Lupfer-Johnson Gwen, Murphy Eric S, Blackwell Linda C, LaCasse Jennifer L, Drummond Sarah
Department of Psychology, University of Alaska Anchorage, Anchorage, AK 99508-4614, USA.
Behav Processes. 2010 Jun;84(2):573-80. doi: 10.1016/j.beproc.2010.02.016. Epub 2010 Feb 25.
We investigated operant behavior in a novel species, the dwarf hamster (Phodopus campbelli). In two experiments, hamsters were trained to lever-press for food reinforcement. In Experiment 1, rate of reinforcement was manipulated across conditions using four variable-interval schedules of reinforcement (delivering one to eight reinforcers per min). As predicted, within-session decreases in responding were steepest on the richest schedule. In Experiment 2, lever-pressing was reinforced by either a constant or a variety of flavored food pellets. Within-session decreases in responding were steeper when the reinforcer flavor remained constant than when it was varied within the session. In both experiments, subjects hoarded most reinforcers in their cheek pouches rather than consuming them in the operant chambers. These results are incompatible with post-ingestive satiety variables as explanations for within-session decreases in operant responding and suggest that habituation to repeatedly presented reinforcers best accounts for subjects' response patterns. Additionally, a mathematical model that describes behavior undergoing habituation also described the present results, thus strengthening the conclusion that habituation mediates the reinforcing efficacy of food.
我们研究了一种新物种——侏儒仓鼠（坎氏毛足鼠）的操作性行为。在两项实验中，训练仓鼠通过按压杠杆来获取食物强化物。在实验1中，使用四种可变间隔强化程序（每分钟提供1至8次强化物）在不同条件下操纵强化率。正如预测的那样，在最丰富的强化程序下，实验过程中反应的减少最为陡峭。在实验2中，按压杠杆通过恒定的或多种口味的食物颗粒得到强化。当强化物的口味在实验过程中保持不变时，实验过程中反应的减少比口味变化时更为陡峭。在两项实验中，实验对象大多将强化物囤积在颊囊中，而不是在操作箱中食用。这些结果与摄食后饱腹感变量作为实验过程中操作性反应减少的解释不相符，并表明对反复呈现的强化物的习惯化最能解释实验对象的反应模式。此外，一个描述行为习惯化的数学模型也描述了当前的结果，从而强化了习惯化介导食物强化效果的结论。
