Behavioral approaches to weight control: An updated review

Recent developments in the behavioral treatment of obesity were surveyed. Since the earlier review (Abramson, 1973) no studies of aversive therapy have been published. Three studies of covert sensitization have yielded discouraging results. Any positive effects of this technique appear to be the result of non-specific demand characteristics rather than aversive conditioning. Several demonstrations of the effects of therapist controlled reinforcement indicate that this technique can promote weight loss while the contingencies are in effect. The weight is rapidly regained, however, after the contingencies are withdrawn. It is concluded that self-control treatments, especially complex self-control, are the most consistently successful treatment approaches. Several methodological problems are presented and unresolved issues are discussed.     

Learned industriousness.

Extensive research with animals and humans indicates that rewarded effort contributes to durable individual differences in industriousness. It is proposed that reinforcement for increased physical or cognitive performance, or for the toleration of aversive stimulation, conditions rewards value to the sensation of high effort and thereby reduces effort's aversiveness. The conditioning of secondary reward value to the sensation of effort provides a dynamic mechanism by which reinforced high performance generalizes across behaviors. Applications to self-control, moral development, and education are described.     

Behavioral self-control of on-task behavior in an elementary classroom

Techniques of behavioral self-control were employed in a class where a high level of on-task behavior had been established with externally administered reinforcement procedures. The behavioral self-control techniques maintained behavior at its ongoing high level both immediately following the externally administered reinforcement treatments and during follow-up treatments after five and seven weeks. Variability in on-task behavior was reduced during the behavioral self-control phases of the study.     

ACQUISITION,DISCRIMINATIVE STIMULUS CONTROL,AND RETENTION OF INCREASES/DECREASES IN BLOOD PRESSURE OF NORMOTENSIVE HUMAN SUBJECTS1

The aims of this study of 24 normotensive subjects were: to compare a free-operant with a discrete-trials training format; to determine the most effective training procedure by comparing instrumental conditioning with instructional set and a control; to see if both increases and decreases in blood pressure could be brought under discriminative control, and to examine the maintenance of acquired self-control of blood pressure. A 2 × 3 design was employed in which two trial formats (free operant and discrete trials) were factorially compared with three training conditions (instrumental conditioning, instructional set, and control). Instrumental conditioning was found superior to both the instructional set and control conditions in producing increases and decreases in mean diastolic blood pressure. The free-operant format led to a greater degree of learned BP control in that subjects were able to increase and decrease their blood pressure by 10% to 15% of basal value and to maintain the blood-pressure operant after contingent auditory feedback/reinforcement was removed. Training was discontinued when subjects in the other five groups failed to reach criterion after 10 consecutive acquisition sessions.     

The allocation of time to temporally defined behaviors: responding during stimulus generalization.

In one stimulus condition, reinforcement depended on rats holding a lever for a duration having both minimum and maximum boundaries. During a second light intensity, reinforcement was not available for some rats; for others, reinforcement depended on a second response duration requirement. Generalization test stimuli controlled the same response durations found during training, and the amount of time allocated to a given response duration depended on the proximity of the test stimulus to the training stimulus which controlled that particular duration. The results indicated that a gradient of stimulus control does not reflect an underlying continuous change in responding, but is a result of the mixing of responses previously controlled by stimuli present during conditioning.     

Controlling human fixed-interval performance

Both high and relatively constant rates of responding without post-reinforcement pauses and lower rates with pauses after reinforcement are produced by human subjects under fixed-interval (FI) schedules. Such FI rates and patterns may be controlled when subjects are provided with different histories of conditioning and different conditions of response cost (reinforcement penalties per response). Subjects with a conditioning history under ratio schedules typically produce high and relatively constant rates of responding under FI schedules; this responding does not change systematically with changes in FI value. In contrast, subjects with a history under schedules which produce little or no responding between reforcements [such as differential-reinforcement-of-low-rate (DRL) schedules] tend to pause after reinforcement and respond at low rates under FI schedules, whether or not they also have ratio conditioning histories; cost increases the likelihood of this type of performance. For DRL-history subjects, post-reinforcement pauses increase and response rates decrease as FI values increase.     

