Kehoe E J, Gibbs C M, Garcia E, Gormezano I
J Exp Psychol Anim Behav Process. 1979 Jan;5(1):1-18. doi: 10.1037//0097-7403.5.1.1.
Four experiments were conducted to determine whether in conditioning to a serial compound, CS1-CS2-UCS, there are (a) associative mechanisms operating to extend conditioning beyond the bounds of a CS-UCS contiguity gradient and (b) stimulus selection processes acting to attenuate the potency of CS-UCS contiguity. In Experiments 1 and 2, the CS2-UCS interval was held at .35 sec while the CS1-UCS interval was varied across groups from .75 to 2.75 sec. CS1 test trials revealed substantial CR acquisition at all CS1-UCS intervals. Moreover, Experiment 2 indicated that when the contribution of cross-modal generalization from CS2 to CS1 was factored out, there still remained a substantial level of conditioning, which Experiment 3 indicated was attributable to an associative mechanism like higher-order or sensory conditioning. The observation of CR acquisition at CS1-UCS intervals of 4.75, 8.75, and 18.75 sec in Experiment 4 suggested that serial compound training yields conditioning to CSs located well beyond the single CS contiguity gradient for the rabbit's nictitating membrane response. Experiments 1 and 2 also indicated the presence of stimulus selection processes because, at the shorter CS1-UCS intervals (.75 and 1.25 sec), the levels of test-trial responding to CS2 fell below those observed to the less contiguous CS1.
进行了四项实验，以确定在对连续复合刺激CS1-CS2-UCS进行条件作用时，是否存在(a) 联想机制，其作用是将条件作用扩展到CS-UCS接近梯度的范围之外；以及(b) 刺激选择过程，其作用是减弱CS-UCS接近性的效力。在实验1和实验2中，CS2-UCS间隔保持在0.35秒，而CS1-UCS间隔在不同组中从0.75秒变化到2.75秒。CS1测试试验显示，在所有CS1-UCS间隔下都有大量的条件反应习得。此外，实验2表明，当排除从CS2到CS1的跨模态泛化的影响时，仍然存在相当程度的条件作用，实验3表明这归因于一种联想机制，如高阶条件作用或感觉条件作用。实验4中在CS1-UCS间隔为4.75秒、8.75秒和18.75秒时观察到条件反应习得，这表明连续复合刺激训练对兔子瞬膜反应的条件作用超出了单个CS接近梯度所确定的范围。实验1和实验2还表明存在刺激选择过程，因为在较短的CS1-UCS间隔（0.75秒和1.25秒）时，对CS2的测试试验反应水平低于对较不接近的CS1的观察水平。
