Reinforcement Patterns Research Articles

Surface of the shoot apex: a reinforcement-field theory for phyllotaxis.

Theory for leaf patterning, phyllotaxis, is usually expressed in terms of interactions in the surface of the apical dome of the shoot. Mechanisms for leaf formation, however, usually relate to phenomena in the longitudinal section, e.g. periclinal divisions. Studying epidermal cell file patterns and the directionality of cellulose in the outer walls of the dome we have found distinct patterns of cells and reinforcing cellulose on the surface. Changes in the epidermal pattern correlate with the phyllotactic sequence to suggest that: Recently established leaves are associated with fields of tangential cellulose reinforcement which extend toward the apical dome. Where such aligned fields come into contact so as to generate relatively abrupt angular changes in reinforcement pattern, a new leaf will appear. As this region of discontinuity develops into a hoop-reinforced structure, the visible primordium, a new single field of tangentially aligned reinforcement is generated. The new field interacts with other fields to continue the cycle. In whorled phyllotaxis two angular discontinuities appear to be involved with each new leaf; the pertinent older leaves are just one plastochron older than the leaf being initiated. In spiral phyllotaxis (3:2) a single angular discontinuity appears to be involved initially; the pertinent older leaves are three and five plastochrons older than the leaf being formed. There are two major differences from previous theories of phyllotaxis. First, the cyclic changes in leaf initiation are thought to be based on the constructive involvement of new leaves in modifying the dome's reinforcement pattern. Many theories assume that leaf formation is spontaneous and the role of nearby leaves is inhibitory. Second, the pattern sequence can explain the concurrent appearance of reinforced stem tissue along with leaves.

Reinforcement pattern learning: Do rats remember all prior events?

Three experiments in a runway investigated how rats remember events occurring in temporal order. In Experiment 1, the reinforced trial was always the last (fifth) trial of the day for Group 4NR, the first trial for Group R4N, and the third trial for Group 2NR2N. For Group NIrg, one of Trials 2–5 was randomly reinforced. The running speeds for Group 2NR2N, an inverted V with its peak on Trial 3, were of special interest. An inverted V was also obtained for Group S-ITI (Experiment 2), which received the 2NR3N schedule at a 30-sec ITI, and for Group L-ITI (Experiment 3), which had a 30-min ITI. However, slow running on Trial 4 and not slow running on Trial 6 were demonstrated for Groups L-INT (Experiment 2) and S-INT (Experiment 3), which received the same schedule as Groups S-ITI and L-ITI, except for a long or short interval inserted between Trials 3 and 4. These results suggest that rats remember all prior events occurring at an equal ITI whether the ITI is short or long, whereas they reset their memory when a longer or shorter interval elapses after the reinforced trial.

Tension tests of concrete containment wall elements

Tension tests of concrete containment wall elements were conducted as part of a three-phase research program sponsored by the Electric Power Research Institute (EPRI). The objective of the EPRI experimental/analytical program is twofold. The first objective is to provide the utility industry with a test-verified analytical method for making realistic estimates of actual capacities of reinforced and prestressed concrete containments under internal over-pressurization from postulated degraded core accidents. The second objective is to determine qualitative and quantitative leak rate characteristics of typical containment cross-sections with and without penetrations. This paper covers the experimental portion the the EPRI program. The testing program for Phase 1 included eight large-scale specimens representing elements from the wall of a containment. Each specimen was 60-in (1525-mm) square, 24-in (610-mm) thick, and had full-size reinforcing bars. Six specimens were representative of prototypical reinforced concrete containment designs. The remaining two specimens represented prototypical prestressed containment designs. Various reinforcement configurations and loading arrangements resulted in data that permit comparisons of the effects of controlled variables on cracking and subsequent concrete/reinforcement/liner interaction in containment elements. Subtle differences, due to variations in reinforcement patterns and load applications among the eight specimens, are being used to benchmark the codes being developed in the analytical portion of the EPRI program. Phases 2 and 3 of the test program will examine leak rate characteristics and failure mechanisms at penetrations and structural discontinuities.

Classroom-Based Intervention for Students Exhibiting Depressive Reactions

Social learning constructs which provide discrete yet complimentary views of the etiology of reactive depression have been advanced in the psychological literature. These viewpoints which include learned helplessness, social skill deficits, and coercive reinforcement patterns offer major implications for classroom practice. This article reviews the literature pertaining to learning theory explanations of reactive depression. Implications for classroom management and future research are provided.

Theory underlying determination of stressed state in composite media with aid of electromagnetic waves in millimeter range

1. The constructed physical model rather adequately explains the earlier established relation [1] between changes in the components of the strain tensor and those in the components of the permittivity tensor. 2. Composite materials with different reinforcement patterns behave differently during deformation in a radio microwave field and, therefore, for determining their stressed state one must take into account the initial dielectric anisotropy in the undeformed specimen.

