Response patterning on an avoidance schedule as a function of time-correlated stimuli

Clock control of human performance on avoidance and fixed-interval schedules

The avoidance and fixed-interval performances of human subjects were studied in two experiments. Addition of time-correlated stimuli (added clock) improved behavioral efficiency, since response rates decreased without decreases in reinforcement rates. Response-dependent display of the clock maintained a second, observing response and reductions in clock duration weakened such observing behavior. Generally, the reinforcing properties of the clock were more apparent with the avoidance than with the fixed-interval schedule, a finding attributed to temporal cues already provided by delivery of the fixed-interval reinforcers. Reduced rates of the main response when the clock was dependent on an observing response were more than offset by rates of the observing response in the majority of subjects. Thus, the results do not support an interpretation of the reinforcing properties of added clocks simply in terms of work reduction.

Performance characteristics of conditioned blood pressure elevations in the baboon

Operant conditioning of diastolic blood pressure elevation was accomplished in six baboons (Papio sp.) by a procedure using food delivery when diastolic pressure was maintained above a prespecified level, and shock delivery when diastolic pressure remained below that level. Data from steady-state performance indicated a rise in diastolic pressure by a median 22 mm Hg when the daily session was begun. Elevated levels of diastolic blood pressure and low shock frequencies were maintained throughout the 12-hour session. The frequency and duration of shifts in diastolic pressure to below criterion level were found to be variable during the first 1-2 hours but were stable throughout the remainder of the session. Heart rate had a phasic temporal pattern over the 12-hour session, characterized for most subjects by a rate increase at session onset followed by a rate decrease. Analysis of individual performance records showed that the blood pressure increases could occur without concomitant elevations in heart rate.

Effects of response-contingent clock stimuli on behavior maintained by intravenous codeine in the rhesus monkey

Response-contingent brief presentations of clock stimuli differentially correlated with food availability altered rates of codeine-maintained lever pressing. Rhesus monkeys performed under a two lever multiple schedule: Multiple fixed interval clock 5 min variable interval 2 min. Different colored lights were presented during successive 75 sec period of the fixed-interval clock component. Lever pressing under the FI Clock schedule was maintained by presentation of 1 g Noyes pellets, and lever pressing under the VI schedule by 0.05 mg/kg infusions of codeine PO4. Characteristic schedule-controlled performance developed in both schedule components. When the clock stimulus from the first or the final period of the FI Clock schedule was presented contingent upon completion of a short fixed ratio of responses during the variable-interval schedule component, the first clock stimulus decreased and the final clock stimulus increased rates of codeine-maintained lever pressing. Neither the first nor the final clock stimulus altered the frequency of codeine injection. The effect of each clock stimulus was accentuated by increasing the duration of stimulus presentation and by decreasing the response requirement for stimulus illumination. These rate-altering effects of the clock stimuli were most pronounced when different reinforcers were presented in the two components of the multiple schedule when either food or intravenous codeine injection was available under both components of the multiple schedule, response-contingent clock stimulus presentation did not alter response rates under the VI schedule.