Steady-state Responding Research Articles

Do Pavlovian Processes Really Mediate Behavioral Momentum? Some Conflicting Issues

According to the behavioral momentum theory of response strength (Nevin et al., Journal of the Experimental Analysis of Behavior, 53, 359–379, 1990), steady-state responding reflects the contingency between a response and a reinforcer (response–reinforcer relationship), whereas behavior’s resistance to change is mediated by a contingency between a stimulus and the reinforcer (stimulus–reinforcer relationship). It is further presumed in this theory that a Pavlovian conditioned stimulus (CS)–unconditioned stimulus (US) contingency overlaps with the discriminative stimulus (SD), signaling a primary reinforcer (SR+) within the 3-term contingency (SD: response [R]–SR+). The mere arranging of a stimulus–reinforcer relation in an operant preparation, however, does not necessarily imply that the resulting behavioral process is Pavlovian. This article questions how important such Pavlovian CS–SR+ relations really are in governing operant behavior and its resistance to change in view of evidence from the operant and Pavlovian literatures showing dissociation between Pavlovian and operant stimulus control. To this end, we highlight studies published in the Pavlovian associative literature (Holman and Mackintosh, The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology, 33, 21–31, 1981; Rescorla, Current Directions in Psychological Science, 1, 66–70, 1992b) as well as at least 1 seldom-cited study published in the Journal of the Experimental Analysis of Behavior (Marcucella, Journal of the Experimental Analysis of Behavior, 36, 51–60, 1981) supporting the view that CS relations embedded in the 3-term operant contingency can act independently of the discriminative stimulus functions of the SD. These CS relations appear to be neither necessary nor sufficient for sustaining operant discriminative control. Pavlovian relations are likely to be artifacts of operant conditioning—not causal mediators. It is suggested that continued and excessive focus on Pavlovian processes that only have meager influence on operant behavior in general, and behavioral momentum more specifically, will likely be an empirical cul-de-sac for improvement of behavioral management for addiction relapse and other behavioral disorders.

Choice in transition: Replication and extension to preschool children in a naturalistic setting.

This study replicated previous basic research into the dynamics of choice and extended this analysis to children's behavior in a naturalistic setting. Two preschoolers with disabilities were observed interacting with their teachers at baseline and during an experimental analysis involving four pairs of concurrent variable-interval schedules of adult attention implemented by an experimenter. Each child was exposed to four experimental phases in which the relative reinforcer rates for on- and off-task behavior were 10:1, 1:1, 1:10, and reversed back to 10:1. The 10:1 phase was designed to mimic the same schedules and types of adult attention observed at baseline. We used the generalized matching equation to model steady-state behavior at the end of the transition phases and to evaluate changes in sensitivity at various points throughout the phases. Choice in transition was evaluated by plotting log behavior ratios by session, cumulated time on- and off-task and cumulated attention for on- and off-task behavior by session, and interreinforcer behavior ratios following different sequences of the first four reinforcer deliveries. The generalized matching equation accounted for a large proportion of variance in steady-state responding, sensitivity values increased steadily throughout the phases, patterns of choice in transition were similar to those reported in basic research, and interreinforcer preference generally shifted toward the just-reinforced alternative. These findings are consistent with previous basic research and support the generality of the dynamics of choice to children's on- and off-task behavior reinforced by adult attention.

Effects of active anti-methamphetamine vaccination on intravenous self-administration in rats

Backgroundd-Methamphetamine (METH) addiction is a serious public health concern for which successful treatment remains elusive. Immunopharmacotherapy has been shown to attenuate locomotor and thermoregulatory effects of METH. The current study investigated whether active vaccination against METH could alter intravenous METH self-administration in rats. MethodsMale Sprague-Dawley rats (Experiment 1: N=24; Experiment 2: N=18) were vaccinated with either a control keyhole-limpet hemocyanin conjugate vaccine (KLH) or a candidate anti-METH vaccine (MH6-KLH) or. Effects of vaccination on the acquisition of METH self-administration under two dose conditions (0.05, 0.1mg/kg/inf) and post-acquisition dose-substitution (0, 0.01, 0.05, 0.20mg/kg/inf, Experiment 1; 0.01, 0.05, 0.10, 0.15mg/kg/inf, Experiment 2) during steady-state responding were investigated. Plasma METH concentrations were determined 30min after an acute challenge dose of 3.2mg/kg METH. ResultsActive vaccination inhibited the acquisition of METH self-administration under the 0.1mg/kg/inf dose condition, with 66% of the MH6-KLH-vaccinated rats compared to 100% of the controls reaching criteria, and produced transient and dose-dependent effects on self-administration during the maintenance phase. Under the 0.05mg/kg/inf dose condition, MH6-KLH-vaccinated rats initially self-administered more METH than controls, but then self-administration decreased across the acquisition phase relative to controls; a subsequent dose–response assessment confirmed that MH6-KLH-vaccinated rats failed to acquire METH self-administration. Finally, plasma METH concentrations were higher in MH6-KLH-vaccinated rats compared to controls after an acute METH challenge, and these were positively correlated with antibody titers. ConclusionsThese data demonstrate that active immunopharmacotherapy for METH attenuates the acquisition of METH self-administration.

