Toward a theory of verbal behavior

This paper is a reply to an accompanying set of six commentaries by Sidman; Hayes and Barnes; Schusterman, Kastak, and Reichmuth; Tonneau and Sokolowski; Lowenkron; and Moerk. Those commentaries were prompted by our article “On the Origins of Naming and Other Symbolic Behavior” (1996), which was, in turn, followed by 26 commentaries and a reply. In the course of the present reply, we further develop the naming account to embrace more complex verbal relations such as same, different, more, and less. We also examine what we see as the lack of conceptual coherence in equivalence theories, including relational frame theory, and the disparities between these accounts and the findings from empirical research.     

A Comparison of Active Student Response and On-Task Instruction on the Acquisition and Maintenance of Health Facts by Fourth Grade Special Education Students

An alternating treatments design was used to compare the effects of active student response (ASR) and on-task (OT) instruction on the acquisition and maintenance of health facts during small-group lessons. Five students with learning difficulties (4 students identified as developmentally handicapped and 1 student identified as learning disabled) participated in daily instruction on weekly sets of 20 unknown health facts (10 facts assigned to the ASR condition and 10 to the OT condition). During ASR instruction, the teacher modeled the correct response to a health question that was presented visually on a health fact card, and the students immediately repeated the correct response in unison three times. During OT instruction, students attended visually to the health fact card as the teacher modeled the correct response. All 5 students made more correct responses on end-of-day tests on health facts taught with ASR instruction than they did on health facts taught with OT instruction. ASR instruction also produced consistently superior results on maintenance tests administered 2 weeks after instruction.     

EFFECTS OF REINFORCEMENT HISTORY AND INSTRUCTIONS ON THE PERSISTENCE OF STUDENT ENGAGEMENT

We examined the effects of three reinforcement histories on the persistence of task engagement by 2 fourth-grade students using a partially counterbalanced ABCDBCD design. In each condition, an experimenter made four student contacts during the first 2 min of each session (reinforcement baseline), followed by an 8-min extinction period. The reinforcement history that contained an instructional control component produced the greatest persistence in student engagement. The applied relevance of instructional control is discussed.     

BEHAVIORAL PERSISTENCE AND VARIABILITY DURING EXTINCTION OF SELF-INJURY MAINTAINED BY ESCAPE

The self-injurious escape behavior of a developmentally disabled adult was treated with extinction. Results of a reversal design showed substantial bursts of responding when extinction was introduced and reintroduced: self-injury remained at a variable and elevated rate for some time before stable, low rates were observed. Data on aggression, a nontarget behavior during both baseline and treatment, showed a pattern similar to that seen for self-injury during the extinction conditions.     

A NOTE ON TRANSFER OF STIMULUS CONTROL IN THE DELAYED-CUE PROCEDURE: FACILITATION BY AN OVERT DIFFERENTIAL RESPONSE

This case study describes initially unsuccessful attempts to use the delayed-cue procedure to teach conditional discriminations to an individual with moderate mental retardation. The task was matching printed-word comparison stimuli to dictated-name sample stimuli. In three experiments, the subject typically waited for the delayed cue unless differential responses to the dictated samples (repeating the sample names) were required. Hence, the study provides an example of a way to make the delayed-cue method more effective. The stimulus control bases for the results are discussed.     

Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.     

The effects of cocaine on behavior maintained by timeout from avoidance.

Rats were trained on concurrent schedules under which responses on one lever postponed shock (avoidance) and responses on the other lever produced brief (2-min) periods of signaled timeout from avoidance. For 6 rats, timeout from avoidance was programmed on a variable-interval 45-s schedule that generally resulted in rates that were lower than those on the avoidance lever. For another 6 rats, timeout was arranged on a variable-ratio 15 schedule that produced higher baseline rates. Cocaine (3 to 40 mg/kg) produced large, dose-dependent increases in behavior maintained by timeout in both groups of rats. Avoidance responding was also generally increased by cocaine, but the increases were of lesser magnitude. Increases in response rates were seen across a broad range of doses on behavior maintained by either interval or ratio schedules, an outcome that was unexpected on the basis of most studies of cocaine on food-maintained behavior. These results were similar to those of previous studies of the effects of amphetamine on behavior maintained by timeout from avoidance and suggest that stimulant drugs affect behavior maintained under a shock-postponement schedule differently than they affect behavior maintained by timeout from avoidance.     

Formation of transitivity in conditional matching to sample by pigeons

Four homing pigeons were trained over 5 months in a zero-delay, “arbitrary” matching-to-sample procedure with sample and comparison stimuli presented on any of three response keys. Birds were also required to complete a fixed-ratio 10 requirement on both sample and comparison stimuli to terminate their presentation. The procedure resulted in the establishment of relations that were not specifically trained and that can be characterized by the property of transitivity in a stimulus equivalence context. This result was in contrast with the findings obtained from most previous research with nonhuman subjects.     

A PRELIMINARY PROCEDURE FOR PREDICTING THE POSITIVE AND NEGATIVE EFFECTS OF REINFORCEMENT-BASED PROCEDURES

In the current investigation, a modification was made to the preference assessment described by Pace, Ivancic, Edwards, Iwata, and Page (1985) to predict the effects of stimuli when used in a differential-reinforcement-of-other-behavior (DRO) schedule for 2 clients with severe self-injurious behavior (SIB) and profound mental retardation. Based on the results of the preference assessment, three types of stimuli were identified: (a) high-preference stimuli associated with high rates of SIB (HP/HS), (b) high-preference stimuli associated with relatively lower rates of SIB (HP/LS), and (c) low-preference stimuli associated with low rates of SIB (LP/LS). Consistent with the results of the preference assessment, the DRO schedule with HP/HS stimuli resulted in increased SIB, and the DRO schedule with LP/LS stimuli resulted in no changes in SIB. HP/LS stimuli were demonstrated reinforcers but did not result in a change in SIB when used in a DRO schedule. Thus, the stimulus preference assessment may be useful clinically in some situations for predicting both the beneficial and the negative side effects of stimuli in DRO procedures.     

Resistance To Change As A Function Of Stimulus-reinforcer And Location-reinforcer Contingencies

Pigeons responded on two keys in each component of a multiple concurrent schedule. In one series of conditions the distribution of reinforcers between keys within one component was varied so as to produce changes in ratios of reinforcer totals for key locations when summed across components. In a second series, reinforcer allocation between components was varied so as to produce changes in ratios of reinforcer totals for components, summed across key locations. In each condition, resistance to change was assessed by presenting response-independent reinforcers during intercomponent blackouts and (for the first series) by extinction of responding on both keys in both components. Resistance to change for response totals within a component was always greater for the component with the larger total reinforcer rate. However, resistance to change for response totals at a key location was not a positive function of total reinforcement for pecking that key; indeed, relative resistance to extinction for the two locations showed a weak negative relation to ratios of reinforcer totals for key location. These results confirm the determination of resistance to change by stimulus—reinforcer contingencies.