The study by Garcia and Koelling explores how cues are selected based on the nature of the subsequent reinforcer in avoidance learning. An audiovisual stimulus was made contingent upon a rat's licking at a water spout, making it analogous to a gustatory stimulus. When both stimuli were paired with electric shock, avoidance reactions transferred to the audiovisual stimulus but not the gustatory one. Conversely, when paired with toxin or x-ray, avoidance reactions transferred to the gustatory stimulus but not the audiovisual one. This suggests that stimuli are selected as cues based on the nature of the reinforcer. Evidence indicates that traditional formulations of reinforcement are inadequate. Wild rats that have survived poisoning avoid poison bait using olfactory and gustatory cues, but not the place where poisoning occurred. Studies show that ionizing radiation can produce avoidance reactions when paired with distinctively flavored fluids, but not with environmental cues. This differential effect is due to the nature of the reinforcer (radiation or toxic effects) or the peculiar relation of gustatory stimuli to the drinking response. The study used four experiments to test the effectiveness of response-controlled stimuli in inhibiting drinking in the absence of reinforcement. The apparatus included a drinking spout connected to an electronic drinkometer. "Bright-noisy" water was provided by an incandescent lamp and a clicking relay, while "tasty" water was flavored. Rats were habituated to drinking, then tested for intake of bright-noisy and tasty water. Acquisition training involved reinforced and nonreinforced trials. Post-tests measured intake after training. In the x-ray study, an audiovisual group and a gustatory group were exposed to identical radiation schedules. In other studies, reinforcement was contingent upon the rat's response. The results showed that x-rays and lithium chloride were readily transferred to the gustatory stimulus but not the audiovisual one. The effect was more pronounced in the x-ray study. Shock reinforcement was delayed in some studies, but the difference in post-test scores was statistically significant. The results suggest that gustatory stimuli paired with agents causing nausea acquire secondary reinforcing properties, while auditory and visual stimuli do not. In contrast, electric shock to the paws transferred to the audiovisual stimulus but not the gustatory one. The study concludes that reinforcers are not equally effective for all stimuli, and cues are selected based on the consequences of the reinforcer. Two hypotheses are offered: one involving time-intensity patterns of stimulation, and another involving natural selection favoring mechanisms associating gustatory and olfactory cues with internal discomfort.The study by Garcia and Koelling explores how cues are selected based on the nature of the subsequent reinforcer in avoidance learning. An audiovisual stimulus was made contingent upon a rat's licking at a water spout, making it analogous to a gustatory stimulus. When both stimuli were paired with electric shock, avoidance reactions transferred to the audiovisual stimulus but not the gustatory one. Conversely, when paired with toxin or x-ray, avoidance reactions transferred to the gustatory stimulus but not the audiovisual one. This suggests that stimuli are selected as cues based on the nature of the reinforcer. Evidence indicates that traditional formulations of reinforcement are inadequate. Wild rats that have survived poisoning avoid poison bait using olfactory and gustatory cues, but not the place where poisoning occurred. Studies show that ionizing radiation can produce avoidance reactions when paired with distinctively flavored fluids, but not with environmental cues. This differential effect is due to the nature of the reinforcer (radiation or toxic effects) or the peculiar relation of gustatory stimuli to the drinking response. The study used four experiments to test the effectiveness of response-controlled stimuli in inhibiting drinking in the absence of reinforcement. The apparatus included a drinking spout connected to an electronic drinkometer. "Bright-noisy" water was provided by an incandescent lamp and a clicking relay, while "tasty" water was flavored. Rats were habituated to drinking, then tested for intake of bright-noisy and tasty water. Acquisition training involved reinforced and nonreinforced trials. Post-tests measured intake after training. In the x-ray study, an audiovisual group and a gustatory group were exposed to identical radiation schedules. In other studies, reinforcement was contingent upon the rat's response. The results showed that x-rays and lithium chloride were readily transferred to the gustatory stimulus but not the audiovisual one. The effect was more pronounced in the x-ray study. Shock reinforcement was delayed in some studies, but the difference in post-test scores was statistically significant. The results suggest that gustatory stimuli paired with agents causing nausea acquire secondary reinforcing properties, while auditory and visual stimuli do not. In contrast, electric shock to the paws transferred to the audiovisual stimulus but not the gustatory one. The study concludes that reinforcers are not equally effective for all stimuli, and cues are selected based on the consequences of the reinforcer. Two hypotheses are offered: one involving time-intensity patterns of stimulation, and another involving natural selection favoring mechanisms associating gustatory and olfactory cues with internal discomfort.