Behavioral adjustment in prenatally cocaine-exposed adolescents

Behavioral adjustment in prenatally cocaine-exposed adolescents

Active vaccination inhibits the acquisition of methamphetamine self-administration in rats

Active vaccination inhibits the acquisition of methamphetamine self-administration in rats

Behavior in Transition

This review of transition states considers their significance in the analysis of behavior, along with methodological and empirical issues related to their analysis. Transition states include both transitions from one baseline to another and transitory states, where responding temporarily deviates from otherwise steady-state responding. Transitions are wellsprings of subsequent steady-state behavior, both transitions and transitory states index the effects of variables in steady state conditions preceding and following the transition state, and problems in applied behavior analysis often involve transition states. Methodological challenges of assessing transition states include identifying their beginning and end, establishing appropriate temporal resolutions for their analysis, and their measurement. Variables affecting transition states include parameters of the preceding and following baseline conditions, establishing operations, and behavioral histories. Although historically less studied in behavior analysis than steady-state behavior, understanding behavior in transition is essential in developing behavior theory and its application.

Measuring adaptation with a sinusoidal perturbation function

We examine the possibility that sensory and motor adaptation may be induced via a sinusoidally incremented perturbation. This sinewave adaptation method provides superior data for fitting a parametric model than when using the standard step-function method of perturbation, due to the relative difficulty of fitting a decaying exponential vs. a sinusoid. Using both experimental data and simulations, we demonstrate the difficulty of detecting the presence of motor adaptation using a step-function perturbation, compared to detecting motor adaptation using our sinewave perturbation method.

A decision model for steady-state choice in concurrent chains.

Grace and McLean (2006) proposed a decision model for acquisition of choice in concurrent chains which assumes that after reinforcement in a terminal link, subjects make a discrimination whether the preceding reinforcer delay was short or long relative to a criterion. Their model was subsequently extended by Christensen and Grace (2008, 2009a, 2009b) to include effects of initial- and terminal-link duration on choice. We show that an expression for steady-state responding can be derived from the decision model, which enables a model for choice that provides an account of archival data that is equal or superior to the contextual choice model (Grace, 1994) and hyperbolic value-added model (Mazur, 2001) in terms of goodness of fit, parsimony, and parameter invariance. The success of the steady-state decision model validates the strategy of understanding acquisition phenomena as a bridge toward explaining choice at the molar level.

Some Effects of Magnitude of Reinforcement on Persistence of Responding

The influence of magnitude of reinforcement was examined on both response rate and behavioral persistence. During Phase 1, a multiple schedule of concurrent reinforcement was implemented in which reinforcement for one response option was held constant at VI 30 s across both components, while magnitude of reinforcement for the other response option was varied across the 2 components. In Phase 2, persistence was evaluated during extinction following steady-state responding. In Phase 1, responding of 3 of the 4 participants was greater on the option that produced the higher magnitude of reinforcement. During Phase 2, 2 of these 3 participants' response persistence under extinction was greater for the signal associated with the greater magnitude of reinforcement. The influence of magnitude of reinforcement on behavioral persistence is discussed, as well as implications for studying behavioral maintenance.

Perinatal lead exposure and relapse to drug-seeking behavior in the rat: a cocaine reinstatement study.

Intravenous self-administration of cocaine at low doses is increased by chronic low-level exposure to lead during gestation and lactation (perinatal lead exposure). Insofar as drug potency is increased by early lead exposure, it must be considered that cocaine-seeking and relapse after periods of withdrawal similarly may be enhanced by perinatal lead exposure. Employing an animal model, the present study examined the effects of lead exposure during gestation and lactation on cocaine-induced reinstatement of drug-seeking, when animals were tested as adults. Adult female rats were gavaged once daily with 0 or 16 mg lead for 30 days prior to breeding with non-exposed males. This exposure regimen continued until offspring were weaned at postnatal day (PND) 21. At PND 120, male offspring were trained to self-administer cocaine intravenously (IV) [0.50 mg/kg cocaine per infusion on a fixed-ratio schedule where two lever presses resulted in drug delivery (FR-2 schedule)]. After steady-state responding was established, cocaine reinstatement responding was assessed for each group within an extinction paradigm. During the initial 1 h of reinstatement testing, the previous baseline contingencies were in place, i.e. animals operated under an FR-2 schedule for an infusion of 0.50 mg/kg cocaine. During the 2 h, 3 h, and 4 h of testing saline infusions were substituted for cocaine infusions. After responding extinguished during hour 4, reinstatement of responding was tested by administering an intraperitoneal (IP) priming injection of 0.00, 5.00, 10.00, or 20.00 mg/kg cocaine. Following these injections, lever responding for saline infusions was monitored during hour 5. The number of saline infusions self-administered during hour 5 increased in a dose-dependent fashion for both controls (group 0-mg) and lead-exposed (group 16-mg) animals. However, lead-exposed animals self-administered significantly more saline infusions than controls at the 5.00 mg/kg and 10.00 mg/kg doses. This apparent metal-related increase in sensitivity to cocaine was evident with blood lead in metal-exposed test animals returning to control levels. However, brain lead levels remained elevated in lead-exposed test animals, relative to controls. The results of this investigation suggest that low-level lead exposure during gestation and lactation increases sensitivity to the relapse phase of drug abuse. It is further apparent that this increased sensitivity to the reinstatement of drug-seeking behavior is long-lasting.

