Individual Pooling for Group-Based Modeling Under the Assumption of Ergodicity

Psychology principally utilizes nomothetic, interindividual approaches to model phenomena of interest. However, it is the case that these approaches do not always capture the processes for each individual in the sample. If the research is focused on individual processes, confining analysis to the idiographic level may be more appropriate. One way to overcome the nomothetic inability to capture idiographic processes is to identify those participants who meet the criteria of ergodicity and restrict analysis to the resulting sample. Under these conditions it is quantitatively justifiable to create a group model without concern that it may fail to represent each member's idiographic process. In this study we explore the utility of such a method by (a) applying an ergodic pooling test to a sample of dyads (N = 128) who provided daily (T = 50) self-reports of affect, (b) applying an ergodic pooling test to samples (N = 4) of simulated ergodic time series data (T = 50, 250, and 1,000), (c) modeling dyads and simulated subgroups identified as ergodic, and (d) comparing the results from a model specified at the group level with those from models specified at the individual level.     

The significance of the ergodic decomposition of stationary measures for the interpretation of probability

De Finetti's representation theorem is a special case of the ergodic decomposition of stationary probability measures. The problems of the interpretation of probabilities centred around de Finetti's theorem are extended to this more general situation. The ergodic decomposition theorem has a physical background in the ergodic theory of dynamical systems. Thereby the interpretations of probabilities in the cases of de Finetti's theorem and its generalization and in ergodic theory are systematically connected to each other.This paper is an extended version of footnote 5 of von Plato (1981).     

An economical system for collecting and reducing heart-rate data,using someone else’s small computer

Hardware and program are described for a heart-rate data collection and reduction system that uses a small computer at a time removed from the actual data collection. The system is portable and inexpensive; exclusive of the computer, it can cost under $1,500. It uses an ordinary tape recorder to record discrete signals upon each occurrence of a heart beat, and it returns edited second-by-second averages of interheart-beat intervals.     

Resilience,Life Events,and Well-Being During Midlife: Examining Resilience Subgroups

Developmental midlife processes involve resilience, changing challenges, and perceptions of getting older. In Study I and II, the Managing Life Survey resulted in growth, managing uncertainty, objectivity, adversity, and strategy use subscales. In Study II, resilience subgroups were identified. High and non-religious resilience groups had significantly higher averages for MLS subscales, time orientations, grit, life satisfaction; and significantly lower averages for adversity and negative event scores, compared to other groups. Noteworthy findings herein consist of (1) differences across resilience groups, with spiritual strategies emerging as an important discriminator; (2) the role of future perspectives on well-being characterizing early midlife; (3) the influence of growth and purpose on well-being characterizing late midlife; and (4) the cumulative effect of education on life satisfaction in late midlife. The results herein are consistent with the psychological benefits of moderate levels of challenge; with developmental differences across early and late midlife, and with Socioemotional Selectivity Theory.     

Average explanations

Good scientific explanations sometimes appear to make use of averages. Using concrete examples from current economic theory, I argue that some confusions about how averages might work in explanations lead to both philosophical and economic problems about the interpretation of the theory. I formulate general conditions on potentially proper uses of averages to refine a notion of average explanation. I then try to show how this notion provides a means for resolving longstanding philosophical problems in economics and other quantitative social sciences.Some of the ideas in this essay were presented at the Philosophy of Economics II Conference at Tilburg University. I thank the participants for helpful remarks.     

Bayesian change-point analysis reveals developmental change in a classic theory of mind task

Although learning and development reflect changes situated in an individual brain, most discussions of behavioral change are based on the evidence of group averages. Our reliance on group-averaged data creates a dilemma. On the one hand, we need to use traditional inferential statistics. On the other hand, group averages are highly ambiguous when we need to understand change in the individual; the average pattern of change may characterize all, some, or none of the individuals in the group. Here we present a new method for statistically characterizing developmental change in each individual child we study. Using false-belief tasks, fifty-two children in two cohorts were repeatedly tested for varying lengths of time between 3 and 5 years of age. Using a novel Bayesian change point analysis, we determined both the presence and—just as importantly—the absence of change in individual longitudinal cumulative records. Whenever the analysis supports a change conclusion, it identifies in that child’s record the most likely point at which change occurred. Results show striking variability in patterns of change and stability across individual children. We then group the individuals by their various patterns of change or no change. The resulting patterns provide scarce support for sudden changes in competence and shed new light on the concepts of “passing” and “failing” in developmental studies.     

Simple software for impedance cardiography

Simple software techniques for the digital analysis of impedance cardiography data are described. The software digitizes simultaneous impedance and ECG signals, averages these signals over time on a beat-by-beat basis, processes the averaged signals to locate relevant features, and computes heart rate, stroke volume, and cardiac output for the averaged period. The source and executable code, written in Pascal for a PDP-11 with standard peripheral addressing and a VT125 graphics terminal, is available from the authors.     

