Stahlman W David, Roberts Seth, Blaisdell Aaron P
Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095-1563, USA.
J Exp Psychol Anim Behav Process. 2010 Jan;36(1):77-91. doi: 10.1037/a0015971.
Gharib, Derby, and Roberts (2001) proposed that reducing reward expectation increases variation of response form. We tested this rule in a new situation and asked if it also applied to variation of response location and timing. In 2 discrete-trial experiments, pigeons pecked colored circles for food. The circles were of 6 possible colors, each associated with a different probability of reward. Reducing reward expectation did not affect peck duration (a measure of form) but did increase horizontal variation of peck location and interpeck-interval variation. The effect of reward probability on the standard deviation of interpeck intervals was clearer (larger t value) than its effect on mean interpeck interval. Two datasets from rats had similar interresponse-interval effects.
加里布、德比和罗伯茨（2001年）提出，降低奖励期望会增加反应形式的变异性。我们在一种新情况下对这一规则进行了测试，并询问它是否也适用于反应位置和时间的变异性。在两项离散试验实验中，鸽子啄彩色圆圈以获取食物。圆圈有6种可能的颜色，每种颜色与不同的奖励概率相关联。降低奖励期望并未影响啄击持续时间（一种形式的度量），但确实增加了啄击位置的水平变异性和啄击间隔变异性。奖励概率对啄击间隔标准差的影响比对平均啄击间隔的影响更明显（t值更大）。来自大鼠的两个数据集有类似的反应间隔效应。
