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,...     

Influence of delayed muscle reflexes on spinal stability: Model-based predictions allow alternative interpretations of experimental data

Model-based calculations indicate that reflex delay and reflex gain are both important for spinal stability. Experimental results demonstrate that chronic low back pain is associated with delayed muscle reflex responses of trunk muscles. The aim of the present study was to analyze the influence of such time-delayed reflexes on the stability using a simple biomechanical model. Additionally, we compared the model-based predictions with experimental data from chronic low back pain patients and healthy controls using surface-electromyography. Linear stability methods were applied to the musculoskeletal model, which was extended with a time-delayed reflex model. Lateral external perturbations were simulated around equilibrium to investigate the effects of reflex delay and gain on the stability of the human lumbar spine. The model simulations predicted that increased reflex delays require a reduction of the reflex gain to avoid spinal instability. The experimental data support this dependence for the investigated abdominal muscles in chronic low back pain patients and healthy control subjects. Reflex time-delay and gain dependence showed that a delayed reflex latency could have relevant influence on spinal stability, if subjects do not adapt their reflex amplitudes. Based on the model and the experimental results, the relationship between muscle reflex response latency and the maximum of the reflex amplitude should be considered for evaluation of (patho) physiological data. We recommend that training procedures should focus on speeding up the delayed reflex response as well as on increasing the amplitude of these reflexes.     

What determines a feeling's position in affective space? A case for appraisal

The location of verbally reported feelings in a three-dimensional affective space is determined by the results of appraisal processes that elicit the respective states. One group of participants rated their evaluation of 59 pictures from the International Affective Picture System (IAPS) on a profile of nine appraisal criteria. Another group rated their affective reactions to the same pictures on the classic dimensions of affective meaning (valence, arousal, potency). The ratings on the affect dimensions correlate differentially with specific appraisal ratings. These results can be interpreted as showing that the reactions to the IAPS pictures are predictably produced through appraisal of picture content. The relevance of the findings for emotion induction paradigms and for emotion theory in general is discussed.     

Parent Programs for Reducing Adolescent’s Antisocial Behavior and Substance Use: A Randomized Controlled Trial

Two theoretically based parent training programs, delivered in real-world settings by the social services, were examined in this randomized controlled trial for effectiveness in reducing adolescents’ antisocial behavior and substance use. Two hundred and thirty-seven (237) adolescents in ages between 12 and 18 and their parents were assigned to one of two programs or to a wait-list control condition. The programs were the nine weekly group sessions program Comet 12–18 (Swedish Parent Management Training Program) and the six weekly ParentSteps (Swedish shortened version by Strengthening Families Program 10–14). Outcome measures were antisocial behavior, substance use, and delinquency, and psychosocial dysfunction. Data based on adolescents’ and parents’ ratings of the adolescents’ problem behavior at baseline and 6 months later were analyzed with repeated measures ANVOA, Logistic regression, and Kruskal–Wallis H test. The results showed that parents’ ratings of adolescents’ antisocial behaviors decreased significantly over time, but no time by group effect emerged. No program effects were found in the adolescents’ self-reported antisocial behavior, delinquency, or psychosocial functioning. A threefold risk of illicit drug use was found in both intervention groups. The results suggest that neither Comet nor ParentSteps had beneficial effects on adolescent’s antisocial or delinquent behavior, or on alcohol use. The only significant group difference found was a threefold risk of drug use in the intervention adolescents at follow-up, but for several reasons this finding should be interpreted with caution. Trial registration number: ISRCTN76141538.     

In‐court versus out‐of‐court testimonies: Children's experiences and adults' assessments

The study examined the effects of different presentation modes on child witnesses' experiences and adults' perception and assessments of the same witnesses. Child witnesses (N = 108) were interviewed about an event that they had either experienced or imagined. Adult mock jurors (N = 240) watched the children's testimonies live, via two‐way closed‐circuit television (CCTV), or via a pre‐recorded video. The results showed that the live observers perceived the children in more positive terms than did the two‐way CCTV observers, who in turn perceived the children in more positive terms than did the video observers. Briefly, it seems as the more proximal the presentation mode, the more positive the observers' perception. Somewhat in contrast to these results, a significantly smaller proportion of the children who testified on video stated that they were nervous, compared to the children who testified live or via two‐way CCTV. Copyright © 2009 John Wiley & Sons, Ltd.