AN EVALUATION OF THE NUMBER OF PRESENTATIONS OF TARGET SOUNDS DURING STIMULUS—STIMULUS PAIRING TRIALS

We evaluated the differential effects of 2 variations of a stimulus–stimulus pairing procedure on the vocalizations of 2 children with autism. For both participants, presenting 1 sound per pairing trial resulted in a higher rate of vocalizations than 3 sounds per pairing trial.     

EVALUATION OF AN ENHANCED STIMULUS‐STIMULUS PAIRING PROCEDURE TO INCREASE EARLY VOCALIZATIONS OF CHILDREN WITH AUTISM

Evidence to support stimulus‐stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure's clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on low‐frequency within‐session vocalizations that were further strengthened through programmed reinforcement. Procedural modifications (e.g., interspersed paired and unpaired trials) were designed to increase stimulus salience during SSP. All 3 participants, preschoolers with autism, showed differential increases of target over nontarget vocal responses during SSP. Results suggested an automatic reinforcement effect of SSP, although alternative interpretations are discussed, and suggestions are made for future research to determine the utility of SSP as a clinical intervention for speech‐delayed children.     

The role of the response-punishment contingency in the suppression of a positively-reinforced operant

Two experiments tested the prediction from current theories of punishment that a response-contingent procedure is superior to a comparable noncontingent procedure for the administration of punishment. Results demonstrated that the two procedures produced comparable contiguity effects and did not contain artifacts present in previous research. Three different measures of suppression corroborated the findings that more response suppression occurred in the contingent procedure. Results were shown to be stable across eight days of shock administration (Experiment 1), and three levels of shock intensity (Experiment 2). In both experiments, response suppression occurred during contingent shocks associated with shock at offset, as well as after conditioned stimulus (CS) offset. The contingent procedure was associated with more suppression during both of these periods and also longer runs of CSs with complete suppression. The relevance of the present findings to current theories of punishment was discussed.     

A derived transfer of simple discrimination and self-reported arousal functions in spider fearful and non-spider-fearful participants

Two experiments investigated the derived transfer of functions through equivalence relations established using a stimulus pairing observation procedure. In Experiment 1, participants were trained on a simple discrimination (A1+/A2-) and then a stimulus pairing observation procedure was used to establish 4 stimulus pairings (A1-B1, A2-B2, B1-C1, B2-C2). Subsequently, a transfer of the simple discrimination functions through equivalence relations was observed (e.g., C1+/C2-). These procedures were modified in Experiment 2, which demonstrated that spider-fearful and non-spider-fearful participants show differing levels of a transfer of self-reported arousal functions for stimuli used in equivalence relations with video-based material depicting scenes with spiders. The results demonstrate that the stimulus pairing observation procedure provides a viable alternative to matching-to-sample, and also offer tentative support for a derived-relations model of the acquisition of anxiety responses in at least one sub-clinical population.     

Priming of emotion recognition

Four experiments investigated priming of emotion recognition using a range of emotional stimuli, including facial expressions, words, pictures, and nonverbal sounds. In each experiment, a prime-target paradigm was used with related, neutral, and unrelated pairs. In Experiment 1, facial expression primes preceded word targets in an emotion classification task. A pattern of priming of emotional word targets by related primes with no inhibition of unrelated primes was found. Experiment 2 reversed these primes and targets and found the same pattern of results, demonstrating bidirectional priming between facial expressions and words. Experiment 2 also found priming of facial expression targets by picture primes. Experiment 3 demonstrated that priming occurs not just between pairs of stimuli that have a high co-occurrence in the environment (for example, nonverbal sounds and facial expressions), but with stimuli that co-occur less frequently and are linked mainly by their emotional category (for example, nonverbal sounds and printed words). This shows the importance of the prime and target sharing a common emotional category, rather than their previous co-occurrence. Experiment 4 extended the findings by showing that there are category-based effects as well as valence effects in emotional priming, supporting a categorical view of emotion recognition.     

