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.     

The influence of restricted viewing conditions on egocentric distance perception: implications for real and virtual indoor environments

We carried out three experiments to examine the influence of field of view and binocular viewing restrictions on absolute distance perception in real-world indoor environments. Few of the classical visual cues provide direct information for accurate absolute distance judgments to points in the environment beyond about 2 m from the viewer. Nevertheless, in previous work it has been found that visually directed walking tasks reveal accurate distance estimations in full-cue real-world environments to distances up to 20 m. In contrast, the same tasks in virtual environments produced with head-mounted displays (HMDs) show large compression of distance. Field of view and binocular viewing are common limitations in research with HMDs, and have been rarely studied under full pictorial-cue conditions in the context of distance perception in the real-world. Experiment 1 showed that the view of one's body and feet on the floor was not necessary for accurate distance perception. In experiment 2 we manipulated the horizontal and the vertical field of view along with head rotation and found that a restricted field of view did not affect the accuracy of distance estimations when head movement was allowed. Experiment 3 showed that performance with monocular viewing was equal to that with binocular viewing. These results have implications for the information needed to scale egocentric distance in the real-world and reduce the support for the hypothesis that a limited field of view or imperfections in binocular image presentation are the cause of the underestimation seen with HMDs.     

List discrimination in associative recognition and implications for representation

Four experiments tested the predictions made by the model outlined in A. H. Criss and R. M. Shiffrin (2004b). Participants studied 2 successive lists of pairs followed by a recognition memory test for the most recent list. Some items and some pairs were repeated across the 2 lists. Critically, a given item could be repeated in the same or different type of pair. For associative recognition, performance was only affected by repetitions in the same pair type. However, in single-item recognition confusions occurred for both types of repetitions. The results are as predicted and confirm the assumption that different associative representations were stored even when the same token repeated in different pair types, whereas similar item representations were used regardless of pair type.     

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.     

Not the same old hindsight bias: Outcome information distorts a broad range of retrospective judgments

The hindsight bias (e.g., Fischhoff, 1975) illustrates that outcome information can make people believe that they would have (or did) predict an outcome that they would not (or did not) actually predict. In two experiments, participants (N = 226) made a prediction immediately before receiving outcome information. Therefore, participants could not distort or misremember their predictions to make them align with the outcome information. In both experiments, participants distorted their reports of how certain they recalled having been in their prediction, how good of a basis they had for making the prediction, how long they took to make the prediction, and so forth. Experiment 2 showed that these effects were diminished when participants engaged in private thought about the upcoming questions prior to receiving outcome information, suggesting that the effect is not due to impression management concerns.     

Sexual victimization in relation to perceptions of risk: mediation, generalization, and temporal stability

There is evidence that personal experience with trauma is associated with increases in both personal and comparative risk perception. This study investigates this relation in terms of sexual victimization among women, focusing on three potential mediators: perceived control over sexual assault, perceived similarity to a typical sexual assault victim, and psychological distress. Mediational analyses were investigated using structural equation modeling. Although victimization experience was not related to comparative risk perception, it was associated with greater personal risk perception. This relation was mediated by perceived similarity to a typical sexual assault victim. Prospective analyses indicated that personal risk perception does change in response to sexual victimization but also indicated that heightened risk perception may be an accurate assessment of risk that actually precedes victimization experience. Implications for the meaning of perceived similarity and perceptions of risk for sexual assault victims are discussed.     

Identity and emergency intervention: how social group membership and inclusiveness of group boundaries shape helping behavior

Two experiments exploring the effects of social category membership on real-life helping behavior are reported. In Study 1, intergroup rivalries between soccer fans are used to examine the role of identity in emergency helping. An injured stranger wearing an in-group team shirt is more likely to be helped than when wearing a rival team shirt or an unbranded sports shirt. In Study 2, a more inclusive social categorization is made salient for potential helpers. Helping is extended to those who were previously identified as out-group members but not to those who do not display signs of group membership. Taken together, the studies show the importance of both shared identity between bystander and victim and the inclusiveness of salient identity for increasing the likelihood of emergency intervention.     

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.