Björkstrand P A
Department of Psychology, University College of Orebro, Sweden.
Biol Psychol. 1990 Feb;30(1):35-50. doi: 10.1016/0301-0511(90)90089-f.
The effects of conditioned stimulus (CS) pre-exposure and fear-relevance of the CS on human Pavlovian electrodermal conditioning were investigated. A differential delayed conditioning paradigm was used with a CS-unconditioned stimulus (US; shock) interval of 8 s. In Experiment 1, 64 subjects were randomized into four groups, two of which received fear-relevant stimuli and the other two fear-irrelevant stimuli. Half of the subjects were pre-exposed to the to-be-CSs and the other half to two not-to-be-CSs, with 15 exposure of each stimulus. During acquisition, subjects received 8 reinforced and 8 nonreinforced CS+ and CS- trials, and during the extinction phase 15 nonreinforced trials of each CS. Pre-exposure to the to-be-CSs retarded conditioning for the first and second interval anticipatory responses (FIRs and SIRs); that is, a latent inhibition effect was demonstrated, although the results for the FIR were inconclusive. The expected effects of fear-relevance were not revealed. Experiment 2 addressed the question whether the long pre-exposure period interfered with the frequently observed "preparedness effect" of higher resistance to extinction to fear-relevant stimuli. The design was similar to that of Experiment 1, but for half of the subjects the acquisition phase was initiated immediately after a short rest period, and for the other half acquisition started after an extended rest period, equal to the duration of the pre-exposure phase in Experiment 1. Twenty extinction trials of each CS were presented. A reliable difference in arousal in terms of spontaneous fluctuations was produced by the rest periods, but although differential conditioning was observed, no effect of fear-relevance was seen during extinction.
研究了条件刺激（CS）预暴露以及CS的恐惧相关性对人类巴甫洛夫式皮肤电条件反射的影响。采用了一种差别延迟条件反射范式，CS与非条件刺激（US；电击）的间隔为8秒。在实验1中，64名受试者被随机分为四组，其中两组接受与恐惧相关的刺激，另外两组接受与恐惧无关的刺激。一半受试者预暴露于即将成为CS的刺激，另一半预暴露于两种不会成为CS的刺激，每种刺激各暴露15次。在习得阶段，受试者接受8次强化和8次非强化的CS+和CS-试验，在消退阶段，每种CS进行15次非强化试验。预暴露于即将成为CS的刺激会延迟第一和第二间隔预期反应（FIRs和SIRs）的条件反射；也就是说，虽然FIR的结果尚无定论，但仍证明了潜伏抑制效应。未发现恐惧相关性的预期效应。实验2探讨了较长的预暴露期是否会干扰对恐惧相关刺激更高的消退抗性这一常见的“准备效应”。实验设计与实验1相似，但对于一半受试者，在短暂休息期后立即开始习得阶段，对于另一半受试者，在相当于实验1中预暴露阶段持续时间的延长休息期后开始习得阶段。每种CS进行20次消退试验。休息期产生了可靠的自发波动唤醒差异，但尽管观察到了差别条件反射，但在消退过程中未发现恐惧相关性的影响。