Behavioral control by an imprinted stimulus

Newly hatched ducklings were exposed to imprinting procedures and subsequently trained to peck a key by presenting the imprinting stimulus as the reinforcing (response contingent) event. It was found that the key peck was learned only when imprinting procedures were initiated during the first 6 to 8 hr after hatch. Additional studies revealed that: (1) the duckling's distress vocalizations were reduced in the presence of the imprinting stimulus and enhanced in its absence; (2) when the ducklings had constant access to the imprinted stimulus (via a key peck), pecking responses occurred in bursts and relatively few distress vocalizations occurred; (3) the initial effect of extinction procedures was an increase in key peck rate. When, however, repeated key pecks failed to produce the imprinted stimulus, distress vocalization ensued and peck rate declined; (4) both the presentation of an unfamiliar mechanical figure and delivery of electrical shock enhanced distress vocalization and key pecks; (5) for some ducklings, certain familiar objects in the environment influenced distress calls in a manner comparable to the imprinted stimulus in that distress calls increased when these objects were removed.     

Establishing praise as a conditioned reinforcer: Pairing with one versus multiple reinforcers

Praise and other forms of attention may not function as reinforcers for the behavior of children with autism. Previous research demonstrated that contingently pairing praise with reinforcers (response stimulus) can establish praise as a conditioned reinforcer. We evaluated a procedure for establishing praise as a generalized conditioned reinforcer (pair praise with four reinforcers) and compared it with a procedure to establish praise as a conditioned reinforcer (pair praise with one reinforcer). We compared the two conditions in a reversal design with “praise” and “no programmed consequence” conditions rapidly alternated after pairing phases. With three out of five participants with autism, responding in the “pair‐with‐four” condition showed higher levels of responding or more increasing trends compared with that in “pair‐with‐one” condition. We also replicated previous contingent pairing research with two participants in a multiple baseline across participants design. A limitation was the absence of manipulating motivating operations in assessing the efficacy of praise as a generalized conditioned reinforcer. Nevertheless, these data contribute to the research on establishing praise as a reinforcer, and we recommend directions for future research.     

Social elicitation of infant vocal behavior.

The time course and the nature of social elicitation of vocalizations in 3-month-old infants were analyzed. Adult stimulation produced an immediate and significant increase in both the rate and the percent of bursts of vocal sounds of eight infants (Experiment 1). Both response-independent and response-dependent social stimulation were effective in producing increased rates of vocalizations, but only when each of four infants could see the eyes of the adult who delivered the social stimulus (Experiment 2).     

Conditioned suppression, punishment, and aversion

Three experiments were conducted to assess the aversive properties of a visual stimulus in the presence of which one group of birds received response-contingent shock (discriminated punishment) while a yoked group of birds received non-contingent shocks (conditioned suppression). In Experiment 1, presentation of the visual stimulus contingent on key pecking reduced the response rate (conditioned punishment effect) for birds under the conditioned suppression procedure but did not reduce the response rate of birds under the discriminative punishment procedure. Non-contingent shocks also produced greater suppression of responding maintained by positive reinforcement in the presence of a visual stimulus than did response-contingent shocks. In Experiment 2, a greater shock intensity (2 mA) was used. All the differences between the two groups found in Experiment 1 were also found in Experiment 2. Experiment 3 demonstrated that response-contingent shock did not result in a conditioned punishment effect even when positive reinforcers were unavailable during the discriminative punishment schedule. The exteroceptive stimulus that was paired with shock in the conditioned suppression procedure acquired the ability to punish behavior. The exteroceptive stimulus in the discriminative punishment schedule did not acquire this ability.     