Illustrative Problems in College-Level Grading

Data from several institutional studies on collegiate grading are presented and warrant the following conclusions: Overtly, grading appears to be uniform and constant, but rising ability levels of students raise a question about consistency. This nonyielding grading distribution makes sequence courses particularly demanding. Wide variations in grade averages in multiple section courses again open up questions about consistency, especially because these fluctuations show no apparent relationship to student quality. Wide variations in grade averages for similar courses also raise questions about the meaningfulness of resulting grades.     

Understanding Personality through Patterns of Daily Socializing: Applying Recurrence Quantification Analysis to Naturalistically Observed Intensive Longitudinal Social Interaction Data

Ambulatory assessment methods provide a rich approach for studying daily behaviour. Too often, however, these data are analysed in terms of averages, neglecting patterning of this behaviour over time. This paper describes recurrence quantification analysis (RQA), a non-linear time series technique for analysing dynamic systems, as a method for analysing patterns of categorical, intensive longitudinal ambulatory assessment data. We apply RQA to objectively assessed social behaviour (e.g. talking to another person) coded from the Electronically Activated Recorder. Conceptual interpretations of RQA parameters, and an analysis of Electronically Activated Recorder data in adults going through a marital separation, are provided. Using machine learning techniques to avoid model overfitting, we find that adding RQA parameters to models that include just average amount of time spent talking (a static measure) improves prediction of four Big Five personality traits: extraversion, neuroticism, conscientiousness, and openness. Our strongest results suggest that a combination of average amount of time spent talking and four RQA parameters yield an R² = .09 for neuroticism. Neuroticism is shown to be associated with shorter periods of extended conversation (periods of at least 12 minutes), demonstrating the utility of RQA to identify new relationships between personality and patterns of daily behaviour. Materials: https://osf.io/5nkr9/ . © 2020 European Association of Personality Psychology     

Personality characteristics of Hare Krishnas

Personality characteristics of 132 males and 94 females of the Hare Krishna movement were assessed using the Comrey Personality Scales (CPS). Subjects were sampled from eight U.S. sites. Their age averaged about 30 years, and their time in the movement averaged 8.6 years. The most prominent and surprising finding is the hallmark characteristic of the Hare Krishna personality, a strong compulsivity trait common to both genders, which is slightly stronger in males. Reduced trust in society was exhibited by both gender averages, with slightly less trust among females. Both these averages, however, were within the normal range for individuals. With the exception of compulsivity, average male CPS scores were within the normal psychological range but differed significantly from the normative male group indicating idiosyncratic traits. Average female CPS scores did not differ significantly from the normative female group except for compulsivity and trust. Study of CPS score distributions about group means supported these findings.     

Personality Characteristics of Hare Krishnas

Personality characteristics of 132 males and 94 females of the Hare Krishna movement were assessed using the Comrey Personality Scales (CPS). Subjects were sampled from eight U.S. sites. Their age averaged about 30 years, and their time in the movement averaged 8.6 years. The most prominent and surprising finding is the hallmark characteristic of the Hare Krishna personality, a strong compulsivity trait common to both genders, which is slightly stronger in males. Reduced trust in society was exhibited by both gender averages, with slightly less trust among females. Both these averages, however, were within the normal range for individuals. With the exception of compulsivity, average male CPS scores were within the normal psychological range but differed significantly from the normative male group indicating idiosyncratic traits. Average female CPS scores did not differ significantly from the normative female group except for compulsivity and trust. Study of CPS score distributions about group means supported these findings.     

Face averages and multiple images in a live matching task

We know from previous research that unfamiliar face matching (determining whether two simultaneously presented images show the same person or not) is very error-prone. A small number of studies in laboratory settings have shown that the use of multiple images or a face average, rather than a single image, can improve face matching performance. Here, we tested 1,999 participants using four-image arrays and face averages in two separate live matching tasks. Matching a single image to a live person resulted in numerous errors (79.9% accuracy across both experiments), and neither multiple images (82.4% accuracy) nor face averages (76.9% accuracy) improved performance. These results are important when considering possible alterations which could be made to photo-ID. Although multiple images and face averages have produced measurable improvements in performance in recent laboratory studies, they do not produce benefits in a real-world live face matching context.     

The analysis of orientation-dependent time costs in visual recognition

How does the visual system recognise stimuli presented at different orientations? According to the multiple-views hypothesis, misoriented objects are matched to one of several orientation-specific representations of the same objects stored in long-term memory. Much of the evidence for this hypothesis comes from the observation of group mean orientation effects in recognition memory tasks showing that the time taken to identify objects increases as a function of the angular distance between the orientation of the stimulus and its nearest familiar orientation The aim in this paper is to examine the validity of this interpretation of group mean orientation effects. In particular, it is argued that analyses based on group performance averages that appear consistent with the multiple-views hypothesis may, under certain circumstances, obscure a different theoretically relevant underlying pattern of results. This problem is examined by using hypothetical data and through the detailed analysis of the results from an experiment based on a recognition memory task used in several previous studies. Although a pattern of results that is consistent with the multiple-views hypothesis was observed in both the group mean performance and the underlying data, it is argued that the potential limitations of analyses based solely on group performance averages must be considered in future studies that use orientation effects to make inferences about the kinds of shape representations that mediate visual recognition.     

