Report of the ABAI Task Force on Contingent Electric Skin Shock.

As a task force appointed by the Executive Council of the Association for Behavior Analysis International (ABAI), we investigated the clinical use of contingent electric skin shock (CESS) in behavior analytic treatments for severe problem behavior. We studied how CESS is used in contemporary behavior analysis, reinforcement-based alternatives to CESS, and current ethical and professional guidelines for applied behavior analysts. We recommended that ABAI uphold clients' right to receive CESS when it is restricted to extreme cases and used under rigorous professional and legal oversight. Our recommendation was rejected by a vote of the full members of ABAI, who instead endorsed an alternative recommendation, developed by members of the Executive Council, that opposed the use of CESS under any condition. Here we present for the record our report and initial recommendations, the formal statement that was rejected by the members of ABAI, and the statement that was endorsed.

We Still Have a Lot to Learn.

Use of contingent electric skin shock in the treatment of severe problem behavior has been criticized on the grounds that (a) it is not necessary because function-based procedures using positive reinforcement are just as effective; (b) it violates contemporary ethical standards; and (c) it lacks social validity. There are good reasons to challenge these claims. The meaning of "severe problem behavior" is imprecise and we should be cautious in our claims about how to treat it. It is not clear that reinforcement-only procedures are sufficient because they are commonly paired with psychotropic medication, and there is evidence that some instances of severe behavior may be refractory to reinforcement-only procedures. Ethical standards, as expressed by the Behavior Analysis Certification Board and the Association for Behavior Analysis International, do not prohibit punishment procedures. Social validity is a complex concept that can be understood and measured in multiple, potentially conflicting ways. Because we still have a lot to learn about these matters, we should be more skeptical of sweeping claims such as the three enumerated above.

Rich-lean transitions produced by stimuli associated with accurate and inaccurate responding by pigeons.

Discriminable transitions from relatively favorable schedules of reinforcement to unfavorable schedules (rich-lean transitions) can produce disruptions in operant behavior. A prior evaluation in our laboratory (Toegel et al., 2021) found that placing a border around a key displayed on a resistive touchscreen increased pigeons' response accuracy relative to conditions without the border. We sought to evaluate (a) whether effects of the key border on accuracy could be replicated in a within-session comparison and (b) whether transitions from a response alternative associated with accurate responding to one associated with inaccurate responding functioned as rich-lean transitions. Pigeons' key pecks were reinforced according to a two-component multiple schedule with identical fixed-ratio (FR) requirements and reinforcer magnitudes. The components differed based on whether the virtual key was displayed behind a border or with no border. In line with prior research, within-session comparisons yielded higher response accuracy in components with the key border than in components without the border. Furthermore, transitions from the border component to the no border component functioned as rich-lean transitions for pigeons whose obtained FRs in no border components were substantially larger than the FR programmed in that component.

The aversiveness of timeout from response-dependent and response-independent food deliveries as a function of delivery rate.

Seven experiments with rats assessed the aversiveness of timeout using punishment and avoidance procedures. Experiments 1 and 2 considered the contributions of stimulus change, suspending the response-reinforcer contingency, response prevention, the general disruption in the reinforcement schedule during time-in, and overall decreases in reinforcement. Results support the conclusion that response-contingent timeouts punish behavior because they are signaled periods during which an ongoing schedule of positive reinforcement is suspended. Experiments 3, 4, and 5 assessed effects of the reinforcement rate during time-in on the punitive efficacy of timeout and, for comparison, electric shock. Evidence for a direct relation between reinforcement rate and punitive efficacy was equivocal. In Experiments 6 and 7, responding avoided timeout from response-independent food deliveries. Responding was acquired rapidly when it avoided timeouts from free deliveries of pellets or a sucrose solution, but not when it avoided free deliveries of water. At steady-state, avoidance rates and proficiency were directly related to the rate of pellet or sucrose deliveries. The relation between the nature of the time-in environment and the aversiveness of timeout was clear in our avoidance experiments, but not in our punishment experiments. We discuss interpretive problems in evaluating the aversiveness of timeout in the punishment paradigm.

Effects of advance notice on transition-related pausing in pigeons.

