THE EFFECT OF UNCONDITIONAL STIMULUS MODALITY AND INTENSITY ON BLINK STARTLE AND ELECTRODERMAL RESPONSES

Attentional accounts of blink facilitation during Pavlovian conditioni ng predict enhanced reflexes if reflex and unconditional stimuli (US) are from the same modality. Emotional accounts emphasize the importanc e of US intensity. In Experiment 1, we crossed US modality (tone vs, s hock) and intensity in a 2 X 2 between-subjects design. US intensity b ut not US modality affected blink facilitation. Tn Experiment 2, we de monstrated that the results from Experiment 1 were not due to the moto r task requirements employed. In Experiment 3, we used a within-subjec ts design to investigate the effects of US modality and intensity. Con trary to predictions derived from an attentional account, blink facili tation was larger during conditional stimuli that preceded shock than during those that preceded tones. The present results are not consiste nt with an attentional account of blink facilitation during Pavlovian conditioning in humans.