Delayed choice responding by pigeons when the correct response is not predictable from the sample stimulus.

Food-deprived pigeons were presented with a row of four response keys situated above a grain hopper aperture. At the start of a trial, three of four keys were randomly selected and illuminated white for six seconds. After a variable blackout period, one of the three previously white keys and the previously dark key were illuminated green, and the remaining white keys were reilluminated as before. A response to the green key that was previously white was reinforced with three-second access to gain, a response to any other key resulted in a three-second blackout and the start of a new trial. Five of six subjects responded to the correct green key more often than chance at an interstimulus interval of 1.5 seconds, and they displayed maximal performance at different intertrial interval values ranging from 15 to 60 seconds. Choice accuracy decreased for all but one subject as the interstimulus interval was increased. For the range of interstimulus interval durations employed, decrements in choice accuracy were qualitatively similar to, but lower than those typically obtained from, delayed-matching-to-sample or delayed-pair comparison procedures.     

Representing within-session response rates proportionally and entirely.

In this technical article, methods for collecting and representing response rates maintained by schedules of reinforcement are presented. First, the time in a session that each important event (e.g., responses, reinforcers) occurs is collected and stored by a computer. Another computer program is used, then, to convert each response to a percentage of the total responses in a session and to plot these percentages cumulatively as a function of the time in the session that they occurred. In this manner, response rates may be expressed proportionally (i.e., using the same y-axis scale regardless of absolute response rate) without requiring the arbitrary selection of an interval over which responses are aggregated and expressed relative to the entire-session rate. A property of these records is that deviations in the slope of the obtained record from the diagonal, which connects (x, y) = (start of session, 0%) to (x, y) = (end of session, 100%), occurring at any point and for any duration, represent changes in the local response rate from the entire-session rate. This method of representing ongoing responding is illustrated by several records of key pecking of a pigeon on a variable-interval 60-s schedule of food reinforcement. Relative local response rates were also computed from these data at several levels of resolution (i.e., the time over which responses were aggregated), including the level typically employed by those interested in within-session changes in response rates.     

A comparison of peer verbal responding directed toward adolescents with behavioral disorders and nonhandicapped peers

One of the primary intents of inclusion is the maximization of interaction between persons with and without disabilities. The purpose of this study was to analyze the verbal responding that peers directed toward adolescents with behavioral disorders and, to this effect, several comparisons were made: verbal responding of peers directed toward adolescents with behavioral disorders was compared to verbal responding of peers directed toward regular class adolescents; verbal responding of peers directed toward the same adolescents with behavioral disorders was compared across their self-contained and integrated settings; and verbal responding of peers directed toward adolescents with behavioral disorders in integrated settings was compared to verbal responding of peers directed toward regular class adolescents. Data, collected in real time using portable microcomputers, focused on positive, negative, and neutral social responding and positive, negative, and neutral academic responding. All verbal responding of peers directed toward 14 adolescents with behavioral disorders and 14 regular class peers was recorded. Data were analyzed by group and setting, as well as by social or academic content. Results of the study support inclusion, with high levels of peer responding directed toward adolescents with behavioral disorders in integrated classrooms. Almost all peer responding was positive or neutral in content. Results were discussed as they related to placement of students, social skills training, and previous research.     

The puzzle of responding maintained by response-contingent shock.

Four squirrel monkeys were first exposed to a sequence of procedures that reliably generate responding maintained by brief response-contingent electric shocks arranged according to a fixed-interval schedule. After responding had become stable on the fixed-interval schedule, additional contingencies were added in tandem, whereby after completion of the interval, the spacing of responses affected shock delivery. In one procedure, responses had to be spaced more widely than their previous median value if shock were to be delivered. In the other procedure, responses had to be spaced more closely to produce shock. On the first of these procedures, decreased but stable responses rates would indicate that shock functioned as a positive reinforcer; on the second, increased response rates would indicate the positively reinforcing function. Instead, response rates accelerated on the procedure that targeted more widely spaced responses for shock delivery, and decelerated or ceased on the procedure that arranged for shocks to be produced by more closely spaced responses. Consistent with other recent findings, these results question the interpretation of performances maintained by response-contingent shock as engendered by positive reinforcement and are consistent with aversive-control interpretations. The details of that aversive control are not entirely clear, however, and these same procedures would be informative if applied to shock-maintained behavior that is generated in other ways.     

GENERALIZED EFFECTS OF A PEER-DELIVERED FIRST AID PROGRAM FOR STUDENTS WITH MODERATE INTELLECTUAL DISABILITIES

Peers with mild intellectual disabilities taught first aid skills to 4 students with moderate intellectual disabilities. A multiple probe design across participants was used to examine the effects of the peer teaching program during an acquisition and a partial sequential withdrawal phase. Generalization assessments were conducted in the participants' homes using novel, randomized simulated injuries. Results suggested that the peer teaching program resulted in acquisition of first aid skills, and the participants' skills generalized to the home, to novel simulated-injury locations, and to new trainers. Additionally, a more detailed analysis of the generalized responding suggested that when given a choice among first aid materials, participants treated burns using large adhesive bandages rather than the materials used in training. Participants also successfully treated injuries when novel instructional cues were used. The findings are discussed with respect to training issues, generalization and maintenance of the acquired skills, and the use of peer tutors with disabilities.     

