Ap Psychology Lab Report

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Method Subjects To complete this experiment, we used Sprague Dawley rats that were obtained from a breeding company entitled Envigo. We used a total of twelve rats. The rats used in this experiment are all 2.5 years old. The rats were each pair-housed in a temperature controlled room at approximately 22 C. All rats are maintained on a 12:12 hour light dark cycle. For the sake of the experiment, we water restricted the rats as a way to contribute to their motivational state. Apparatus Each animal was placed into small animal operant conditioning chambers. The walls of the chambers are constructed of plexiglass. The ceiling, as well as the front and back of the chamber, are each made of aluminum. The chamber itself is 22 centimeters wide and 25 centimeters long. Located on the left side of the chamber, there is a lever that is approximately eight and a half centimeters long and about one centimeter wide. The lever delivers the water to the aperture where the rats can access …show more content…

Shaping is the process by which we reinforce all closer approximations to the desired behavior, while fading out previous approximations of the already trained behavior. To shape this new behavior, the rats were no longer reinforced for nose poking into the hopper. Before beginning shaping, we allowed the rat to habituate into the chamber for five minutes and recorded all behavioral observations. Next, we reinforced the rats when they began to approach the area near the lever. An example of the behaviors that were reinforced were the rats raising their bodies in front of the lever, touching the lever, touching the lever with its paw, pressure exerted on the lever, and a full lever press. We observed and recorded all behaviors for 60 minutes. To precisely measure all behaviors we recorded it in intervals of 2. For each interval, we recorded the cumulative number of responses and the number of reinforcers.

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