Parameters of variable reward distributions that affect risk sensitivity of honey bees
Parameters of variable reward distributions that affect risk sensitivity of honey bees
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DOI：
10.1242/jeb.02656
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发表时间：
2007-01-15
影响因子：
2.8
通讯作者：
Shafir, Sharoni
中科院分区：
文献类型：
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作者：
Drezner-Levy, Tamar;Shafir, Sharoni
我们研究了风险敏感性与利用蜜蜂在长鼻延伸条件反射范例。我们让每个受试者转动头部，将鼻子伸向两种气味中的一种;一种气味与恒定的奖励相关，另一种气味与可变的奖励相关，奖励的概率分别为P和（1-P）。奖励值和概率被设置为使得可变备选方案的期望值等于恒定备选方案的期望值。我们进行了六个实验条件，其中变异性是在奖励量和三个条件，其中变异性是在奖励浓度。这些实验旨在系统地测试描述风险敏感度水平的奖励分布的各种参数的影响。风险厌恶是最大的可变性时，在奖励量，变量分布包括零奖励，并有一个高变异系数（CV = s.d./平均值）。方差本身并不影响风险敏感性。当变量分布不包括零奖励时，受试者对风险无所谓，但这些分布是正偏的。零奖励和分布偏斜的独立影响仍有待检验。受试者的风险无关紧要的条件下，可变性是在奖励浓度，但浓度范围是有限的，这些分布不包括零奖励和倾斜。我们的结论是，风险厌恶的回报金额的变化是一个强大的现象，一些奖励分布。系统地评估各种奖励分配参数对选择行为的影响，应该是对功能和机械方法的补充。
We investigated risk sensitivity with harnessed honey bees in a proboscis-extension conditioning paradigm. We conditioned each subject to turn its head and extend its proboscis towards one of two presented odors; one odor was associated with a constant reward and the other with a variable reward that was either low or high, with probabilities P and (1-P), respectively. Reward values and probabilities were set so that the expected value of the variable alternative was equal to that of the constant one. We performed six experimental conditions in which variability was in reward volume and three conditions in which variability was in reward concentration. The experiments were designed to systematically test the effect of various parameters that describe the reward distributions on levels of risk sensitivity. Risk aversion was greatest when variability was in reward volume, and the variable distribution included zero rewards and had a high coefficient of variation (CV = s.d./mean). The variance itself did not affect risk sensitivity. Subjects were risk indifferent when the variable distribution did not include zero rewards, however these distributions were positively skewed. The independent effects of zero rewards and distribution skew remain to be tested. Subjects were risk indifferent in conditions where variability was in reward concentration, but concentration range was limited and these distributions did not include zero rewards and were skewed. We conclude that risk aversion to variability in reward amount is a robust phenomenon for some reward distributions. A systematic evaluation of the effect of various reward distribution parameters on choice behavior should complement functional and mechanistic approaches.