Acute and chronic effects of cocaine on extinction-induced aggression.

Pigeons worked individually in a chamber containing a response key and a mirror. Pecking on the key was controlled by a multiple schedule in which a brief period of continuous food reinforcement alternated with a 5-minute period of extinction. Under baseline conditions, aggressive behavior (responding on the mirror) occurred at the onset of each extinction period. In Experiment I (acute drug administration), the aggressive behavior was decreased by doses of cocaine that had little or no effect on key pecking. Such food-reinforced responding was disrupted, however, by higher doses of cocaine. An attempt to mimic the disruptive drugs effects by a prefeeding manipulation was unsuccessful. In Experiment II (chronic drug administration), some tolerance developed to the disruptive effects of cocaine on the food-reinforced responding, except at the highest dose tested. There was no clear-cut indication of tolerance to the initial effect of cocaine on the aggressive behavior at any dose.     

Effects of self‐enhancement on agreement on personality profiles

Effects of self‐enhancement and socially desirable responding (SDR) on rater agreement for personality profiles were studied in 304 students. Dyads of participants described themselves and their peer on the Revised NEO Personality Inventory (NEO‐PI‐R) that measures 30 facets of personality. In addition, participants filled in six scales measuring self‐enhancement or SDR. Data analyses focussed on moderator and suppressor effects of SDR on the similarity between self‐reported and other reported NEO‐PI‐R profiles. Three kinds of profile agreement were distinguished: (a) normative agreement; (b) distinctive agreement and (c) profile normativeness, that is, how strongly a self‐reported personality profile resembled the average profile of all participants. There were no moderator or suppressor effects on distinctive agreement, but SDR predicted profile normativeness quite strongly. Copyright © 2009 John Wiley & Sons, Ltd.     

The impact of arbitrarily applicable relational responding on evaluative learning about hypothetical money and shock outcomes

Evaluative learning comprises changes in preferences after co-occurrences between conditioned stimuli (CSs) and an unconditioned stimulus (US) of affective value. Co-occurrences may involve relational responding. Two experiments examined the impact of arbitrary relational responding on evaluative preferences for hypothetical money and shock outcomes. In Experiment 1, participants were trained to make arbitrary relational responses by placing CSs of the same size but different colours into boxes and were then instructed that these CSs represented different intensities of hypothetical USs (money or shock). Liking ratings of the CSs were altered in accordance with the underlying bigger/smaller than relations. A reversal of preference was also observed: the CS associated with the smallest hypothetical shock was rated more positively than the CS associated with the smallest amount of hypothetical money. In Experiment 2, procedures from Relational Frame Theory (RFT) established a relational network of more than/less than relations consisting of five CSs (A-B-C-D-E). Overall, evaluative preferences were altered, but not reversed, depending on (a) how stimuli had been related to one another during the learning phase and (b) whether those stimuli referred to money or shocks. The contribution of RFT to evaluative learning research is discussed.     

The effect of test schedules on the formation of linked perceptual classes

After training conditional discriminations among selected stimuli from two perceptual classes, the emergence of novel relations involving other members of both classes was assessed using cross-class probes. The cross-class probes were presented using one of four different testing schedules. In the 2/9 test, nine different probes were presented in each of two test blocks. In the 6/3 test, three different probes were presented in each of six test blocks. In the 18/1-RND test, each of the 18 cross-class probes was presented in separate test blocks. In the 2/9 and 6/3 tests, the cross-class probes were presented in a randomized order within test block. In the 18/1-RND test, the cross-class probes were presented in a randomized sequence. In the 18/1-PRGM test, however, the cross-class probes were presented in a programmed order (i.e., the values of the stimuli in each cross-class probe were changed systematically in the succession of probe presentations). About 55% of the linked perceptual classes emerged during the 2/9, 6/3, and 18/1-RND tests. Thus the number of different probes in a test block did not influence the emergence of classes as long as the probes were presented in a random order. Virtually all classes emerged during the 18/1-PRGM test. Thus at least one ordered introduction of different cross probes resulted in the reliable emergence of linked perceptual classes. Mechanisms responsible for linked perceptual class formation are discussed along with the relation of these classes to other complex categories.     

The effects of differential and lag reinforcement schedules on varied verbal responding by individuals with autism

Variability has been shown to be a reinforceable dimension of behavior. One procedure that has been demonstrated to increase variability in basic research is the lag reinforcement schedule. On this type of schedule, a response is reinforced if it differs from a specified number of previous responses. Lag schedules are rarely used, however, for increasing response variability in applied settings. The purpose of the present study was to investigate the effects of a lag schedule of differential reinforcement on varied and appropriate verbal responding to social questions by 3 males with autism. A reversal design with a multiple baseline across subjects was used to evaluate the effects of the lag schedule. During baseline, differential reinforcement of appropriate responding (DRA) resulted in little or no varied responding. During the intervention, a Lag 1 requirement was added to the DRA (Lag 1/DRA) resulting in an increase in the percentage of trials with varied and appropriate verbal responding for 2 of the 3 participants. In addition, an increase in the cumulative number of novel verbal responses was also observed for the same 2 participants. These results are discussed in terms of reinforcement schedules that support variability, generalization, and potential stimulus control over varied responding.