Understanding memory impairment with memory models and hierarchical Bayesian analysis

The study of human episodic memory is a topic that interests cognitive and mathematical psychologists as well as clinicians interested in the diagnosis and assessment of Alzheimer’s disease and related disorders (ADRD). In this paper, we use simple cognitive models for the recognition and recall tasks typically applied in clinical assessments of ADRD to study memory performance in ADRD patients. Our models make use of hierarchical Bayesian methods as a way to model individual differences in patient performance and to facilitate the modeling of performance changes that occur during multiple recall tasks. We show how the models are able to account for different aspects of patient performance, and also discuss some of the predictive capabilities of the model. We conclude with a discussion on the scope to improve on our results by discussing the link between memory theory in psychology and clinical practice.     

Hierarchical models of simple mechanisms underlying confidence in decision making

Choice confidence is a central measure in psychological decision research, often being reported on a probabilistic scale. Simple mechanisms that describe the psychological processes underlying choice confidence, including those based on error and confirmation biases, have typically received support via fits to data averaged over subjects. While averaged data ease model development, they can also destroy important aspects of the confidence data distribution. In this paper, we develop a hierarchical model of raw confidence judgments using the beta distribution, and we implement two simple confidence mechanisms within it. We use Bayesian methods to fit the hierarchical model to data from a two-alternative confidence experiment, and we use a variety of Bayesian tools to diagnose shortcomings of the simple mechanisms that are overlooked when applied to averaged data. Bugs code for estimating the models is also supplied.     

Real three-dimensional objects: effects on mental rotation

The current experiment investigated real three-dimensional (3D) objects with regard to performance on a mental rotation task and whether the appearance of sex differences may be mediated by experiences with spatially related activities. 40 men and 40 women were presented with alternating timed trials consisting of real-3D objects or two-dimensional illustrations of 3D objects. Sex differences in spatially related activities did not significantly influence the finding that men outperformed women on mental rotation of either stimulus type. However, on measures related to spatial activities, self-reported proficiency using maps correlated positively with performance only on trials with illustrations whereas self-reported proficiency using GPS correlated negatively with performance regardless of stimulus dimensionality. Findings may be interpreted as suggesting that rotating real-3D objects utilizes distinct but overlapping spatial skills compared to rotating two-dimensional representations of 3D objects, and real-3D objects can enhance mental rotation performance.     

Self-other rating agreement and leader-member exchange (LMX)

Data from a sample of 83 elected community leaders and 391 direct-report staffers (resulting in 306 useable leader-member dyads) were used to test relations between self-other rating agreement of leadership and member-reported leader-member exchange (LMX). Results of polynomial regression analysis indicated that the self-other rating agreement model was not significantly related to member-reported LMX. Instead, virtually all of the variance in member-reported LMX was accounted for by others' ratings.     

Self-reported experience of bullying of students who stutter: relations with life satisfaction, life orientation, and self-esteem

Self-reported self-esteem, life orientation, satisfaction with life, and bullying were examined in relation to victimization experiences among 54 students who stuttered and 54 students who did not stutter. Those who stuttered reported greater, i.e., clinically significant, victimization (44.4%) than students who did not stutter (9.2%). Significant differences were found between means for self-esteem and life orientation, with students who stuttered reporting lower self-esteem and less optimistic life orientation than those who did not stutter. In both groups of students, high victimization scores had statistically significant negative correlations with optimistic life orientation, high self-esteem, and high satisfaction with life scores. Given the increased likelihood of students who stuttered being bullied, the negative relation of adjustment variables and bullying, and the potentially negative long-term effects of bullying, increased vigilance and early intervention are discussed.     

Frequency of lucid dreaming in a representative German sample

Lucid dreams occur when a person is aware that he is dreaming while he is dreaming. In a representative sample of German adults (N = 919), 51% of the participants reported that they had experienced a lucid dream at least once. Lucid dream recall was significantly higher in women and negatively correlated with age. However, these effects might be explained by the frequency of dream recall, as there was a correlation of .57 between frequency of dream recall and frequency of lucid dreams. Other sociodemographic variables like education, marital status, or monthly income were not related to lucid dream frequency. Given the relatively high prevalence of lucid dreaming reported in the present study, research on lucid dreams might be pursued in the sleep laboratory to expand the knowledge about sleep, dreaming, and consciousness processes in general.     

Dynamic adaptation to history of trial difficulty explains the effect of congruency proportion on masked priming

In reaction time research, there has been an increasing appreciation that response-initiation processes are sensitive to recent experience and, in particular, the difficulty of previous trials. From this perspective, the authors propose an explanation for a perplexing property of masked priming: Although primes are not consciously identified, facilitation of target processing by a related prime is magnified in a block containing a high proportion of related primes and a low proportion of unrelated primes relative to a block containing the opposite mix (Bodner & Masson, 2001). In the present study, this phenomenon is explored with a parity (even/odd) decision task in which a prime (e.g., 2) precedes a target that can be either congruent (e.g., 4) or incongruent (e.g., 3). It is shown that the effect of congruence proportion with masked primes cannot be explained in terms of the blockwise prime-target contingency. Specifically, with masked primes, there is no congruency disadvantage in a block containing a high proportion of incongruent primes, but there is a congruency advantage when the block contains an equal proportion of congruent and incongruent primes. In qualitative contrast, visible primes are sensitive to the blockwise prime-target contingency. The authors explain the relatedness proportion effect found with masked primes in terms of a model according to which response-initiation processes adapt to the statistical structure of the environment, specifically the difficulty of recent trials. This account is supported with an analysis at the level of individual trials using the linear mixed effects model.     

Miller (1944) revisited: Movement times in relation to approach and avoidance conflicts

Three experiments (total N = 291) sought to provide support for the idea that avoidance conflicts, relative to approach conflicts, are more difficult to motorically resolve. Conflicts were instantiated by asking individuals to approach desirable stimuli and avoid undesirable stimuli under conditions in which there was no objectively-correct direction of movement. To control for baseline movement speeds, non-conflict trials presented desirable (e.g., reward) and undesirable (e.g., threat) stimuli in the absence of any spatial conflict. In addition, movement times were isolated through the use of a joystick movement paradigm in which movement speeds were quantified subsequent to some initial tendency to move in one direction or the other. Consistent with hypotheses, all experiments found that movement times were slowed in the context of avoidance conflicts relative to approach conflicts. Results are discussed in terms of theories of motivation, affective processing, conflict, and anxiety.     

Companions in Presence: Animal Assistants and Eldercare

Honoring the scholarship and teaching of Professor William M. Clements, this critically reflective essay expands the possibilities for a ministry of presence. The paper argues that animals can be helpful companions in care with elderly adults. The author draws from experiential stories, object relations theory, process theology, and empirical studies, to argue the beneficial aspects of animal assistants for human care receivers and caregivers. A creation-inclusive relational theology informs strategies for care.