Psychometric Modeling of response speed and accuracy with mixed and conditional regression

Human performance in cognitive testing and experimental psychology is expressed in terms of response speed and accuracy. Data analysis is often limited to either speed or accuracy, and/or to crude summary measures like mean response time (RT) or the percentage correct responses. This paper proposes the use of mixed regression for the psychometric modeling of response speed and accuracy in testing and experiments. Mixed logistic regression of response accuracy extends logistic item response theory modeling to multidimensional models with covariates and interactions. Mixed linear regression of response time extends mixed ANOVA to unbalanced designs with covariates and heterogeneity of variance. Related to mixed regression is conditional regression, which requires no normality assumption, but is limited to unidimensional models. Mixed and conditional methods are both applied to an experimental study of mental rotation. Univariate and bivariate analyzes show how within-subject correlation between response and RT can be distinguished from between-subject correlation, and how latent traits can be detected, given careful item design or content analysis. It is concluded that both response and RT must be recorded in cognitive testing, and that mixed regression is a versatile method for analyzing test data.I am grateful to Rogier Donders for putting his data at my disposal.     

Adolescent Psychopathy and the Big Five: Results from Two Samples

The present study examines the relation between psychopathy and the Big Five dimensions of personality in two samples of adolescents. Specifically, the study tests the hypothesis that the aspect of psychopathy representing selfishness, callousness, and interpersonal manipulation (Factor 1) is most strongly associated with low Agreeableness, whereas the aspect of psychopathy representing impulsivity, instability, and social deviance (Factor 2) is associated with low Agreeableness, low Conscientiousness, and high Neuroticism. Data from 13- and 16-year-old boys and their mothers from two samples of the Pittsburgh Youth Study are used to test these hypotheses. Results were consistent across age and rating source in supporting the initial hypotheses, providing support for the construct of juvenile psychopathy and the interpretation of psychopathy as a constellation of traits drawn from a general model of personality functioning.     

Distinctive processing underlies skilled memory

Research on skilled memory has focused on organizational processes to the exclusion of item-specific processes, although theories of skilled memory do acknowledge the importance of both kinds of processes. Using the isolation methodology, we presented lists of American football team names to participants who had either a high or a low level of knowledge about American football. An isolation effect (greater recall of the target in the isolate list than in a homogeneous control list) was observed only with high-knowledge participants. When standard lists were used, an isolation effect was observed with both groups. These findings empirically validate the importance of both organizational and item-specific processing as the basis of distinctive processing underlying skilled memory performance.     

Human cognition and 1/f scaling

Ubiquitous 1/f scaling in human cognition and physiology suggests a mind-body interaction that contradicts commonly held assumptions. The intrinsic dynamics of psychological phenomena are interaction dominant (rather than component dominant), and the origin of purposive behavior lies with a general principle of self-organization (rather than a special neurocognitive mechanism). E.-J. Wagenmakers, S. Farrell, and R. Ratcliff (2005) raised concerns about the kinds of data and analyses that support generic 1/f scaling. This reply is a defense that furthermore questions the model that Wagenmakers and colleagues endorse and their strategy for addressing complexity.     

Individual pattern representations are context independent, but their collective representation is context dependent.

We studied context dependency of the representations underlying perceptual "goodness". Three experiments used a same-different task with classical Garner 5-dot patterns presented with an interstimulus interval (ISI) of 500 ms. Same patterns were allowed to be rotated or reflected versions of each other. Pattern goodness was varied according to rotation and reflection equivalence, using Garner's equivalence set size (ESS) measure. The ESS of both first and second patterns affected reaction time and accuracy. A model based on assumptions that Garner's equivalence sets constitute the generic representation of these patterns and that items within these sets are accessed serially was fitted to the data. Excellent fits were obtained, which were robust against frequency-induced bias at the level of the individual pattern, but sensitive to such bias at the level of the equivalence set. It was concluded that individual pattern representations are context independent, whereas their collective representations are context dependent. Simplicity and likelihood principles, therefore, seem to apply to different levels of a representation hierarchy.     

Studying individual aging in an interindividual context: typical paths of age-related, dementia-related, and mortality-related cognitive development in old age

This study has 2 objectives: (a) to explore typical paths of cognitive development associated with aging, terminal decline, and dementia and (b) to promote and illustrate an individual-oriented approach to the study of cognitive aging based on longitudinal panel data from a population-based sample (N = 500; age range-sub(T1)= 60-80, where T refers to time) tested at 3 occasions 5 years apart. Results document interindividual differences in multivariate patterns of change. Although cognitive changes generally covary, the present study indicates that subgroups of individuals develop along different paths characterized by selective changes in subsets of cognitive functions. Typical progression of dementia followed a developmental cascade from low declarative memory, via low functioning across all observed cognitive measures, to dementia diagnosis, and finally, death.     

Classification of Antisocial Behaviors Along Severity and Frequency Parameters

Antisocial behaviors were systematically classified along a hierarchy of seriousness or severity that also accounted for frequency of occurrence and heterogeneity of behaviors. Items from the CD and ODD schedules of the NIMH DISC-IV and from the Elliot Delinquency Scales were listed at specified frequencies. Nine mental health clinicians rated the level of seriousness of each alternative on a scale from 0 (trivial) to 5 (very serious). Reliability of the ratings was assessed. Over two thirds of the items showed excellent agreement among the raters, 8% showed poor agreement and 21% showed fair to moderate agreement. The overall reliability of a single rater’s score was 0.56 and the reliability of the average was 0.84. The classification meets high psychometric standards for reliability and has face validity. The final output provides a classification along a spectrum that takes into account severity, frequency of occurrence during the previous year, and presence of multiple behaviors. It is useful for classification purposes and for longitudinal tracking of antisocial behavior.     

Compatibility effects based on stimulus and response numerosity

Four choice reaction time experiments documented a stimulus-response (S-R) compatibility effect involving the numbers of stimuli and responses. In Experiment 1, the stimulus consisted of one or two tones, and the correct response was either one or two taps of a response key. Responses were much faster with a compatible S-R assignment, in which the number of taps matched the number of tones, than with an incompatible assignment in which these numbers mismatched. Experiments 2 and 3 replicated this effect, using visual stimuli and bimodal stimuli, respectively, suggesting that auditory/manual rhythmic compatibility is not essential to it. Experiment 4 showed that an analogous but smaller effect is obtained when stimuli are the digits 1 and 2. This new numerosity-based compatibility effect has general theoretical implications regarding the mechanisms responsible for compatibility effects and practical implications for interface design.