Effects of risk experience on choice behavior in rats under concurrent chained schedule

将6只雄性Wister大鼠置于两个操作箱中，按照相关的链式时间表暴露。在竞争初始链接时间表（FR 1）后，大鼠在两个选项之间进行选择，随后产生两种不同的结果。然后，他们在所选的备选方案上制定了终端链路时间表（FR 25）。如果sebetan选择了风险选项，则10粒药丸或持续10秒的停电（BO）的概率（p）为0.5。如果受试者选择了无风险的替代方案，则发生了5个P=0.9的颗粒或P=0.1的BO（5秒）。两只大鼠在风险替代方案中经历了10粒（p=0.1）/BO（p=0.9），在无风险替代方案中经历了1粒（p=0.9）/BO（p=0.1）。其中一个环节包括强迫选择试验和自由选择试验，强迫选择试验中，受试者应选择一个预先确定的选择，自由选择试验中，受试者可以选择两个选项之一。在这种非分离条件下，四只大鼠中的三只表现出风险厌恶，但一只大鼠表现出风险倾向，其颗粒呈现概率（PPP）在风险与无风险的选择分别为0.5和0.9。购买力平价为0.1和0.9的两只大鼠表现出风险厌恶。所有大鼠表现出非常稳定的选择时，FR比率在终端链接增加和被迫选择试验改变为斯塔布斯和Pliskoff型使用两个歧视性刺激在初始链接。在分离条件下，呈现的后果在terminakl链接被分成五个小的后果，例如，一个单一的呈现10个颗粒分离成五个多个呈现的两个颗粒。在非分离条件下表现出风险厌恶的五只大鼠在分离条件下都产生了不稳定的选择模式。

Six male Wister rats, placed in the two-leveroperant boxes, were exposed under the concerrernt chained schedule. After competion of the initial link schedule (FR1), rats chose between two alternatives which were followed by two different consequences. Then they worked on the terminal link schedule (FR25) on the chosen alternative. If the sebjects chose the risk alternative, ten pellets or the black-out (BO) lasting ten seconds were presented with probility (p) 0.5. If the subjects selected the riskless alternative, five pellets with p=0.9 or BO (five seconds) with P=0.1 were occurred. Two rats experienced ten pellets (p=0.1) /BO (p=0.9) in the risk alternative and one pellet (p=0.9) /BO (p=0.1) in the riskless alternative. One session consisted of the forced choice trials in which subjects should select a pre-determined alternative and the free choice traials in which subjects could select one of two alternatives. In this non-separate condition, three of four rats whose pellet presentation probabilities (PPP) in risk vs.riskless alternative were 0.5 vs.0.9 showed risk aversion, but one rat showed risk prone. Two rats with PPP 0.1 vs.0.9 showed risk aversion. All rats showed very stable choices when FR ratios in the terminal link were increased and the forced choice trials changed to a Stubbs & Pliskoff type using two discriminative stimuli in the initial iink. In the separate condition, presentation of the consequence in the terminakl link was separated into five small consequences, e.g.a single presentation of ten-pellets separated into five multiple presentations of two-pellets. All five rats which showed risk averse in the non-separate condition produced unstable choice patterns the in separate condition.