Inhibitory stimulus control and the magnitude of delayed reinforcement

The key pecking of pigeons was reinforced according to a variable-interval 1-min schedule during each of two successively presented stimuli. When the key was illuminated by a black line on a white background, reinforcement was delayed for 10 sec. When the key was illuminated by a plain white light, reinforcement was not delayed. For half of the subjects, the delayed reinforcer was 4.0-sec access to mixed grain, and for the remaining subjects it was 1.5-sec access. The immediate reinforcer was 1.5-sec access for all subjects. All subjects responded at a lower rate during the presentation of the black line; no between-group difference in terms of terminal response rate during the presentation of the line was found. However, subjects that received 4.0 sec of delayed reinforcement responded at a lower terminal rate during presentation of the plain white light than subjects that received 1.5 sec of delayed reinforcement. A subsequent generalization test along the line-orientation dimension produced flatter U-shaped gradients for subjects that received 4.0-sec of delayed reinforcement.     

REPLACING MALADAPTIVE SPEECH WITH VERBAL LABELING RESPONSES: AN ANALYSIS OF GENERALIZED RESPONDING

We taught three mentally handicapped students to answer questions with verbal labels and evaluated the generalized effects of this training on their maladaptive speech (e.g., echolalia) and correct responding to untrained questions. The students received cues-pause-point training on an initial question set followed by generalization assessments on a different set in another setting. Probes were conducted on novel questions in three other settings to determine the strength and spread of the generalization effect. A multiple baseline across subjects design revealed that maladaptive speech was replaced with correct labels (answers) to questions in the training and all generalization settings. These results replicate and extend previous research that suggested that cues-pause-point procedures may be useful in replacing maladaptive speech patterns by teaching students to use their verbal labeling repertoires.     

Failure to find evidence of stimulus generalization within pictorial categories in pigeons

Pigeons' key pecks were reinforced in the presence of pictures from one of two categories, cats or cars. A single picture associated with reinforcement was used in Experiment 1, and 20 pictures from the same category were associated with reinforcement in Experiment 2. Pigeons then were presented with novel test pictures from the training category and from the other, previously unseen, category. During Session 1 of testing, pigeons pecked no more often at pictures from the reinforced category than at pictures from the previously unseen category. When pigeons were trained with pictures associated with reinforcement or its absence from different categories in Experiment 3, differential responding to novel pictures from different categories appeared during Session 1. These findings argue against a process of automatic stimulus generalization within natural categories and in favor of the position that category distinctions are not made until members of at least two categories are compared with one another.     

TRAINING AND GENERALIZATION OF AFFECTIVE BEHAVIOR DISPLAYED BY YOUTH WITH AUTISM

The purpose of this study was to teach contextually appropriate affective behavior to 4 youths with autism. Treatment consisted of modeling, prompting, and reinforcement introduced in a multiple baseline design across response categories of affective behavior. During treatment, verbal praise and tokens were delivered contingent on appropriate affective responding during training trials. Modeling and verbal prompting were used as correction procedures. Each youth received treatment in either three or four response categories. Treatment systematically increased responding within the response categories for all 4 participants, with effects being specific to the affective response categories under treatment. Treatment effects occurred across untrained scenarios, therapists, time, and settings, suggesting that generalization had occurred.     

Perceptual classes established with forced-choice primary generalization tests and transfer of function

In Experiment 1, 20 college students learned two identity conditional discriminations using squares that differed in interior-fill percentage (called Fill23 and Fill77). A two-choice generalization test was then presented with number of test trials varied across groups of subjects. The test samples were 19 squares that ranged in fill value from 23% to 77%; the comparisons were squares with Fill23 and Fill77. The resulting gradients did not vary as a function of number of test trials. When the generalization test was repeated with a third comparison, "neither," the ranges of fill values that occasioned the exclusive selection of Fill23 or Fill77 were direct functions of the number of prior two-choice generalization trials. Finally, a disriminability test revealed that Fill23 and Fill77 were disciminable from the intermediate fill values. In Experiment 2, perceptual classes were established with 5 new students using 760 forced-choice generalization test trials. The student were then trained to select a different glyph in the presence of Fill23 and Fill77, followed by a three-choice generalization test in which the 19 fill stimuli served as samples and the two glyphs served as comparisons. The gradients ovelapped with those previously obtained during the three-choice generalization test that used Fill23 and Fill77 as comparisons. Finally, a discriminability test showed that many adjacent stimuli along thc fill dimension were discriminable from each other. Together, the results of both experiments suggest that ranges of fill-based stimuli functioned as members of perceptual classes, and each class also functioned as a transfer network for a new selection-based response.     

