Persistence early and late in extinction as a function of number of continuous reinforcements preceding partial reinforcement training

In two experiments rats were given straight-alley training in the following sequence: continuous reward (CR), partial reward (PR), extinction (EXT). Independent groups differed only in the amount of CR training. In both experiments,. early-EXT performance was directly related to amount of CR training and late-EXT performance was inversely related to amount of CR training. These data were related to a possible specific s_F intensity hypothesis, an extension of frustration theory.     

Reward sequence and reinforcement level as determinants of S− behavior in differential conditioning

In two differential conditioning experiments, groups of 10 rats each differed with respect to average reward and schedule of reward received in S+. Nonreward (N) occurred on all S? trials. In both experiments, extinction of responding to S? (resistance to discrimination) was extensively regulated by reward sequence and was largely independent of average reward. In Experiment 1, resistance to discrimination was a function of transitions from N to rewarded (R) trials (N-R transitions). In Experiment 2, resistance to discrimination was increased by large reward on the R trial of N-R transitions and decreased by large reward on the R trial of R-N transitions. These schedule effects on resistance to discrimination parallel the effects of comparable schedules on resistance to extinction following partial reinforcement. The results are discussed in terms of sequential theory, reinforcement level theory, and their implications for various schedule manipulations that have previously shown S? behavior to be inversely related to average reward in S+.     

Operant variability when reinforcement is delayed

Operant responses are often weakened when delays are imposed between the responses and reinforcers. We examined what happens when delayed reinforcers were contingent upon operant responsevariability. Three groups of rats were rewarded for varying their response sequences, with one group rewarded for high variability, another for middle, and the third for low levels. Consistent with many reports in the literature, responding slowed significantly in all groups as delays were lengthened. Consistent with other reports, large differences in variability were maintained across the three groups despite the delays. Reinforced variability appears to be relatively immune to disruption by such things as delays, response slowing, prefeeding, and noncontingent reinforcement. Furthermore, the small effects on variability depended on baseline levels: As delays lengthened, variability increased in the low group, was statistically unchanged in the middle group, and decreased in the high group, an interaction similar to that reported previously when reinforcement frequencies were lowered. Thus, variable operant responding is controlled by reinforcement contingencies, but sometimes differently than more commonly studied repetitive responding.     

The role of stimulus disparity in concurrently available reinforcement schedules

Eight White King pigeons were exposed to various two-component arrangements of concurrently available variable-interval reinforcement schedules. Line orientation stimuli associated with each component differed by 45,15, or 0 deg for different subjects. Relative responding matched relative reinforcement with 45 deg separation, while undermatching resulted with 15 deg separation and extreme undermatching resulted with 0 deg separation. Since obtained relative reinforcement indicated contact with the contingencies in all conditions of line orientation disparity, it is concluded that stimulus disparity between components of concurrently available reinforcement schedules is an important determinant of response distribution between components.     

Partial reinforcement in autoshaping with pigeons

The acquisition, maintenance, and extinction of autoshaped responding in pigeons were studied under partial and continuous reinforcement. Five values of probability of reinforcement, ranging from .1 to 1.0, were combined factorially with five values of intertrial interval ranging from 15 to 250 sec for different groups. The number of trials required before autoshaped responding emerged varied inversely with the duration of the intertriai interval and probability of reinforcment, but partial reinforcement did not increase the number of reinforcers before acquisition. During maintained training, partial reinforcement increased the overall rate of responding. A temporal gradient of accelerated responding over the trial duration emerged during maintenance training for partial reinforcement groups, and was evident for all groups in extinction. Partial reinforcement groups responded more than continuous reinforcement groups over an equivalent number of trials in extinction. However, this partial-reinforcment extinction effect disappeared when examined in terms of the omission of “expected” reinforcers.     

The role of response-reinforcer correlation in signaled reinforcement effects

In three experiments, we examined the effects of signaling reinforcement during operant responding in order to illuminate the factors underlying instrumental overshadowing and potentiation effects. Specifically, we examined whether signaling reinforcement produces an enhancement and attentuation of responding when the response-reinforcer correlation is weak and strong, respectively. In Experiment 1, rats responded on variable-ratio (VR) or variable-interval (VI) schedules that were equated for the number of responses emitted per reinforcer. A signal correlated with reinforcement enhanced response rates on the VR schedule, but attenuated response rates were produced by the signal on the VI schedule. In Experiment 2, two groups of rats responded on a VI schedule while the two other groups received a conjoint VI, negative fixed-ratio schedule in which the subjects lost the availability of reinforcements if they emitted high response rates. A reinforcement signal attenuated responding for the simple VI groups but not for the animals given the negative fixed-ratio component, although the signal improved response efficiency in both groups. In Experiment 3, a poor correlation between responding and reinforcement was produced by a VI schedule onto which the delivery of response-independent food was superimposed. A signal for reinforcement initially elevated responding on this schedule, relative to an unsignaled condition; however, this pattern was reversed with further training. In sum, the present experiments provide little support for the view that signaling reinforcement enhances responding when the response-reinforcer correlation is weak and attenuates responding when this correlation is strong.     

