Fluctuations of answer and confidence rating in a general-knowledge problem task: Is confidence rating a result of direct memory-relevant output monitoring?

In order to examine whether confidence rating is a result of direct memory-relevant output monitoring, a general-knowledge test was used. A question set was answered in experimental session 1, and the same question set was employed in session 2. Subjects chose one answer from two alternatives. No significant difference in answer accuracy was found between sessions, which suggests that identical information processing was carried out, and that any difference between sessions was based on probabilistic fluctuation. The major results were as follows: (a) In both sessions, answer accuracy was an increasing function of confidence. (b) Answer-change rate (rate of different answers to the same question between sessions) decreased monotonically with confidence. (c) The distributions of confidence rating in session 2, conditional on the rating in session 1, were nearly identical in no-answer-change and answer-change cases. These results suggest that confidence rating is not a result of monitoring memory-relevant output itself but an estimation of possibility of answer fluctuation.     

The effects of reinforcement rate on the spontaneous social initiations of socially withdrawn preschoolers.

Social skills priming was used to increase the spontaneous social initiations of 2 socially withdrawn preschoolers, 1 of whom had been diagnosed with autism. During priming sessions, the teacher prompted and reinforced social behaviors (e.g., smiling, verbal initiations). We varied the rate of reinforcement during priming sessions and measured the effects of this manipulation on the rate of spontaneous social initiations during the subsequent classroom activity. Spontaneous initiations were more frequent after high rates of reinforcement than after low rates of reinforcement.     

Stimulus Equivalence: Effects Of A Default-response Option On Emergence Of Untrained Stimulus Relations

Human subjects were exposed to a concurrent-chains schedule in which reinforcer amounts, delays, or both were varied in the terminal links, and consummatory responses were required to receive points that were later exchangeable for money. Two independent variable-interval 30-s schedules were in effect during the initial links, and delay periods were defined by fixed-time schedules. In Experiment 1, subjects were exposed to three different pairs of reinforcer amounts and delays, and sensitivity to reinforcer amount and delay was determined based on the generalized matching law. The relative responding (choice) of most subjects was more sensitive to reinforcer amount than to reinforcer delay. In Experiment 2, subjects chose between immediate smaller reinforcers and delayed larger reinforcers in five conditions with and without timeout periods that followed a shorter delay, in which reinforcer amounts and delays were combined to make different predictions based on local reinforcement density (i.e., points per delay) or overall reinforcement density (i.e., points per total time). In most conditions, subjects' choices were qualitatively in accord with the predictions from the overall reinforcement density calculated by the ratio of reinforcer amount and total time. Therefore, the overall reinforcement density appears to influence the preference of humans in the present self-control choice situation.     

Response persistence under ratio and interval reinforcement schedules

In Experiment 1, rats were exposed to progressive-ratio schedules of food reinforcement while other rats were exposed simultaneously to yoked-interval schedules that arranged equivalent interreinforcer intervals but required only a single response at the end of the interval for food delivery. In Experiment 2, a within-subject yoked-control procedure was employed in which pigeons were exposed to alternating sessions (one per day) of progressive-ratio schedules and yoked-interval schedules as described above. In both experiments, responding under the yoked-interval schedule persisted beyond the point at which responding under the progressive-ratio schedule had ceased. The progressive-ratio schedules controlled break-and-run distributions, and the yoked-interval schedules controlled more even distributions of responses in time. Response rates decreased and postreinforcement pauses increased over time within individual sessions under both schedules. The results suggest that responding maintained by interval schedules is more persistent than that maintained by ratio schedules. The limitations and implications of this conclusion are discussed in the context of other investigations of response strength and behavioral momentum.     

Choice with delayed and probabilistic reinforcers: effects of prereinforcer and postreinforcer stimuli.

In Experiment 1, pigeons' pecks on a green key led to a 5-s delay with green houselights, and then food was delivered on 20% (or, in other conditions, 50%) of the trials. Pecks on a red key led to an adjusting delay with red houselights, and then food was delivered on every trial. The adjusting delay was used to estimate indifference points: delays at which the two alternatives were chosen about equally often. Varying the presence or absence of green houselights during the delays that preceded possible food deliveries had large effects on choice. In contrast, varying the presence of the green or red houselights in the intertrial intervals had no effects on choice. In Experiment 2, pecks on the green key led to delays of either 5 s or 30 s with green houselights, and then food was delivered on 20% of the trials. Varying the duration of the green houselights on nonreinforced trials had no effect on choice. The results suggest that the green houselights served as a conditioned reinforcer at some times but not at others, depending on whether or not there was a possibility that a primary reinforcer might be delivered. Given this interpretation of what constitutes a conditioned reinforcer, most of the results were consistent with the view that the strength of a conditioned reinforcer is inversely related to its duration.     

