Analyzing experimental data using the Rasch model

We present a method for studying experimental data based on a psychometric model, the “Rasch model” (Rasch, 1966; Thissen & Steinberg, 1986). We illustrate the method with the use of a data set in the field of concept research. More specifically, we investigate whether a conjunctive concept can be seen as an additive combination of its constituents. High correlations between model and data are obtained, but a formal goodness-of-fit test indicates that the model does not completely account for the data. We then alter the Rasch model in such a way as to capture our idea of why the model deviates from the data. This results in higher correlations and a strong increase in goodness-of-fit. It is concluded that our ideas, as incorporated in the model, adequately summarize the data. More generally, this research illustrates that applying the Rasch model and altering it according to one’s hypotheses is an excellent way to analyze experimental data.     

The start-stop procedure: Estimation

In four experiments investigating human timing, subjects produced estimates of sample durations by bracketing their endpoints. On each trial, subjects reproduced a sample duration by pressing a button before the estimated sample duration elapsed (start time) and releasing it after the estimated duration elapsed (stop time). From these responses, middle time (start + stop/2) and spread time (stop — start) were calculated, representing the point of subjective equality and the difference limen, respectively. In all experiments, subjects produced middle times that varied directly with sample duration. In Experiment 2, middle times lengthened when feedback was withheld. Consistent with Weber timing, spread times, as well as the standard deviation of middle times, varied directly with middle time (Experiments 1, 3, and 4). On the basis of an internal clock model of timing (Gibbon & Church, 1990), the data permitted inferences regarding memory processes and response threshold. Correlations between start and stop times and between start and spread times agreed with earlier findings in animals suggesting that the variance of temporal estimates across trials is based in part upon the selection of a single temporal memory sample from a reference memory store and upon one or two threshold samples for initiating and terminating each estimate within a trial.     

Teaching reading and spelling: exclusion and stimulus equivalence

In Experiment 1, 7 nonreading children were exposed to a program designed to teach reading of 51 training words. The program featured an exclusion-based procedure in which the children (a) matched printed to dictated words and (b) constructed (copied) printed words with movable letters and named them. All children learned to read the training words. Five children also read generalization words and showed progress in spelling. Experiment 2 applied the program to 4 different children, omitting the word-construction task. They also learned to read the training words, but only 1 participant read generalization words. The data support a stimulus equivalence account of reading acquisition and suggest that reading generalization may be obtained, especially when the teaching program includes word construction.     

Schools,identity and the conception of the good. The denominational tradition as an example

The Dutch education system relies upon a large number of publicly-subsidized, denominational schools. The authors defend the importance of schools that educate children within a specific — including denominational — conception of the good by arguing for the importance of such a conception for the development of the child's identity. An essential component of this developmental process is critical reflection, conceived as crucial to the formation of moral autonomy.     

Verbal fluency and verbal comprehension abilities in synonym tasks

Generating different synonym candidates and evaluating these candidates with respect to their synonymy with the stimulus word are two components of solving an open synonym task, which requires giving synonyms for a given word (cf. Janssen, Hoskens, & De Boeck, 1993). Separate subtasks were designed to identify these components. It is shown in this study that the generation component ability is primarily related to verbal fluency abilities, whereas the evaluation component ability is primarily related to verbal comprehension abilities. Moreover, evidence is given that these two component abilities can account for the correlations of the open synonym task with other ability measures.     

AIDS and condom-related knowledge,beliefs, and behaviors in Mexican migrant laborers

