On the relative contributions of positive reinforcement and escape extinction in the treatment of food refusal

We compared the effects of positive reinforcement alone, escape extinction alone, and positive reinforcement with escape extinction in the treatment of the food and fluid refusal of 4 children who had been diagnosed with a pediatric feeding disorder. Consumption did not increase when positive reinforcement was implemented alone. By contrast, consumption increased for all participants when escape extinction was implemented, independent of the presence or absence of positive reinforcement. However, the addition of positive reinforcement to escape extinction was associated with beneficial effects (e.g., greater decreases in negative vocalizations and inappropriate behavior) for some participants.     

Increasing variety of foods consumed by blending nonpreferred foods into preferred foods

A treatment with differential or noncontingent reinforcement and nonremoval of the spoon increased the acceptance of one or two of 16 foods for 2 participants with severe food refusal. These differential levels of acceptance were demonstrated empirically in an ABAB design in which A was the presentation of the accepted (preferred) foods and B was the presentation of foods the participants refused (nonpreferred foods). Subsequently, we implemented a blending treatment that consisted of mixing (blending) nonpreferred foods into preferred foods in various ratios (e.g., 10% nonpreferred/90% preferred, 20% nonpreferred/80% preferred). We then presented nonpreferred foods that had been exposed to blending to determine if consumption of nonpreferred foods would increase following the blending treatment. We also conducted periodic reversals in which we presented nonpreferred foods that had not been exposed to the blending treatment. Following initial implementation of the blending treatment, consumption was high for nonpreferred foods that had been blended and low for nonpreferred foods that had not been blended. Consumption increased for all foods (i.e., foods that had been exposed to blending and foods that had not been exposed to blending) after seven or eight foods had been exposed to the blending treatment. Thus, the variety of foods consumed by the participants increased from one or two to 16. These results are discussed in terms of stimulus fading, conditioned food preferences, and escape extinction. DESCRIPTORS: conditioned food preferences, food refusal, negative reinforcement, stimulus fading     

The distinction between positive and negative reinforcement: use with care

It is customary in behavior analysis to distinguish between positive and negative reinforcement in terms of whether the reinforcing event involves onset or offset of a stimulus. In a previous article (Baron & Galizio, 2005), we concluded that a distinction of these terms is not only ambiguous but has little if any functional significance. Here, we respond to commentaries by a group of distinguished behavior analysts about the issues we raised. Although several of the commentators argued for preservation of the distinction, we remain unconvinced that its benefits outweigh its weaknesses. Because this distinction is so deeply embedded in the language of behavior analysis, we hardly expect that it will be abandoned. However, we hope that the terms positive and negative reinforcement will be used with circumspection and with full knowledge of the confusion they can engender.     

An evaluation of two differential reinforcement procedures with escape extinction to treat food refusal

Consumption of solids and liquids occurs as a chain of behaviors that may include accepting, swallowing, and retaining the food or drink. In the current investigation, we evaluated the relative effectiveness of differential reinforcement of the first behavior in the chain (acceptance) versus differential reinforcement for the terminal behavior in the chain (mouth clean). Three children who had been diagnosed with a feeding disorder participated. Acceptance remained at zero when differential reinforcement contingencies were implemented for acceptance or mouth clean. Acceptance and mouth clean increased for all 3 participants once escape extinction was added to the differential reinforcement procedures, independent of whether reinforcement was provided for acceptance or for mouth clean. Maintenance was observed in 2 children when escape extinction was removed from the treatment package. The mechanism by which consumption increased is discussed in relation to positive and negative reinforcement contingencies.     

Preliminary comparison of two negative reinforcement schedules to reduce self-injury

This study compared the effectiveness of differential negative reinforcement of other behavior (DNRO) and alternative behavior (DNRA) for reducing self-injurious tantrums maintained by escape from demands in a 4-year-old girl with severe retardation. Both DNRA and DNRO reduced self-injury and increased independent performance of two tasks (tooth brushing and bathing); however, improvement on both measures was greater with the DNRA intervention.     

Reduction of shock duration as negative reinforcement in free-operant avoidance

Rats were trained on a free-operant procedure in which shock duration was controlled by responses within a limited range of interresponse times. Shocks of 1.6-mA intensity occurred randomly with average density of 10 shocks per minute. As long as interresponse times were 15 seconds or less, any shocks received were at the briefer of two durations (.3 second). Whenever interresponse times exceeded 15 seconds, any shocks received were at the longer duration (1.0 second). For six of eight animals, avoidance responding developed quickly and reached levels of better than 90%. Four yoked animals stopped responding within the first few sessions. Shock duration reduction without change in shock probability or intensity was sufficient for the acquisition and maintenance of avoidance responding.     

