Huskinson Sally L, Anderson Karen G
West Virginia University, United States.
Behav Processes. 2013 Nov;100:18-22. doi: 10.1016/j.beproc.2013.07.013. Epub 2013 Jul 23.
In delay discounting, choice is between two reinforcers that differ in amount and delay, and the subjective value of either reinforcer decreases as a function of delay to its receipt. The steepness of the discounting function is thought to reflect the degree of impulsive choice. Many factors can influence impulsive choice, including the addition of a constant delay or response requirement to the smaller sooner (SS) and larger later (LL) reinforcers. A delay-discounting procedure developed by Evenden and Ryan (1996) is commonly used in behavioral research, yet effects of adding a response requirement to both alternatives with this procedure has not been examined. If different delay-discounting procedures are measuring the same phenomenon, preference reversals should occur with the Evenden and Ryan procedure as they do with other procedures with an added response requirement. The current experiment used an Evenden and Ryan procedure, and choice was examined when the response requirement was a small, intermediate, and large fixed ratio (FR). Fewer LL choices occurred with the small FR, and more LL choices occurred with the intermediate and large FR. The present experiment extends preference-reversal findings to a different and commonly used delay-discounting procedure.
在延迟折扣中，选择是在数量和延迟方面存在差异的两种强化物之间进行的，并且任一强化物的主观价值会随着获得它的延迟时间而降低。折扣函数的陡峭程度被认为反映了冲动选择的程度。许多因素会影响冲动选择，包括对较小且较早（SS）和较大且较晚（LL）强化物增加恒定的延迟或反应要求。埃文登和瑞安（1996年）开发的一种延迟折扣程序在行为研究中常用，但尚未研究在此程序中对两种选择都增加反应要求的效果。如果不同的延迟折扣程序测量的是同一现象，那么使用埃文登和瑞安程序时应会像使用其他增加了反应要求的程序一样出现偏好逆转。当前实验使用了埃文登和瑞安程序，并在反应要求为小、中、大固定比率（FR）时对选择进行了检验。小FR时较少出现选择LL的情况，而中FR和大FR时较多出现选择LL的情况。本实验将偏好逆转的研究结果扩展到了一种不同的且常用的延迟折扣程序。