A survey of 87 Mexican migrants (55 males and 32 females) who have lived and worked in the US since 1982 assessed AIDS and condom-related knowledge, beliefs, and sexual practices. Although respondents were highly knowledgeable about major modes of HIV transmission, one-third to one-half believed that HIV could be contracted from mosquito bites, public bathrooms, kissing, and the HIV test. Only 15% knew someone with AIDS. Ever-use of condoms was reported by 70.9% of men and 41.9% of women. Of the 68 subjects who had been sexually active in the year preceding the survey, 20 reported two or more partners. Among sexually active respondents, 16.2% always used condoms with their primary partner, while 43.0% used condoms consistently with occasional partners. 48.9% of men and 57.1% of women never used condoms with their primary partner; with casual partners, these rates were 30.8% and 44.4%, respectively. Worry about contracting AIDS, self-rated on a scale from 1 (very often) to 4 (never), averaged 2.84, with higher worry scores among those 18-31 years of age and with multiple partners. Respondents did not anticipate negative consequences of condom use (e.g., reduced sexual pleasure), but females expressed concern that carrying condoms would cause them to be viewed as promiscuous.     

The validity of personality,service orientation,and reading comprehension measures as predictors of Flight Attendant training performance

The present study examined the predictive power of Big Five personality dimensions, a situational measure of service orientation and a reading comprehension measure as predictors of Flight Attendant training criteria. The criteria consisted of multiple ratings made by trainers of trainees across a number of training dimensions. At least partial data was collected on 424 Flight Attendant trainees. Results indicated significant correlations between all three predictors and a number of the training criteria.The authors would like to thank the Editor and two anonymous reviewers for their help revising this article.     

Gender relations,the gendered division of labour and health: the case of the women factory workers of Rio Tinto,northeast Brazil, 1924-91

This article examines gendered work-health relationships among female factory workers in Rio Tinto, a textile factory town in Brazil. The author draws on her own and her parents' experiences as factory workers and as residents of Rio Tinto. In addition, she gathered research during 1982-86 and 1988-93, interviewing 30 female and 12 male workers. Findings from 1924-58 and 1959-91 indicate that the family structure and work process were interlinked. Self-images are construed to be the intersection of social relations of sex and class, psychopathology, and the concept of work positions. Gendered relations are a social construction, and awareness of these relations is based on a hierarchy and form of power based on a gendered division of labor. Gendered relations arise out of a specific historical context. Social practices reflect the relationship between sexual division of labor and gendered social relations, their modalities, shape, and periodization. The work-health relationship is expressed in the gendered technical organization of work, the gendered socialization of work, and domestic labor. The period of 1917-58 reflects the capitalist influences. When women became wage earners, their management of household tasks was changed. Men took over the heavy tasks, and women performed tasks that required skill and patience. Work-related health impacts, such as deformed knees or severed fingers, and accidents varied with the task. Women adapted to work conditions. During the 1940s, female workers refused to join the collective protests of men for better wages and conditions. The dream of progress faded by 1964. After 1959, new gendered relations of production and reproduction emerged. Labor laws were passed; new machines were introduced. During 1965-70, the health issues were headaches, irritability, and anxiety. 1970-91 brought a hollowness of spirit and the search for an explanation for the violence they had experienced.     

Vector coding in slow goal-directed arm movements

It has been found that the estimate of relative target direction is consistently biased. Relative target direction refers to the direction in which a target is located relative to another location in space (e.g., a starting position in the case of goal-directed movements). In this study, we have tested two models that could underlie this biased estimate. The first proposed model is based on a distorted internal representation of locations (i.e., we perceive a target at the “wrong” location). We call this thedistorted location model. The second model is based on the idea that the derivation of target direction from spatial information about starting and target position is biased. We call this thebiased direction model. These two models lead to different predictions of the deviations that occur when the distance between the starting position and the target position is increased. Since we know from previous studies that the initial direction of slow arm movements reflects the target direction estimate, we tested the two models by analyzing the initial direction of slow arm movements. The results show that the biased direction model can account for the biases we find in the target direction estimate for various target distances, whereas the distorted location model cannot. In two additional experiments, we explored this model further. The results show that the biases depend only on the orientation of the line through starting position and target position relative to the plane through longitudinal head or body axis and starting position. We conclude that the initial part of (slow) goal-directed arm movements is planned on the basis of a (biased) target direction estimate and not on the basis of a wrong internal representation of target location. This supports the hypothesis that we code displacements of our limbs in space as a vector.