Prediction and classification in nonlinear data analysis: Something old,something new,something borrowed,something blue

Prediction and classification are two very active areas in modern data analysis. In this paper, prediction with nonlinear optimal scaling transformations of the variables is reviewed, and extended to the use of multiple additive components, much in the spirit of statistical learning techniques that are currently popular, among other areas, in data mining. Also, a classification/clustering method is described that is particularly suitable for analyzing attribute-value data from systems biology (genomics, proteomics, and metabolomics), and which is able to detect groups of objects that have similar values on small subsets of the attributes.This article is based on the Presidential Address Jacqueline Meulman gave on July 9, 2003 at the 68th Annual Meeting of the Psychometric Society held near Cagliari, Italy on the island of Sardinia.—Editor     

Genetic and environmental causes of the interrelationships between self-reported fears. A study of a non-clinical sample of Norwegian identical twins and their families

The present study reports results from a study of the self-reported fears of identical twins and their spouses and offspring. Factor analysis with oblique rotation of questionnaire responses yielded four correlated fear dimensions: situational fears, illness-injury fears, social fears, and fear of small animals. Models allowing for genetic and cultural transmission, together with specially correlated environments for twins, were fitted, both for separate fears and across fears. Simple models with only genetic and uncorrelated environments were sufficient to account for each the fear dimensions considered separately. The cross-dimensional analyses revealed a genetic and an environmental factor common to the four fear dimensions, together with fear-specific genetic and environmental factors. The impact of the common genetic and common environmental factor varied across dimensions. No evidence of cultural transmission or specially correlated twin environments of the cross-dimensional environments was detected. It is concluded that both common and fear-specific genes and (individual-specific) common and fear-specific environments are necessary to account for the data. The results are discussed in terms of the prepared learning hypothesis and the expectancy bias hypothesis.     

Genetic and environmental influences on individual differences in printed word recognition

The genetic and environmental etiologies of individual differences in printed word recognition and related skills were explored in 440 identical and fraternal twin pairs between 8 and 18 years of age. A theoretically driven measurement model identified five latent variables: IQ, phoneme awareness, word recognition, phonological decoding, and orthographic coding. Cholesky decomposition models on these five latent constructs revealed the existence of both common and independent genetic effects, as well as non-shared environmental influences. There was evidence for moderate genetic influences common between IQ, phoneme awareness, and word-reading skills, and for stronger IQ-independent genetic influences that were common between phoneme awareness and word-reading skills, particularly phonological decoding. Phonological and orthographic coding skills in word recognition had both significant common and significant independent genetic influences, with implications for "dual-route" and "connectionist" reading models, subtypes of reading disabilities, and the remediation of reading disabilities.     

Do current connectionist learning models account for reading development in different languages?

Learning to read a relatively irregular orthography, such as English, is harder and takes longer than learning to read a relatively regular orthography, such as German. At the end of grade 1, the difference in reading performance on a simple set of words and nonwords is quite dramatic. Whereas children using regular orthographies are already close to ceiling, English children read only about 40% of the words and nonwords correctly. It takes almost 4 years for English children to come close to the reading level of their German peers. In the present study, we investigated to what extent recent connectionist learning models are capable of simulating this cross-language learning rate effect as measured by nonword decoding accuracy. We implemented German and English versions of two major connectionist reading models, Plaut et al.'s (Plaut, D. C., McClelland, J. L., Seidenberg, M. S., & Patterson, K. (1996). Understanding normal and impaired word reading: computational principles in quasi-regular domains. Psychological Review, 103, 56-115) parallel distributed model and Zorzi et al.'s (Zorzi, M., Houghton, G., & Butterworth, B. (1998a). Two routes or one in reading aloud? A connectionist dual-process model. Journal of Experimental Psychology: Human Perception and Performance, 24, 1131-1161); two-layer associative network. While both models predicted an overall advantage for the more regular orthography (i.e. German over English), they failed to predict that the difference between children learning to read regular versus irregular orthographies is larger earlier on. Further investigations showed that the two-layer network could be brought to simulate the cross-language learning rate effect when cross-language differences in teaching methods (phonics versus whole-word approach) were taken into account. The present work thus shows that in order to adequately capture the pattern of reading acquisition displayed by children, current connectionist models must not only be sensitive to the statistical structure of spelling-to-sound relations but also to the way reading is taught in different countries.     