Contingent Stimuli Signal Subsequent Reinforcer Ratios

Conditioned reinforcer effects may be due to the stimulus' discriminative rather than its strengthening properties. While this was demonstrated in a frequently‐changing choice procedure, a single attempt to replicate in a relatively static choice environment failed. We contend that this was because the information provided by the stimuli was nonredundant in the frequently‐changing preparation, and redundant in the steady‐state arrangement. In the present experiments, 6 pigeons worked in a steady‐state concurrent schedule procedure with nonredundant informative stimuli (red keylight illuminations). When a response‐contingent red keylight signaled that the next food delivery was more likely on one of the two alternatives, postkeylight choice responding was reliably for that alternative. This effect was enhanced after a history of extended informative red keylight presentation (Experiment 2). These results lend support to recent characterizations of conditioned reinforcer effects as reflective of a discriminative, rather than a reinforcing, property of the stimulus.     

Sexual reinforcement in the female rat.

Sexual reinforcement in the female rat was studied in a preparation that allowed continuous operant responding for access to a male rat leading to intromission. Experiment 1 used a high operant level nose-poke response to test the possible reinforcing effects of some components of access to a male. A simple tone stimulus used as a conditioned reinforcer and two odor stimuli, target male bedding and emulsified preputial gland, were tested. None of these contingent events altered responding above or below operant level. Access to the male, which was always accompanied by intromission, immediately increased response rate when it was made contingent upon the nose-poke response. Performance on fixed-ratio schedules was erratic, and response rate was low in comparison to typical food-reinforced responding. An interresponse-time analysis indicated, however, that some effect of the ratio contingency may have been present. In Experiment 2, several modifications of the procedure were tested with the objective of creating a more tractable preparation for behavior analysis. Response type and the hormone delivery method were changed, and 2 target males were used instead of 1. The latter tripled the average number of reinforcers earned in a single session. Differences between sexual and other reinforcers are discussed in terms of procedural, quantitative, and motivational aspects of the sexual reinforcement procedure.     

The Effects of Using a Conditioned Stimulus to Cue DRO Schedules

A reversal design was used to examine the effects of a differential reinforcement of other behavior (DRO) procedure and the presence of a stimulus (i.e., a bracelet), conditioned via discrimination training, on reducing socially maintained non‐contextual vocalizations in an adolescent girl with autism. Initially, a functional analysis determined that non‐contextual vocalizations were maintained by social attention. Then, discrimination training was used to establish the presence of the bracelet as a discriminative stimulus for the absence of vocalizations. Specifically, when the bracelet was on, non‐contextual vocalizations were interrupted, and edible reinforcement was provided for the absence of vocalizations. When the bracelet was off, vocalizations were not interrupted and the teacher provided social attention to the participant (i.e., reciprocated conversation with the participant about the topic). During intervention, a DRO procedure was used. The participant was presented with the bracelet, a timer set for a specified interval, and the instruction to work quietly. If vocalizations did not occur for the entire duration of the interval, the bracelet was removed and the learner was given the opportunity to engage in vocalizations. The DRO interval was systematically increased throughout the intervention. Results are discussed in terms of discrimination training as an effective addition to differential reinforcement procedure. Copyright © 2015 John Wiley & Sons, Ltd.     

Sign-tracking in aversive conditioning

Two experiments were conducted to determine if rats tend to avoid contact with a stimulus that signals the occurrence of shock and contact a stimulus that signals the nonoccurrence of shock. The conditioned stimulus was a 60-sec platform presentation, and the unconditioned stimulus was a 2-sec inescapable shock. In each experiment, the emphasis was on two types of Pavlovian pairings: forward pairing in which each platform presentation was followed by shock, and backward pairing in which each platform presentation was preceded by shock and followed by a lengthy shock-free interval. Experiment 1 showed that in comparison with Random and CS-only procedures, the backward procedure produced a significant increase in approach and contact with the platform, but the forward procedure failed to produce a significant decrease in contact with the platform. Experiment 2, in which all groups were roughly equated for baseline levels of platform preference, demonstrated strong effects of both forward and backward conditioning. The experiments provide evidence for an aversive sign-tracking system in which animals' tendencies to withdraw from or approach and contact a platform CS are determined by the Pavlovian contingencies which render it a reliable signal for the occurrence or nonoccurrence of shock.     

