Harris Justin A
School of Psychology, University of Sydney, Sydney, NSW, Australia.
J Exp Psychol Anim Behav Process. 2011 Apr;37(2):151-64. doi: 10.1037/a0021883.
This report analyzes the acquisition of conditioned responses in rats trained in a magazine approach paradigm. Following the suggestion by Gallistel, Fairhurst, and Balsam (2004), Weibull functions were fitted to the trial-by-trial response rates of individual rats. These showed that the emergence of responding was often delayed, after which the response rate would increase relatively gradually across trials. The fit of the Weibull function to the behavioral data of each rat was equaled by that of a cumulative exponential function incorporating a response threshold. Thus, the growth in conditioning strength on each trial can be modeled by the derivative of the exponential--a difference term of the form used in many models of associative learning (e.g., Rescorla & Wagner, 1972). Further analyses, comparing the acquisition of responding with a continuously reinforced stimulus (CRf) and a partially reinforced stimulus (PRf), provided further evidence in support of the difference term. In conclusion, the results are consistent with conventional models that describe learning as the growth of associative strength, incremented on each trial by an error-correction process.
本报告分析了在食物盘接近范式中训练的大鼠条件反应的习得情况。按照加利斯特尔、费尔赫斯特和巴尔萨姆（2004年）的建议，将韦布尔函数拟合到各只大鼠逐次试验的反应率上。结果显示，反应的出现往往会延迟，之后反应率会在各次试验中相对逐渐增加。将韦布尔函数拟合到每只大鼠的行为数据上，与包含反应阈值的累积指数函数的拟合效果相当。因此，每次试验中条件作用强度的增长可以用指数的导数来建模——这是许多联想学习模型（如雷斯克拉和瓦格纳，1972年）中使用的一种差异项形式。进一步的分析比较了连续强化刺激（CRf）和部分强化刺激（PRf）下反应的习得情况，为差异项提供了进一步的支持证据。总之，这些结果与传统模型一致，这些模型将学习描述为联想强度的增长，每次试验通过误差校正过程增加。
