Staying Together: A Bidirectional Delay–Coupled Approach to Joint Action

To understand how individuals adapt to and anticipate each other in joint tasks, we employ a bidirectional delay–coupled dynamical system that allows for mutual adaptation and anticipation. In delay–coupled systems, anticipation is achieved when one system compares its own time‐delayed behavior, which implicitly includes past information about the other system’s behavior, with the other system’s instantaneous behavior. Applied to joint music performance, the model allows each system to adapt its behavior to the dynamics of the other. Model predictions of asynchrony between two simultaneously produced musical voices were compared with duet pianists’ behavior; each partner performed one voice while auditory feedback perturbations occurred at unpredictable times during live performance. As the model predicted, when auditory feedback from one musical voice was removed, the asynchrony changed: The pianist’s voice that was removed anticipated (preceded) the actions of their partner. When the auditory feedback returned and both musicians could hear each other, they rapidly returned to baseline levels of asynchrony. To understand how the pianists anticipated each other, their performances were fitted by the model to examine change in model parameters (coupling strength, time‐delay). When auditory feedback for one or both voices was removed, the fits showed the expected decrease in coupling strength and time‐delay between the systems. When feedback about the voice(s) returned, the coupling strength and time‐delay returned to baseline. These findings support the idea that when people perform actions together, they do so as a coupled bidirectional anticipatory system.     

Scaling properties of three-dimensional random fibre networks

Random fibre networks have unique mechanical properties and appear as the primary building blocks of many biological and structural materials. Although fibre networks are usually three-dimensional in nature, prior studies have mainly used simplistic two-dimensional models to characterize their properties. The present study creates a 3D strain-based nonaffinity measure and investigates the mechanical behaviour and scaling properties of 3D fibre networks. This measure is used to fully examine the influence of primarily characteristic length scales, i.e. mean segment length and bending length, on nonaffine mechanical behaviour of 3D filamentous networks. It is observed that all nonaffinity measure components exhibit a power-law variation with the probing length scale. Furthermore, it is found that while the degree of nonaffinity in both 2D and 3D systems decreases with increasing the probing length scale, the two power-law scaling regimes previously reported for 2D networks do not appear in 3D.     

A one-boundary drift-diffusion model for time to collision estimation in a simple driving task

ABSTRACT

Driving is a complex everyday task. Every year a huge number of driving accidents around the world causes serious physical and mental injuries and deaths. The correct estimation of the remaining time to reach the other vehicles on the road, known as time to collision (TTC), is an important factor to avoid accidents. In this study, we aimed to use a drift-diffusion model (DDM) to better understand the participants’ estimation of TTC in two driving experiments. Both experiments were the same, except that in one of them participants were asked to finish the experiment as fast as they could, while in the other experiment there was no time constraint. DDM fitted the data from all participants well in both experiments according to the chi-square goodness of fit criterion. Also, results showed that time pressure increases subjects’ estimated TTC, the rate of accumulation of sensory information and the response threshold.     

Innovative Work Behavior in Public Organizations: The Roles of Ethical and Knowledge Sharing Behaviors

Public organizations are in continuous need of innovation in their products, services, and processes in order to grow and survive. Innovative work behaviors play important role in employee innovation in these organizations. The present study aimed to test the roles of ethical and knowledge sharing behaviors on innovative work behavior in public organizations. The questionnaire consisting of 44 items was used. The data were collected from 266 participants in public organizations, and data analysis was performed through Structural Equation Modeling (SEM). According to the results, ethical behaviors had positive and significant effect on innovative work behavior, and knowledge sharing behaviors mediate the effect of ethical behavior on innovative work behaviors. The proposed model highlighted the importance of sharing mistakes and best practices in an organization to develop innovative work behavior. Furthermore, ethical behaviors were likely to be more significant predictors of innovative work behavior through knowledge sharing behaviors.     