Load Capacity of Concrete Bridge Decks

The behavior of two reduced-scale concrete bridge decks subjected to simulated wheel loads was evaluated in a series of tests. One slab was reinforced in accordance with AASHTO requirements; the other had three areas with varying amounts of isotropic reinforcement. Results show that with either reinforcement pattern, service load bending moments are from 40 to 65 percent of those predicted by flexural theory. Failures were by punching shear rather than flexure and occurred at loads at least six times larger than design.

Toward a biophysical theory of organogenesis: Birefringence observations on regenerating leaves in the succulent, Graptopetalum paraguayense E. Walther

Polarity shifts occur during organogenesis. The histological criterion for polarity is the direction of cell division. The biophysical criterion is the orientation of reinforcing cellulose microfibrils which lie normal to the organ axis and which determine the preferred growth direction. Using cell pattern to deduce cell lineage, and polarized light to study cellulose alignment, both aspects of polarity were examined in the epidermis of regenerating G. paraguayense. In this system new leaves and a stem arise from parallel cell files on a mature leaf. Large (90°) shifts in polarity occur in regions of the epidermis to give the new organs radial symmetry in the surface plane (files radiating from a pole). Study of the shifts in the epidermis showed that, during certain stages, shifts in the division direction are accompanied by shifts in the cellulose deposition direction, as expected. The new cellulose orientation is parallel to the new cross wall. During normal organ extension, however, shifts in division direction do not bring on changes in cellulose pattern. Thus the coupling between the two kinds of polarity is facultative. This variable relation is used in a biophysical model which can account for the reorganization of cell file pattern and cellulose reinforcement pattern into the radial symmetry of the new organ.

The temporal structure of motivation II: determinants of reinforcement patterns in the local organization of intracranial reward

When rats and other animals are permitted chronic and continuous access to intracranial reinforcement (intracranial self-stimulation (ICS)) they typically display episodic response patterns (bursts). The motivational determinants of response bursts are not known; however, previous studies have pointed to the importance of priming effects in ICS. To further investigate the role of priming in ICS bursts adult male Sprague-Dawley rats were allowed chronic (minimally 2-week) access to ICS, with bursts collected for a subsequent 10-day period. Analysis of burst patterns indicated (a) relatively higher initial response rates were associated with longer bursts, (b) rates of response generally increased within individual response bursts, and (c) higher initial rates were associated with bursts that persisted in contrast to those which did not. In addition, a tonic reinforcement effect was found in the analysis of overnight records. Several burst parameters were increased in the final vs the initial 2 hr of responding. The first three findings support a role for priming as one determinant of burst patterns. The final effect may point to a second mechanism involved in incentive seeking.

The Development of Social Exchange Under Incompatible Social Contingencies

Matrix-gaming experiments on cooperation have typically structured some conflict between persons' outcomes whereas most reinforcement studies of cooperation have not. In two laboratory experiments, reinforcement principles were applied to the question of how cooperative social exchange can be established when persons' outcomes are negatively correlated and social exchange must consist of alternating behaviors and rewards. Two variables are manipulated in the first experiment: the presence or absence of direct reinforcement for alternating, and the presence or absence of information of the other person's reinforcement. Both variables effectively established social exchange but even in their absence, half of the dyads still learned to exchange by performing response patterns that provided contingency information to the other person. These results may hold only for very simple operants, however. When a two-response sequence was required for reinforcement in the second experiment, neither information of the other person's reinforcement nor particular response patterns provided sufficient cues for the dyads to learn to exchange.

Inadvertent Reinforcement in Oral Myofunctional Therapy

The possibility of inadvertent reinforcement of undesirable behaviors during oral myofunctional therapy is examined. It is suggested that inappropriate use of therapist attention is often responsible for such reinforcement and it is concluded that: I) attention may function as a positive reinforcer for any behavior upon which it is contingent, 2) attention may serve as a reinforcer regardless of the intent of therapists' verbal statements which accompany it, and 3) therapist attention affects group behavior and patterns of peer reinforcement.