Effects of differential negative reinforcement on disruption and compliance

We examined the effects on compliance of two types of differential negative reinforcement (DNR) with a 5-year-old girl with a history of severe disruption. During DNR (communication), escape from instructional trials was provided contingent on a communicative behavior. During DNR (compliance), escape was provided contingent on compliance. Both interventions decreased inappropriate behavior and increased appropriate behavior. However, during DNR (communication), compliance rarely occurred.     

Noncontingent reinforcement as treatment for food refusal and associated self-injury

We examined the use of noncontingent reinforcement to decrease self-injury and increase bite acceptance in a child who exhibited food refusal. First, a brief functional analysis suggested that self-injury was maintained by escape from food presentation. Next, we evaluated an intervention that involved noncontingent access to a video during feeding sessions. Results of the intervention showed a decrease in self-injury and an increase in bite acceptance.     

Responding under positive and negative response contingencies in pigeons and crows

Four crows were trained to key peck for food. Then, they were exposed to a positive response contingency that required them to peck the key when it was illuminated briefly (the trial) in order to receive food. This procedure resulted in consistent within-trial pecking. When the contingency changed so that food was presented at the end of a trial when no response occurred, but the trial terminated immediately and food was omitted when a response occurred (negative response contingency), responding decreased markedly. Eight pigeons were studied under the same change in contingencies. These birds varied in their response histories from naive to having several years' experience. The previously naive pigeons also showed rapid declines in responding under the negative contingency; the responding of the birds with extended training histories declined much more slowly. Eventually, however, six of the eight pigeons showed little or no responding under the negative contingency, while they responded consistently when re-exposed to the positive contingency. These findings question the power and the generality of the negative automaintenance phenomenon.     

Acquisition of a spatially defined operant with delayed reinforcement.

Two experiments investigated the role of an immediate, response-produced auditory stimulus during acquisition, via delayed reinforcement, of a response selected to control for possible unprogrammed, operandum-related sources of response feedback. Experimentally naive rats were exposed to a delayed-food reinforcement condition, specifically a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior 30-s schedule. The response was defined as breaking a photocell beam located near the ceiling at the rear of the operant conditioning chamber. In Experiment 1, rates of photobeam breaking by each rat increased from near zero, regardless of the presence or absence of a tone that immediately followed the response initiating the delay interval. Though not essential, the tone facilitated response acquisition and resulted in more efficient response patterns at stability. Experiment 2 demonstrated that photobeam-breaking response rates under the delayed reinforcement contingency exceeded those in a preceding baseline condition in which no food was delivered. In addition, upon introduction of the delayed reinforcement procedure, correspondence between response patterns and the requirements of the reinforcement schedule increased over baseline levels in the absence of a food contingency. Together with a previous report of Lattal and Gleeson (1990), the present results suggest that response acquisition with delayed reinforcement is a robust phenomenon that may not depend on a mechanically defined response or an immediate external stimulus change to mediate the temporal gap between response and reinforcer.     

The effects of negative reinforcement for irritable aggression on resident-intruder behavior

This experiment demonstrated that rats trained to display elevated levels of shock-induced aggression in a negative reinforcement paradigm displayed more boxing behavior than yoked control groups in a later test in which intruder rats were placed in the home cage of resident rats. Resident or intruder status did not affect the influence of the negative reinforcement procedure on the observed resident-intruder behavior of trained animals; however, naive intruders paired with trained residents displayed increased defensive behavior, suggesting that negative reinforcement for shock-induced aggression affected the behavior of these residents.     

The independence of positive and negative affect depends on the affect measure

This study examined the degree of independence between Positive Affect (PA) and Negative Affect (NA) within a given situation. The affective state was measured before and after an experimentally induced success or failure experience in an anagram task. Two types of affect measures were used to assess PA and NA: the Positive and Negative Affect Schedule (PANAS) and a Pleasantness-Unpleasantness scale. Consistent with our hypotheses, results show that PA and NA are independent when measured with the PANAS but are correlated when assessed with the other scale. These PA-NA correlations differed significantly from each other before and after emotion induction, respectively. Additional analyses indicate that both PA scales are differentially sensitive to the mood induction procedure. The findings are discussed with respect to circumplex models of emotion.     

