DELAY-AMOUNT TRADEOFFS IN CHOICES BY PIGEONS AND RATS: HYPERBOLIC VERSUS EXPONENTIAL DISCOUNTING
DELAY-AMOUNT TRADEOFFS IN CHOICES BY PIGEONS AND RATS: HYPERBOLIC VERSUS EXPONENTIAL DISCOUNTING
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DOI：
10.1901/jeab.2009.91-197
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发表时间：
2009-03-01
影响因子：
2.7
通讯作者：
Biondi, Dawn R.
中科院分区：
文献类型：
--
作者：
Mazur, James E.;Biondi, Dawn R.
采用调整延迟法研究了不同延迟量和增援数量时鸽子和大鼠的选择。在不同的条件下，选择方案包括一个。与两个增强体，一个与三个增强体，三个与两个增强体。在一个条件下，对一种选择(Lite标准选择)的延迟保持不变，而对另一种选择(调整选择)的延迟在一次会话中多次增加或减少，以便估计；在无差别点--两种选择大致相等的延迟。通过绘制调整延迟作为每对增强剂用量的标准延迟的函数来构造无差异函数。这些实验旨在测试双曲衰变方程的预测。无差别函数的斜率应随两种增强剂的比例增加而增大。与双曲线方程一致，无差异函数的斜率取决于两种增强剂的比例；对于鸽子和大鼠。这些结果不符合所有的指数衰减方程，该方程预测i的斜率与增强剂的量无关。结合其他数据，这些发现提供了进一步的证据，延迟贴现很好地描述了两个物种的双曲线方程，但。而不是通过指数方程。来自Lite两个物种的冷漠功能的y截距的数量差异表明，随着延迟的增加，大鼠的增强剂强度下降的速度可能比鸽子慢四到五倍。
An adjusting-delay procedure was used to study the choices of pigeons and rats when both delay and amount of reinforcement were varied. In different conditions, the choice alternatives included one. versus two reinforcers, one versus three reinforcers, and three versus two reinforcers. The delay to one alternative (Lite standard alternative) was kept constant in a condition, and the delay to the other (the adjusting alternative) was increased or decreased many times a session so as to estimate;in indifference point-a delay at which the two alternatives were chosen about equally often. Indifference Functions were constructed by plotting the adjusting delay as a function of the standard delay for each pair of reinforcer amounts,. The experiments were designed to test the prediction of a hyperbolic decay equation that. the slopes of the indifference functions should increase as the ratio of the two reinforcer amounts increased. Consistent with the hyperbolic equation, the slopes of the indifference functions depended on the ratios of the two reinforcer amounts,; for both pigeons and rats. These results were not compatible with all exponential decay equation, which predicts slopes of I regardless of the reinforcer amounts. Combined with other data, these findings provide further evidence that delay discounting is well described by a hyperbolic equation for both species, but. not by an exponential equation. Quantitative differences in the y-intercepts of the indifference functions from Lite two species suggested that the rate at which reinforcer strength decreases with increasing delay may be four or five times slower for rats than for pigeons.