Walker D J, Branch M N
University of Florida, USA.
J Exp Anal Behav. 1998 Sep;70(2):139-63. doi: 10.1901/jeab.1998.70-139.
In Experiment 1 pigeons pecked a key that was illuminated with a 501-nm light and obtained food by doing so according to a variable-interval (VI) schedule of reinforcement, the mean value of which differed across groups: either 30 s, 120 s, or 240 s. The pigeons in all three groups were trained for 10 50-min sessions. Generalization testing was conducted in extinction with different wavelengths of light. Absolute and relative generalization gradients were similar in shape for the three groups. Experiment 2 was a systematic replication of Experiment 1 using line orientation as the stimulus dimension and a mean VI value of either 30 s or 240 s. Again, gradients of generalization were similar for the two groups. In Experiment 3 pigeons pecked a key that was illuminated with a 501-nm light and obtained food reinforcers according to either a VI 30-s or a 240-s schedule. Training continued until response rates stabilized (> 30 sessions). For subjects trained with the 30-s schedule, generalization gradients were virtually identical regardless of whether training was for 10 sessions (Experiment 1) or until response rates stabilized. For subjects trained with the VI 240-s schedule, absolute generalization gradients for subjects trained to stability were displaced upward relative to gradients for subjects trained for only 10 sessions (Experiment 1), and relative generalization gradients were slightly flatter. These results indicate that the shape of a generalization gradient does not necessarily depend on the rate of reinforcement during 10-session single-stimulus training but that the effects of prolonged training on stimulus generalization may be schedule dependent.
在实验1中，鸽子啄一个用501纳米光照明的按键，并根据可变间隔（VI）强化程序通过这样做获得食物，该程序的平均值在不同组中有所不同：要么是30秒、120秒，要么是240秒。所有三组鸽子都接受了10次50分钟的训练。泛化测试是在消退状态下用不同波长的光进行的。三组的绝对和相对泛化梯度在形状上相似。实验2是对实验1的系统重复，使用线条方向作为刺激维度，平均VI值为30秒或240秒。同样，两组的泛化梯度相似。在实验3中，鸽子啄一个用501纳米光照明的按键，并根据VI 30秒或240秒的程序获得食物强化物。训练持续到反应率稳定（>30次训练）。对于按照30秒程序训练的受试者，无论训练是进行10次（实验1）还是直到反应率稳定，泛化梯度实际上都是相同的。对于按照VI 240秒程序训练的受试者，训练至稳定的受试者的绝对泛化梯度相对于仅训练10次的受试者（实验1）的梯度向上偏移，并且相对泛化梯度略为平坦。这些结果表明，泛化梯度的形状不一定取决于10次单刺激训练期间的强化率，但长期训练对刺激泛化的影响可能取决于程序。