A Brief Experimental Analysis of Reinforcer and Response Dimensions Related to Self-Control in an Outpatient Clinic

We conducted an assessment of self-control and impulsivity with 9 children referred to an outpatient clinic for impulsive, inattentive, and hyperactive behaviors. Each condition of the assessment consisted of a choice between 2 concurrently presented math or writing tasks, with 1 alternative reflecting impulsive responding and 1 alternative reflecting self-control. For the participants who demonstrated impulsive responding in 1 of 2 baseline conditions, we systematically varied reinforcer quality, delay to reinforcement, and response effort to evaluate the effects of these dimensions on the participants’ choices. Results of the assessment revealed that 3 participants displayed self-control responding, and 6 participants displayed impulsive responding during baseline conditions. Of the participants who displayed initial impulsivity, all showed self-control when 1 or more response or reinforcement dimensions were modified to bias responding within a brief multielement design. Results provide a unique application of concurrent schedules for conducting a brief assessment of impulsive responding in an outpatient clinical setting.     

Operant behavior and the galvanic skin potential under DRL schedule

Motor and galvanic skin potential (GSP) activity were investigated during the conditioning, extinction, and reconditioning of motor responses under a differential reinforcement of low rate (DRL) schedule of reinforcement. Interresponse time (IRT) distributions for motor responses during conditioning and reconditioning gradually stabilized at a peak just beyond the minimal IRT required for reinforcement. Few unreinforced motor responses and "bursts" of motor responses were observed during conditioning and reconditioning. Relative to conditioning and reconditioning, extinction effected larger IRTs and smaller GSP amplitudes. GSP amplitudes were greater for unreinforced than for reinforced motor responses during conditioning and reconditioning. However, GSP amplitudes associated with the unreinforced extinction responses were smaller than either the reinforced or unreinforced responses during conditioning and reconditioning.     

The development of skin conductance fear conditioning in children from ages 3 to 8 years

Although fear conditioning is an important psychological construct implicated in behavioral and emotional problems, little is known about how it develops in early childhood. Using a differential, partial reinforcement conditioning paradigm, this longitudinal study assessed skin conductance conditioned responses in 200 children at ages 3, 4, 5, 6, and 8 years. Results demonstrated that in both boys and girls: (1) fear conditioning increased across age, particularly from ages 5 to 6 years, (2) the three components of skin conductance fear conditioning that reflect different degrees of automatic and controlled cognitive processes exhibited different developmental profiles, and (3) individual differences in arousal, orienting, and the unconditioned response were associated with individual differences in conditioning, with the influence of orienting increasing at later ages. This first longitudinal study of the development of skin conductance fear conditioning in children both demonstrates that children as young as age 3 years evidence fear conditioning in a difficult acquisition paradigm, and that different sub-components of skin conductance conditioning have different developmental trajectories.     

Soft commitment: self-control achieved by response persistence.

With reinforcement contingent on a single peck on either of two available keys (concurrent continuous reinforcement schedules) 4 pigeons, at 80% of free-feeding weights, preferred a smaller-sooner reinforcer (2.5 s of mixed grain preceded by a 0.5-s delay) to a larger-later reinforcer (4.5 s of mixed grain preceded by a 3.5-s delay). However, when the smaller-sooner and larger-later reinforcers were contingent on a concurrent fixed-ratio 31 schedule (the first 30 pecks distributed in any way on the two keys), all pigeons obtained the larger-later reinforcer much more often than they did when only a single peck was required. This "self-control" was achieved by beginning to peck the key leading to the larger-later reinforcer and persisting on that key until reinforcement occurred. We call this persistence "soft commitment" to distinguish it from strict commitment, in which self-control is achieved by preventing changeovers. Soft commitment also effectively achieved self-control when a brief (1-s) signal was inserted between the 30th and 31st response of the ratio and with concurrent fixed-interval 30-s schedules (rather than ratio schedules) of reinforcement. In a second experiment with the same subjects, the fixed ratio was interrupted by darkening both keys and lighting a third (center) key on which pecking was required for various fractions of the fixed-ratio count. The interruption significantly reduced self-control. When interruption was complete (30 responses on the center key followed by a single choice response), pigeons chose the smaller-sooner reinforcer as frequently as they did when only a single choice response was required.     

