Changes in functional response units with briefly delayed reinforcement

In two experiments, key-peck responding of pigeons was compared under variable-interval schedules that arranged immediate reinforcement and ones that arranged unsignaled delays of reinforcement. Responses during the nominal unsignaled delay periods had no effect on the reinforcer presentations. In Experiment 1, the unsignaled delays were studied using variable-interval schedules as baselines. Relative to the immediate reinforcement condition, 0.5-s unsignaled delays decreased the duration of the reinforced interresponse times and increased the overall frequency of short (<0.5-s) interresponse times. Longer, 5.0-s unsignaled delays increased the duration of the reinforced interresponse times and decreased the overall frequency of the short interresponse times. In Experiment 2, similar effects to those of Experiment 1 were obtained when the 0.5-s unsignaled delays were imposed upon a baseline schedule that explicitly arranged reinforcement of short interresponse times and therefore already generated a large number of short interresponse times. The results support earlier suggestions that the unsignaled 0.5-s delays change the functional response unit from a single key peck to a multiple key-peck unit. These findings are discussed in terms of the mechanisms by which contingencies control response structure in the absence of specific structural requirements.     

Theory change in immunology part II: The clonal selection theory

This two-part article examines the competition between the clonal selection theory and the instructive theory of the immune response from 1957–1967. In Part I the concept of a temporally extended theory is introduced, which requires attention to the hitherto largely ignored issue of theory individuation. Factors which influence the acceptability of such an extended theory at different temporal points are also embedded in a Bayesian framework, which is shown to provide a rational account of belief change in science. In Part II these factors, as elaborated in the Bayesian framework, are applied to the case of the success of the clonal selection theory and the failure of the instructive theory.     

A nonparametric approach for assessing latent trait unidimensionality

Assuming a nonparametric family of item response theory models, a theory-based procedure for testing the hypothesis of unidimensionality of the latent space is proposed. The asymptotic distribution of the test statistic is derived assuming unidimensionality, thereby establishing an asymptotically valid statistical test of the unidimensionality of the latent trait. Based upon a new notion of dimensionality, the test is shown to have asymptotic power 1. A 6300 trial Monte Carlo study using published item parameter estimates of widely used standardized tests indicates conservative adherence to the nominal level of significance and statistical power averaging 81 out of 100 rejections for examinee sample sizes and psychological test lengths often incurred in practice.The referees' comments were remarkably detailed and greatly enhanced the writeup and sensitized the author to certain pertinent issues. Discussions with Fritz Drasgow, Lloyd Humphreys, Dennis Jennings, Brian Junker, Robert Linn, Ratna Nandakumar, and Robin Shealy were also very useful.This research was supported by the Office of Naval Research under grant N00014-84-K-0186; NR 150-533, and by the National Science Foundation under grant DMS 85-03321.     

Latent trait models and dichotomization of graded responses

This paper discusses thecompatibility of the polychotomous Rasch model with dichotomization of the response continuum. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum, ranging for example from total rejection or disagreement to total acceptance or agreement of an item or statement. Because of this arbitrariness, the measurement outcome should be independent of the specific polychotomization applied, for example, presenting a specific multicategory response format should not affect the measurement outcome. When such is the case, the original polychotomous model is called compatible with dichotomization.A distinction is made between polychotomization or dichotomization before the fact, that is, in constructing the response format, and polycho- or dichotomization after the fact, for example in dichotomizing existing graded response data.It is shown that, at least in case of dichotomization after-the-fact, the polychotomous Rasch model is not compatible with dichotomization, unless a rather special condition of the model parameters is met. Insofar as it may be argued that dichotomization before the fact is not essentially different from dichotomization after the fact, the value of the unidimensional polychotomous Rasch model is consequently questionable. The impact of our conclusion on related models is also discussed.     

