Chained concurrent schedules: reinforcement as situation transition

Pigeons' pecks at two white response keys (initial-link situation) occasionally turned both keys red (terminal-link situation). When the two keys were red, pecks occasionally produced food, after which the keys were again white. In both situations, a changeover delay prevented the response-produced outcome from immediately following a change of responding from either key to the other. In the initial-link situation, the ratio of pecks at the keys closely paralleled the ratio of transitions into the terminal-link situation produced by the pecks, conforming to the well-known matching relation. In the terminal-link situation, the peck ratios deviated from the matching relation toward indifference. Overall response rate and rate of changeover were generally higher in the terminal-link situation than in the initial-link situation. The finding of matching in the initial-link situation supports a definition of reinforcement as situation transition. The differences in performance between the two situations, viewed in the light of other recent findings, suggest that the effects of a changeover delay depend on the overall reinforcing value of the choice alternatives.     

Behavioral contrast of time allocation

Pigeons' standing on a platform produced food reinforcement according to two-component multiple schedules in which either both components consisted of the same variable-interval schedule or one of these was replaced with a component without reinforcement (extinction). The components of the multiple schedule alternated every 30 sec, and were signalled by changes in the color of diffuse overhead illumination. Changing the schedule of one of the components to extinction increased the percentage of time spent on the platform during the unchanged component (behavioral contrast). This result casts doubt on accounts that attribute behavioral contrast to variations in the rate of noninstrumental elicited responses.     

EFFECTS OF ALTERNATIVE REINFORCEMENT: DOES THE SOURCE MATTER?1

In a chamber with a single response key, pigeon's key pecks were reinforced with food according to a variable-interval schedule. In addition, extra reinforcements occurred concurrently according to an independent schedule. In one condition, availability of the extra reinforcements was signalled by a change in key color from white to red. The extra reinforcements occurred after a peck on the red key. In a second condition, the extra reinforcements were unsignalled and occurred only after a 2-sec pause in pecking for one group of subjects and were unsignalled and occurred freely as scheduled for another group of subjects. In the first two conditions, duration of reinforcement was varied. A third condition duplicated the second but varied rate rather than duration of reinforcement. The rate of pecking varied inversely with the amount of extra reinforcement per unit time according to the same function, regardless of the condition regulating occurrence of the extra reinforcements, and regardless of whether or not a 2-sec pause was required for their occurrence. The shape of this function was predicted by Herrnstein's (1970) matching law.     

Counselling breast cancer patients: A specialist nurse service

The evaluation of a specialist nurse-counselling service is described. Forty newly diagnosed breast cancer patients, treated by mastectomy, were randomised to receive either routine care or routine care plus counselling by a nurse. Psychological morbidity was assessed at one week, 3 months and 12 months postoperatively to determine the efficacy of this service. Comparisons between the groups indicated that counselled patients were significantly less depressed at 3 months postoperatively and reported more beliefs in personal control over health. At 12 months postoperatively there were no significant differences between the groups. Although both groups continued to adjust throughout the year following surgery, this adjustment occurred more rapidly if patients were counselled. The results suggest that a nurse-counselling service can be of value in helping to reduce the amount of distress experienced as a result of the diagnosis and treatment of breast cancer.     

Effects of Control on the Stress Reactions of Commuters1

The effects of morning, rush hour commuting were examined in a quasi-experimental field study involving government-employed commuters (single and carpool drivers). Commuting stress was measured as a response to variations in how difficult it was for commuters to move from home to work. The mediation of these effects by two sources of control in the commuting situation also were assessed. Control was operationalized as control over the internal environment of the car (single versus carpool driver) and choice over routes taken to get to work. Among commuters with a high impedance route, driving to work was associated with significant increases in systolic and diastolic blood pressure and decreases in behavioral performance. The stress of commuting under high impedance conditions was reduced for single drivers relative to carpoolers. Under similar conditions of high impedance, however, having the option to select more than one route to get to work seemed to be more stressful than having only one route. The practical implications of these results are discussed.     

Response rate as a function of amount of reinforcement for a signalled concurrent response

Pigeons were exposed to two equal, concurrent variable-interval schedules of reinforcement on two response keys. One key was continuously illuminated. Pecking on that key produced reinforcements of constant duration. The other key was normally dark, except that availability of reinforcement was signalled by illuminating the key. The duration of access to a grain reinforcer was varied on the key that signalled reinforcement. Rate of response on the first key, the one that did not signal reinforcement, was found to vary inversely with duration of signalled reinforcement on the other key. The latency between the signal and the peck that produced signalled reinforcement remained about constant. These results show that responding on one key in concurrent variable-interval schedules depends on the reinforcement delivered by both schedules and is independent of responding on the other key.