Date of Award
Bachelor of Science (BS)
Negative reinforcers serve to maintain or increase behavior through the removal of an aversive stimulus. The primary method of studying negative reinforcement in non-humans has been through the use of electrical shock. While this method has proven to be reliable, many negative reinforcers that humans and non-humans encounter do not elicit tactile pain. Therefore, the purpose of this study was to explore a novel, non-human animal model of aversive control without the use of electrical shock as the negative reinforcer. A considerable amount of research has shown that various strains of rats find ultrasonic tones of certain frequencies and amplitudes to be aversive. Furthermore, ultrasonic tones do not elicit tactile pain, and unlike electrical shock, escape from an unpleasant sound is more analogous to circumstances that both humans and nonhumans encounter in their natural habitats on a daily basis. For the purposes of this study, four rats learned to escape an aversive tone by poking their head into a receptacle equipped with an infrared beam. When the beam was broken, the tone was turned off. After 20 baseline sessions of escaping the tone, that behavior was placed on extinction. In other words, the tone was no longer played during the experimental session. Therefore, the subjects had no reason to make the previously learned escape response. Our results showed a significant decrease in the escape response during extinction sessions for two of the three subjects from which we were able to obtain useable data, as well as for the mean data. While further refinement of this model is recommended, the results obtained show that the use of ultrasound as an aversive stimulus with rats can be a viable alternative to current models that use electrical shock. This novel, nonhuman animal model will make it possible to explore new procedures for researching conditions where negatively reinforced, maladaptive behaviors are maintained through other means than tactile pain.
Norlund, Brandon, "Ultrasound as an Aversive Stimulus for Use with Rats: A Novel Model of Aversive Control" (2011). Undergraduate Honors Capstone Projects. 94.
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Dr. Amy L. Odum