Why do people factor?

This is a very simple explanation of factor analysis primarily for the factorial layman. The interpretation of factors and the comparisons of various factor solutions are illustrated with a hypothetical example so designed that the reader can visualize all the relationships in a two-dimensional graph.     

On the estimation of polychoric correlations and their asymptotic covariance matrix

A general theory for parametric inference in contingency tables is outlined. Estimation of polychoric correlations is seen as a special case of this theory. The asymptotic covariance matrix of the estimated polychoric correlations is derived for the case when the thresholds are estimated from the univariate marginals and the polychoric correlations are estimated from the bivariate marginals for given thresholds. Computational aspects are also discussed.The research was supported by the Swedish Council for Research in the Humanities and Social Sciences (HSFR) under the programMultivariate Statistical Analysis. The author thanks a reviewer for pointing out an error in the original version of the paper.     

Editorial

Science and religion share the conviction that the world is intelligible, susceptible to being logically understood, but they delineate this under different paradigms. In the cleanest cases we can say that science operates with the presumption that there are causes to things, religion with the presumption that there are meanings to things.
—Holmes Rolston III     

The processing of inflected words

Summary Is an inflected word identified by first decomposing it into stem plus suffix or, instead, is it recognized as a whole? Several lexical decision experiments studied the recognition of inflected words in English (a language with few inflections) and Serbo-Croatian (a heavily inflected language). If recognition depended on decomposition, preceding the inflection with a brief exposure of the stem (<100 ms) should have primed the lexical entry for the stem and, therefore, facilitated recognition of the whole inflected word that followed. It did not. It was also found that the speed of recognizing an inflected word was more strongly associated with the frequency of the whole inflected form than with the frequency of its stem. The results suggested that in word recognition, lexical contact is first made with the whole word form. Nevertheless, morphological decomposition may still occur in subsequent processing.     

Development and learning: a TASC-based perspective of the acquisition of perceptual-motor behaviors

The concepts of development and learning are discussed in terms of different theoretical orientations to the study of motor behavior. It is argued that although these concepts are commonly used to discuss various aspects of change across the life span, there is little agreement regarding the definition of these terms and even whether these are useful concepts for researchers studying change over time. A theoretical approach, the TASC-based approach is presented as an alternative account for examining change over time. The TASC label stands for a focus on particular tasks, adaptation and selection of behaviors as a function of constraints. This account is grounded in evolutionary theory and assumes that variability, selection, and adaptation are central to change over time within individuals. Emphasis is placed on the tasks individuals attempt to solve in achieving particular goals given the constraints of the local environment and the organism. An alternative manner to conceptualize the concepts of development and learning are presented within the TASC-based approach.     

A dynamical systems interpretation of epigenetic landscapes for infant motor development

This paper presents a unified dynamical systems theory of motor learning and development and addresses the normative order and timing of activities in the infant motor development sequence. The emphasis is on the role of intention in modulating the epigenetic landscapes to the emerging forms of infant motor development and how the evolution of attractor landscape dynamics in infancy arises from the multiple time scales of constraints to action. The development of prone progression in infancy is exemplified as a case study and experimental hypotheses of the theory of attractor landscape dynamics and infant motor development are provided.     

Compensatory properties of visual information in the control of isometric force

This experiment investigated the effects of spatial (gain) and temporal (frequency) properties of visual feedback on the control of isometric force output. Participants performed an index finger isometric force production task with five different levels of visual gain and four feedback frequencies. There was a significant effect of gain on mean and standard deviation (SD) of the force output, whereas feedback frequency significantly affected the force SD and root-mean square error. Significant effects of gain and frequency and a gain X frequency interaction on the approximate entropy (ApEn) of the force revealed the effect of visual feedback uncertainty on the force fluctuation dynamics. The combined effects of the spatial and temporal properties of visual feedback on ApEn were approximated by a sum of quadratic functions, indicating their compensatory effect on the informational content of the dynamics of isometric force.     

Effects of race on responses and response latencies in the weapon identification task: a test of six models

The authors consider six models of underlying process in the weapon identification task: The first two are response-time extensions of signal detection models; the last four, of the process dissociation model. Predictions for accuracy data, correct response latencies, and false response latencies are used to discriminate between models. In the present study, racial bias in responses and correct response latency was replicated. New findings were that the direction of bias was reversed in error latency and that errors were faster than correct responses. These findings rule out four models, in particular, the idea that race biases early perception and interpretation of targets. Implications for reducing errors in the weapon identification task and possibilities of discriminating between the remaining two models are discussed.     

Social presence effects on the stroop task: Boundary conditions and an alternative account

Two studies investigated boundary conditions of an effect of social presence on the Stroop task and its interpretation in terms of an attentional view (P. Huguet, M. P. Galvaing, J. M. Monteil, & F. Dumas, 1999). In this view, social presence leads to attentional focusing, enhancing participants’ ability to screen out the distracting features of Stroop stimuli. As predicted, Stroop interference was found to be reduced by social presence, but an alternative account in which social presence exerts an effect on task selection received more support.     

Episodic future thought and its relation to remembering: evidence from ratings of subjective experience

The goal of the present study was to examine the hypothesis that the ability to construct vivid mental images of the future involves sampling the contents of memory. In two experiments, participants envisioned future scenarios occurring in contextual settings that were represented in memory in varying degrees of perceptual detail. In both experiments, detailed contextual settings were associated with more detailed images of the future and a stronger subjective experience. Our findings suggest that the contents of memory are routinely sampled during the construction of personal future scenarios.