Pre-service teachers' ethical stances on unethical professional behaviors: The roles of professional identity goals and efficacy beliefs

By considering the mediating roles of efficacy beliefs, this study examined whether pre-service teachers' ethical stances on student-related unethical teacher behaviors significantly differed according to the levels of their professional commitment when they received bogus negative feedback for their teaching competencies. Pre-service teachers (n = 128) were assigned to either experimental groups (i.e., high commitment-negative feedback/low commitment-negative feedback) or control groups (i.e., high commitment-no feedback/low commitment-no feedback). The results revealed that pre-service teachers' ethical stances on unethical teacher behaviors significantly differed according to their professional commitment. Notably, this result was significantly explained by the mediating roles of efficacy beliefs.     

Use of context in the word recognition process by adults with a significant history of reading difficulties

We examined whether university students who report a significant history of reading difficulties (RD; n = 24) differed from university students with no history of reading difficulties (NRD; n = 31) in how sentence context affects word recognition. Experiment 1 found no differences in how congruent sentence primes or syntactic manipulations of the sentence primes affected the performance of the two groups. However, only the RD group displayed a significant inhibition effect when the target word was preceded by an incongruent sentence prime. Experiment 2 found that the groups differed in how meaning frequency of the target word and context strength of the sentence prime affected word recognition latencies. The results suggest that the RD participants’ performance is context-sensitive and better explained by interactive models of language processing than by modular models.     

Sexual abuse in young children: its clinical presentation and characteristic patterns

A retrospective record survey was performed using all child clients aged less than 7 years seen at a community mental health center during the period 1982-1984. The total number of 202 children fell into three groups: sexually abused (n = 37), physically abused (n = 35), and nonabused clinical children (n = 130). These groups were compared in order to learn more about sexual abuse in young children. Family background of both abused groups were similar to each other but differed from the nonabused group in having more factors related to family stress than the nonabused group. Clinical presentations of all the children overlapped a great deal symptomatically; however, the sexually abused children had a statistically significant higher frequency of inappropriate sexual behavior than the other two groups. Several characteristics of the abusive patterns suffered by the two abuse groups differed at or near statistical significance: sexually abused children were more often victimized in single acts by nonrelated child perpetrators than were physically abused children.     

Durability of the partial reinforcement and partial delay of reinforcement extinction effects after minimal acquisition training

Four groups of 10 rats each were given six acquisition trials (Phase 1) under continuous reinforcement (CR), partial reinforcement (PR), constant delay (CD), or partial delay of reinforcement (PD) conditions. In Phase 2, all Ss were given 18 nonreinforced trials, followed by 12 continuously reinforced trials in Phase 3. In Phase 4, all Ss were given 12 more extinction trials. A constant 24-h ITI was observed throughout the experiment. A strong partial reinforcement extinction effect (PREE) was obtained in both Phases 2 and 4. Only a temporary partial delay of reinforcement effect (PDRE) was observed, which was restricted to the first nine trials of the first extinction phase. No constant delay of reinforcement effect (CDRE) was observed in either extinction phase. The results were discussed in terms of both frustration and sequential theories.     

The effects of token reinforcement versus cognitive behavior modification on learning-disabled students' math skills

The effects of token reinforcement, cognitive behavior modification, and direct instruction on learning-disabled students' math skills were compared. Math skills were measured by 2-minute classroom timings of basic addition and subtraction problems, and the Stanford Diagnostic Mathematics Test. Treatment was provided to 94 students for 4 weeks in daily 1-hour sessions. Significant differential gain between treatment and direct instruction groups in achievement test scores was found, F(4, 182) = 4.03, p<.01. Token reinforcement and cognitive behavior modification were found to be equally effective. All three groups improved with 2-minute classroom timings, F(2, 91) = 8.53,p<.001. Retention of skills for both treatments was maintained over a 2-week no-treatment period. Teachers' social validity ratings indicated differences between the two treatments relative to student behaviors and teacher roles. It is concluded that token reinforcement and cognitive behavior modification are equally effective techniques to remediate learning-disabled students' math achievement, and both are superior to direct instruction in some cases.     

