了解。
我们设计了一个简单的测试，用于研究受试者如何整合关于收益幅度和概率的信息，该测试可以确定风险下决策的辨别阈值和选择偏差。
设计/方法：要求 20 名受试者在两个明确描述的前景之间进行选择，一个的收益概率较高，但幅度较低，两个前景之间的预期价值差异从 3%到 23%不等。
受试者的平均阈值敏感性为预期价值差异的 43%。关于选择偏差，存在 38%的“风险溢价”，表明倾向于选择更高的概率而不是更高的奖励。使用前景理论进行的分析表明，这种风险溢价是对奖励价值和概率的主观感知中假设的非线性的预测结果。
这个简单的测试为风险下决策的辨别阈值和偏差提供了一个可靠的衡量标准。前景理论还可以对奖励或概率的主观感知异常时的决策做出预测，这种异常可能发生在多巴胺能或纹状体功能障碍的人群中，如帕金森病和精神分裂症。
