Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.     

An empirical test of a comprehensive model of intrapersonal empowerment in the workplace

A comprehensive model of intrapersonal empowerment in the workplace posits that empowerment mediates the relationship between the social structural context and behavioral outcomes. The social structural context is operationalized as perceptions of role ambiguity, sociopolitical support, access to strategic information and resources, and work unit culture, whereas behavioral outcomes are operationalized as innovativeness and effectiveness. The model is examined on a sample of 324 middle managers from different units of a Fortune 50 organization. Survey data are examined using a series of regression analyses to assess the mediating effect of intrapersonal. Results suggest that intrapersonal empowerment mediates the relationship between some elements of workplace social structure and innovativeness, but not effectiveness. Although not a mediating mechanism for effectiveness, intrapersonal empowerment is nonetheless directly related to effectiveness (as assessed by the respondent's subordinates). Implications of the results are discussed as are study limitations and directions for future research. This paper is based on the author's dissertation, presented in partial fulfillment of the requirement for the doctoral degree at the University of Michigan. I am grateful to my dissertation committee which included Robert E. Quinn (chair), Susan Ashford, Richard Bagozzi, Karl Weick, and Marc Zimmerman for their thoughtful guidance. Thanks is also extended to Neil Sendelbach for his help in facilitating data collection. The University of Michigan and the University of Southern California both provided financial support for this research. This paper was prepared while the author was a Zumberge Fellow at the University of Southern California.     

Identification of inconsistent variates in factor analysis

When some of observed variates do not conform to the model under consideration, they will have a serious effect on the results of statistical analysis. In factor analysis the model with inconsistent variates may result in improper solutions. In this article a useful method for identifying a variate as inconsistent is proposed in factor analysis. The procedure is based on the likelihood principle. Several statistical properties such as the effect of misspecified hypotheses, the problem of multiple comparisons, and robustness to violation of distributional assumptions are investigated. The procedure is illustrated by some examples.     

An extension of the partial credit model with an application to the measurement of change

The partial credit model is considered under the assumption of a certain linear decomposition of the item × category parameters _ih into basic parameters _j. This model is referred to as the linear partial credit model. A conditional maximum likelihood algorithm for estimation of the j is presented, based on (a) recurrences for the combinatorial functions involved, and (b) using a quasi-Newton approach, the so-called Broyden-Fletcher-Goldfarb-Shanno (BFGS) method; (a) guarantees numerically stable results, (b) avoids the direct computation of the Hesse matrix, yet produces a sequence of certain positive definite matricesB _k ,k=1, 2, ..., converging to the asymptotic variance-covariance matrix of the . The practicality of these numerical methods is demonstrated both by means of simulations and of an empirical application to the measurement of treatment effects in patients with psychosomatic disorders.The authors thank one anonymous reviewer for his constructive comments. Moreover, they thankfully acknowledge financial support by the Österreichische Nationalbank (Austrian National Bank) under Grant No. 3720.     

A PRELIMINARY PROCEDURE FOR PREDICTING THE POSITIVE AND NEGATIVE EFFECTS OF REINFORCEMENT-BASED PROCEDURES

In the current investigation, a modification was made to the preference assessment described by Pace, Ivancic, Edwards, Iwata, and Page (1985) to predict the effects of stimuli when used in a differential-reinforcement-of-other-behavior (DRO) schedule for 2 clients with severe self-injurious behavior (SIB) and profound mental retardation. Based on the results of the preference assessment, three types of stimuli were identified: (a) high-preference stimuli associated with high rates of SIB (HP/HS), (b) high-preference stimuli associated with relatively lower rates of SIB (HP/LS), and (c) low-preference stimuli associated with low rates of SIB (LP/LS). Consistent with the results of the preference assessment, the DRO schedule with HP/HS stimuli resulted in increased SIB, and the DRO schedule with LP/LS stimuli resulted in no changes in SIB. HP/LS stimuli were demonstrated reinforcers but did not result in a change in SIB when used in a DRO schedule. Thus, the stimulus preference assessment may be useful clinically in some situations for predicting both the beneficial and the negative side effects of stimuli in DRO procedures.     