Effects of variable-interval value and amount of training on stimulus generalization.

In Experiment 1 pigeons pecked a key that was illuminated with a 501-nm light and obtained food by doing so according to a variable-interval (VI) schedule of reinforcement, the mean value of which differed across groups: either 30 s, 120 s, or 240 s. The pigeons in all three groups were trained for 10 50-min sessions. Generalization testing was conducted in extinction with different wavelengths of light. Absolute and relative generalization gradients were similar in shape for the three groups. Experiment 2 was a systematic replication of Experiment 1 using line orientation as the stimulus dimension and a mean VI value of either 30 s or 240 s. Again, gradients of generalization were similar for the two groups. In Experiment 3 pigeons pecked a key that was illuminated with a 501-nm light and obtained food reinforcers according to either a VI 30-s or a 240-s schedule. Training continued until response rates stabilized (> 30 sessions). For subjects trained with the 30-s schedule, generalization gradients were virtually identical regardless of whether training was for 10 sessions (Experiment 1) or until response rates stabilized. For subjects trained with the VI 240-s schedule, absolute generalization gradients for subjects trained to stability were displaced upward relative to gradients for subjects trained for only 10 sessions (Experiment 1), and relative generalization gradients were slightly flatter. These results indicate that the shape of a generalization gradient does not necessarily depend on the rate of reinforcement during 10-session single-stimulus training but that the effects of prolonged training on stimulus generalization may be schedule dependent.     

Response generalization under verbal conditioning in alcoholics, delinquents and students

Response generalization of a verbal CR was examined in an experiment which was repeated three times, each with a different sample of subjects (alcoholics, delinquents and students). An operant conditioning procedure using verbal reinforcement was employed to develop a verbal CR. In each study the sample was divided so that one section was reinforced for verbal overestimates of the diameter of a circle and the remaining section was reinforced for underestimates. Each verbal estimate of a circle was followed by a drawing estimate of its diameter which received no reinforcement. In each experiment, the verbal estimates were observed to increase in size in the section reinforced for overestimating while the remainder of the sample, reinforced for underestimating, decreased the size of their verbal estimates. In addition, response generalization was observed in accord with the experimental hypothesis for the size of the drawings tended to shift in the same direction as the verbal CR. The experimental procedure was considered to be reliable for the evidence on conditionability and response generalization, as defined in this research, was consistently obtained in these three experiments even though different kinds of subjects were employed in each study and different Es conducted the experiment. The evidence was considered to be in line with the general body of learning theory of response generalization and also possible to hold some important implications for understanding behaviour changes in patients undergoing psychotherapy.     

Stimulus generalization and delay of reinforcement during one component of a multiple schedule

The key pecking of six pigeons was reinforced according to a variable-interval 1-min schedule during each of two successively presented stimuli. When the key was illuminated by a black line on a white background, reinforcement was delayed for 10 sec. When the key was illuminated by a plain white light, reinforcement was not delayed. All subjects responded at a lower rate during the presentation of the black line. A subsequent generalization test along the line-orientation dimension produced a U-shaped gradient, with the nadir located at or near the training stimulus, for each subject. These gradients suggested that the lower rate of response during the stimulus associated with delayed reinforcement may have been due to an inhibition of responding.     

Contextual control of stimulus generalization and stimulus equivalence in hierarchical categorization

The purpose of this study was to determine whether hierarchical categorization would result from a combination of contextually controlled conditional discrimination training, stimulus generalization, and stimulus equivalence. First, differential selection responses to a specific stimulus feature were brought under contextual control. This contextual control was hierarchical in that stimuli at the top of the hierarchy all evoked one response, whereas those at the bottom each evoked different responses. The evocative functions of these stimuli generalized in predictable ways along a dimension of physical similarity. Then, these functions were indirectly acquired by a set of nonsense syllables that were related via transitivity relations to the originally trained stimuli. These nonsense syllables effectively served as names for the different stimulus classes within each level of the hierarchy.     

