Exposure to noncontingent food delivery has been shown to elicit an increase in nociceptive thresholds in food-deprived rats. In Experiment 1, we examined whether this hypoalgesic response might be attributed to a loss of control over food delivery. Rats were exposed to noncontingent food delivery with or without prior exposure to contingent food delivery, and nociceptive thresholds were recorded using the tail-immersion test. Both groups of rats exhibited significant increases in nociceptive thresholds, and no differences were found between rats that had experienced a loss of control and those that had not. In Experiment 2, we examined the role of predictability in the hypoalgesic response to noncontingent food delivery. Food-deprived rats were exposed to noncontingent food delivery with or without a light signal preceding the delivery of each food pellet. Both groups of animals exhibited significant increases in nociceptive thresholds. However, the hypoalgesic response was significantly reduced when food delivery was preceded by a light signal. These findings suggest that it is not merely a lack of control over food delivery which may be responsible for the activation of analgesic mechanism, but that the availability of predictability has an important modulatory role as well.Exposure to a wide variety of stressors has been shown to increase nociceptive thresholds in rats. This phenomenon, referred to as "stress-induced analgesia" (SIA), involves the activation of multiple pain inhibitory systems-some opioid mediated, others nonopioid mediated-that inhibit nociception via neural and/or hormonal mechanisms (for reviews, see Bodnar, 1986;Kelly, 1986;Rodgers & Randall, 1988). Although much of the research on SIA has utilized nociceptive stimuli, there is evidence that nonnociceptive stimuli can also activate these mechanisms (