Resistance To Change As A Function Of Stimulus-reinforcer And Location-reinforcer Contingencies

Pigeons responded on two keys in each component of a multiple concurrent schedule. In one series of conditions the distribution of reinforcers between keys within one component was varied so as to produce changes in ratios of reinforcer totals for key locations when summed across components. In a second series, reinforcer allocation between components was varied so as to produce changes in ratios of reinforcer totals for components, summed across key locations. In each condition, resistance to change was assessed by presenting response-independent reinforcers during intercomponent blackouts and (for the first series) by extinction of responding on both keys in both components. Resistance to change for response totals within a component was always greater for the component with the larger total reinforcer rate. However, resistance to change for response totals at a key location was not a positive function of total reinforcement for pecking that key; indeed, relative resistance to extinction for the two locations showed a weak negative relation to ratios of reinforcer totals for key location. These results confirm the determination of resistance to change by stimulus—reinforcer contingencies.     

Procedural dependence in action memory: Effects of verb form and individual vs group conditions

Two experiments explored whether the magnitude of the enactment effect in action memory (i. e., higher recall with motor than with non-motor encoding) may depend upon the use of individual or group testing procedures. Nonmotor encoding instructions, requiring the subjects to listen to orally presented action items, were compared to instructions which also required enactment. With encoding treated as a within-subject factor, the observations failed to reveal any significant difference between individual and group testing. With encoding treated as a between-subject factor, the results showed an interaction between test and encoding conditions, such that an enactment effect was found only with group testing. Different support value for auditory cues in group and individual test situations was assumed to account for this difference. In a third experiment the indicative and imperative verb forms were compared. An interaction was observed, showing that in Norwegian, enacted verbs were remembered better when presented in the indicative than in the imperative. No corresponding difference was found under non-enactment conditions. For this finding, a social interaction interpretation was offered.     

A comparison of multiple versus single examples of the correct stimulus on task acquisition and generalization by persons with developmental disabilities

In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.     

Pre-screening education in multiple marker screening programs: The effect on patient anxiety and knowledge

Previous studies have shown that unexplained deviations in maternal serum multiple marker screening (MMS) generate considerable anxiety during the remainder of pregnancy. While the role of education in decreasing anxiety is documented, to date there has been no prospective evaluation of which educational practices might minimize this emotional stress. In a pilot study, we prospectively examined the effects on anxiety and knowledge by providing information about MMS (1) by genetic counselor, (2) by pamphlet, and (3) by primary physician. Women randomized to one of these three modalities were administered the Spielberger State- Trait Anxiety Inventory [STAI] and knowledge questionnaires at their initial obstetrics visit, at their second visit after educational intervention and 1–2 weeks after MMS results were provided to patients. Education resulted in an increase in knowledge and post-education knowledge was different between educational modalities. Anxiety declined in patients educated through genetic counseling or a pamphlet.     

初中生友谊质量与孤独感的变化轨迹:一项多元潜变量增长模型分析

为考察初中生友谊质量与孤独感的变化轨迹及两者间的关系,采用关系网络问卷、孤独感量表对西安市的875名初中生（M=12.73±0.18;男生494名）进行三年追踪测量,使用多元潜变量增长模型进行分析。结果发现：（1）初中三年,中学生的友谊质量逐渐提高,孤独感水平逐渐下降;（2）初一时的友谊质量和孤独感水平存在显著的个体差异,初中三年期间二者的发展速度也存在个体差异;（3）初一时的友谊质量可显著预测初一时的孤独感水平（β=-1.77,p<0.001）及随后的发展速度（β=0.20,p<0.05）;（4）男生的孤独感水平初始值高于女生,友谊质量的初始值则低于女生;高SES个体孤独感的起始值高于低SES个体。本研究结果揭示了初中三年期间个体友谊质量与孤独感的动态变化关系及友谊质量对孤独感的预测作用,对改善青少年孤独感的现状有一定的现实指导意义。