Discriminability and Stimulus Generalization

Question: Describe about the Discriminability and Stimulus Generalization. Answer: Introduction The study is based on Stimulus generalization. It is a kind of learned response related to a stimulus that is similar but of different stimuli in the environment. Stimulus generalization measures the extent to which the transfer has occurred. The differential response of animals to different stimuli involves the difference in degrees like the intensity, the size, the wavelength is said to be based on the relational character of the environment of stimulus (Kalish Guttmann, 1956). The subjects reinforce for response that has occurred in the availability of a specific training stimulus. In case, any of the stimulus are not present than then responding cannot be reinforced. In the process of stimulus generalization the subjects or the animals are to be present in a range of stimuli. The stimuli should include the original stimulus and some more similar stimulus with variant stimuli situated on continuum. It means that the stimuli have to be of different nature like difference in wavele ngth of light. When the process is carried out, all the behavior is on Extinction and the response rate is measured for each of the stimulus located on the continuum. In general language, differential reinforcement is the rescheduling of the reinforcement rate in the existence of training stimulus, and a high or low variant rate of reinforcement in the existence of variant training stimulus. The original research by Guttman and Kalish was remarkable as it was the prime methodological contribution. Intermittent reinforcement in training, and the repeated presentation of test stimuli in randomly permuted orders during extinction. In the experiment, we will examine the extent to which stimulus generalization would occur for two different stimuli, when each of the stimulus is related to a different reinforcement rate. The experiment is carried out on two conditions. First condition runs for fourteen sessions. It is the Discrimination training. The condition takes Pigeon as the subjects. They are trained to produce a response to a key which lits with 1 wavelength and is reinforced corresponding to the VI 30-s schedule. The pigeons are also trained to produce a response for the same key but with a variant wavelength and is reinforced corresponding to VI 150-s schedule. Here, the focus would be on the response of pigeons to the different wavelength. The second condition runs on two sessions. It is Stimulus generalisation test. The behavior for this condition is EXT. The pigeons here would be subjected to a series of wavelengths including from the condition 1 and some more slightly variant wavelengths. In total, th e pigeons will be subjected to around 10 wavelengths (Kailash Guttmann, 1957). The focus of the stimulus generalization test is to see the difference in the rate of response between the two training stimuli that were differentially reinforced. The shape or the pattern of generalization gradient is also looked upon. The generalization gradient is formed via the different rate in response with variant stimuli located on the continuum. Method Subject: In the experiment, pigeons were used as the subject. They species of the pigeons used were Homing pigeons. The experiment used six Homing pigeons. Each pigeon was labeled with an alphabet and a digit. The alphabet assigned to the pigeons will tell about the group they belong to. The digit assigned to the pigeon will tell the subject number each of the pigeon has. Like for example if the Pigeon is labeled A1 that says the pigeon belongs to Group A and is Subject 1. The pigeons were divided into two groups. Each group had three pigeons. The subjects were working in turns for the experiment. They were put in 1 of the 3 chambers for once in a day. The labeling given to the pigeons were as follows: Group A: 211, 212, 213 Group B: 214, 215, 216 All the pigeons used for the experiment were maintained at a weight of 10g of their set weight. The set weight of the pigeons was measured by 85% of their free feeding weight. Free feeding weight here meant the weight of each of the pigeons when the amount of food given to them was not under control. The pigeon had access to water and grit. They were kept in the home cages for all the time and they were fed there itself. The experiment was conducted in different cages (Thomas King, 1959). Generally, the pigeons are experimental subjects. They are given food during the course of the lab experiment. In case, the weight of the pigeon becomes too low then they were given some extra food. Apparatus The major apparatus for the lab experiment was the Experimental Chamber. The chamber has measurements 300mm by 250mm. The depth of the experimental chamber is 290mm. It has Back wall and floor. The floor of the experimental chamber was build from iron bars. The front and the back walls of the experimental chamber were build from Perspex. The other walls of the chamber were made of sheet metal. The house light of the experiment chamber was on the back wall (Margolius, 1955). The response panel of the experimental chamber has keys made up of plastic discs and are glowing with a coloured light. The three keys are of 25mm and are a situated at a distance of 60mm from one another. There is square hole in the response panel and is known as Magazine Aperture. It is 70mm by 50mm. The magazine aperture lights up during reinforcement. A hopper is present behind the magazine and is made up of grain sits. The hopper was to be raised for reinforcement. The hopper consists of grain sits is raised for reinforcement and the magazine aperture lights up. At the same plastic keys discs are unlit. The room located next to the experimental has a computer running. The computer is IBM Med-PC IV. The main function of computer here was to control and record up all the experimental events including the response data. There are three pigeon chamber for six pigeons as two pigeons belonging to the two different groups were kept in one chamber. For example in the first chamber pigeon labelled Group A-211 and Group B- 214 were kept. Procedure In the lab experiment conducted there were two conditions. The first condition was discrimination training and the second condition was Stimuli generalization. In the first condition two components were taken with multiple schedules. The first component took up the Pigeon as the subjects who were trained to respond to a key lit with one wavelength(colour) and reinforced according to a VI 30-s schedule (Hoing Urcuioli, 1981). The wavelength for the first component was 520-nm light. In the second component, the same pigeons were trained to respond to the same key lit with a different wavelength and reinforced according to a VI 150-s schedule. The wavelength of light for this was 570-nm. Both the component was of 30 seconds duration. They were separated by a 10-s inter-component interval (ICI). Both the components were run for 48 times in each of the session. In total, there were 96 sessions for both the components. In the second condition the two-component multiple schedule from the baseline condition was repeated three times. The left over test was conducted for EXT. The pigeons here were subjected to a series of wavelengths including from the condition 1 and some more slightly variant wavelengths (Wagner et al., 1968). The pigeons were subjected to different wavelengths in a random order for about 30 seconds. They were separated by a 10-s inter-component interval. In total, the pigeons will be subjected to around 10 wavelengths. The wavelength used for this experiment was from 500 nm to 590 nm. In this condition two sessions were performed. For each of the sessions response rate was to be calculate at each wavelength. After calculating, the response rate was 4.5 minutes at each wavelength per session. The two conditions were based on the Kalish and Guttmann studies but were different in terms the reinforcement schedules, component length, number of component per sessions, and the Similarity b etween the baseline and the generalisation test. The procedure was carried out keeping in my mind the Kalish and Guttmann. The basis of the lab experiment was same but it was carried out by changing certain conditions. References Guttman, N. Kalish, H.I. (1956). Discriminability and stimulus generalization.Journal of Experimental Psychology, 51 (1), 79-88. Honig, W.K. Urcuioli, P.J. (1981). The legacy of Guttman and Kalish (1956): 25 years of research on stimulus generalization. Journal of the Experimental Analysis of Behavior, 36, 405-445. Kalish, H. I., Guttman, N. (1957).Stimulus generalization after equal training on two stimuli.Journal of Experimental Psychology,53(2), 139. Margolius, G. (1955). Stimulus generalization of an instrumental response as a function of the number of reinforced trials. /. exp. Psychol.,,49,105-111. Thomas, D. R., King, R. A. (1959). Stimulus generalization as a function of level of motivation. Journal of Experimental Psychology, 57, 323-328. Wagner, A. R., et al. (1968). Stimulus selection in animal discrimination learning. Journal of Experimental Psychology, 76, 171-180