MULTIDIMENSIONAL SCALING OF GEOMETRICAL FIGURES

In two experiments with geometrical figures as stimuli, constructed in order to generate perceptual variation of roundness and height, four multidimensional scaling methods were compared, two metric and two nonmetric. The methods gave similar solutions. The fact that the solutions could be interpreted in accordance with expectations, points to the validity of the methods.     

Reply to William R. Ferrell’s paper “A model for realism of confidence judgments: Implications for underconfidence in sensory discrimination”

Ferrell’s decision-variable partition model and our subjective distance model belong to the same family of Thurstonial models. The subjective distance model is limited to sensory discrimination with the method of constant stimuli and rooted in such notions as discriminal dispersion and sense distance. Ferrell’s model is intended to be wider in scope and to apply to both cognitive and sensory tasks. Both models need supplementary assumptions to predict calibration phenomena. The point of departure for us is the fact that the model predicts under-confidence under “guessing” and the empirical finding that people are about 100% correct when they report “absolutely certain.” Ferrell makes assumptions about cutoffs on the decision variable. The respondent is assumed to adjust or not adjust cutoffs according to “cues to difficulty.” We disagree with Ferrell’s claim that the hard-easy effect is explained by the respondent’s failure to adjust cutoffs sufficiently when there is a change in level of difficulty, and argue that this amounts to little more than a translation of the hard-easy effect into the lingua of Ferrell’s decision-variable partition model. Our argument is that the hard-easy effect is a consequence of the post hoc division of items according to solution probability. In addition, error variance may contribute to regression effects that enlarge the hard-easy effect. Finally, in contrast to Ferrell’s position, we regard inference (cognitive uncertainty) and discrimination (sensory uncertainty) as different psychological processes. An understanding of calibration in these two areas requires separate models.     

Two-step weighted least squares factor analysis of dichotomized variables

A two-step weighted least squares estimator for multiple factor analysis of dichotomized variables is discussed. The estimator is based on the first and second order joint probabilities. Asymptotic standard errors and a model test are obtained by applying the Jackknife procedure.     

A Dyadic IRT Model

Psychometrika - We propose a dyadic Item Response Theory (dIRT) model for measuring interactions of pairs of individuals when the responses to items represent the actions (or behaviors,...     

Distributional typicality: a new approach to estimating noun and verb usage from large scale text corpora

This paper reports a new approach to estimating the extent to which words have predominant noun and verb usages which do not require human judgments about parts of speech. The Hyperspace Analog to Language model (HAL, Lund & Burgess, 1996) was used to computationally estimate noun vs verb usage based on the statistical regularities present in a large-scale electronic text corpus. This measure can be used to estimate the extent to which a given word occurs in typical noun or verb sentence contexts (i.e., its distributional typicality) in informal contemporary discourse.     

Comparisons of three different investigative interview techniques with young children

After viewing a film of a mother hitting her son, a film not seen by the college student interviewers, children were misinformed about a detail (via exposure to a misleading question) as well as explicitly coached to disclose 3 false details. The children were then interviewed by interviewers who had previously learned 1 of 3 different interviewing procedures: the Yuille Step-Wise Interview developed by J. C. Yuille, R. Hunter, R. Joffe, & J. Zapamiuk (1993); a doll play interview developed by Action for Child Protection Inc. (1994); or the Modified Structured Interview developed for this study. The Modified Structured Interview yielded more "where" information and was better at detecting if coaching had occurred. However, the interviewers were not very good at discriminating suggested versus coached versus correct witnessed information. The authors found that the deeper one digs for memories, the more one uncovers incorrect versus correct items. They concluded that although the Modified Structured Interview was superior to the techniques currently in use, cautions are necessary.     

The Göteborg discothèque fire, 1998

Findings from a study of 563 adolescents’ reactions following a discotheque fire that killed 63 young people in Göteborg in October 1998 are presented. The group answered a questionnaire seven months following the disaster. The questionnaire included the Impact of Event Scale (IES) and the Birleson Depression Self‐Rating Scale (DSRS). The level of trauma was found to be very high, while depression scores were less elevated. A little under a third of the students scored above a clinical cut‐off point (> 35) on the IES, indicating high posttraumatic stress levels. Girls evidenced more depression and traumatic stress reactions than boys. Levels of reactions increased with more closeness (knowing victims personally) and if the adolescents were of non‐Swedish origin.