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

6只雄性Wister大鼠被放置在两个杠杆操作箱中，按照令人担忧的连锁时间表进行暴露。在竞争初始链路时间表(FR1)后，大鼠在两个选项中进行选择，随后是两个不同的结果。然后，他们在选定的替代方案上制定了终端链路时间表(FR25)。如果受试者选择风险选项，10粒小球或持续10秒的昏迷(BO)的概率(P)为0.5。如果受试者选择无风险的替代方案，则会出现五个P=0.9的小球或P=0.1的BO(5秒)。两只大鼠在风险替代中经历了10粒(p=0.1)/BO(p=0.9)，在无风险替代中经历了1粒(p=0.9)/BO(p=0.1)。其中一个环节包括强制选择试验和自由选择试验。在强迫选择试验中，受试者应该选择一个预先确定的备选方案，而在自由选择试验中，受试者可以从两个备选方案中选择一个。在这种非独立的条件下，有风险和无风险替代方案中颗粒呈现概率(PPP)分别为0.5和0.9的四只大鼠中，有三只表现出风险厌恶，但一只大鼠表现出风险倾向。PPP为0.1vs.0.9的两只大鼠表现出风险厌恶。所有大鼠都表现出非常稳定的选择，当在末端环节的FR比率增加，强迫选择试验改变为Stubbs&Pliskoff类型时，在初始链接中使用两个辨别性刺激。在分离的条件下，结果在终端链接中的呈现被分成五个小的结果，例如，一个十个小球的单一呈现分为五个两个小球的多个呈现。所有五只在非分离条件下表现出风险厌恶的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.