Null effects of exposure duration and heterogeneity of difference on thesame-different disparity in letter matching

The rechecking and external-noise postulates of Krueger’s (1978) noisy-operator theory were examined in three letter-matching experiments. Rechecking was tested by varying exposure duration, both without (Experiment 1) and with (Experiment 2) a subsequent noise mask. Predictions of a decreasedsame-different reaction time disparity and an increase in falsedifferent errors at brief exposures were not borne out. The external-noise postulate was tested by varying the degree of heterogeneity of difference between letter sets. The prediction of a smallersamedifferent reaction time disparity for the more heterogeneous letter set was not obtained. Thus, the results did not support internal noise as the basis of thesame-different disparity, but were more consistent with response-inhibition accounts.     

Estimation and tests of significance in factor analysis

A distinction is drawn between the method of principal components developed by Hotelling and the common factor analysis discussed in psychological literature both from the point of view of stochastic models involved and problems of statistical inference. The appropriate statistical techniques are briefly reviewed in the first case and detailed in the second. A new method of analysis called the canonical factor analysis, explaining the correlations between rather than the variances of the measurements, is developed. This analysis furnishes one out of a number of possible solutions to the maximum likelihood equations of Lawley. It admits an iterative procedure for estimating the factor loadings and also for constructing the likelihood criterion useful in testing a specified hypothesis on the number of factors and in determining a lower confidence limit to the number of factors.     

Mahatma Gandhi’s Pragmatic Spirituality: Its Relevance to Psychology East and West

M. K. Gandhi is no academic psychologist; but his philosophy and practice of pragmatic spirituality have important implications for psychology in general and Indian psychology in particular. Psychology as taught and practised in India is mostly Western and not Indian psychology. Indian psychology is an emerging system of psychology with its roots in classical Indian thought. According to Gandhi, the person is instinctively brute, but inherently spiritual. Consequently, he/she has on the one hand natural attraction to sensory gratification and indulgence, selfish desires and craving. On the other hand, he or she aspires for self-realization. Human development is a dialectical process where people seek to find a workable synthesis between sensory indulgence and spiritual aspirations, between egotistic selfishness and altruistic urges. Gandhi’s life provides an excellent case study of the ways of spiritual development. The techniques he crafted like satyagraha and the strategies he followed in his public life give us insights into how spirituality can be applied to improve human condition. The applications are not India specific, but universal. Therefore, psychologists from the East as well as from the West can join in exploring Gandhian ideas and techniques of psycho-spiritual development and their relevance to today’s troubled world.     

Using perfusion fMRI to measure continuous changes in neural activity with learning

In this study, we examine the suitability of a relatively new imaging technique, arterial spin labeled perfusion imaging, for the study of continuous, gradual changes in neural activity. Unlike BOLD imaging, the perfusion signal is stable over long time-scales, allowing for accurate assessment of continuous performance. In addition, perfusion fMRI provides an absolute measure of blood flow so signal changes can be interpreted without reference to a baseline. The task we used was the serial response time task, a sequence learning task. Our results show reliable correlations between performance improvements and decreases in blood flow in premotor cortex and the inferior parietal lobe, supporting the model that learning procedures that increase efficiency of processing will be reflected in lower metabolic needs in tissues that support such processes. More generally, our results show that perfusion fMRI may be applied to the study of mental operations that produce gradual changes in neural activity.     

“One-thousand<Emphasis Type="Italic">one</Emphasis> … one-thousand<Emphasis Type="Italic">two</Emphasis> …”: Chronometric counting violates the scalar property in interval timing

Medical College of Wisconsin, Milwaukee, Wisconsin Weber’s law applied to interval timing is called thescalar property. A hallmark of timing in the secondsto-minutes range, the scalar property is characterized by proportionality between the standard deviation of a response distribution and the duration being timed. In this temporal reproduction study, we assessed whether the scalar property was upheld when participants chronometrically counted three visually presented durations (8, 16, and 24 sec) as compared with explicitly timing durations without counting. Accuracy for timing and accuracy for counting were similar. However, whereas timing variability showed the scalar property, counting variability did not. Counting variability across intervals was accurately modeled by summing a random variable representing an individual count. A second experiment replicated the first and demonstrated that task differences were not due to presentation order or practice effects. The distinct psychophysical properties of counting and timing behaviors argue for greater attention to participant strategies in timing studies.     

Measuring nominal scale agreement between a judge and a known standard

Two designs for comparing a judge's ratings with a known standard are presented and compared. Design A pertains to the situation where the judge is asked to categorize each ofN subjects into one ofr (known) classes with no knowledge of the actual number in each class. Design B is employed when the judge is given the actual number in each class and is asked to categorize the individuals subject to these constraints. The probability distribution of the total number of correct choices is developed in each case. A power comparison of the two procedures is undertaken.     

The Influence of Positive and Negative Affectivity on Attitude Change Toward Organizations

This study tests hypothesized differences in pre-post (product-harm) crisis attitude change toward an organization for positively and negatively oriented individuals. Contrary to theoretical predictions, there was not a strong differential attitude change between positively and negatively oriented individuals. The results suggest a possible boundary condition for the influence of positive and negative affectivity on attitude change. Two explanations are offered for these findings: (1) that the vividness of the situation might override affectivity and (2) that affectivity might not be a strong predictor of attitude change for nonpersonalized attitudes.     

刺激呈现时间对汉字语义加工脑偏侧化的影响

以往关于汉字字词识别脑功能偏侧化的研究发现了左半球优势、右半球优势或者大脑两半球均势三种不同的结果。该研究采用一侧化Stroop范式(刺激分别只呈现于左视野、中央视野或右视野中),通过系统地改变刺激呈现时间以期探讨刺激呈现时间是可以解释这些不一致结果的可能因素之一。结果显示:对于右利手被试,在刺激呈现时间为60 ms时右半球出现了较强的Stroop效应,在刺激呈现200 ms时左右半球的Stroop效应没有表现出差异,在刺激呈现时间较长时左半球表现出较强的Stroop效应。该结果提示,随着刺激呈现时间的延长,语义优势发生了从右半球到左半球的转换。