Estimating averages from distributions of tone durations

We examined whether estimating average duration was influenced by the distribution peak location. We presented participants with samples of various tone durations and then presented comparison tone durations. Participants judged whether each comparison duration was longer than the average sample duration. Estimates of the averages were inferred from the psychophysical functions. The durations were sampled from three distributions: one positively skewed, one symmetric, and one negatively skewed. In Experiment 1, every participant was presented with every distribution. Estimates of the averages were unbiased for the symmetric distribution but were biased toward the long tail of each skewed distribution. This would occur if participants combined the sample to be judged with the previous, irrelevant samples, or with the comparison durations. In Experiment 2, each participant was presented with samples from only one of the distributions. Estimates of the averages were still biased toward the long tails of the skewed distributions. This would occur if participants combined the sample to be judged with the comparison durations, which were the same for the three distributions. In Experiment 3, each participant was presented with only one distribution, and each distribution was tested with its own comparison durations, selected as percentiles from the distribution. The estimates were accurate for the smallest population mean (positively skewed distribution) but underestimated the larger means. These results could be explained by subjective shortening of the durations in memory, with a simple equation from scalar timing theory. This equation correctly predicted two results: The estimated averages were a linear function of the stimulus means, and the variances were a linear function of the squared stimulus means. Neither prediction was dependent on the skewness of the stimulus durations.     

The New Person-Specific Paradigm in Psychology

ABSTRACT— Most research methodology in the behavioral sciences employs interindividual analyses, which provide information about the state of affairs of the population. However, as shown by classical mathematical-statistical theorems (the ergodic theorems), such analyses do not provide information for, and cannot be applied at, the level of the individual, except on rare occasions when the processes of interest meet certain stringent conditions. When psychological processes violate these conditions, the interindividual analyses that are now standardly applied have to be replaced by analysis of intraindividual variation in order to obtain valid results. Two illustrations involving analysis of intraindividual variation of personality and emotional processes are given.     

Social Capital and Happiness in the United States

This paper explores the association between social capital and average happiness in the United States. Social capital is measured as a multidimensional concept consisting of social trust and two different indicators of sociability. In order to employ the variation both over time and across states, the data are organized in either a panel of nine US Census regions over the period 1983–1998 or in averages over this period in a cross-section of 48 states. The results show that social trust is positively associated with happiness while the potential effects of informal sociability at the level of society only appear significant in the regional estimates. The findings document the importance of social trust for average happiness but also hold more general implications for social capital theory.     

Inspection time and high-speed ball games

It has been suggested that successful batsmen in cricket are not distinguished by their fast speed of visual information intake. A study is presented in which a season's batting averages for twenty regular cricketers, all members of the same local team, were correlated with the cricketers' visual inspection times. The correlation was -0.63 (p less than 0.005), suggesting that the successful batsmen were faster at picking up information from briefly presented visual displays. When the age factor was eliminated, the partial correlation between inspection time and batting average remained significant at -0.52 (p less than 0.01). This finding is discussed with respect to the sources of information available from a ball in flight.     

A longitudinal study of school adjustment in urban,minority adolescents: Effects of a high school transition program

Described an intervention program designed to prepare elementary school (K-8) eighth-grade students for their transition to high school the following year. Participants in the study were 145, predominantly Hispanic, inner-city public school adolescents. The experimental group received an augmented condition, consisting of Education and Peer Support Components. The control group received a minimal condition consisting of only the Education Component. While no group effects were observed, time effects indicated experimental and control students' improved perceptions of school readiness, but deteriorated perceptions of support from both home and school and diminished grade-point averages and attendance. Time effects also revealed variable changes in school perceptions. Findings are discussed in terms of a developmental perspective of the school transition process. Implications for high school transition programming with the target population and directions for future research are also addressed.     

Age-Related Changes in Executive Function: An Event-Related Potential (ERP) Investigation of Task-Switching

ABSTRACT

Older adults have difficulty when executive control must be brought on line to coordinate ongoing behavior. To assess age-related alterations in executive processing, task-switching performance and event-related potential (ERP) activity were compared in young and older adults on switch, post-switch, pre-switch, and no-switch trials, ordered in demand for executive processes from greatest to least. In stimulus-locked averages for young adults, only switch trials elicited fronto-central P3 components, indicative of task-set attentional reallocation, whereas in older adults, three of the four trial types evinced frontal potentials. In response-locked averages, the amplitude of a medial frontal negativity (MFN), a component reflecting conflict monitoring and detection, increased as a function of executive demands in the ERPs of the young but not those of the older adults. These data suggest altered executive processing in older adults resulting in persistent recruitment of prefrontal processes for conditions that do not require them in the young.