Relationship between contingency awareness and human performance on random ratio and random interval schedules

In three experiments, human participants pressed the space bar on a computer keyboard to earn points on random-ratio (RR) and random-interval (RI) schedules of reinforcement. Verbalized contingency awareness (CA) for each schedule was measured after the entire task (Experiments 1 and 2), or after each RR–RI trial (Experiment 3). In all three experiments, an ability to accurately verbalize the appropriate contingency for each schedule was associated with typical schedule responding. In addition, lagged correlational analysis of verbalized contingency awareness and schedule performance was undertaken in Experiment 3. Results of these correlations initially suggested that CA scores were better predictors of typical schedule performance on the following trial than typical schedule performance was of CA scores on the following trial; however, further analysis revealed no significant differences between the alternate lagged correlation types in each pair. Findings, therefore, suggest that operant performance on RR and RI schedules is associated with participant-derived rule governed behavior, and results are discussed in terms of the introduction of a new paradigm for measuring this association, and the potential for further research to manipulate these parameters further in order to investigate causality in this respect.     

Choice and the rate of punishment in concurrent schedules

Rats' responses on two levers were reinforced according to independent random-interval 1.5-min food schedules. In addition, both lever presses were intermittently punished according to several concurrent random-interval random-interval shock schedules. For the left, the scheduled rate of punishment was kept constant according to a random-interval 6-min schedule. For the right, the rate of punishment varied. As the frequency of punishment for the right lever press increased, its rate decreased. The rate of the left punished lever press increased, however, even though its scheduled reinforcement rate and punishment rate remained unchanged.     

Selective punishment early and late in fixed-ratio schedules of food reinforcement

Pigeons key pecked for grain on a fixed-ratio 100 schedule; electric shocks occurred intermittently at the fifteenth or eighty-fifth response in the ratio. In Experiment I, shock was at the fifteenth response for two birds, and at the eighty-fifth response for two others, in every sixth, twelfth, or eighteenth ratio. Rate of responding decreased as frequency of shock increased, and the pattern of responding included an increased initial pause and low rates or pause-run sequences that extended further into the ratio when shock was at the fifteenth response than when it was at the eighty-fifth response. Shock early in the ratio engendered longer initial pauses than shock late in the ratio. In Experiment II, four birds responded on a two-component multiple schedule in which shock occurred at the fifteenth response of the third ratio in the presence of a white keylight and at the eighty-fifth response of the third ratio in the presence of a green keylight. The overall rates of responding decreased as shock intensity increased. All four birds responded differentially to the white and green keylights, but with a pattern that varied between birds. In general, punishment reduced the probability of responses that preceded it, regardless of the ordinal position of those responses. Both studies confirm that the probability of responding is reduced less by aversive stimuli produced late in a fixed-ratio than by aversive stimuli produced early in a fixed-ratio.     

Strict and random alternation in concurrent variable-interval schedules

Six pigeons responded on pairs of concurrent variable-interval schedules with, in different parts, four different arrangements of alternation between schedules. Following a single switching-key response, alternation was either strict or random, and the alternative presented after a switch (the postswitch alternative) was either signaled by the location of the switching key or unsignaled. Generalized-matching analyses showed little difference in behavior among the different alternation arrangements, except the usual finding of lower sensitivity of response allocation than time allocation was eliminated by arranging random alternation. Patterns of interchangeover times were similar for all arrangements except signaled random alternation. Differences in behavior preceding the different postswitch alternatives were found in the signaled random alternation procedure. Preference was biased towards the color of the signaled postswitch alternative and showed increased sensitivity when the postswitch alternative was to be the one with the higher reinforcer rate. Interchangeover times were substantially shorter when the postswitch alternative was signaled to be different from the current alternative than when it was signaled to be the same. However, when separate reinforcer ratios were calculated for the different postswitch alternatives, those effects were eliminated or greatly reduced. We suggest that, although behavior is indeed influenced by the postswitch alternative, the mechanism is indirect. That is, the distributions of reinforcers between alternatives obtained before each postswitch alternative differ when those alternatives are signaled, and those distributions are discriminated, but the same relations between choice and relative reinforcement hold irrespective of which postswitch alternative is signaled.     

Comparison of reinforcement and punishment functions produced by the same contingent event in the same subjects

The same event, forced running, was used to reinforce the lever-pressing of six rats in one component of a multiple schedule and to punish their drinking in another component. When the durations of running were converted to probabilities that Ss would not be running at t + n sec, given that the run gegan at t = 0 sec, both reinforcement and punishment were found to be linear (inverse) functions of the probability of not-running. A high concordance (0.90) between slopes of the reinforcement and punishment functions indicated that individual Ss were either sensitive to both reinforcement and punishment or sensitive to neither.     