Deaf college students' attitudes toward racial/ethnic diversity, campus climate, and role models

Deaf college students' attitudes toward a variety of issues related to racial/ethnic diversity were surveyed by contacting all racial/ethnic minority deaf students and a random sample of Caucasian deaf students attending the National Technical Institute for the Deaf (NTID), Rochester Institute of Technology; 38% completed the survey. Although racial/ethnic groups similarly perceived NTID's commitment and efforts related to diversity, they differed significantly on some items related to campus climate and role models. Furthermore, the racial/ethnic minority groups differed from each other in their perceptions of campus comfort level, racial conflict, friendship patterns, and availability of role models. Educational satisfaction was positively correlated with campus comfort level; both correlated negatively with perception of discrimination and racial conflict. Qualitative data analyses supported quantitative data analyses and provided rich detail that facilitated interpretation of deaf students' experiences related to racial/ethnic diversity.     

Optimizing quality of dental carving by preclinical dental students through anatomy theory reinforcement

Knowledge of dental anatomy is of great importance in the practice of dentistry, especially in oral rehabilitation, because without this knowledge, professional practice is not possible. Dental carving plays a major role in training dental students as it develops their manual dexterity. This randomized controlled trial aimed to evaluate the influence of didactic‐theoretical reinforcement on the theoretical and practical knowledge of dental anatomy of preclinical students by examining the quality of the anatomical restorations performed by these students before and after a didactic‐theoretical reinforcement. For the evaluation of theoretical knowledge, a questionnaire with closed questions about dental anatomy was used. To evaluate the effect of didactic reinforcement on dental carvings, two groups of 15 preclinical students were assessed. Experimental group (G1) received a three‐hour theoretical tutoring on dental anatomy, while the control group (G2) did not. The dental carving scores obtained by the two different groups were compared using Student's t‐test. Cohen's d was used to estimate the effect sizes between groups. The frequency of correct answers given for each theoretical knowledge question was compared in each group using Fisher's exact test. T‐test was also used to compare the means of the two groups' final scores of theoretical evaluations. To compare these final scores obtained in both carving and theoretical tests, a principal component analysis was performed with different items assessed in each test to obtain factor loading scores and a final weighted score, where factor loadings were considered for each item. Weighted scores were compared using t‐test. Also, scores obtained during the head and neck course were assessed and compared using t‐test. Spearman's correlation test was used to assess the correlation between scores obtained prior to the anatomy course and scores obtained in the dental carving exercise. The theoretical evaluation revealed no significant difference between the grades (mean ± SD) of G1 (85.1 ± 6.6%) and G2 (86.2 ± 9.1%) with the grades of a baseline test that was previously obtained when students submitted to the study (P = 0.725). Regarding the tooth carving assessment, the dental carving quality by students of G1 has significantly improved, except for tooth #23 (P = 0.096). Theoretical reinforcement of dental anatomy seems to improve the students' carving performance but does not enhance their knowledge about dental anatomy. Anat Sci Educ 11: 377–384. © 2017 American Association of Anatomists.     

Temporal integration and instrumental conditioned reinforcement

Stimuli associated with primary reinforcement for instrumental behavior are widely believed to acquire the capacity to function as conditioned reinforcers via Pavlovian conditioning. Some Pavlovian conditioning studies suggest that animals learn the important temporal relations between stimuli and integrate such temporal information over separate experiences to form a temporal map. The present experiment examined whether Pavlovian conditioning can establish a positive instrumental conditioned reinforcer through such temporal integration. Two groups of rats received either delay or trace appetitive conditioning in which a neutral stimulus predicted response-independent food deliveries (CS1→US). Both groups then experienced one session of backward second-order conditioning of the training CS1 and a novel CS2 (CS1–CS2 pairing). Finally, the ability of CS2 to function as a conditioned reinforcer for a new instrumental response (leverpressing) was assessed. Consistent with the previous demonstrations of temporal integration in fear conditioning, a CS2 previously trained in a trace-conditioning protocol served as a better instrumental conditioned reinforcer after backward second-order conditioning than did a CS2 previously trained in a delay protocol. These results suggest that an instrumental conditioned reinforcer can be established via temporal integration and raise challenges for existing quantitative accounts of instrumental conditioned reinforcement.     

Response sequence learning as a function of primary versus conditioned reinforcement

Two groups of pigeons were required to generate a fixed sequence of responses on three keys, for example, middle-left-right. One group received a small food reward (S^Food) following each correct response except the terminal one, which was followed by a large food reward. The second group received conditioned reinforcement from an overhead light (S^Light) for each correct response, with the terminal correct response followed by both S^Light and the large food reward. We manipulated length of sequence (3 or 7 responses) and duration of required interresponse interval (IRI; 1 to 9 sec). S^Light contingencies generated more accurate performances than did S^Food when sequence length was 3 responses but not when it was 7 responses. IRI duration influenced accuracy under the S^Light contingencies but not under S^Food. These results show that conditioned reinforcers sometimes generate more accurate sequence learning than do primary reinforcers, and that schedule contigencies influence which type of feedback will optimize performance. The results parallel those from the matching-to-sample and conditional discrimination literature.     