Further evaluation of response interruption and redirection as treatment for stereotypy

The effects of 2 forms of response interruption and redirection (RIRD)-motor RIRD and vocal RIRD-were examined with 4 boys with autism to evaluate further the effects of this intervention and its potential underlying mechanisms. In Experiment 1, the effects of motor RIRD and vocal RIRD on vocal stereotypy and appropriate vocalizations were compared for 2 participants. In Experiment 2, the effects of both RIRD procedures on both vocal and motor stereotypy and appropriate vocalizations were compared with 2 additional participants. Results suggested that RIRD was effective regardless of the procedural variation or topography of stereotypy and that vocal RIRD functioned as a punisher. This mechanism was further explored with 1 participant by manipulating the schedule of RIRD in Experiment 3. Results were consistent with the punishment interpretation.     

Irrelevant response effects improve serial learning in serial reaction time tasks

Tones were introduced into a serial reaction time (SRT) task to serve as redundant response effects. Experiment 1 showed that the tones improved serial learning with a 10-element stimulus sequence, but only if the tone effects were mapped onto the responses contingently. Experiment 2 demonstrated that switching to noncontingent response-effect mapping increased SRT only when participants had previously adapted to contingent response-effect mapping. In Experiment 3, the beneficial influence of contingent tone effects on serial learning occurred only when there was sufficient time between the response effects and the next imperative stimuli. The results are discussed in terms of the ideomotor principle. It is claimed that an internal representation of the to-be-produced tone effects develops and gains control over the execution of the response sequence.     

The effects of reinforcement upon the prepecking behaviors of pigeons in the autoshaping experiment

The autoshaping procedure confounds the effects of pairing a keylight and food with the effect of adventitious food reinforcement of responses that typically occur before the pecking response. In Experiment I, acquisition of the orientation to the key, the approach toward the key, and the peck at the key were systematically monitored. Orientations to the key and approaches toward the key frequently occurred in contiguity with food presentation before peck acquisition. In Experiment II, a negative contingency procedure was used to assess the sensitivity of the approach toward the key to its consequences. When the approach toward the key resulted in nonreinforcement, the probability of occurrence of that response decreased to zero despite repeated light-food pairings. In Experiment III, peck probability was shown to be determined during the approach toward the key by the presence of stimuli that had previously been either paired or nonpaired with food. In Experiment IV, it was shown that the effects of the stimulus present during the approach toward the key were not due solely to the effects of pairing that stimulus with food. Autoshaped key pecking appears to be determined by the interacting effects of stimulus-reinforcer and response-reinforcer variables upon orientations to, approaches toward, and pecks at the lighted key.     

A COMPARISON OF TWO PAIRING PROCEDURES TO ESTABLISH PRAISE AS A REINFORCER

Some individuals with intellectual disabilities do not respond to praise as a reinforcer, which may limit their ability to learn. We evaluated 2 procedures (stimulus pairing and response—stimulus pairing), both of which involved pairing previously neutral praise statements with preferred edible items, to determine their usefulness in establishing praise as a reinforcer. Results of Study 1 indicated that stimulus pairing was not effective in conditioning praise as a reinforcer for 3 of 4 subjects; results were inconclusive for the 4th subject. Results of Study 2 indicated that response—stimulus pairing was effective in conditioning praise as a reinforcer for 4 of 8 subjects. After conditioning, praise also increased the occurrence of additional target responses for these 4 subjects.     