The effects of value confrontation and reinforcement counseling on the career planning attitudes and behavior of adolescent males

An experiment was conducted to compare the relative effectiveness of a value confrontation procedure and a procedure based on verbal operant conditioning in enhancing career development attitudes and increasing the frequency of information-seeking behavior in rural adolescent males. Ninety subjects were identified as internally controlled or externally controlled based on their locus of control scores and then randomly assigned to one of the two experimental treatment groups or a control group. The value confrontation procedure involved developing an awareness of self-dissatisfaction about one's career planning and relating this self-dissatisfaction to the importance one gave to the values logical and responsible. These values had been identified empirically in this study as having a relationship to career planning. The reinforcement counseling treatment involved the interpretation of individual career maturity data followed by the verbal operant conditioning of responses indicative of career maturity. Post tests administered 7 weeks after the treatments showed that the value confrontation procedure resulted in significantly greater frequency of information seeking for internally controlled subjects when compared to the reinforcement counseling and control procedures. No treatment was significant in increasing the maturity level of career development attitudes.     

Designing interventions that include delayed reinforcement: implications of recent laboratory research

The search for robust and durable interventions in everyday situations typically involves the use of delayed reinforcers, sometimes delivered well after a target behavior occurs. Integrating the findings from laboratory research on delayed reinforcement can contribute to the design and analysis of those applied interventions. As illustrations, we examine articles from the Journal of the Experimental Analysis of Behavior that analyzed delayed reinforcement with respect to response allocation (A. M. Williams & Lattal, 1999), stimulus chaining (B. A. Williams, 1999), and self-control (Jackson & Hackenberg, 1996). These studies help to clarify the conditions under which delayed reinforcement (a) exercises control of behavior, (b) entails conditioned reinforcement, and (c) displaces the effects of immediate reinforcement. The research has applied implications, including the development of positive social behavior and teaching people to make adaptive choices. DESCRIPTORS: delayed reinforcement, response allocation, stimulus chains, self-control, integration of basic and applied research     

Importance of trials versus accumulating time across trials in partially reinforced appetitive conditioning

Four experiments with rats examined partial reinforcement in appetitive conditioning. In Experiment 1, adding nonreinforced trials to a continuous reinforcement schedule slowed acquisition, whereas deleting reinforcers did not. Trial massing suppressed performance and learning. In Experiment 2, conditioning with a short conditioned stimulus (CS) was rapid, and partial reinforcement with a short CS was as effective as continuous reinforcement with equal accumulated time in the CS. In Experiment 3, conditioning was nevertheless influenced by the probability of reinforcement. In Experiments 3 and 4, conditioning was especially disrupted when nonreinforced trials preceded reinforced trials closely in time. The results underscore the importance of temporal variables in conditioning but are more consistent with trial-based accounts than time-accumulation accounts of conditioning.     

A hot/cool-system analysis of delay of gratification: dynamics of willpower

A 2-system framework is proposed for understanding the processes that enable--and undermine--self-control or "willpower" as exemplified in the delay of gratification paradigm. A cool, cognitive "know" system and a hot, emotional "go" system are postulated. The cool system is cognitive, emotionally neutral, contemplative, flexible, integrated, coherent, spatiotemporal, slow, episodic, and strategic. It is the seat of self-regulation and self-control. The hot system is the basis of emotionality, fears as well as passions--impulsive and reflexive--initially controlled by innate releasing stimuli (and, thus, literally under "stimulus control"): it is fundamental for emotional (classical) conditioning and undermines efforts at self-control. The balance between the hot and cool systems is determined by stress, developmental level, and the individual's self-regulatory dynamics. The interactions between these systems allow explanation of findings on willpower from 3 decades of research.     

Partial reinforcement effects in classical aversive conditioning in rabbits and human beings.

