A Structural Modeling Examination of the Executive Decline Hypothesis of Cognitive Aging Through Reanalysis of Crawford et al.'s (2000) Data

This study presents a new analysis of data previously published by Crawford, Bryan, Luszcz, Obansawin, and Stewart (2000) examining the role of executive function in age-related declines in general cognitive ability and memory. Although the original authors' question is relevant to understanding the role of executive function in aging, this paper argues that the methods used can be substantially improved to more accurately answer the question. Thus, Crawford et al.'s data are here analyzed using a more parsimonious methodological approach (structural equation modeling), and the results obtained depart from the authors' results but are in line with their original hypotheses. First, for younger individuals, age was differently associated with verbal measures of cognitive ability than with performance measures. Although the relation of age to executive function was stronger than the relation of age to verbal abilities, this difference was not apparent with regard to performance abilities. Second, across samples (i.e., younger and older individuals), memory was not accounted for by cognitive ability but was related to age and executive function. Finally, also across samples, executive function was strongly linked to recall and recognition measures, accounting for the largest variance in memory. These results are discussed in relation to previous findings as well as their theoretical significance for aging research.     

Compression as a Universal Principle of Animal Behavior

A key aim in biology and psychology is to identify fundamental principles underpinning the behavior of animals, including humans. Analyses of human language and the behavior of a range of non‐human animal species have provided evidence for a common pattern underlying diverse behavioral phenomena: Words follow Zipf's law of brevity (the tendency of more frequently used words to be shorter), and conformity to this general pattern has been seen in the behavior of a number of other animals. It has been argued that the presence of this law is a sign of efficient coding in the information theoretic sense. However, no strong direct connection has been demonstrated between the law and compression, the information theoretic principle of minimizing the expected length of a code. Here, we show that minimizing the expected code length implies that the length of a word cannot increase as its frequency increases. Furthermore, we show that the mean code length or duration is significantly small in human language, and also in the behavior of other species in all cases where agreement with the law of brevity has been found. We argue that compression is a general principle of animal behavior that reflects selection for efficiency of coding.     

Exploring the Dynamics of Dyadic Interactions via Hierarchical Segmentation

In this article we present an exploratory tool for extracting systematic patterns from multivariate data. The technique, hierarchical segmentation (HS), can be used to group multivariate time series into segments with similar discrete-state recurrence patterns and it is not restricted by the stationarity assumption. We use a simulation study to describe the steps and properties of HS. We then use empirical data on daily affect from one couple to illustrate the use of HS for describing the affective dynamics of the dyad. First, we partition the data into three periods that represent different affective states and show different dynamics between both individuals’ affect. We then examine the synchrony between both individuals’ affective states and identify different patterns of coherence across the periods. Finally, we discuss the possibilities of using results from HS to construct confirmatory dynamic models with multiple change points or regime-specific dynamics.     

Reducing teachers' psychological distress through a mindfulness training program

Teachers constitute one of the professional collectives most affected by psychological problems. The purpose of this quasi-experimental study is to examine the efficacy of a mindfulness training programme to reduce psychological distress in a group of teachers. The sample comprised 68 teachers of Secondary School Education, from various public schools; half of them formed the experimental group, and the another half the control group. The levels of psychological distress were measured, in both groups, by the Symptom Checklist-90-R (SCL-90-R) before and after the application of the programme. Statistical analysis shows the significant reduction of three general measures of psychological distress (Global Severity Index, Positive Symptom Distress Index, and Positive Symptom Total), as well in all its dimensions (somatization, obsessive-compulsive, interpersonal sensibility, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism), in the experimental group compared with the control group. Follow-up measures show that these results were maintained for four months after termination of the intervention in the experimental group.