A comparison of three simple test theory models

In very simple test theory models such as the Rasch model, a single parameter is used to represent the ability of any examinee or the difficulty of any item. Simple models such as these provide very important points of departure for more detailed modeling when a substantial amount of data are available, and are themselves of real practical value for small or even medium samples. They can also serve a normative role in test design.As an alternative to the Rasch model, or the Rasch model with a correction for guessing, a simple model is introduced which characterizes strength of response in terms of the ratio of ability and difficulty parameters rather than their difference. This model provides a natural account of guessing, and has other useful things to contribute as well. It also offers an alternative to the Rasch model with the usual correction for guessing. The three models are compared in terms of statistical properties and fits to actual data. The goal of the paper is to widen the range of minimal models available to test analysts.This research was supported by grant AP320 from the Natural Sciences and Engineering Research Council of Canada. The author is grateful for discussions with M. Abrahamowicz, I. Molenaar, D. Thissen, and H. Wainer.     

Children's Explanations as a Window Into Their Intuitive Theories of the Social World

Social categorization is an early emerging and robust component of social cognition, yet the role that social categories play in children's understanding of the social world has remained unclear. The present studies examined children's (N = 52 four‐ and five‐year olds) explanations of social behavior to provide a window into their intuitive theories of how social categories constrain human action. Children systematically referenced category memberships and social relationships as causal‐explanatory factors for specific types of social interactions: harm among members of different categories more than harm among members of the same category. In contrast, they systematically referred to agents' mental states to explain the reverse patterns of behaviors: harm among members of the same category more than harm among members of different categories. These data suggest that children view social category memberships as playing a causal‐explanatory role in constraining social interactions.     

Relationship between social anxiety and perceived trustworthiness

Four different patterns of biased ratings of facial expressions of emotions have been found in socially anxious participants: higher negative ratings of (1) negative, (2) neutral, and (3) positive facial expressions than nonanxious controls. As a fourth pattern, some studies have found no group differences in ratings of facial expressions of emotion. However, these studies usually employed valence and arousal ratings that arguably may be less able to reflect processing of social information. We examined the relationship between social anxiety and face ratings for perceived trustworthiness given that trustworthiness is an inherently socially relevant construct. Improving on earlier analytical strategies, we evaluated the four previously found result patterns using a Bayesian approach. Ninety-eight undergraduates rated 198 face stimuli on perceived trustworthiness. Subsequently, participants completed social anxiety questionnaires to assess the severity of social fears. Bayesian modeling indicated that the probability that social anxiety did not influence judgments of trustworthiness had at least three times more empirical support in our sample than assuming any kind of negative interpretation bias in social anxiety. We concluded that the deviant interpretation of facial trustworthiness is not a relevant aspect in social anxiety.     

Two causal theories of counterfactual conditionals

Bayes nets are formal representations of causal systems that many psychologists have claimed as plausible mental representations. One purported advantage of Bayes nets is that they may provide a theory of counterfactual conditionals, such as If Calvin had been at the party, Miriam would have left early. This article compares two proposed Bayes net theories as models of people's understanding of counterfactuals. Experiments 1-3 show that neither theory makes correct predictions about backtracking counterfactuals (in which the event of the if-clause occurs after the event of the then-clause), and Experiment 4 shows the same is true of forward counterfactuals. An amended version of one of the approaches, however, can provide a more accurate account of these data.     

Agents and Causes: Dispositional Intuitions As a Guide to Causal Structure

Currently, two frameworks of causal reasoning compete: Whereas dependency theories focus on dependencies between causes and effects, dispositional theories model causation as an interaction between agents and patients endowed with intrinsic dispositions. One important finding providing a bridge between these two frameworks is that failures of causes to generate their effects tend to be differentially attributed to agents and patients regardless of their location on either the cause or the effect side. To model different types of error attribution, we augmented a causal Bayes net model with separate error sources for causes and effects. In several experiments, we tested this new model using the size of Markov violations as the empirical indicator of differential assumptions about the sources of error. As predicted by the model, the size of Markov violations was influenced by the location of the agents and was moderated by the causal structure and the type of causal variables.     

Do We “do”?

A normative framework for modeling causal and counterfactual reasoning has been proposed by Spirtes, Glymour, and Scheines (1993; cf. Pearl, 2000). The framework takes as fundamental that reasoning from observation and intervention differ. Intervention includes actual manipulation as well as counterfactual manipulation of a model via thought. To represent intervention, Pearl employed the do operator that simplifies the structure of a causal model by disconnecting an intervened-on variable from its normal causes. Construing the do operator as a psychological function affords predictions about how people reason when asked counterfactual questions about causal relations that we refer to as undoing, a family of effects that derive from the claim that intervened-on variables become independent of their normal causes. Six studies support the prediction for causal (A causes B) arguments but not consistently for parallel conditional (if A then B) ones. Two of the studies show that effects are treated as diagnostic when their values are observed but nondiagnostic when they are intervened on. These results cannot be explained by theories that do not distinguish interventions from other sorts of events.     

On the Stability of Psychological Hardiness: A Three-Year Longitudinal Study

More than 30 years of research has established psychological hardiness as an important individual resiliency resource. One important question still remaining is whether psychological hardiness can be trained. The present study explored this question longitudinally within the context of a 3-year military academy training program. Cadets from 3 different Norwegian military academies (N = 293) completed hardiness questionnaires during the first week of their training, and then again at the end of each year, resulting in a total of 4 waves of data. Using hierarchical linear modeling, no statistically significant effect of time on hardiness scores was found. The nonsignificant growth parameter was examined further using Bayesian statistics as an indicator of the relative evidence for the null hypothesis of no change over time versus the alternative hypothesis of change. The resulting Bayes factor provided substantial support in our data for the null hypothesis of no hardiness development during the 3-year officer training programs.     

The intuitive case for naïve realism

Naïve realism, the view that perceptual experiences are irreducible relations between subjects and external objects, has intuitive appeal, but this intuitive appeal is sometimes thought to be undermined by the possibility of certain kinds of hallucinations. In this paper, I present the intuitive case for naïve realism, and explain why this intuitive case is not undermined by the possibility of such hallucinations. Specifically, I present the intuitive case for naïve realism as arguing that the only way to make sense of the phenomenal character associated with perceptual experiences is by means of a naïve realist ontology. I then explain why this intuitive argument is not undermined by the possibility of hallucinatory experiences that possess the phenomenal character associated with perceptual experiences but, being hallucinations, do not have the ontological nature specified by naïve realism.