Infant vocal development during the first 6 months: speech quality and melodic complexity

The early development of infant non‐distress vocalizations was investigated in this study. Thirteen infants, from 4 to 24 weeks of age, and their mothers were observed weekly in a face‐to‐face interaction situation. The speech quality (syllabic versus vocalic) and melodic complexity (simple versus complex) of infant vocalizations were coded independently. Based on speech quality and melodic complexity, four types of infant non‐distress vocalizations were categorized: simple and complex syllabic (speech‐like) vocalizations as well as simple and complex vocalic (non‐speech‐like) vocalizations. Results showed that complex syllabic sounds were of longer duration and complex vocalic sounds were less frequent than the other types of vocalizations. Curvilinear developmental trends were found in the rate of simple vocalic sounds and in the mean duration of complex syllabic sounds. Furthermore, before 4 months of age, vocalic sounds were more likely to be associated with simple melodic contours, after which syllabic sounds were more likely to be associated with complex melodic contours. A dynamic systems perspective on the early development of infant vocalization is discussed. Copyright © 2000 John Wiley & Sons, Ltd.     

GENERALITY AND SIDE EFFECTS OF OVERCORRECTION1

The effects and side effects of overcorrection for self-stimulatory behaviors of two children in a specialized day-care program were evaluated. For one child, a “hand” overcorrection procedure involving arm and hand exercises was introduced contingent upon inappropriate hand movements and later contingent upon inappropriate foot movements. After “hand” overcorrection was withdrawn for inappropriate foot movements, a “foot” overcorrection procedure involving foot and leg exercises was introduced contingent upon inappropriate foot movements. For a second child, the “hand” overcorrection procedure was introduced contingent upon inappropriate hand movements during a free-play period, and later contingent upon inappropriate vocalizations at naptime. “Hand” overcorrection was withdrawn and then re-introduced sequentially for both behaviors. Several concurrent behaviors were measured to assess multiple effects of treatment. Results for both children indicated the “hand” overcorrection procedure suppressed inappropriate hand movements and inappropriate behaviors that were topographically dissimilar. In addition, inverse relationships were observed between the second child's inappropriate hand movements and appropriate toy usage during free play and between his inappropriate vocalizations and inappropriate foot movements during naptime. Results suggest that overcorrection procedures that are effective for one behavior can be used to reduce the frequency of topographically different behaviors. This finding is discussed in terms of its practical implications for therapists.     

The effects of diazepam and triazolam on repeated acquisition and performance of response sequences with an observing response.

Drugs often disrupt the acquisition of new response sequences at doses that fail to disrupt the performance of a previously acquired response sequence. This selective drug effect may result from differences in the control exerted by the stimuli presented after each response in the acquisition and performance sequences. To examine the function of these stimuli, an observing procedure was incorporated into a multiple schedule of repeated acquisition and performance of response sequences, in which stimulus presentations were contingent upon an observing response. Three experiments were conducted with humans. Experiment 1 compared responding with and without the observing contingency. No difference was found in the overall percentage of errors across the two conditions. Within the observing condition, observing behaviour was maintained in the acquisition component as long as errors occurred, but was not maintained in the performance component. Experiment 2 examined whether a contingency that increased errors also would increase observing in both the acquisition and performance components. Specifically, reinforcer delivery in each component was contingent upon emitting 10 correct responses and one, two, or four errors. Observing responses increased in the acquisition component as the error requirement increased, whereas observing responses in the performance component increased only when the error requirement was four. Experiment 3 assessed the effects of diazepam (0, 7.5, 15, and 30 mg/70 kg, p.o.) and triazolam (0, 0.375, and 0.75 mg/70 kg, p.o.) on repeated acquisition and performance baselines with the observing contingency. Selective drug effects were obtained in this modified procedure; that is, the percentage of errors in the acquisition component increased at doses that failed to affect the percentage of errors in the performance components. Importantly, drug effects were selective, even though observing responses were not emitted in the performance component and, hence, the stimulus presentations did not occur in that component. These findings suggest that alternative explanations for these differential effects are needed; in that regard, a response-unit account of the selective drug effects is discussed.