La balance optimisme/pessimisme : détermination des styles d’expectations envers le futur en se basant sur la bidimensionnalité du Life Orientation Test–Revised

IntroductionSince the 1980s, two major conceptions of the representation of optimism and pessimism have been disputed: a unidimensional structure and a bidimensional structure.ObjectiveThe bidimensional properties of the LOT-R in French are further explored in order to determine the styles of expectations towards the future according to the levels of optimism and pessimism.MethodA study carried out on a sample of 913 adults from France (72.7% women, M = 41.14 years) proposes (1) to analyze the factorial structure of the instrument, the relationship between the two constructs as well as their separability, (2) to explore the styles of expectations according to the levels of positive and negative expectations by latent profile analysis, (3) to study the influence of socio-demographic factors (age, sex, socio-professional category) on cognitive expectations about the future.ResultsThe confirmatory factor analyzes establish the replicability of the bidimensional latent structure of the instrument across age and gender groups, with the separability between the two constructs increasing with advancing age. The latent profile analysis supports the existence of three styles of expectations towards the future within the sample: the optimistic style, the mixed style and the pessimistic style. The MIMIC model demonstrates that increasing age and socio-professional category are determinants of levels of optimism and pessimism as well as of expectation styles.ConclusionThis research makes it possible to use the styles of expectations towards the future which empirically models the balance between the levels of optimism and pessimism.     

特质自我控制对食物线索注意偏向的影响及干预：来自眼动的证据

采用眼动技术,以BMI指数处于正常范围的女性为被试,考察特质自我控制对食物线索注意偏向的影响以及注意偏向训练在改变注意偏向强度上的干预效果。结果发现,对于高热量食物线索,低特质自我控制水平女性表现出了更强的注意偏向;注意偏向训练有效降低了低特质自我控制水平女性对高热量食物线索注意偏向的强度。上述结果表明,特质自我控制影响个体对食物线索的注意偏向,注意偏向训练能有效改变个体对食物线索注意偏向的强度。     

Psychometric properties and factor structure of the Fear Questionnaire phobia subscale items in two normative samples

Normative data for the Fear Questionnaire (Marks & Mathews, 1979), a popular self-report instrument measuring phobic concerns, were collected from both a community and a collegiate sample. The covariation and internal consistency of the blood-injury phobia (BI), social phobia (SO), and agoraphobia (AG) subscales were assessed in each sample, and the factor structure of the items from these three subscales was examined. Results indicated that, in general, community subjects reported more phobic concerns than did collegiate subjects, and females reported greater phobic concerns than did males. Results from confirmatory factor analyses suggest that the three factors of BI, SO, and AG did not emerge from either data set. Follow-up exploratory factor analyses did identify the general factors of blood-injury phobia and agoraphobia. Normative data from the present study are compared to those obtained previously, and directions for future research are provided.     

Argument as a formulation-decision-decision... sequence

Problems with regard to the analysis of argumentative partly discourse arise from definitorial disconformity. In this article, Informal argument is taken as the primary definition to study the basic structure of argument from a fragment of an Agatha Christie novel. Bilmes' account of the notions of Formulation (F) and Decision (D+/D-) are adapted to describe the relations of opposition which are displayed in informal argument. The minimal structure of argument is represented by the formula F/D-/D-, in which F is a speaker's personal composition of a fact, the first D- is the disconfirming uptake of it by another speaker and the second D- is the completing disconfirming uptake by the initial speaker. Some of the speaker's possibilities to initiate an argument by expressing a Formulation are explored, as well as the social and cultural norms which play a role in argument-initiation and the concepts of win and loss.     

从情绪描述看青少年期到成人期认知结构的发展

该研究依据研究者制定的认知发展水平评价系统,对年龄范围在13—55岁之间的90名被试关于生气、害怕、伤心、高兴四种情绪的自我描述进行了评价分析。结果表明,青少年期的思维具有形式化、外在、抽象等特点,成人期的思维具有内在、具体、形象等特点,前者具有刻板性、封闭性,后者具有灵活性、开放性。     

Interpreting canonical correlation analysis through biplots of structure correlations and weights

This paper extends the biplot technique to canonical correlation analysis and redundancy analysis. The plot of structure correlations is shown to the optimal for displaying the pairwise correlations between the variables of the one set and those of the second. The link between multivariate regression and canonical correlation analysis/redundancy analysis is exploited for producing an optimal biplot that displays a matrix of regression coefficients. This plot can be made from the canonical weights of the predictors and the structure correlations of the criterion variables. An example is used to show how the proposed biplots may be interpreted.