Immediate and delayed punishment of human behavior by loss of reinforcement

Young adult humans pressed a key to obtain money. When responding was punished by presentation of a stimulus signifying that money was lost, response frequencies decreased and response latencies increased. Since these changes did not increase relative earnings, the aversive properties of loss of reinforcement were manifested independently or reinforcement gain. When loss punishment was delayed for either 10, 20, or 40 sec the extent of suppression was found to vary inversely with the response-punishment interval. Subsequent manipulations indicated that the effectiveness of delayed punishment was increased when the response also produced immediate conditioned punishment, i.e., a stimulus paired with the delayed loss stimulus. Instructions about the response-punishment contingency had similar effects. The findings were consistent with animal studies of delayed shock punishment, insofar as a similar delay-of-punishment gradient was observed, and with studies of delayed positive reinforcement, insofar as mediation through conditioned punishment (or instructions) increased the effectiveness of delayed punishment.     

Reinforcement and punishment effects in concurrent schedules: A test of two models

The joint effects of punishment and reinforcement on the pigeon's key-peck response were examined in three choice experiments conducted to compare predictions of Farley and Fantino's (1978) subtractive model with those made by Deluty's (1976) and Deluty and Church's (1978) model of punishment. In Experiment 1, the addition of equal punishment schedules to both alternatives of a concurrent reinforcement schedule enhanced the preference exhibited for the more frequent reinforcement alternative. Experiment 2 demonstrated decreases in the absolute response rate for each member of a concurrent reinforcement schedule when increasing frequencies of punishment were added to each alternative. Experiment 3 found that preference for the denser of two reinforcement schedules diminished when the absolute frequencies of reinforcement were increased by a constant factor and conditions of punishment for both alternatives were held constant. Diminished preferences were obtained regardless of whether the frequency of punishment associated with the denser reinforcement schedule was greater or less than that associated with the lean reinforcement alternative. The results from all three experiments uniquely supported Farley and Fantino's (1978) subtractive model of punishment and reinforcement.     

Effect of variable-interval punishment on the behavior of humans in variable-interval schedules of monetary reinforcement

One male and three female human subjects pressed a button for monetary reinforcement under a range of variable-interval schedules specifying different frequencies of reinforcement. On alternate days, responding was also punished (by subtraction of money) according to a variable-interval 170-second schedule. In the absence of punishment, the rate of responding was an increasing negatively accelerated function of reinforcement frequency, as predicted by Herrnstein's equation. The effect of the punishment schedule was to suppress responding under lower frequencies of reinforcement; responding under higher reinforcement frequencies was much less affected. This was reflected in an increase in the value of K_H (the constant expressing the reinforcement frequency corresponding to the half-maximal response rate), whereas there was no significant change in the value of R_max (the constant expressing the maximum response rate). Previous results had shown that variable-ratio punishment resulted in a change in the values of both constants (Bradshaw, Szabadi, and Bevan, 1977). The results of the present study were consistent with the concept that the suppressive effects of punishment on responding depend on the nature of the punishment schedule.     

Continuous punishment of free-operant avoidance in the rat

Three groups of albino rats were trained under a free-operant avoidance (Sidman) procedure with equal shock-shock and response-shock intervals. After stable performance was achieved, the animals were concurrently exposed to a brief electric shock after each response. The procedures were as follows: Punishment Schedule I: punishment shock was introduced at an intensity approximately one quarter that of avoidance shock; increments of nearly this same size were made as stable performance was achieved at succeeding punishment shock intensities. Punishment Schedule II: punishment shock was introduced at approximately one-half the intensity of avoidance shock; after stable performance, punishment shock was increased to the same intensity as avoidance shock. Punishment Schedule III: punishment shock was introduced and maintained at the same intensity as avoidance shock. Punishment was continued for all groups until one of two suppression criteria was attained. All animals made fewer responses and received more avoidance shocks as a function of increasing punishment shock. Half of the animals under Punishment Schedule I required punishment shock higher than avoidance shock to meet their assigned suppression criterion. A comparison of all procedures showed that suppression was greater when punishment shock was initially at high intensity.     

Schedule-induced defecation by rats during ratio and interval schedules of food reinforcement.

Lever pressing in rats was maintained by continuous and intermittent schedules of food while defecation was monitored. In Experiment 1, reinforcement densities were matched across variable-ratio and variable-interval schedules for three pairs of rats. Defecation occurred in all 3 rats on the variable-ratio schedule and in all 3 rats on the yoked variable-interval schedule. In Experiment 2, fixed-ratio and fixed-interval schedules with similar reinforcement densities maintained lever pressing. Defecation occurred in 3 of 4 rats on the fixed-ratio schedule and in 4 of 4 rats on the fixed-interval schedule. Almost no defecation occurred during continuous reinforcement in either experiment. These results demonstrate that defecation may occur during both ratio and interval schedules and that the inter-reinforcement interval is more important than the behavioral requirements of the schedule in generating schedule-induced defecation.     