DECISION RULES AND SIGNAL DETECT ABILITY IN A REINFORCEMENT‐DENSITY DISCRIMINATION

Two probabilistic schedules of reinforcement, one richer in reinforcement, the other leaner, were overlapping stimuli to be discriminated in a choice situation. One of two schedules was in effect for 12 seconds. Then, during a 6-second choice period, the first left-key peck was reinforced if the richer schedule had been in effect, and the first right-key peck was reinforced if the leaner schedule had been in effect. The two schedule stimuli may be viewed as two binomial distributions of the number of reinforcement opportunities. Each schedule yielded different frequencies of 16 substimuli. Each substimulus had a particular type of outcome pattern for the 12 seconds during which a schedule was in effect, and consisted of four consecutive light-cued 3-second T-cycles, each having 0 or 1 reinforced center-key pecks. Substimuli therefore contained 0 to 4 reinforcers. On any 3-second cycle, the first center-key peck darkened that key and was reinforced with probability .75 or .25 in the richer or leaner schedules, respectively. In terms of the theory of signal detection, detectability neared the maximum possible d' for all four pigeons. Left-key peck probability increased when number of reinforcers in a substimulus increased, when these occurred closer to choice, or when pellets were larger for correct left-key pecks than for correct right-key pecks. Averaged over different temporal patterns of reinforcement in a substimulus, substimuli with the same number of reinforcers produced choice probabilities that matched relative expected payoff rather than maximized one alternative.

An Analysis of the Reinforcing Function of Clinician Attention

This paper examines the reinforcing effects of attention in speech-language remediation. It concludes that: 1) attention may be a strong positive reinforcer for any behavior upon which it is contingent, 2) attention may serve as a reinforcer regardless of the intent of clinicians' verbal statements which accompany it, and 3) clinician attention affects group behavior and patterns of peer reinforcement.

The Effects of Distribution Pattern of Partial Reinforcement on Resistance to Extinction

Summary Three groups of rats (Total N = 21) were trained and extinguished in a straight alley to investigate the effects of a shift of reinforcement percentage upon resistance to extinction. Two partial groups were there which received gradually increased (gI) or gradually decreased (gD) ratios of reinforcement (55% schedule) in the course of training. A third group was a continuous control group. The three groups attained asymptotic performance at the last day of acquisition, and the partial reinforcement effect (PRE) was obtained. The gI was more resistant than the gD. These results were discussed in terms of the reinforcement level view derived from the sequential theory of the PRE.

モデルの遂行水準, 代理自己強化, 代理外的強化が観察者の遂行と自己評価様式に及ぼす効果

The present experiment was designed,(1) to clarify the functional characteristics of vicarious self reinforcement comparing with the function of vicarious external reinforcement, and (2) to estimate the relative effect of modeled performance level and modeled vicarious reinforcement patterns to the performances and self evaluative pattern of observers.The subject were 86 boys and 72 girls, ranging in age from 10 years 5 months to 11 and half years, drown from 5 classes in 5th grade in a public primary school. Model was a 19 years old female undergraduate, and experimenter was a 23-year old male graduate.So as to equalize the task abilities in each experimental and each control groups, the figurenumber substitution task was first administered to all subjects in classroom settings. Then, model and/or each subject was administered three trials of simple arithmetic calculation based upon figurenumber substitution (e. g. _??_) in a booklet. 18 calculation problems were printed, for each trials, Model and subject were given 50 sec. to resolve the problems and 30 sec. inter-trial intervals to rest and to evaluate one's performance. The self evaluation of each subject was measured on the 3 point-graphic scale (not enough, nough, highly enough) after each trial.A 2×2×2×2 factorial design was employed. Half of the experimental children observed high performance model, and half were exposed to low performance model. In both conditions, half the children observed vicarious reward. While the remaining children in each group witnessed vicarious punishments. In addition, each group was further divided into external (reinforcement was administered by experimenter) or internal (model's self reinforcement) control condition.In high performance condition, model performed 10 problems, and in low performance condition, model performed 6 or 7 problems in each trial. These scores were determined based upon the performance level of no-model control group (Mean=8.25, SD=1.87) of 39 subjects.In reward condition, model or experimenter evaluated model's performance as highly enough, and in punishment condition, they devaluated model's performance as not enough.The main results were p resented in FIG. 1. 2. 3. Analysis of variance performed on over-all self evaluation scores disclosed that highly significant effects were produced by the vicarious reward punishment (F=52.85, P<0.001), and not produced by the other variables. So, vicarious self reinforcement and vicarious external reinforcement were found to be equally efficacious in the modification of self evaluative behavior of observers.Children who obsarved model's self punishment raised significantly their evaluation more affirmatively from first trial to third trial.(t=3.16, P<0.01) But children who observed model receive external punishment did not altered their evaluative standard. So we consider that there should be subtle but important differences between the informative functions of vicarious self reinforcement and vicarious external reinforcement. Vicarious self reinforcement may transmit the self-monitoring flexible self reinforcement pattern, while vicarious external reinforcement, may transmit other-oriented inflexible self reinforcement pattern.Analysis of variance on performance scores revealed that any independent variables we introduced did not produce significant differences.

Reinforcement patterns in depression

Seventeen depressed and seventeen nondepressed subjects indicated when they would have socially reinforced two speakers whose speeches were tape-recorded. It was hypothesized that depressed subjects would exhibit a lower frequency and less skill (timing) of social reinforcement. The data were not consistent with the hypotheses as there was an almost total overlap of response patterns for the two groups. Alternative explanations are discussed.

