Taylor Kathleen M, Joseph Victory T, Balsam Peter D, Bitterman M E
Barnard College, New York, New York, USA.
Learn Behav. 2008 May;36(2):145-8. doi: 10.3758/lb.36.2.145.
In three between-groups blocking experiments with rats, two concurrent and one forward, several common control procedures were employed: Reinforced trials with the putative blocking stimulus were either omitted entirely (Kamin control), replaced by unsignaled reinforcements (Wagner control), or replaced by reinforced trials with a different stimulus (C+ control). In each experiment, parallel treatments with the target stimulus absent during training served to examine the possibility that differential responding in tests with the target stimulus might be traced solely to differential exposure to the nontarget stimuli. In Experiment 1, responding by a concurrent blocking group during the test was no different than responding by a Kamin control group, and responding by a Wagner control group was greater than that of either of the other groups--a pattern of results, mirrored in the performance of the target-absent groups, that could be attributed to the elevation of contextual excitation by unsignaled reinforcement. In Experiment 2, responding in the test by a concurrent blocking group was no different than that by a C+ control group. In Experiment 3, a finding of less responding by a forward blocking group than by a C+ control group when the target stimulus was present during training, but not when it was absent, provided plausible evidence of blocking.
在对大鼠进行的三项组间阻断实验中，两项为同时性阻断实验，一项为前瞻性阻断实验，采用了几种常见的对照程序：对假定的阻断刺激的强化试验要么完全省略（卡明对照），要么用无信号强化替代（瓦格纳对照），要么用对不同刺激的强化试验替代（C +对照）。在每个实验中，在训练期间没有目标刺激的平行处理用于检验以下可能性，即在有目标刺激的测试中差异反应可能仅仅归因于对非目标刺激的不同暴露。在实验1中，同时性阻断组在测试期间的反应与卡明对照组的反应没有差异，而瓦格纳对照组的反应比其他任何一组都大——这种结果模式在没有目标刺激的组的表现中也有体现，这可归因于无信号强化引起的情境兴奋的提高。在实验2中，同时性阻断组在测试中的反应与C +对照组的反应没有差异。在实验3中，当前瞻性阻断组在训练期间有目标刺激时，其反应比C +对照组少，但在没有目标刺激时则不然，这一发现为阻断提供了合理的证据。