Transitions between tasks can produce behavioral disruptions that are characterized as problematic. Advance notice, a procedure designed to reduce disruptions, involves presenting a stimulus to warn of the end of the ongoing activity and the nature of the upcoming activity. Clinical evaluations of advance notice have produced mixed results. We studied advance notice in a controlled laboratory setting. Pigeons' keypecking was maintained on a multiple schedule with 2 fixed-ratio components. In the lean component, completing the ratio produced brief access to food; in the rich component, completing the ratio produced longer access. Disruptions in operant behavior, measured as pauses in pecking, were reliably produced in the transition from a rich component to a lean one. Advance notice was provided by flashing the houselight before transitions to lean components. Advance notice did not reduce pausing in the rich-lean transition; instead, it tended to increase it. When the flashing houselight warned of a transition but was equally likely to be followed by the rich component as the lean one, the stimulus had no reliable effect on pausing. Despite its limitations as a translational model of clinical settings, this experiment suggests that clinical use of advance notice should be approached with caution.

Design and evaluation of a touchscreen apparatus for operant research with pigeons.

We developed a touchscreen apparatus for pigeons and conducted a series of experiments that assessed its utility for free-operant procedures. The apparatus incorporated an on-board Windows computer, an electromechanical interface, an amplified speaker, and the touchscreen. We found that merely projecting a virtual key on the screen was insufficient; too many pecks missed the key. Adding a visual target in the center of the key and providing visual feedback for on-key pecks both failed to improve response accuracy. Accuracy was improved by imposing a timeout after off-key pecks or providing a physical boundary around the key. With the physical boundary, response accuracy was comparable to that obtained with conventional plastic keys, and response acquisition via autoshaping also was comparable. Mixing the color elements of the screen's pixels produced color stimuli, but the colors did not function as pure wavelengths of light in tests of stimulus generalization. Both colors and geometric shapes functioned as discriminative stimuli in multiple schedules with variable-interval and extinction components or rich and lean fixed-ratio components. In general, our touchscreen apparatus is a viable alternative to conventional pigeon chambers and increases the experimenter's options for visual stimuli, auditory stimuli, and the number and location of response keys.

How I Learned to Stop Worrying and Love Replication Failures.

Worries about the reproducibility of experiments in the behavioral and social sciences arise from evidence that many published reports contain false positive results. Misunderstanding and misuse of statistical procedures are key sources of false positives. In behavior analysis, however, statistical procedures have not been used much. Instead, the investigator must show that the behavior of an individual is consistent over time within an experimental condition, that the behavior changes systematically across conditions, and that these changes can be reproduced - and then the whole pattern must be shown in additional individuals. These high standards of within- and between-subject replication protect behavior analysis from the publication of false positive findings. When a properly designed and executed experiment fails to replicate a previously published finding, the failure exposes flaws in our understanding of the phenomenon under study - perhaps in recognizing the boundary conditions of the phenomenon, identifying the relevant variables, or bringing the variables under sufficient control. We must accept the contradictory findings as valid and pursue an experimental analysis of the possible reasons. In this way, we resolve the contradiction and advance our science. To illustrate, two research programs are described, each initiated because of a replication failure.

Behavioral functions of stimuli signaling transitions across rich and lean schedules of reinforcement.

On multiple fixed-ratio schedules, pausing is extended at the start of a component ending in a small reinforcer (a lean component) but only when this component follows a component ending in a large reinforcer (a rich component). In two experiments, we assessed whether a stimulus correlated with a lean component is aversive and how its function is affected by the preceding component. In Experiment 1, pigeons responded on mixed fixed-ratio schedules ending in large or small reinforcers. Observing responses converted the mixed schedule to a multiple one by producing a stimulus correlated with the current component. Overall, the lean stimulus did not suppress observing, suggesting that it was not sufficiently aversive. In Experiment 2, an escape procedure was used, and pigeons could convert a multiple schedule to a mixed one by pecking a key to remove the discriminative stimuli. Pigeons escaped from the lean-schedule stimulus more than they did from the rich one. For two pigeons, this effect was enhanced when a rich component preceded the lean stimulus. The results indicate that a stimulus correlated with the leaner of two reinforcement schedules can acquire aversive functions, but observing and escape procedures may differ in their abilities to detect this effect.

Assessing the role of effort reduction in the reinforcing efficacy of timeout from avoidance.