The effect of rate of reinforcement and time in session on preference for variability

Pigeons pecked keys on concurrent-chains schedules that provided a variable interval 30-sec schedule in the initial link. One terminal link provided reinforcers in a fixed manner; the other provided reinforcers in a variable manner with the same arithmetic mean as the fixed alternative. In Experiment 1, the terminal links provided fixed and variable interval schedules. In Experiment 2, the terminal links provided reinforcers after a fixed or a variable delay following the response that produced them. In Experiment 3, the terminal links provided reinforcers that were fixed or variable in size. Rate of reinforcement was varied by changing the scheduled interreinforcer interval in the terminal link from 5 to 225 sec. The subjects usually preferred the variable option in Experiments 1 and 2 but differed in preference in Experiment 3. The preference for variability was usually stronger for lower (longer terminal links) than for higher (shorter terminal links) rates of reinforcement. Preference did not change systematically with time in the session. Some aspects of these results are inconsistent with explanations for the preference for variability in terms of scaling factors, scalar expectancy theory, risk-sensitive models of optimal foraging theory, and habituation to the reinforcer. Initial-link response rates also changed within sessions when the schedules provided high, but not low, rates of reinforcement. Within-session changes in responding were similar for the two initial links. These similarities imply that habituation to the reinforcer is represented differently in theories of choice than are other variables related to reinforcement.     

Family Risk and Externalizing Problems in Chilean Children: Mediation by Harsh Parenting and Emotional Support

Latent class analysis and multigroup mediation were used with 8,860 families in Chile to identify risk groups varying in socioeconomic status, family structure, and maternal depression, to determine whether profiles differed in children’s development of externalizing problems (EP) from 35 to 61 months, and maternal parenting that predicted EP. Four groups were identified: one no-risk profile and three risk profiles, impoverished and undereducated, depressed and impoverished, and father-absent and impoverished. All classes differed in EP. Maternal emotional support and harsh parenting were differentially associated with the development of EP across the three risk groups, relative to the low-risk group. Thus, specific constellations of adversities differentially predicted children’s EP and socialization processes mediating links between risk and EP. Implications are discussed.     

A closed-loop algorithm to detect human face using color and reinforcement learning

A closed-loop algorithm to detect human face using color information and reinforcement learning is presented in this paper. By using a skin-color selector, the regions with color “like” that of human skin are selected as candidates for human face. In the next stage, the candidates are matched with a face model and given an evaluation of the match degree by the matching module. And if the evaluation of the match result is too low, a reinforcement learning stage will start to search the best parameters of the skin-color selector. It has been tested using many photos of various ethnic groups under various lighting conditions, such as different light source, high light and shadow. And the experiment result proved that this algorithm is robust to the varying lighting conditions and personal conditions. Project supported by the National Natural Science Foundation of China (No. 60105003) and Zhejiang Provincial Natural Science Foundation of China (No. 600025).     

Influence of schizotypy on responding and contingency awareness on free-operant schedules of reinforcement

Schedules of reinforcement typically produce reliable patterns of behaviour, and one factor that can cause deviations from these normally reliable patterns is schizotypy. Low scorers on the unusual experiences subscale of the Oxford-Liverpool Inventory of Feelings and Experiences performed as expected on a yoked random-ratio (RR), random-interval (RI) schedule of reinforcement, with significantly higher rates of responding on the RR schedule than in the RI schedule. However, high scorers in UE showed no such differences between response rates between the RR and RI schedules. In addition, contingency awareness scores were high, and did not differ in low UE scorers for both types of schedule, whilst awareness scores differed significantly between the schedules in high UE scorers, with more awareness of the RR schedule than the RI one. These results suggest that, as well as being unable to differentiate between the RR and RI schedules in terms of response rates, high UE scorers are also unable to verbally describe the RI schedule parameters.     

Tests of two explanations of response elimination by noncontingent reinforcement

Two experiments are reported on the elimination of autoshaped keypecking in pigeons by introducing added feedings that have the effect of removing the contingency between keylight (CS) and feedings. In Experiment 1, added feedings were signaled, by an already conditioned stimulus, in one group but not in another. Contrary to the Rescorla-Wagner theory, but consistent with scalar expectancy theory, responding in these groups declined at equal rates. In Experiment 2, following acquisition, some groups were exposed to repeated sessions in which they received feedings alone prior to receiving both CS and feedings noncontingently. Although prior exposure to feedings did reduce the total amount of responding in subsequent noncontingent sessions, it did not, contrary to scalar expectancy theory, reduce the initial level of responding to the CS. It is suggested that a differential between reinforcing conditions in the CS as compared with neighboring non-CS periods is more fundamental to conditioning than is acknowledged in the Rescorla-Wagner theory or in scalar expectancy theory.