DO PARAKEETS EXHIBIT DERIVED STIMULUS CONTROL? SOME THOUGHTS ON EXPERIMENTAL CONTROL PROCEDURES

Breaking new ground in the study of emergent stimulus control in nonverbal subjects may require innovation in procedures. A recent study of parakeets is exemplary. This study used intricate procedures for maintaining test-trial performance without differential reinforcement of the target emergent performance. Also, it used successive simple discrimination procedures, which are rare in such studies. Given the importance of these innovations and the outcomes that they produced, we suggest additional control procedures that would rule out the possibility of adventitious reinforcement of the test-trial performances.     

THE USE OF PROMPTS TO ENHANCE VICARIOUS EFFECTS OF NONVERBAL APPROVAL

The effect of nonverbal teacher approval (physical contact in the form of patting approvingly) delivered to target subjects on the attentive behavior of adjacent peers was examined in a special-education classroom. In a reversal design, two pairs of moderately retarded children were exposed to nonverbal approval, with only one subject in each pair receiving approval. In different phases, nonverbal approval was delivered alone or in conjunction with a verbal prompt directed to the adjacent peer or to the class as a whole. The prompt was designed to make salient the target subject's attentive behavior and the nonverbal reinforcing consequences that followed. Providing contingent nonverbal approval alone consistently altered attentive behavior of the target subjects but did not alter the attentive behavior of adjacent peers. However, accompanying nonverbal approval with a verbal prompt did increase attentive behavior of nonreinforced peers.     

DOES USE OF TANGIBLE REWARDS WITH INDIVIDUAL CHILDREN AFFECT PEER OBSERVERS?1

The common assumption that employing tangible rewards with individual children will have adverse effects upon peer observers was studied in the preschool setting. Multiple-subject, multiple-baseline procedures were applied to two classes of children, aged 3.5 to 6 yr. In each group, three consecutive children with low base rates of in-seat behavior received a verbal contingency and food rewards for sitting, while peers (with either low or high rates of in-seat behavior) received neither food nor teacher attention for sitting. Peer reactions measured were in-seat behavior, aggression, nonaggressive disruptive behavior, and complaints. The procedures neither decreased the in-seat behavior of peer observers, nor increased their aggressive or disruptive behavior. On the contrary, peers with low base rates of sitting initially displayed an abrupt, but temporary, increase in sitting. Moreover, although no compensatory attention was delivered, all children exhibited improved sitting by the end of the study. Complaints, which consisted mainly of requests for rewards, decreased in frequency with successive program phases, and within each phase. It is suggested that the class improvement in sitting behavior and the absence of negative effects on observers may be partially due to the high frequency of attention the teacher maintained for other desired behavior and the lack of attention to children's complaints.     

DIFFERENTIAL REINFORCEMENT OF OTHER BEHAVIOR AND NONCONTINGENT REINFORCEMENT AS CONTROL PROCEDURES DURING THE MODIFICATION OF A PRESCHOOLER'S COMPLIANCE1

Differential reinforcement of other behavior (DRO) and noncontingent reinforcement were compared as control procedures during the modification of a 3-yr-old preschooler's compliance. The recorded reinforcer was teacher proximity (within 3 ft (0.9 m) of the subject for at least 5 sec) which was often accompanied by positive verbal comments that varied in content across experimental conditions. The verbal content during contingent reinforcement might have been: “Thank you for picking up the blocks”; during noncontingent reinforcement: “You're wearing a pretty dress”; and during DRO: “I don't blame you for not picking up because it isn't any fun”. Contingent reinforcement increased compliance in all manipulation conditions. Noncontingent reinforcement decreased compliance during two reversal conditions. However, the behavior was variable and did not decrease to the low levels reached during the two DRO reversals.     

MODIFICATION OF HUMAN GASTRIC ACID SECRETION WITH OPERANT-CONDITIONING PROCEDURES1

In an attempt to control gastric acid secretion with operant-conditioning techniques, four normal women were given visual feedback on gastric pH plus money reinforcers. When money was made dependent on increased secretion in a differential-reinforcement-of-high-rates schedule, the rate of secretion of three of the four subjects increased to three times baseline. When money was then made dependent on decreased secretion in a differential-reinforcement-of-other-behaviors schedule, the rate of secretion of these three subjects returned to baseline levels. Heart rate, respiratory frequency, abdominal electromyographic activity, and stomach motility (measured by the electrogastrogram method) were not consistently correlated with acid secretion across subjects, although individual subjects showed substantial correlations between acid secretion and one or more other physiological response.