Acquisition of lever-press responding in rats with delayed reinforcement: A comparison of three procedures

The present study examined the acquisition of lever pressing in rats under three procedures in which food delivery was delayed by 4, 8, and 16 seconds relative to the response. Under the nonresetting delay procedure, food followed the response selected for reinforcement after a specified interval elapsed; responses during this interval had no programmed effect. Under the resetting procedure, the response selected for reinforcement initiated an interval to food delivery that was reset by each subsequent response. Under the stacked delay procedure, every response programmed delivery of food t seconds after its occurrence. Two control groups were studied, one that received food immediately after each lever press and another that never received food. With the exception of the group that did not receive food, responding was established with every procedure at every delay value without autoshaping or shaping. Although responding was established under the resetting delay procedure, response rates were generally not as high as under the other two procedures. These findings support the results of other recent investigations in demonstrating that a response not previously reinforced can be brought to strength by delayed reinforcement in the absence of explicit training.     

Generalization peak shift in rats under conditions of positive reinforcement and avoidance

Rats were trained to discriminate between two click frequencies. One frequency was associated with either variable-interval food reinforcement (Experiment 1) or free-operant avoidance (Experiment 2). The other frequency was associated with the absence of food in Experiment 1 and the absence of shock in Experiment 2. On a click frequency generalization test, the rats in both experiments showed positive peak shift with the shape of the relative gradients being very similar. This is the first reported instance of peak shift in rats when responding was maintained by an avoidance contingency. Nondifferentially trained controls showed that this shift was due exclusively to associative processes, with nonassociative stimulus factors in themselves apparently making no contribution to increased rates at particular stimulus values. These results show the comparability of appetitive and aversive control and support the position that gradient differences do not result from approach versus avoidance per se.     

The effects of response cost in the treatment of aberrant behavior maintained by negative reinforcement

Positive reinforcement contingencies can sometimes be used to decrease problem behavior maintained by negative reinforcement (e.g., escape). In the current study, we evaluated the extent to which response cost (i.e., contingent removal of a preferred stimulus) would compete with the negative reinforcer maintaining destructive behavior. The response cost contingency reduced destructive behavior by 87% from baseline levels even though the negative reinforcement contingency (i.e., escape) remained in place.     

Performance of rats under concurrent variable-interval schedules of negative reinforcement

The behavior of rats under concurrent variable-interval schedules of negative reinforcement was examined. A single one-minute variable-interval programmer determined the availability of 30-second timeouts from electric shock. These were assigned to one or the other of the two component schedules with a probability of 0 to 1.0. The response requirement for the component schedules was standing to the right or left of the center of the experimental chamber. With a six-second changeover delay, the relative time spent under one component schedule varied directly and linearly with the relative number of timeouts earned under that component schedule. The absolute number of changeovers was highest when a similar number of timeouts was earned under each component schedule, and lowest when all or nearly all timeouts were earned under one component schedule. In general, these relations are similar to those reported with concurrent variable-interval schedules of positive reinforcement.     

The role of positive and negative affect on well-being amongst Swedish and Iranian university students

The roles of positive and negative affect in well-being were studied in two different societies, namely the Iranian and the Swedish. A total of 606 university students (296 Iranian and 310 Swedish) participated in the study. The results showed that, whereas there was no difference between Iranian and Swedish participants in their general level of life satisfaction, differences with regard to positive and negative affect were found. Swedish participants had more positive affect, whereas Iranian participants had more negative affect. In the Swedish sample, the most predictive factor of flourishing was positive affect, while there was a balance affect (between positive and negative affects) in the Iranian sample. The results are discussed from a individualistic–collectivistic perspective.     

Cross-language negative priming remains intact,while positive priming disappears: evidence for two sources of selective inhibition

In the current experiments, within- and between-language primed lexical decision tasks with Twi-English bilinguals were used. The aim was to explore the priming effects produced by attended and ignored words, in an effort to draw theoretical and empirical parallels and differences between the mechanisms of excitation and inhibition and to isolate the different circumstances in which these mechanisms operate in bilingual language processing. In the within-language (Twi) experiment, facilitatory (positive) priming resulted when a prime word and subsequent probe target word were identical, whereas delayed decisions to probe targets (negative priming) ensued when the ignored prime word was conceptually identical to the subsequent probe target word. In contrast, while the between-language (Twi-English) experiments replicated the ignored repetition negative priming effect, no evidence of positive priming was observed. These between-language findings undermine episodic retrieval models of selective attention that discount inhibitory processes in negative priming paradigms. Instead, our findings substantiate inhibition-based accounts by showing that there are two sources of inhibition operating at the local word and global language levels of abstraction. The findings also support bilingual language representations in which the words of the two languages are integrated.