Gross-motor skill acquisition by preschool dance students under self-instruction procedures

The effects of two training procedures--(a) modeling and praise and (b) self-instruction, modeling, and praise--on complex gross-motor chain acquisition for preschool dance class students were evaluated. Six girls participated in the study. A multiple baseline design across six gross-motor chains with a secondary group comparison for treatment order effects was used. Both procedures were effective in teaching the gross-motor chains. Nevertheless, for 4 of the 6 participants, the self-instruction procedure produced a faster acquisition rate in at least two of the three comparable pairs of gross-motor chains. Furthermore, very early in gross-motor chain acquisition, for five of the six gross-motor chains, the self-instruction condition was associated with faster response acquisition.     

Effects of video modeling on social initiations by children with autism

We examined the effects of a video modeling intervention on social initiation and play behaviors with 3 children with autism using a multiple baseline across subjects design. Each child watched a videotape showing a typically developing peer, and the experimenter engaged in a simple social interactive play using one toy. For all children, social initiation and reciprocal play skills were enhanced, and these effects were maintained at 1- and 3-month follow-up periods.     

Effects of modeling versus instructions on sensitivity to reinforcement schedules

This study examined the effects of modeling versus instructions on the choices of 3 typically developing children and 3 children with attention deficit hyperactivity disorder (ADHD) whose academic responding showed insensitivity to reinforcement schedules. During baseline, students chose between successively presented pairs of mathematics problems associated with different variable-interval schedules of reinforcement. After responding proved insensitive to the schedules, sessions were preceded by either instructions or modeling, counterbalanced across students in a multiple baseline design across subjects. During the instruction condition, students were told how to distribute responding to earn the most reinforcers. During the modeling condition, students observed the experimenter performing the task while describing her distribution of responding to obtain the most reinforcers. Once responding approximated obtained reinforcement under either condition, the schedules of reinforcement were changed, and neither instruction nor modeling was provided. Both instruction and modeling interventions quickly produced patterns of response allocation that approximated obtained rates of reinforcement, but responding established with modeling was more sensitive to subsequent changes in the reinforcement schedules than responding established with instructions. Results were similar for students with and without ADHD.     

A multivariate reduced-rank growth curve model with unbalanced data

A multivariate reduced-rank growth curve model is proposed that extends the univariate reducedrank growth curve model to the multivariate case, in which several response variables are measured over multiple time points. The proposed model allows us to investigate the relationships among a number of response variables in a more parsimonious way than the traditional growth curve model. In addition, the method is more flexible than the traditional growth curve model. For example, response variables do not have to be measured at the same time points, nor the same number of time points. It is also possible to apply various kinds of basis function matrices with different ranks across response variables. It is not necessary to specify an entire set of basis functions in advance. Examples are given for illustration.The work reported in this paper was supported by Grant A6394 from the Natural Sciences and Engineering Research Council of Canada to the second author. We thank Jennifer Stephan for her helpful comments on an earlier version of this paper. We also thank Patrick Curran and Terry Duncan for kindly letting us use the NLSY and substance use data, respectively. The substance use data were provided by Grant DA09548 from the National Institute on Drug Abuse.     

Appraised psychological workload, musculoskeletal symptoms, and the mediating effect of fatigue: a structural equation modeling approach

The aim of the present study was to test two structural models of the relationship between appraised psychological workload and musculoskeletal symptoms from the neck, shoulder, and upper and lower back with different aspects of perceived fatigue as mediating variables. In this cross-sectional study a questionnaire survey was conducted among employees at three Swedish assembly plants (n= 305). The proposed models were tested for one general fatigue dimension--lack of energy--and four specific fatigue dimensions--physical discomfort, physical exertion, lack of motivation, and sleepiness--using structural equation modeling. The results indicate that the role of perceived fatigue in the relationship between appraised workload and musculoskeletal symptoms is different for different aspects of fatigue. The general fatigue dimension, lack of energy, does not mediate the relationship. As regards the specific fatigue dimensions, the relationship is partially mediated by physical discomfort and lack of motivation but not by physical exertion or sleepiness. Appraised psychological workload has a unique effect on musculoskeletal symptoms not mediated by fatigue.     

贝叶斯多组比较——渐近测量不变性

在行为科学研究领域中,检验测量工具的测量不变性是进行群体差异比较的前提。目前,多组验证性因子分析(多组CFA)方法被广泛用于检验测量不变性,但是它对跨组等值的限制过于严格,在实际应用中常常存在大量局限。贝叶斯渐近测量不变性方法基于贝叶斯思想的优良特性,放宽了传统多组CFA方法对跨组差异的严格限制,避免了传统方法的问题,具有较高的应用价值。文章详细介绍了贝叶斯渐近测量不变性方法的原理及优势,同时通过实例展示了渐近测量不变性方法在Mplus软件中的具体分析过程。