Verbal coding and the elimination of Stroop interference in a matching task

Translational models of the Stroop effect (Virzi & Egeth, 1985) predict that Stroop interference can be eliminated if subjects can be induced to process target colors using a coding system separate from the coding system used to process distractors. This hypothesis was tested in two experiments. In the first experiment, we attempted to eliminate the need for subjects to translate target colors to verbal codes when responding to Stroop stimuli. Before responding to verbal incongruent color word distractors, subjects practiced matching colors to irregular shapes. It was expected that subjects would use nonverbal codes to mediate responding in this task. After practice, subjects continued the matching task in the presence of incongruent color words. Stroop interference persisted, contrary to predictions. Because subjects reported adopting verbal strategies to perform the matching task, Experiment 2 was designed to control the verbal coding strategies that subjects employed. Before responding to Stroop distractor stimuli, subjects in the nonsense name group practiced using nonsense names to mediate the matching of shapes to colors; subjects in the actual name group used actual color names to mediate performance in the matching task. When incongruent color word distractors were introduced, Stroop interference was eliminated for subjects in the nonsense name group, but persisted for subjects in the actual name group. The results are interpreted as consistent with an outcome conflict (Navon & Miller, 1987) or a modified translational model of the Stroop effect.     

Object name learning provides on-the-job training for attention

By the age of 3, children easily learn to name new objects, extending new names for unfamiliar objects by similarity in shape. Two experiments tested the proposal that experience in learning object names tunes children's attention to the properties relevant for naming—in the present case, to the property of shape—and thus facilitates the learning of more object names. In Experiment 1, a 9-week longitudinal study, 17-month-old children who repeatedly played with and heard names for members of unfamiliar object categories well organized by shape formed the generalization that only objects with similar shapes have the same name. Trained children also showed a dramatic increase in acquisition of new object names outside of the laboratory during the course of the study. Experiment 2 replicated these findings and showed that they depended on children's learning both a coherent category structure and object names. Thus, children who learn specific names for specific things in categories with a common organizing property—in this case, shape—also learn to attend to just the right property—in this case, shape—for learning more object names.     

Category width and expectancies: Risk conservatism or generalization?

To compare interpretations of category width as an equivalence range and as a risk-taking dimension, an experiment by Phares and Davis (1966) was replicated and extended to examine the effects of unexpected failure and success on expectations for subsequent task performance. High scoring subjects on Pettigrew's (1958) Category Width Scale showed less generalization of expectancy following success and greater generalization following unexpected failure. A measure of similarity between tasks failed to differentiate from narrow categorizers and suggests that broad categorizers may adopt more conservative expectancies following unexpected outcomes of any favorability.     

AN EVALUATION OF LABELING-THEN-DOING WITH MODERATELY HANDICAPPED PERSONS: ACQUISITION AND GENERALIZATION WITH COMPLEX TASKS

We conducted two experiments in which moderately mentally retarded persons were trained first to label and then to enter characters into a computer, calculator, or checkbook (label-then-do) within a multiple baseline design. In Experiment 1, 5 young adults were trained to enter statistical programs into computers in an office setting. Following training, all subjects' use of verbal labels and key-entry skills generalized across tasks (programs) and settings (offices and computer terminals). In Experiment 2, 3 junior high school students were trained with self-labeling procedures to complete a key-entry task and to balance a checkbook. The performance of all students generalized across tasks and settings, and the use of labels generalized for 2 of the students. Results are discussed relative to mediated generalization and to establishing verbal control over behavior.     

Control of a continuous response dimension by a continuous stimulus dimension

Pigeons were trained to respond to stimuli from a continuous stimulus dimension (tonal frequency) with response values from a continuous response dimension. Both the number of points of correspondence and problem difficulty were varied. After training, subjects were tested with stimulus values intermediate to those trained. During these test tones, subjects emitted only those response values reinforced during training. The study suggested that if there are fast and efficient methods to obtain control of a continuous response dimension by a continuous stimulus dimension, these methods must depend on factors other than simple generalization.     

Category Use in Abstract Mental Comparisons

A recent model proposes that at least two processes are involved in mental comparisons; use of analogue and use of category information. The evidence that category information is used is not strong, however. It comes mainly from studies which had subjects overlearn the objects associated with arbitrary categories in the laboratory, and which used concrete dimensions. In the present study, two experiments were conducted to see if subjects spontaneously use natural categories from an abstract dimension (occupational status) in mental status comparisons. Subjects scaled occupations into status categories before each experiment and then compared the status of within-category and between-category occupation pairs. Within-category status comparisons reliably took longer than between-category ones of the same distance, suggesting that natural status categories were used.     