Partial Reinforcement and the Learning of a Strategy in the Rat

When reinforcement was contingent on response variation, rats exhibited spontaneous stop-and-look behavior and acquired the strategy of response variation. This strategy-learning paradigm constituted a skill partial-reinforcement (PRF) condition where reinforcement was both predictable and controllable. Skill PRF produced greater resistance to extinction as compared with either a chance PRF control group yoked for percentage and pattern of reinforcement, or a variation consistent reinforcement control yoked for frequency of response variation. The result was interpreted in terms of Weiner's attribution model.

Cognitive and Emotional Factors Representative of Reinforcement Patterns among an Amateur Softball Team

Pre-game performance expectations, emotions, and post-game performance ratings were measured among members of an amateur Softball team. The results showed that pre-game performance expectations and reported happiness were at high levels and did not differ between won or lost games or between skilled and lesser skilled players. Reported depression was found to rise significantly among skilled players prior to lost games. Post-game performance ratings were significantly lower than pre-game performance expectations among both skilled and lesser skilled players. Post-game performance ratings of both the players and coach were significantly higher for games won than games lost, but the ratings of the coach after all games were significantly higher than those of the players. Post-game performance ratings by the coach of skilled and lesser skilled players did not differ significantly. These results indicate that cognitive (expectation) and emotional factors, as well as self-reported performance ratings, may be useful in determining reinforcement patterns among amateur players and coaches. In the present situation, uniform, positive reinforcement by the coach appears to be perceived differently among skilled and lesser skilled players depending on whether the game was won or lost.

Socialization of sex roles in the counseling setting: Differential counselor behavioral and attitudinal responses to typical and atypical female sex roles

Counseling and therapy have frequently been attacked by feminists for the role they play in socializing women to a limited and ultimately untenable sex role. Male counselors in particular have been singled out as special oppressors of women. This study attempted to determine whether, in fact, counselor behavior and attitudes operated as a means of sex-role socialization, and whether male counselors tended to be more biased than female counselors when interacting with female clients. Subjects were eight male and eight female graduate students in counseling psychology who conducted initial interview sessions with two client-confederates, volunteer graduate students trained in role-playing situations representing a typical and an atypical sex-role condition. Videotapes of the interviews were subsequently analyzed to assess counselor reinforcement patterns of specific client “cue” sentences. In addition to these behavioral data, paper-and-pencil inventories were used to determine counselors' perception of clients, counselors' degree of attitudinal sex-stereotyping, and client-confederates' subjective evaluation of counselors. Contrary to expectations, results indicated that counselors as a whole exhibited more behavioral bias with typical than with atypical clients. Further, counselors reacted more positively toward the atypical than toward the typical clients, and counselor response to a global sex-role inventory indicated that counselors described the healthy, well-adjusted female as significantly more instrumental than the healthy, well-adjusted male. Female counselors appeared to be both more reinforcing and less punishing than male counselors with female clients in both roles, as well as less behaviorally biased than the male counselors. Female counselors also evaluated the atypical clients more positively than did the male counselors, and were in turn evaluated more positively than were the male counselors by clients in both roles. The study concludes with a discussion of implications for counselor training.

Reward Distribution and Goal Selection of Kibbutz and City Mothers in Israel

Two experiments compared the behavior of kibbutz and city mothers in Israel toward the achievement behavior of their children. The first experiment studied the mothers' reinforce ment patterns and found kibbutz mothers were less conditional in their distribution of rewards than city mothers. The second ex periment studied goal selection by the mothers and found a similar pattern of goal selection in the two cultures. These maternal differences and similarities were discussed in relation to differ ences in cooperation and competition between kibbutz and city children, as found in previous research.

Family Interaction and Adolescent Suicidal Behaviour: A Preliminary Investigation

While investigators have emphasized the importance of familial relations in the production of suicidal behaviour in adolescence, experimental evaluation of specific family interaction processes has, thus far, been neglected. The aim of the present study was to investigate possible relationships between adolescent suicidal behaviour and total on-going family functioning. Hypotheses were advanced to evaluate the communication, interaction and reinforcement patterns in families. A modified revealed differences technique was employed to elicit standardized segments of interaction which were video-taped and later studied by two independent raters. The sample consisted of twelve individually matched, intact family tetrads, six normal (N) and six containing an adolescent female who had exhibited suicidal behaviour (SM). Results suggest that SM families constitute a malfunctioning system which can be differentiated from that of normal samples. As compared with the N group, SM family interaction evidenced less effective productivity, specificity, and adaptive interaction, and higher rates of conflict and negative reinforcement. Overall findings were discussed in terms of current family theory and their possible relationship to the genesis, maintenance and management of some classes of suicidal behaviour.