The expression of c-Fos and colocalisation of c-Fos and glucocorticoid receptors in brain structures of low and high anxiety rats subjected to extinction trials and re-learning of a conditioned fear response

We designed an animal model to examine the mechanisms of differences in individual responses to aversive stimuli. We used the rat freezing response in the context fear test as a discriminating variable: low responders (LR) were defined as rats with a duration of freezing response one standard error or more below the mean value, and high responders (HR) were defined as rats with a duration of freezing response one standard error or more above the mean value. We sought to determine the colocalisation of c-Fos and glucocorticoid receptors-immunoreactivity (GR-ir) in HR and LR rats subjected to conditioned fear training, two extinction sessions and re-learning of a conditioned fear. We found that HR animals showed a marked decrease in conditioned fear in the course of two extinction sessions (16 days) in comparison with the control and LR groups. The LR group exhibited higher activity in the cortical M2 and prelimbic areas (c-Fos) and had an increased number of cells co-expressing c-Fos and GR-ir in the M2 and medial orbital cortex after re-learning a contextual fear. HR rats showed increased expression of c-Fos, GR-ir and c-Fos/GR-ir colocalised neurons in the basolateral amygdala and enhanced c-Fos and GR-ir in the dentate gyrus (DG) in comparison with LR animals. Our data indicate that recovery of a context-related behaviour upon re-learning of contextual fear is accompanied in HR animals by a selective increase in c-Fos expression and GRs-ir in the DG area of the hippocampus.     

Change it Up: Inactivity and Repetitive Activity Reduce Creative Thinking

Across three experiments, we show that a change in the levels of physical activity increases creative thinking, whereas inactivity or repetitive activity lowers it. Participants walking forward were more creative the first few minutes of initiating physical activity than those sitting, or those merely watching changing scenery, and these effects dissipated when they continued the forward movement over time (within 8 minutes). Furthermore, merely anticipating a change in physical activity, for example, when participants were aware a task is coming to its conclusion, also increased creative thinking. We hypothesize that a change in physical activity cues the need to navigate new situations, and thus, can increase mental flexibility and creative thinking to deal with new circumstances. But once people habituate to their physical state, either of being at rest or being in motion, their level of creative thinking also returns to baseline levels. We confirm that mood, feelings of achievement, and energy are not responsible for the observed effects.     

A Comprehensive Literature Review of the Rank Reversal Phenomenon in the Analytic Hierarchy Process

During the last few decades, several multi‐criteria decision analysis methods have been proposed to help in selecting the best compromise alternatives. Among them, analytic hierarchy process (AHP) and its applications have attracted much attention from academics and practitioners. However, since the early 1980s, critics have raised questions regarding its proper use. One of them concerns the unacceptable changes in the ranks of the alternatives, called rank reversal, upon changing the structure of the decision. Several modifications were suggested to preserve ranks. In this paper, a classification scheme and a comprehensive literature review are presented in order to uncover, classify and interpret the current research on AHP methodologies and rank reversals. On the basis of the scheme, 61 scholarly papers from 18 journals are categorized into specific areas. The specific areas include the papers on the topics of adding/deleting alternatives and the papers published in adding/deleting criteria. The scholarly papers are also classified by (1) year of publication, (2) journal of publication, (3) authors' geographic location and (4) using the AHP in association with other methods. It is hoped that the paper can meet the needs of researchers and practitioners for convenient references of AHP methodologies and rank reversals and hence promote the future of rank reversal research. Copyright © 2012 John Wiley & Sons, Ltd.     

Multisensory integration in multiple reference frames in the posterior parietal cortex

Spatial information processing takes place in different brain regions that receive converging inputs from several sensory modalities. Because of our own movements—for example, changes in eye position, head rotations, and so forth—unimodal sensory representations move continuously relative to one another. It is generally assumed that for multisensory integration to be an orderly process, it should take place between stimuli at congruent spatial locations. In the monkey posterior parietal cortex, the ventral intraparietal (VIP) area is specialized for the analysis of movement information using visual, somatosensory, vestibular, and auditory signals. Focusing on the visual and tactile modalities, we found that in area VIP, like in the superior colliculus, multisensory signals interact at the single neuron level, suggesting that this area participates in multisensory integration. Curiously, VIP does not use a single, invariant coordinate system to encode locations within and across sensory modalities. Visual stimuli can be encoded with respect to the eye, the head, or halfway between the two reference frames, whereas tactile stimuli seem to be prevalently encoded relative to the body. Hence, while some multisensory neurons in VIP could encode spatially congruent tactile and visual stimuli independently of current posture, in other neurons this would not be the case. Future work will need to evaluate the implications of these observations for theories of optimal multisensory integration.Edited by: Marie-Hélène Giard and Mark Wallace