On conditioned reinforcing effects of negative discriminative stimuli

Observing responses and serial stimuli: searching for the reinforcing properties of the S-

The control exerted by a stimulus associated with an extinction component (S-) on observing responses was determined as a function of its temporal relation with the onset of the reinforcement component. Lever pressing by rats was reinforced on a mixed random-interval extinction schedule. Each press on a second lever produced stimuli associated with the component of the schedule in effect. In Experiment 1 a response-dependent clock procedure that incorporated different stimuli associated with an extinction component of a variable duration was used. When a single S- was presented throughout the extinction component, the rate of observing remained relatively constant across this component. In the response-dependent clock procedure, observing responses increased from the beginning to the end of the extinction component. This result was replicated in Experiment 2, using a similar clock procedure but keeping the number of stimuli per extinction component constant. We conclude that the S- can function as a conditioned reinforcer, a neutral stimulus or as an aversive stimulus, depending on its temporal location within the extinction component.

Conditioned reinforcement of human observing behavior by descriptive and arbitrary verbal stimuli

College students earned monetary reinforcers by pressing a key according to a compound schedule with variable-interval and extinction components. Pressing additional keys occasionally produced displays of either of two verbal stimuli; one was uncorrelated with the schedule components, and the other was correlated with the extinction component. In Experiments 1 and 2, the display area of the apparatus was blank unless an observing key was pressed, whereupon a descriptive message appeared. Most students preferred an uncorrelated stimulus stating that "Some of this time scores are TWICE AS LIKELY as normal, and some of this time NO SCORES can be earned" over a stimulus stating that "At this time NO SCORES can be earned." In Experiment 3, the display area indicated that "The Current Status of the Program is: NOT SHOWN." Presses on the observing keys replaced this message with stimuli that provided arbitrary labels for the schedule conditions. All of the students preferred a stimulus stating that "The Current Status of the Program is: B" over an uncorrelated stimulus stating that "The Current Status of the Program is: either A or B." Thus, under some circumstances, observing was maintained by a stimulus correlated with extinction-a finding that poses a challenge for Pavolvian accounts of conditioned reinforcement. Differences in the maintenance of observing by the descriptive and arbitrary stimuli may be attributed to differences in either the strength or nature of the instructional control exerted by the verbal stimuli.

The generality of selective observing

Four rats obtained food pellets by poking a key and 5-s presentations of the discriminative stimuli by pressing a lever. Every 1 or 2 min, the prevailing schedule of reinforcement for key poking alternated between rich (either variable-interval [VI] 30 s or VI 60 s) and lean (either VI 240 s, VI 480 s, or extinction) components. While the key was dark (mixed-schedule stimulus), no exteroceptive stimulus indicated the prevailing schedule. A lever press (i.e., an observing response), however, illuminated the key for 5 s with either a steady light (S+), signaling the rich reinforcement schedule, or a blinking light (S-), signaling the lean reinforcement schedule. One goal was to determine whether rats would engage in selective observing (i.e., a pattern of responding that maintains contact with S+ and decreases contact with S-). Such a pattern was found, in that a 5-s presentation of S+ was followed relatively quickly by another observing response (which likely produced another 5-s period of S+), whereas exposure to S- resulted in extended breaks from observing. Additional conditions demonstrated that the rate of observing remained high when lever presses were effective only when the rich reinforcement schedule was in effect (S+ only condition), but decreased to a low level when lever presses were effective only during the lean reinforcement component (S- only condition) or when lever presses had no effect (in removing the mixed stimulus or presenting the multiple-schedule stimuli). These findings are consistent with relativistic conceptualizations of conditioned reinforcement and extend the generality of selective observing to procedures in which the experimenter controls the duration of stimulus presentations, the schedule components both offer intermittent food reinforcement, and rats serve as subjects.

Applied behavior analysis at West Virginia University: A brief history

The development of an emphasis on applied behavior analysis in the Department of Psychology at West Virginia University is traced. The emphasis began primarily in the early 1970s, under the leadership of Roger Maley and Jon Krapfl, and has continued to expand and evolve with the participation of numerous behavior analysts and behavior therapists, both inside and outside the department. The development has been facilitated by several factors: establishment of a strong behavioral emphasis in the three Clinical graduate programs; change of the graduate program in Experimental Psychology to a program in basic Behavior Analysis; development of nonclinical applied behavior analysis within the Behavior Analysis program; establishment of a joint graduate program with Educational Psychology; establishment of a Community/Systems graduate program; and organization of numerous conferences. Several factors are described that seem to assure a stable role for behavior analysis in the department: a stable and supportive "culture" within the department; American Psychological Association accreditation of the clinical training; a good reputation both within the university and in psychology; and a broader community of behavior analysts and behavior therapists.