The present study was designed to analyze the transfer of stimulus control in temporal fading procedures. Several aspects of temporal fading procedures were manipulated including sources of inhibitory stimulus control, delays of reinforcement, and rates of increase in the temporal parameter of a fading procedure. In Experiment I, previous research producing transfer of stimulus control in a temporal fading procedure was directly replicated and controls were implemented for the operation of inhibition. The results showed that inhibitory stimulus control is not necessary in order to produce a transfer as participants with neutral stimulus backgrounds also transferred from one dimension to another without errors. However, positive stimulus backgrounds in the fading procedure prohibited the participants from achieving an errorless transfer of discrimination learning. In Experiment II, a fixed trial duration was employed with a constant and equal delay of reinforcement for both new and original stimulus dimensions. In this condition, participants did not transfer from one dimension to another with up to 30-second delays. Control participants were yoked to participants exposed to delayed and fading procedures to examine response latencies under delayed reinforcement for a simultaneous discrimination. There were no discernible response patterns under this condition except that participants continued to emit relatively short response latencies with a 40-second delay of reinforcement. In Experiment III, the effects of different steps of temporal fading on transfer were examined. The results showed that as the step of delay increased (10 sec. per trial), subjects transferred earlier in the fading series. Also, subjects with extremely low steps of delay (.1 sec. per trial) tended to remain with the original stimulus dimension. Experiments I through III demonstrated the necessity of either inhibitory or neutral stimulus backgrounds, differential delays of reinforcement correlated with each stimulus dimension, and relatively rapid increments in delay of the original stimulus dimension to obtain transfers of stimulus control in temporal fading procedures. When excitatory stimulus backgrounds were employed, or no differential delay of reinforcement was present, or the delay of the original stimulus dimension increased slowly, errorless transfers were not obtained. Overall, the results indicate that temporal fading procedures are a reliable, although complexly controlled, means of obtaining transfer between two stimulus dimensions.

The present experiment investigated the application of Green and Swets (1966) signal-detection theory to undesirable behavior as a method of reducing unwanted behaviors using reinforcement and extinction. This experiment investigated the use of this stimulus control technique to reduce undesirable behaviors using a multiple-baseline design. Once the cue for a target behavior was established and maintained, the use of the verbal cue was reduced in frequency and the rate of unprompted undesirable behavior was recorded. Generalization was tested across multiple people. Data for this experiment showed that undesirable behavior could be reduced by altering the stimulus control that maintained it.

<p> At least five different uses of the term "attention" can be detected in the literature on animal discrimination learning. One of these predicts "blocking": decreased learning about one of two covarying cues, resulting from prior training to discriminate on the basis of the other cue. In Experiment 1, four groups of 6 pigeons received different sorts of training in Phase 1; in Phase 2 all groups received go/no-go discrimination training in which positive trials (tone; pale red key) and negative trials (noise, pale green key) differed on both an auditory and a visual dimension. A group that received Phase 1 training to discriminate on the basis of the visual cue alone showed less stimulus control by tone-noise on a test given after all training than did a control group that received no Phase 1 training. It is concluded that acquisition of control by the auditory cue in Phase 2 was blocked by prior training to discriminate on the basis of the visual cue. Results for the two remaining groups and a detailed analysis of the test data rule out certain alternative explanations of the reduced auditory control, including the possibilities that it resulted from (a) the occurrence of any Phase 1 training, (b) partial reinforcement received during Phase 1 discrimination training, (c) training with an auditory value present but not predicting reinforcement during Phase 1, or (d) an interaction on the test for stimulus control. </p> <p> Three subsidiary experiments involving a total of 20 pigeons show that blocking the acquisition of visual control by prior training on an auditory discrimination may also occur, but do not conclusively demonstrate it. In a concluding discussion it is argued that, although the results of the first experiment are evidence for "blocking" as defined here, the results do not require a two-stage model of learning for their explanation. </p> / Thesis / Master of Arts (MA)

Events that occur early in the life of birds greatly influence social and sexual preferences throughout the course of life. Traditionally, this is explained by a learning process known as imprinting. Young birds are thought to imprint to early stimuli, causing the development of permanent preferences for those stimuli. In the present study, imprinting is examined with respect to behaviors of an adult human-reared pigeon in several conditions. The subject was either presented with no stimulus, a conspecific stimulus, a novel stimulus, a human stimulus, or the human and novel stimuli simultaneously. Several phases within these conditions were employed to pinpoint the variables that produced the most social and sexual behavior. The results showed that while some conditions produced unclear behavior, other conditions produced very clear indications of sexual preference for humans and fear of conspecifics. The results suggest that the concept of imprinting may not be needed to explain the sexual preference of the subject, and that operant contingencies may play a large role in sexual behavior.