Cooperative responding in rats maintained by fixed‐ and variable‐ratio schedules

The present study investigated the effects of fixed‐ratio (FR) and variable‐ratio (VR) reinforcement schedules on patterns of cooperative responding in pairs of rats. Experiment 1 arranged FR 1, FR 10, and VR 10 schedules to establish cooperative responding (water delivery depended on the joint responding of two rats). Cooperative response rates and proportions were higher under intermittent schedules than under continuous reinforcement. The FR 10 schedule generated a break‐and‐run pattern, whereas the VR 10 schedule generated a relatively high and constant rate pattern. Experiment 2 evaluated the effects of parametric manipulations of FR and VR schedules on cooperative responding. Rates and proportions of cooperative responding generally increased between ratio sizes of 1 and 5 but showed no consistent trend as the ratio increased from 5 to 10. Experiment 3 contrasted cooperative responding between an FR6 schedule and a yoked control schedule. Coordinated behavior occurred at a higher rate under the former schedule. The present study showed that external consequences and the schedules under which the delivery of these consequences are based, select patterns of coordinated behavior.     

Resistance to the response-decrementing effects of response-independent reinforcement produced by delay and non-delay schedules of reinforcement

In two experiments, animals were initially exposed to response-dependent schedules of food before exposure to response-independent reinforcement matched for overall rate and temporal distribution of reinforcers to the preceding condition. In Experiment I, response decrements during the response-independent phase were smaller after delayed reinforcement training than after a comparable immediate reinforcement schedule, for both doves and rats. In Experiment II variable-interval and variable-ratio schedules, both with either immediate or delayed reinforcement, were used with rats. Both the delayed reinforcement schedules produced resistance to subsequent response-independent reinforcement, but response decrements were larger after either of the immediate reinforcement conditions. It was concluded that the critical factor in response maintenance under response-independent reinforcement was the type of response-reinforcer contiguities permitted under the response-dependent schedule rather than perception of response-reinforcer “contingencies”. If the response-dependent schedule was arranged so that behaviours other than a designated operant (key pecking or lever pressing) could be contiguous with food, responding was maintained well under response-independent schedules.     

Response suppression produced by vestibular stimulation in the rat

Seven rats were trained to stable performance levels on either Fixed Ratio 47, Variable Ratio 47, Variable Interval 1-min, or Fixed Interval 1-min schedules of food reinforcement. Subjects were then tested for sensitivity to vestibular stimulation from rotation, using an ascending method of limits technique with increments in velocity of one revolution per minute every 5 min. Centrifugal forces were minimized by locating the test chamber over the axis of rotation. Response rates decreased in all subjects as a function of increasing rotation speed. In addition, characteristic differences in the patterns of response decrement were found between subjects on ratio and on interval schedules. Repeated tests indicated high intra-subject reliability in sensitivity to rotation. Similarities of these data to "motion sickness" phenomena in other species were noted. It is suggested that this behavioral approach provides a sensitive and quantifiable technique for assessing the effects of vestibular stimulation in animals.     

Suppression of behavior by timeout punishment when suppression results in loss of positive reinforcement

This investigation, using rats as subjects and punishment by timeout for responses maintained on a ratio schedule, sought to determine whether behavior would be suppressed by timeout punishment when such suppression also reduced reinforcement density or frequency. A series of experiments indicated that timeout punishment suppressed responding, with the degree of suppression increasing as a function of the duration of the timeout period. Suppressive effects were found to decrease as a function of increases in deprivation (body weight) and were eliminated when the punished response also was reinforced. It was concluded that timeout can produce aversive effects even when loss of reinforcement results. An alternative interpretation of the findings, based on the effects of extinction periods and delay of reinforcement on chained behavior, was discussed.     

Incentive shift in the rat following training to resist punishment

An incentive shift paradigm was used to test for the similarity of fear and frustration. In Experiment 1, rats trained to resist electric shock punishment showed neither a negative contrast effect nor any performance decrement when reward was shifted from 10 to one pellet. Experiment 2 replicated the basic findings of Experiment 1, but also showed that punishment training did not influence the magnitude of performance shift for animals receiving increases in reward magnitude. Finally, Experiment 3 additionally found that rats sensitized to punishment showed an increase in negative contrast effect. These results support the hypothesized functional similarity between conditioned fear and conditioned frustration with learned persistence or sensitivity to one generalizing to the other as suggested by Amsel's (1972) theory of persistence.