Extending the Basic Local Independence Model to Polytomous Data

Psychometrika - A probabilistic framework for the polytomous extension of knowledge space theory (KST) is proposed. It consists in a probabilistic model, called polytomous local independence model,...     

A New Perspective on the Philosophical Implications of Quantum Field Theory

I discuss issues concerning the philosophical foundations andimplications of quantum field theory, renormalization inparticular. A new understanding of the correspondence principle,an unexpected role of perturbation theory and, most of all, acriterion to reduce the set of consistent theories frominfinitely many to finitely many, are the key concepts of atheoretical set-up that appears to overcome in a natural wayvarious consistency problems of quantum mechanics and offerseveral hints for further developments.     

Altered Cortico-Limbic Functional Connectivity During an Empathy Task in Subjects with Post-Traumatic Stress Disorder

Empathy is a multidimensional construct consisting of cognitive (inferring mental states) and emotional (empathic concern) components. Emotional empathy is severely impaired in individuals affected by Post-Traumatic Stress Disorder (PTSD). Here, we investigated the neural correlates of such an emotional empathy dysfunction to shed light on the neural circuitry responsible for the social and emotional dysfunction in PTSD. We asked a group of PTSD and a group of healthy controls to solve a Multifaceted Empathy Test, measuring both cognitive and emotional empathy, and investigated the functional connectivity of the cortical areas involved in solving the test. The results revealed that, in healthy individuals, increased neural activity in the frontal cortex modulates activity in the insula while subjects perform the emotional empathy task; whereas, in individuals affected by PTSD, increased activity in limbic regions such the insula and the amygdala modulates activity in the frontal cortex while performing the emotional empathy task. These findings suggest that the lack of cortical top-down control of the frontal cortex on the limbic system in PTSD during empathic processing may explain the emotional and social difficulties experienced by individuals suffering from PTSD.     

The assessment of knowledge and learning in competence spaces: The gain–loss model for dependent skills

The gain–loss model (GaLoM) is a formal model for assessing knowledge and learning. In its original formulation, the GaLoM assumes independence among the skills. Such an assumption is not reasonable in several domains, in which some preliminary knowledge is the foundation for other knowledge. This paper presents an extension of the GaLoM to the case in which the skills are not independent, and the dependence relation among them is described by a well‐graded competence space. The probability of mastering skill s at the pretest is conditional on the presence of all skills on which s depends. The probabilities of gaining or losing skill s when moving from pretest to posttest are conditional on the mastery of s at the pretest, and on the presence at the posttest of all skills on which s depends. Two formulations of the model are presented, in which the learning path is allowed to change from pretest to posttest or not. A simulation study shows that models based on the true competence space obtain a better fit than models based on false competence spaces, and are also characterized by a higher assessment accuracy. An empirical application shows that models based on pedagogically sound assumptions about the dependencies among the skills obtain a better fit than models assuming independence among the skills.     

The Quality of Home Environment in Brazil: An Ecological Model

Based on Bronfenbrenner's (1999) ecological perspective, a longitudinal, prospective model of individual differences in the quality of home environment (Home Observation for Measurement of the Environment—HOME) was tested in a sample of 179 Brazilian children and their families. Perinatal measures of family socioeconomic status (SES) and child birth weight had direct effects on HOME at preschool age. As either family SES or child birth weight increased, HOME also increased through diminished emotional distress in the mother a month following childbirth. SES had a negative effect on number of children in the household, which in turn had a long-term negative impact on HOME. Compared to mothers who had reported not to plan their pregnancy, those who did were more likely to have fewer children, to report more spouse support during childbearing, and to show less emotional distress a month after childbirth, all of which also influenced HOME at preschool age. These findings are discussed in light of the broader socio-ecological Brazilian context, with direct implications to clinical practice aimed at improving the quality of home environment.     

Positive associations primacy in the IAT: a many-facet rasch measurement analysis

Two studies investigated the different contribution of positive and negative associations to the size of the Implicit Association Test (IAT) effect. A Many-Facet Rasch Measurement analysis was applied for the purpose. Across different IATs (Race and Weight) and different groups of respondents (White, Normal weight, and Obese people) we observed that positive words increase the IAT effect whereas negative words tend to decrease it. Results suggest that the IAT is influenced by a positive associations primacy effect. As a consequence, we argue that researchers should be careful when interpreting IAT effects as a measure of implicit prejudice.     

A discrimination–association model for decomposing component processes of the Implicit Association Test

A formal model is proposed that decomposes the Implicit Association Test (IAT) effect into three process components: stimuli discrimination, automatic association, and termination criterion. Both response accuracy and reaction time are considered. Four independent and parallel Poisson processes, one for each of the four label categories of the IAT, are assumed. The model parameters are the rate at which information accrues on the counter of each process and the amount of information that is needed before a response is given. The aim of this study is to present the model and an illustrative application in which the process components of a Coca–Pepsi IAT are decomposed.     

Uncovering the Best Skill Multimap by Constraining the Error Probabilities of the Gain-Loss Model

The Gain-Loss model is a probabilistic skill multimap model for assessing learning processes. In practical applications, more than one skill multimap could be plausible, while none corresponds to the true one. The article investigates whether constraining the error probabilities is a way of uncovering the best skill assignment among a number of alternatives. A simulation study shows that this approach allows the detection of the models that are closest to the correct one. An empirical application shows that it allows the detection of models that are entirely derived from plausible assumptions about the skills required for solving the problems.     

Testing the actual equivalence of automatically generated items

If the automatic item generation is used for generating test items, the question of how the equivalence among different instances may be tested is fundamental to assure an accurate assessment. In the present research, the question was dealt by using the knowledge space theory framework. Two different ways of considering the equivalence among instances are proposed: The former is at a deterministic level and it requires that all the instances of an item template must belong to exactly the same knowledge states; the latter adds a probabilistic level to the deterministic one. The former type of equivalence can be modeled by using the BLIM with a knowledge structure assuming equally informative instances; the latter can be modeled by a constrained BLIM. This model assumes equality constraints among the error parameters of the equivalent instances. An approach is proposed for testing the equivalence among instances, which is based on a series of model comparisons. A simulation study and an empirical application show the viability of the approach.