A computerized program was designed to test whether arranging a common element in two, otherwise independent, 2-term correlations (stimulus-stimulus and response-stimulus) would result in emergent simple discriminative-stimulus properties for the antecedent stimulus relative to an arrangement with no common elements programmed. Data from 8 adult participants in this experiment indicate that common element arrangements led to relatively high rates of responding in the presence of the putative discriminative stimulus and relatively low rates or no responding in the presence of the putative s-delta during testing in extinction. Conversely, the uncommon element arrangements produced no clear discriminative control. The current data reflect a comparison of arrangements across subjects. These data support Sidman's (2000) suggestion that common elements among contingencies are sufficient to produce stimulus classes and cause class mergers. The data also have implications for thinking about the mechanism by which and the conditions under which discriminative control develops. Finally, these data have the potential to inform the programming and implementation of reinforcement contingencies in applied settings.

<p> Two experiments, involving 140 subjects, were performed to study the effects of two partial reinforcement variables on measures of stimulus control in extinction. Pigeons were required to make a fixed number of responses ranging from 1 to 64) to terminate discrete trial presentations and were rewarded on a predetermined percentage (ranging from 100% to 25%) of those completed trials. Generalization tests involved repeated nonreinforced presentations of the training stimulus and a new stimulus until animals ceased responding. Stimulus control measured by differences or ratios of responding to the two stimuli increased as response requirement increased. The percent of trials reinforced had no significant effect on either measure of control. Within-trial analyses showed that maximum stimulus control is exerted over the first response, some control continues to be exerted over successive responses, and there is a tendency for control to increase near the end of the requirement. Implications of the research were discussed.</p> / Thesis / Doctor of Philosophy (PhD)

This paper explores research on the misinformation effect and hypothesizes a new explanation for the occurrence misinformation effect. Current psychological theories states the misinformation effect occurs when memories are skewed by the presentation of new information after an initial event. This effect has been tested in a multitude of ways, including testing words lists, pictures, colors, and change blindness. Socially, the misinformation effect has been used to explain the inaccuracies of eyewitness testimony. The current judicial system relies on the fallible memory of people and has wrongfully imprisoned numerous innocents. The purpose of this research is to show the misinformation effect is not a problem with memory storage and retrieval, but rather a product of selective stimulus control.

A functional analysis, conducted to assess the variables maintaining the chronic eye poking of a female diagnosed with profound mental retardation, indicated that the behavior persisted in the absence of social contingencies. A procedure was initiated in a training environment in which a punisher (mild reprimand) was delivered contingent on eye poking in the presence, but not in the absence, of a neutral stimulus (wristbands). Using a combination of multiple baseline and multielement experimental designs, it was determined that that eye poking was suppressed in the presence of the previously neutral stimulus, even in environments in which the reprimand contingency was inoperative.

This study partially replicated the research of Cook, Kwak, Hoffman, & Loftus where they examined post-event activities that induces subjects to pick a wrong person in a forced choice identification procedure. The goal was to investigate if providing a neither option to a match to sample task increases the accuracy of responding. Subjects were asked to study three faces for 10 seconds, after which they were asked to pick out the faces in a forced choice setting where two other faces were presented. Later the subjects were asked to pick out faces in a setting in which they could use a neither option. Results indicated that a generalization effect occurs when identifying faces and the effect is seen as subjects choosing the wrong face. This suggests that when using faces with some similar features in a lineup setting the procedure may cause the subject to pick the wrong person.

One language intervention approach for individuals with autism involves teaching one response topography under multiple sources of control and then establishing that response under individual controlling variable. Another approach involves establishing one response topography under singular control and then using that response to establish the response topography under different controlling variables. The study sought to extend previous research by investigating the impact of each approach on the acquisition of verbal responses. Three of the eight participants acquired all target responses for at least one response topography. The results of previous research were not replicated directly and the findings were discussed in terms of preexperimental verbal repertoires and restricted interests.