Learning faces from photographs

Previous studies examining face learning have mostly used only a single exposure to 1 image of each of the faces to be learned. However, in daily life, faces are usually learned from multiple encounters. These 6 experiments examined the effects on face learning of repeated exposures to single or multiple images of a face. All experiments provided evidence for image-specific picture learning taking place over and above any invariant face learning, with recognition accuracy always highest for the image studied and performance falling across transformations between study and test images. The relative roles of pictorial and structural codes in mediating learning faces from photographs need to be reconsidered.     

A modified procedure for parallel analysis of ordered categorical data

Parallel analysis has been well documented to be an effective and accurate method for determining the number of factors to retain in exploratory factor analysis. The O'Connor (2000) procedure for parallel analysis has many benefits and is widely applied, yet it has a few shortcomings in dealing with missing data and ordinal variables. To address these technical issues, we adapted and modified the O'Connor procedure to provide an alternative method that better approximates the ordinal data by factoring in the frequency distributions of the variables (e.g., the number of response categories and the frequency of each response category per variable). The theoretical and practical differences between the modified procedure and the O'Connor procedure are discussed. The SAS syntax for implementing this modified procedure is also provided.     

Queuing network modeling of the psychological refractory period (PRP)

The psychological refractory period (PRP) is a basic but important form of dual-task information processing. Existing serial or parallel processing models of PRP have successfully accounted for a variety of PRP phenomena; however, each also encounters at least 1 experimental counterexample to its predictions or modeling mechanisms. This article describes a queuing network-based mathematical model of PRP that is able to model various experimental findings in PRP with closed-form equations including all of the major counterexamples encountered by the existing models with fewer or equal numbers of free parameters. This modeling work also offers an alternative theoretical account for PRP and demonstrates the importance of the theoretical concepts of "queuing" and "hybrid cognitive networks" in understanding cognitive architecture and multitask performance.     

Subjective Well-Being and Its Determinant from A Study of Beijing＇s Urban Elderly

Abstract This study was designed to obtain an understanding of the subjective well - being ( SWB ) status amongChina‘s urban elderly, and to find out the major factors that could influence the status in question. Our survey wasconducted of 233 urban elderly individuals, and the data was statistically examined by multiple regression analysiswith the results that: 1 ) The SWB of China‘ s urban elderly was relatively high as only 4.5 96 of all respondentsconsidered themselves unhappy or very unhappy; 2) Major factors that had an influence on SWB included economicresource, mobility, age and social support; and 3 ) Five demographic variables accounted for 18.6 96 of the variancein SWB, which was slightly higher than that of foreign findings. It is concluded that financial security, active par-ticipation in physical and social activities, and social support are necessary for the improvement of the SWB of the el-derly.     

Genetic and environmental etiology of emotional and social behaviors in 5-month-old infant twins: influence of the social context

The study investigated the genetic and environmental contributions to individual differences in measures of socioemotional reactivity and emotion regulation with a sample of 115 monozygotic (MZ) and 156 dizygotic (DZ) 5-month-old twin pairs. Twins' zygosity was determined by a combination of DNA typing and physical similarity. Twins' behaviors (motor activity level, social gaze, gaze aversion, positive expression, negative expression, and self-comfort) were videotaped in a laboratory while infants were presented televised sequences of neutral and happy emotional expressions posed by their mother (familiar condition) and a female stranger (unfamiliar condition). Regardless of the social context, the findings based on model-fitting analyses indicated that nonshared environmental influences explained most of the variance of behavioral data. However, there was evidence that motor activity level (an index of emotional arousal) and the latency and frequency of gaze aversion (an index of emotional regulation) were best represented by a model incorporating both additive genetic and nonshared environmental (i.e., AE) influences when infants were exposed to the unfamiliar adult (heritability estimates ranging from 19% to 31%). The results suggest the importance of nonshared environmental influences during early infancy and stress the role of social context for revealing moderate genetic contributions to individual differences in emotional arousal and emotion regulation.     

Qualitative and quantitative change in the dynamics of motor learning

The experiments examined qualitative and quantitative changes in the dynamics of learning a novel motor skill (roller ball task) as a function of the manipulation of a control parameter (initial ball speed). The focus was on the relation between the rates of change in performance over practice time and the changing time scales of the evolving attractor dynamic. Results showed 3 different learning patterns to the changes in the dynamics as a function of practice that were mediated by the initial ball speed. Only participants who learned the task showed a bifurcation in coordination mode that was preceded by enhanced performance variability. The observed multiple time scales to motor learning are interpreted as the products of the dynamical stability and instability realized from (a) the continually evolving landscape dynamics due to bifurcations between attractor organization and (b) the transient phenomena associated with moving toward and away from fixed-point dynamics.     

Scaling of theory-of-mind understandings in Chinese children

Prior research demonstrates that understanding of theory of mind develops at different paces in children raised in different cultures. Are these differences simply differences in timing, or do they represent different patterns of cultural learning? That is, to what extent are sequences of theory-of-mind understanding universal, and to what extent are they culture-specific? We addressed these questions by using a theory-of-mind scale to examine performance of 140 Chinese children living in Beijing and to compare their performance with that of 135 English-speaking children living in the United States and Australia. Results reveal a common sequence of understanding, as well as sociocultural differences in children's developing theories of mind.     

A note on time-frequency analysis of finger tapping

Finger tapping involves 3 important features: time, spatial amplitude, and frequency. In classical analysis, investigators examine timing parameters; in spectral analysis, they examine frequency parameters. Both types of analysis are based on stationary tap information. The authors propose that time-frequency analysis is a useful tool for analyzing nonstationary finger tapping. They describe the method and give examples of frequency modulation, age difference, and speed transition that demonstrate additional insights one can gain by using this analysis.     

Perceived stress and physiological dysregulation in older adults

We use a population-based representative sample of older Taiwanese to investigate links between respondents' perceived levels of stress and a broad set of biological measures. These biomarkers were collected at a single time (2000) and reflect sympathetic nervous system (SNS)-activity, hypothalamo-pituitary-adrenal (HPA)-activity, immune function, cardiovascular function, and metabolic pathways. We model the relationship between perceived stress and (1) extreme values for each of 16 individual biological indicators; and (2) a measure of cumulative physiological dysregulation based on the full set of biomarkers. We consider two measures of perceived stress, one derived from the 2000 interview and the second based on data from three interviews (1996-2000). Age and sex-adjusted models reveal significant associations between measures of perceived stress and extreme values of cortisol, triglycerides, interleukin-6 (IL-6), dehydroepiandrosterone sulphate (DHEAS) and fasting glucose. Examined individually, numerous biomarkers, including those pertaining to blood pressure and obesity, are not significantly related to perceived stress. Jointly, however, the measure of cumulative physiological dysregulation is associated with both the level of perceived stress at a given time and to a longitudinal measure of perceived stress. Some results suggest that the relationship between level of perceived stress and physiological response is stronger for women than men.     

Implications of statistical power for confidence intervals

The statistical power of a hypothesis test is closely related to the precision of the accompanying confidence interval. In the case of a z-test, the width of the confidence interval is a function of statistical power for the planned study. If minimum effect size is used in power analysis, the width of the confidence interval is the minimum effect size times a multiplicative factor φ. The index φ, or the precision-to-effect ratio, is a function of the computed statistical power. In the case of a t-test, statistical power affects the probability of achieving a certain width of confidence interval, which is equivalent to the probability of obtaining a certain value of φ. To consider estimate precision in conjunction with statistical power, we can choose a sample size to obtain a desired probability of achieving a short width conditional on the rejection of the null hypothesis.