PSICOLOGIA & INFORMÁTICA - BVS Psicologia ULAPSI Brasil

second or so. Others last for up to 20 sec. The videos were taken asthese rats were habituated to the chamber, magazine trained, shapedto bar press and trained to press the bar under various schedules ofwater reinforcement. The clips were chosen to represent the many thingsthat rats do in a Skinner box. They include poking their noses in corners,rearing and touching the top of the cage with their nose, turningthis way and that, sitting, sleeping, drinking from the location wheredrops of water are given as reinforcers, approaching this location fromseveral different spots, approaching the bar in several ways and, ofcourse, pressing the bar. Some clips have rapid bar pressing, somehave slower bar pressing. Some clips have single bar presses. Since thechamber is small, there are many clips that have approximately thesame initial location and posture for the rat. All these clips smoothlyfollow from other clips that end with the rat in approximately the samelocation and posture. Consider the clips to be in an extended matrixwhere all transitions that appear “smooth” are listed with a probabilitythat has an initial value (for a new CyberRat) drawn from what the ratswere observed to do at the beginning of training. If we start with oneclip, therefore, we will see the rat move about the cage and when thatclip ends, another clip starts — one that will continue the rat’s movementwith a smooth transition. When that clip ends, another will start,and so on. These transitions are chosen from a kinematic analysis ofthe probabilities for various behaviors of rats in the different locationswithin the chamber. Such a kinematic analysis determines the conditionalprobability of a transition from any one behavior to each of theother possible behaviors. These initial probability values are then dynamicallychanged depending on setting factors such as current deprivation,time within the session, and the accumulating history of theCyberRat. CyberRat will, for example, demonstrate typical habituationif it is merely left in the chamber for an extended period.The program has a special role for the presentation of dropsof water. For a water-deprived CyberRat, being in front of the waterdeliveryarea when a drop of water is available leads to drinking witha very high probability. As each successive drop is presented andeventually consumed, the sound of the water drop being deliveredacts to increase the probability of orienting toward and approachingthe water delivery area of the chamber. This dynamic sequence simulatesmagazine training. When successful, a CyberRat who is waterPSICOLOGIA & INFORMÁTICA | 183