Task shifting in dual-task settings

When a participant is asked to perform two tasks in alternation, their mean reaction times were slower than when they performed the same tasks repeatedly. This "shift cost" has been hypothesized to reflect the time course of a single central executive that exerts control over thought and actions in task shifting. This study attempted to test this hypothesis using dual-task methodology. Participants were asked to carry out both a subtracting task and a rule-shifting task simultaneously. The main interest is to examine the effect of dual task on the magnitude of shift cost. The results showed that performing a concurrent subtracting task significantly interfered with the shifting operation resulting in over-additive time cost for shifting of task set. We further suggest that such interference may arise from the competition between activations of various rules.     

Motion fading and the motion aftereffect share a common process of neural adaptation

After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. Here, we show that this motion fading occurs not only for slowly moving stimuli, but also for stimuli moving at high speed; after prolonged viewing of high-speed stimuli, the stimuli appear to slow down but not to stop. We report psychophysical evidence that the same neural adaptation process likely gives rise to motion fading and to the motion aftereffect.     

Detection of spatial cues in linear and logarithmic frequency-modulated sweeps

Frequency- and amplitude-modulated (FM and AM) sounds are the building blocks of complex sounds. In the present study, we investigated the ability of human observers to process spatial information in an important class of FM sounds: broadband directional sweeps common in natural communication signals such as speech. The stimuli consisted of linear or logarithmic unidirectional FM pulses that swept either up or down in frequency at various rates. Spatial localization thresholds monotonically improved as sweep duration decreased and as sweep rate increased, but no difference in performance was observed between logarithmic and linear or between upand down-frequency sweeps. Counterintuitive reversals in localization were observed which suggested that the localization of high-frequency sweeps may be strongly dominated by amplitude information even in situations in which one might consider timing cues to be critical. Implications of these findings for the localization of complex sounds are discussed.     

A Network Approach for Evaluating Coherence in Multivariate Systems: An Application to Psychophysiological Emotion Data

We present an approach for evaluating coherence in multivariate systems that considers all the variables simultaneously. We operationalize the multivariate system as a network and define coherence as the efficiency with which a signal is transmitted throughout the network. We illustrate this approach with time series data from 15 psychophysiological signals representing individuals’ moment-by-moment emotional reactions to emotional films. First, we summarize the time series through nonparametric Receiver Operating Characteristic (ROC) curves. Second, we use Spearman rank correlations to calculate relationships between each pair of variables. Third, based on the obtained associations, we construct a network using the variables as nodes. Finally, we examine signal transmission through all the nodes in the network. Our results indicate that the network consisting of the 15 psychophysiological signals has a small-world structure, with three clusters of variables and strong within-cluster connections. This structure supports an effective signal transmission across the entire network. When compared across experimental conditions, our results indicate that coherence is relatively stronger for intense emotional stimuli than for neutral stimuli. These findings are discussed in relation to multivariate methods and emotion theories.     

Loving-kindness brings loving-kindness: The impact of Buddhism on cognitive self–other integration

Common wisdom has it that Buddhism enhances compassion and self-other integration. We put this assumption to empirical test by comparing practicing Taiwanese Buddhists with well-matched atheists. Buddhists showed more evidence of self-other integration in the social Simon task, which assesses the degree to which people co-represent the actions of a coactor. This suggests that self-other integration and task co-representation vary as a function of religious practice.     

Spatial and temporal frequency in figure-ground organization

Figure-ground organization of an ambiguous pattern can be manipulated by the spatial and temporal frequency content of the two regions of the pattern. Controlling for space-averaged luminance and perceived contrast, we tested patterns in which the two regions of the ambiguous pattern contained sine-wave gratings of 8, 4, 1, or 0.5 cycles per degree (cpd) undergoing on:off flicker at the rates of 0, 3.75, 7.5, or 15 Hz. For a full set of combinations of temporal frequency differences, with each spatial frequency the higher temporal frequency was seen as background for more of the viewing time. For two spatial frequency combinations, 1 and 4 cpd, and 1 and 8 cpd, tested under each of the four temporal frequencies, the lower spatial frequency region was seen as the background for more of the viewing time. When the effects of spatial and temporal frequency were set in opposition, neither was predominant in determining perceptual organization. It is suggested that figure-ground organization may parallel the sustained-transient response characteristics of the visual system.     

Intended Sex With Fewer Partners: An Empirical Test of the AIDS Risk Reduction Model Among Injection Drug Users1

The AIDS risk reduction model (ARRM) is a theory-based representation of psychosocial processes by which people may attempt to change their HIV risk behavior. This study tests the degree to which hypothesized relationships among ARRM factors are consistent with cross-sectional data collected from a sample of HIV-negative injection drug users in Los Angeles, California. The data pertain to users' intentions to reduce HIV transmission risk incurred through sex with multiple partners. Findings conform to ARRM hypotheses in some important respects. In particular, findings suggest that perceived self-efficacy for sexual risk reduction may be a crucial factor leading to the formation of intentions to change sex-related HIV risk behavior.     

Core Self-Evaluations and Job and Life Satisfaction: The Mediating and Moderated Mediating Role of Job Insecurity

This study examined the mediating role of job insecurity in the relationship between core self-evaluations (CSE) and job satisfaction, while also investigating the moderating role of job insecurity in the mediated relationship between CSE and life satisfaction via job satisfaction. Survey data were collected from a sample of 346 full-time employees in Taiwan. We found that job insecurity partially mediated the CSE-job satisfaction relationship. Moreover, we found that job insecurity moderated not only the relationship between CSE and job satisfaction but also the mediated relationship between CSE and life satisfaction via job satisfaction. Specifically, both the CSE-job satisfaction relationship and the CSE-job satisfaction-life satisfaction relationship became stronger when job insecurity was low. Our results emphasize the importance of raising employees' CSE, which is beneficial not only for diminishing their perceptions of job insecurity, but also for boosting their job and life satisfaction. Practical implications and directions for future research are discussed.