The partial reinforcement extinction effect (the PREE) in classical aversive conditioning was investigated in 2 experiments. In the first, the nictitating membrane responses of 120 rabbits were conditioned at a 250-msec. interstimulus interval (ISI) under continuous reinforcement, partial reinforcement with the unconditioned stimulus (US) omitted (Group PO), or partial reinforcement with the US delayed to 1,500 msec. (Group PD). These 3 groups were factorially extinguished under US-Omitted, US-Unpaired, or US-Delayed extinction regimens. A significant PREE was obtained, but only for PO training and US-Omitted extinction. The second experiment, employing human subjects in a masked eye blink conditioning task, produced parallel results. A general discrimination view of the classical PREE seems applicable, but one in which neither cognitive factors nor intertrial conditioning of reinforcement aftereffects play a significant role.     

The dynamics of operant conditioning

Existing models of operant learning are relatively insensitive to historical properties of behavior and applicable to only limited data sets. This article proposes a minimal set of principles based on short-term and long-term memory mechanisms that can explain the major static and dynamic properties of operant behavior in both single-choice and multiresponse situations. The critical features of the theory are as follows: (a) The key property of conditioning is assessment of the degree of association between responses and reinforcement and between stimuli and reinforcement; (b) the contingent reinforcement is represented by learning expectancy, which is the combined prediction of response-reinforcement and stimulus-reinforcement associations; (c) the operant response is controlled by the interplay between facilitatory and suppressive variables that integrate differences between expected (long-term) and experienced (short-term) events; and (d) very-long-term effects are encoded by a consolidated memory that is sensitive to the entire reinforcement history. The model predicts the major qualitative features of operant phenomena and then suggests an experimental test of theoretical predictions about the joint effects of reinforcement probability and amount of training on operant choice. We hypothesize that the set of elementary principles that we propose may help resolve the long-standing debate about the fundamental variables controlling operant conditioning.     

Helpful Self-Control: Autonomy Support, Vitality, and Depletion

Why someone exerts self-control may influence how depleting a task is. Feeling compelled to exert self-control require more self-control strength than exerting self-control for more autonomous reasons. Across three experiments, individuals whose autonomy was supported while exerting self-control performed better on a subsequent test of self-control as compared to individuals who had more pressure placed upon them while exerting self-control. The differences in self-control performance were not due to anxiety, stress, unpleasantness, or reduced motivation among the controlled participants. Additional analyses suggested that the decline in self-control performance was mediated by subjective vitality. Feelings of autonomy support lead to enhanced feelings of subjective vitality. This increased vitality may help replenish lost ego-strength, which lead to better self-control performance subsequently.     

Stimulus generalization: some predictions from a model of Pavlovian conditioning.

Three experiments examined predictions generated by incorporating a common-elements account of stimulus generalization within the Rescorla-Wagner model of conditioning. All experiments employed rats in a conditioned suppression situation. Experiments 1 and 2 found that conditioning of a similar stimulus augmented the excitation controlled by a near-asymptotic target stimulus more than did further conditioning of the target itself. Prior discrimination training between the target and the similar stimulus enlarged this effect, compared with prior discrimination between the target and another dissimilar stimulus. Nonreinforced exposure of the similar stimulus prior to its reinforcement also increased the effect. Experiment 3 examined a related prediction for inhibition. After discrimination training, extinction of the previously reinforced stimulus revealed more inhibition to the previously nonreinforced stimulus when those two stimuli were more similar. These outcomes are consistent with deductions from the present model and encourage further testing of its expansion to the case of stimulus generalization.     

Overlearning and instructional control of extinction of vasomotor responding

In a previous study by the authors, immediate extinction of conditioned vasomotor responding was obtained, under conditions of both continuous and partial reinforcement, when the UCS delivery apparatus was removed and subjects were informed that there would be no further UCS presentations. The present study varied the number of continuous reinforcement trials using the same conditioning procedure. Forty human subjects were randomly divided into two groups, given thermal vasomotor conditioning procedures on either 25 or 100 continuous reinforcement trials. At the onset of extinction half of each group was given traditional noninformed extinction procedures, while the other (informed) half had the thermal stimulator removed. Immediate extinction was obtained in informed subjects given 25 conditioning trials. However, there was no significant reduction of responding in informed subjects given 100 conditioning trials. Consequences for behavior theories and therapies are discussed.