Lead/ethanol interactions I: Rate-depressant effects

Adult male rats were exposed to a diet containing 500 ppm added lead as lead acetate (group lead-diet) or a control diet containing no added chemicals (group control-diet) for 61 days prior to commencing fixed-ratio 32 (FR 32) lever press training for water reinforcement. After steady state responding was achieved, all animals received serial administrations of acute doses of ethanol prior to the daily training session. Specifically, lead-diet and control-diet rats received i.p. injections of .25, .5, .75, 1.0, and 1.25 g/kg ethanol, in ascending order, alternating daily with injections of saline. The results revealed a dose-dependent rate-depressant effect, with higher doses of ethanol producing more behavioral suppression than lower doses for both groups. In addition, at the dose of 1.0 g/kg it was observed that the suppressive effects of ethanol on schedule-controlled responding were reduced among lead-treated animals relative to controls. These data are discussed in terms of lead-induced attenuation of the pharmacologic effects of ethanol.

RESISTANCE TO CHANGE AND THE LAW OF EFFECT

Three experiments using multiple schedules of reinforcement explored the implications of resistance-to-change findings for the response-reinforcer relation described by the law of effect, using both steady-state responding and responding recorded in the first few sessions of conditions. In Experiment 1, when response-independent reinforcement was increased during a third component, response rate in Components 1 and 2 decreased. This response-rate reduction was proportionately greater in a component in which reinforcer magnitude was small (2-s access to wheat) than in the component in which it was large (6-s access to wheat). However, when reinforcer rates in the two components were varied together in Experiments 2 and 3, response-rate change was the same regardless of the magnitude of reinforcers used in the two components, so that sensitivity of response rates to reinforcer rates (Experiment 2) and of response-rate ratios to reinforcer-rate ratios (Experiment 3) was unaffected by the magnitude of the reinforcers. Therefore, the principles determining resistance to change, described by behavioral momentum theory, seem not to apply when the source of behavior change is the variation of reinforcement contingencies that maintain the behavior. The use of extinction as a manipulation to study resistance to change is questioned.

Discriminative stimulus control and the effects of concurrent operants.

Discriminative-stimulus-control functions were investigated in a concurrent operant context. Variable-interval reinforcement schedules were arranged for pigeons on two response keys. One key, illuminated with a white vertical line on green background (position irrelevant), was programmed with a given schedule value across groups. For different groups of pigeons, the alternative key, illuminated with green alone, was programmed with twice, the same, or half the reinforcement frequency of the other key. Stimulus-control gradients were collected from both keys as line orientation was varied. On the green-plus-line alternative, flattest gradients were observed when twice the reinforcement frequency was concurrently programmed and the steepest were observed when equal values were concurrently programmed. Also examined were the effects of a programmed changeover delay, important in maintaining the independence of concurrent operants. The changeover delay was found to have relatively minor effects upon stimulus control, despite its typical and marked effects upon steady-state responding.

INSTRUCTIONS, MULTIPLE SCHEDULES, AND EXTINCTION: DISTINGUISHING RULE‐GOVERNED FROM SCHEDULE‐CONTROLLED BEHAVIOR

Schedule sensitivity has usually been examined either through a multiple schedule or through changes in schedules after steady-state responding has been established. This study compared the effects of these two procedures when various instructions were given. Fifty-five college students responded in two 32-min sessions under a multiple fixed-ratio 18/differential-reinforcement-of-low-rate 6-s schedule, followed by one session of extinction. Some subjects received no instructions regarding the appropriate rates of responding, whereas others received instructions to respond slowly, rapidly, or both. Relative to the schedule in operation, the instructions were minimal, partially inaccurate, or accurate. When there was little schedule sensitivity in the multiple schedule, there was little in extinction. When apparently schedule-sensitive responding occurred in the multiple schedule, however, sensitivity in extinction occurred only if differential responding in the multiple schedule could not be due to rules supplied by the experimenter. This evidence shows that rule-governed behavior that occurs in the form of schedule-sensitive behavior may not in fact become schedule-sensitive even though it makes contact with the scheduled reinforcers.