Muscle Synergies for Turning During Human Walking

Muscle synergy describes reduced set of functional muscle co-activation patterns. We aimed to identify muscle synergies of turning compared with straight walking. Twelve healthy adults (men: 7, women: 5) performed straight walking (SW), left turning (LT), and right turning (RT) at self-selected speeds. By using non-negative matrix factorization (NMF), we extracted muscle synergies from sixteen electromyography (EMG) signals on the right side and assigned similar muscle synergies among SW, LT, and RT into the same cluster by combining k-means clustering and intraclass correlation coefficient (ICC) analysis. We obtained task-specific clusters of muscle synergies extracted from SW, LT, or RT condition and identified the clusters that share synergies among the conditions. The central nervous system produces specific synergies involving turning behaviors and fundamental synergies for walking.     

Inclusive Leadership and Employee Well-Being: The Mediating Role of Person-Job Fit

This study explored the effects of inclusive leadership on employee well-being and innovative behavior. We also investigated the mediating role of person-job fit in these relationships. We tested these effects on a sample of 207 employees in five telecommunication companies in Vietnam, using a questionnaire survey. The results showed that inclusive leadership is positively related to employee well-being and innovative behavior, and that person-job fit mediates these relationships. The study makes theoretical contributions to the literature of leadership and organizational psychology, and suggests useful managerial implications for organizations to boost employee well-being and innovative behavior. Taking a cultural approach, this study provides empirical cross-cultural validity of the effect of inclusive leadership on employee well-being.     

Understanding the Influence Theory of Causation: A Critique of Strevens

In this paper, I will first clarify Lewis’s influence theory of causation by relying on his theory of events. And then I will consider Michael Strevens’s charge against the sufficiency of Lewis’s theory. My claim is that it is legitimate but does not pose as serious a problem for Lewis’s theory as Strevens thinks because Lewis can surmount it by limiting the scope of his theory to causation between concrete events. Michael Strevens raises an alleged counterexample to the necessity of Lewis’s theory that, if successful, would have a very important advantage over other alleged counterexamples. But I will assert that it is simply mistaken. My defense of Lewis’s theory will shed interesting light on the relationship between Lewis’s theory and Salmon’s mark theory.     

Likelihood of attending to the color word modulates Stroop interference

Three experiments investigated whether the Stroop color-naming effect is modulated by the likelihood of a color word capturing visual attention. In Experiment 1, a bar or a neutral word was presented at fixation as a color carrier, along with a color word randomly appearing in either an achromatic color (white in the main experiment, gray in a follow-up) or purple. Reduction of the Stroop effect (known as Stroop dilution) occurred when the color word was achromatic but not (or to a lesser extent) when it was in purple. In Experiment 2, the color of the color word remained constant throughout trial blocks, and Stroop dilution was equally evident when the word was always in purple and when it was always in white. In Experiment 3, a color bar was presented as the color carrier with both a color word and a neutral word. In this case, the Stroop effect was larger when the color word appeared in purple, and smaller when the neutral word appeared in purple, than when neither word did. These results imply that the extent to which processing of a color word occurs is determined by the likelihood of the word capturing attention.     

The malleability of age-related positive gaze preferences: training to change gaze and mood

Older adults show positive gaze preferences, but to what extent are these preferences malleable? Examining the plasticity of age-related gaze preferences may provide a window into their origins. We therefore designed an attentional training procedure to assess the degree to which we could shift gaze and gaze-related mood in both younger and older adults. Participants completed either a positive or negative dot-probe training. Before and after the attentional training, we obtained measures of fixations to negatively valenced images along with concurrent mood ratings. We found differential malleability of gaze and mood by age: for young adults, negative training resulted in fewer posttraining fixations to the most negative areas of the images, whereas positive training appeared more successful in changing older adults' fixation patterns. Young adults did not differ in their moods as a function of training, whereas older adults in the train negative group had the worst moods after training. Implications for the etiology of age-related positive gaze preferences are considered.     

The origins of causal perception: evidence from postdictive processing in infancy

The currency of our visual experience consists not only of visual features such as color and motion, but also seemingly higher-level features such as causality--as when we see two billiard balls collide, with one causing the other to move. One of the most important and controversial questions about causal perception involves its origin: do we learn to see causality, or does this ability derive in part from innately specified aspects of our cognitive architecture? Such questions are difficult to answer, but can be indirectly addressed via experiments with infants. Here we explore causal perception in 7-month-old infants, using a different approach from previous work. Recent work in adult visual cognition has demonstrated a postdictive aspect to causal perception: in certain situations, we can perceive a collision between two objects in an ambiguous display even after the moment of potential 'impact' has already passed. This illustrates one way in which our conscious perception of the world is not an instantaneous moment-by-moment construction, but rather is formed by integrating information over short temporal windows. Here we demonstrate analogous postdictive processing in infants' causal perception. This result demonstrates that even infants' visual systems process information in temporally extended chunks. Moreover, this work provides a new way of demonstrating causal perception in infants that differs from previous strategies, and is immune to some previous types of critiques.     

Collaborate and share: an experimental study of the effects of task and reward interdependencies in online games.

Today millions of players interact with one another in online games, especially massively multiplayer online role-playing games (MMORPGs). These games promote interaction among players by offering interdependency features, but to date few studies have asked what interdependency design factors of MMORPGs make them fun for players, produce experiences of flow, or enhance player performance. In this study, we focused on two game design features: task and reward interdependency. We conducted a controlled experiment that compared the interaction effects of low and high task-interdependency conditions and low and high reward-interdependency conditions on three dependent variables: fun, flow, and performance. We found that in a low task-interdependency condition, players had more fun, experienced higher levels of flow, and perceived better performance when a low reward-interdependency condition also obtained. In contrast, in a high task-interdependency condition, all of these measures were higher when a high reward-interdependency condition also obtained.     

Propofol induction reduces the capacity for neural information integration: Implications for the mechanism of consciousness and general anesthesia

The cognitive unbinding paradigm suggests that the synthesis of neural information is attenuated by general anesthesia. Here, we analyzed the functional organization of brain activities in the conscious and anesthetized states, based on functional segregation and integration. Electroencephalography (EEG) recordings were obtained from 14 subjects undergoing induction of general anesthesia with propofol. We quantified changes in mean information integration capacity in each band of the EEG. After induction with propofol, mean information integration capacity was reduced most prominently in the γ band of the EEG (p = .0001). Furthermore, we demonstrate that loss of consciousness is reflected by the breakdown of the spatiotemporal organization of γ waves. We conclude that induction of general anesthesia with propofol reduces the capacity for information integration in the brain. These data directly support the information integration theory of consciousness and the cognitive unbinding paradigm of general anesthesia.     

Skill transfer through goal-driven representation mapping

In this paper, we present an approach to transfer that involves analogical mapping of symbols across different domains. We relate this mechanism to Icarus, a theory of the human cognitive architecture. Our system can transfer skills across domains hypothesizing maps between representations, improving performance in novel domains. Unlike previous approaches to analogical transfer, our method uses an explanatory analysis that compares how well a new domain theory explains previous solutions under different mapping hypotheses. We present experimental evidence that the new mechanism improves transfer over Icarus’ basic learning processes. Moreover, we argue that the same features which distinguish Icarus from other architectures support representation mapping in a natural way and operate synergistically with it. These features enable our analogy system to translate a map among concepts into a map between skills, and to support transfer even if two domains are only partially analogous. We also discuss our system’s relation to other work on analogy and outline directions for future research.