Remembering computer command names: Effects of subject generation versus experimenter imposition

Two experiments analyzed the effectiveness of goal statements in aiding recall of self-generated as opposed to experimenter-imposed command names. Subjects were presented with a series of before-after pairs representing the computer states before and after a command was executed. In Experiment 1, during study, one group of subjects generated a command name in response to each pair; a second group generated a goal statement describing the goal to be accomplished in addition to generating a command name. During recall, half of each group was required to recall the name, whereas the other half was required to describe the goal before attempting to recall the name. In Experiment 2, during study, command names (and goals for those subjects in the goal condition) were imposed by the experimenter rather than generated by the subject. Subjects who generated goals and names recalled more command names than did those who generated only names or who received imposed goals and/or names. Generation of an appropriate goal at study improved encoding by helping subjects to select more appropriate command names; generation of an appropriate goal at test improved retrieval for appropriate names only, presumably by activating a relevant subset of names. Even in the relatively simple task of naming and remembering command names, having an appropriate model of the domain through the use of specific goal statements substantially improved performance.     

INCREASING VERBAL INTERACTION AMONG ELDERLY SOCIALLY ISOLATED MENTALLY RETARDED ADULTS: A GROUP LANGUAGE TRAINING PROCEDURE

The present study examined the effectiveness of a group language training procedure for directly increasing and generalizing the rate of verbal interaction among four elderly, socially isolated, moderately mentally retarded men. A withdrawal of treatment design was used to examine the effect of the procedure that used verbal prompts, behavioral rehearsal, and contingent social praise. Changes in behavior were examined in two generalization settings, one similiar to the training environment (Generalization I) and the other arranged as part of the subjects' daily routine (Generalization II). Baseline data indicated no verbal interaction among the subjects. During treatment the training procedure increased the rate of subjects' verbal interactions not only in the training situation, but also in the two generalization settings. An analysis of the data obtained during the Generalization II situation indicated that subjects' verbal interaction increased not only among themselves, but with nonsubject peers present in this setting. Follow-up data showed that increases in rates of verbal interaction were maintained four months after the cessation of training. The implications of the results for program generalization and work with the language deficient individual is discussed.     

Inhibitory stimulus control following errorless discrimination learning

Three generalization procedures were used to investigate inhibitory stimulus control following discrimination learning with few errors. Three groups of pigeons acquired a discrimination between a green stimulus (the positive stimulus) and a vertical or horizontal line (the negative stimulus) through differential autoshaping followed by multiple schedule presentation of the two stimuli with gradually increasing stimulus durations. Genereralization testing was along a line-tilt continuum. For one group, the test involved a resistance-to-reinforcement procedure in which responses to all line tilts were reinforced on a variable-interval schedule. For a second group, also tested with the resistance-to-reinforcement procedure, the lines were superimposed on the green field that formerly served as the positive stimulus. A third group was tested in extinction with the combined stimuli. Control groups had no discrimination training but responding to green was nondifferentially reinforced. The control subjects responded more to all line tilts during testing than did the comparable experimental subjects, indicating that the negative stimulus had become an inhibitory stimulus. Both resistance-to-reinforcement groups revealed inhibitory gradients around the negative stimulus, but the gradient for the extinction group was relatively flat. These data are consistent with others that modify Terrace's early conclusion concerning the failure of inhibition to develop during errorless training.     

Retrieval opportunities while multitasking improve name recall

In two experiments we tested whether providing retrieval opportunities while people were multitasking would improve memory for names. College students (n=195) in Experiment 1 did addition problems and intermittently were “introduced” to 12 face–name pairs to learn. For half the names students were given three within-list retrieval opportunities. Name recall (cued with the faces) was tested either immediately or after 24 hours. Retrieval opportunities improved name recall with both immediate and delayed tests. Experiment 2 more closely resembled the multitasking required in a real-life social situation. College students (n=98) viewed a videotape and were asked to learn the names of 12 dormitory residents who were introduced during an ongoing conversation. Retrieval opportunities were provided for 8 of the 12 residents by having them appear three additional times in the video without repeating their names. Retrieval opportunities improved name recall, but the effect was much smaller than in Experiment 1. The present research demonstrates that distributed retrieval can be effective when people are multitasking including when the multitasking involves a conversation.