Rats responded on concurrent schedules of shock-postponement or deletion (avoidance) and timeout from avoidance. In Experiment 1, 3 rats' responses on one lever postponed shocks for 20 s and responses on a second lever produced a 1-min timeout according to a variable-interval 45-s schedule. Across conditions, a warning signal (white noise) was presented 19.5 s, 16 s, 12 s, 8 s, or 4 s before an impending shock. Raising the duration of the warning signal increased both avoidance and timeout response rates. Timeout responding, although positively correlated with avoidance responding, was not correlated with the prevailing shock rate. In Experiment 2, 3 rats' responses on one lever deleted scheduled shocks according to a variable-cycle 30-s schedule and responses on a second lever produced a 2-min timeout as described above. After this baseline condition, the avoidance lever was removed and noncontingent shocks were delivered at intervals yoked to the receipt of shocks in the baseline sessions. Timeout responding decreased when the avoidance lever was removed, even though the shock-frequency reduction afforded by the timeout remained constant. These results suggest that a key factor in the reinforcing efficacy of timeout is suspension of the requirement to work to avoid shock, rather than the reduction in shock frequency associated with timeout.

Suppressive and facilitative effects of shock intensity and interresponse times followed by shock.

Although response-dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable-interval 40-s schedule of food presentation. Shock followed either long or short interresponse times. Shock intensity was raised from 0.05 mA to 0.4 mA or 0.8 mA. Overall, shock contingent on long interresponse times punished long interresponse times and increased response rates. Shock contingent on short interresponse times punished short interresponse times and decreased response rates. In Experiment 1, raising the range of interresponse times that produced shock enhanced these effects. In Experiment 2, the effects of shock intensity depended on the interresponse times that produced shock. When long interresponse times produced shock, low intensities increased response rates. High intensities decreased response rates. When short interresponse times produced shock, high shock intensities punished short interresponse times and decreased response rates more than low intensities. The results may explain why punishment procedures occasionally facilitate responding and establish parameters for future studies of punishment.

Extended pausing by humans on multiple fixed-ratio schedules with varied reinforcer magnitude and response requirements.

We conducted three experiments to reproduce and extend Perone and Courtney's (1992) study of pausing at the beginning of fixed-ratio schedules. In a multiple schedule with unequal amounts of food across two components, they found that pigeons paused longest in the component associated with the smaller amount of food (the lean component), but only when it was preceded by the rich component. In our studies, adults with mild intellectual disabilities responded on a touch-sensitive computer monitor to produce money. In Experiment 1, the multiple-schedule components differed in both response requirement and reinforcer magnitude (i.e., the rich component required fewer responses and produced more money than the lean component). Effects shown with pigeons were reproduced in all 7 participants. In Experiment 2, we removed the stimuli that signaled the two schedule components, and participants' extended pausing was eliminated. In Experiment 3, to assess sensitivity to reinforcer magnitude versus fixed-ratio size, we presented conditions with equal ratio sizes but disparate magnitudes and conditions with equal magnitudes but disparate ratio sizes. Sensitivity to these manipulations was idiosyncratic. The present experiments obtained schedule control in verbally competent human participants and, despite procedural differences, we reproduced findings with animal participants. We showed that pausing is jointly determined by past conditions of reinforcement and stimuli correlated with upcoming conditions.

Effects of past and upcoming response-force requirements on fixed-ratio pausing.

Four rats obtained food by pressing a lever 30 times in each component of a two-component multiple schedule. Across conditions, the force required to press the lever was increased in one component and held constant in the other. Pausing at the outset of each component was controlled by both the past and upcoming force requirements: Pauses were longer when the upcoming requirement was high and this effect was intensified when the past requirement was low. In concert with previous research, the results support the general proposition that behavior is disrupted by abrupt, discriminable transitions from favorable to unfavorable schedule conditions, across a range of subjects and operational definitions of favorability.

Effects of alternative reinforcement on human behavior: the source does matter.

Competing theories regarding the effects of delivering periodic response-independent reinforcement (more accurately, response-independent points exchanged for money) on a baseline rate of behavior were evaluated in human subjects. Contiguity theory holds that these events decrease target responding because incompatible behavior is adventitiously strengthened when the point deliveries follow target behavior closely in time. Matching theory holds that response-independent points, like any other alternative reinforcer, should reduce target responding. On this view, temporal contiguity between target responding and response-independent point delivery is unimportant. In our experiment, four different responses (moving a joystick in four different directions) were reinforced with points exchangeable for money according to four independent variable-interval schedules. Different schedules of point delivery were then superimposed on these baselines. When all superimposed point deliveries occurred immediately after one of the four responses (the target response), time allocated to target responding increased. When the superimposed point deliveries could be delivered at any time, time allocated to target responding declined and other behavior increased. When superimposed points could never immediately follow target responses, time allocated to target responding decreased further and other behavior or pausing predominated. The findings underscore the contribution of temporal contiguity in the effects of response-independent deliveries of food, money, points, etc.

Negative effects of positive reinforcement.

Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive-those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures.