Event-based prospective remembering in a virtual world

Most laboratory-based prospective memory (PM) paradigms pose problems that are very different from those encountered in the real world. Several PM studies have reported conflicting results when comparing laboratory with naturalistic based studies (e.g., Bailey,Henry, Rendell, Phillips & Kliegel, 2010). One key contrast is that for the former, how and when the PM cue is encountered typically is determined by the experimenter, whereas in the latter case, cue availability is determined by participant actions. However, participant-driven access to the cue has not been examined in laboratory studies focused on healthy young adults, and its relationship with planned intentions is poorly understood. Here we report a study of PM performance in a controlled, laboratory setting, but with participant-driven actions leading to the availability of the PM cue. This uses a novel PM methodology based upon analysis of participant movements as they attempted a series of errands in a large virtual building on the computer screen. A PM failure was identified as a situation in which a participant entered and exited the “cue” area outside an errand related room without performing the required errand whilst still successfully remembering that errand post-test. Additional individual difference measures assessed retrospective and working memory capacity, planning ability and PM. Multiple regression analysis showed that the independent measures of verbal working memory span, planning ability and PM were significant predictors of PM failure. Correlational analyses with measures of planning suggest that sticking with an original plan (good or bad) is related to better overall PM performance

Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons

The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY at J\"ulich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe.Comment: 10 pages, 10 figures, 4 table

Crowd behaviour during high-stress evacuations in an immersive virtual environment

Understanding the collective dynamics of crowd movements during stressful emergency situations is central to reducing the risk of deadly crowd disasters. Yet, their systematic experimental study remains a challenging open problem due to ethical and methodological constraints. In this paper, we demonstrate the viability of shared 3D virtual environments as an experimental platform for conducting crowd experiments with real people. In particular, we show that crowds of real human subjects moving and interacting in an immersive 3D virtual environment exhibit typical patterns of real crowds as observed in real-life crowded situations. These include the manifestation of social conventions and the emergence of self-organized patterns during egress scenarios. High-stress evacuation experiments conducted in this virtual environment reveal movements characterized by mass herding and dangerous overcrowding as they occur in crowd disasters. We describe the behavioral mechanisms at play under such extreme conditions and identify critical zones where overcrowding may occur. Furthermore, we show that herding spontaneously emerges from a density effect without the need to assume an increase of the individual tendency to imitate peers. Our experiments reveal the promise of immersive virtual environments as an ethical, cost-efficient, yet accurate platform for exploring crowd behaviour in high-risk situations with real human subjects.Comment: 17 pages, 5 figure

Detecting cognitive impairment through an age-friendly serious game: The development and usability of the Spatial Performance Assessment for Cognitive Evaluation (SPACE)

The Spatial Performance Assessment for Cognitive Evaluation (SPACE) is a novel iPad serious game designed to identify differences in spatial ability indicative of early signs of cognitive impairment. This paper reports on the development of SPACE and presents the results from three usability studies across different ages. Study 1 compared the traditional tap and swipe control interface with a semiautomated interface. Study 2 investigated the benefits of a UI widget that displayed the rotation performed in the Virtual Environment (VE). Study 3 evaluated the effects of a simplified configuration of landmarks explored in the VE. Findings across the studies indicated that age was the primary factor influencing performance. Younger participants consistently outperformed older ones across various tasks and reported higher usability and lower workload. Despite notable performance improvements for the tasks in SPACE, the new control interface, UI widget, and simplified configuration only had a minimal impact on usability. Younger participants rated SPACE above the level of mature products, while older participants found it useable but not always engaging. Critically, the significant interactions between age and experimental conditions indicated that younger and older participants benefited differently from the design modifications. Here, the semi-automated control, the simplified configuration, and, to a lesser extent, the UI widget showed promise in mitigating age-related performance differences while maintaining the level of challenge necessary to assess differences in cognitive status. This research showcases the potential of SPACE as a serious game and emphasises the importance of balancing simplicity with task demands for future unsupervised deployment.</p

Interaction imaging with amplitude-dependence force spectroscopy

Knowledge of surface forces is the key to understanding a large number of processes in fields ranging from physics to material science and biology. The most common method to study surfaces is dynamic atomic force microscopy (AFM). Dynamic AFM has been enormously successful in imaging surface topography, even to atomic resolution, but the force between the AFM tip and the surface remains unknown during imaging. Here, we present a new approach that combines high accuracy force measurements and high resolution scanning. The method, called amplitude-dependence force spectroscopy (ADFS) is based on the amplitude-dependence of the cantilever's response near resonance and allows for separate determination of both conservative and dissipative tip-surface interactions. We use ADFS to quantitatively study and map the nano-mechanical interaction between the AFM tip and heterogeneous polymer surfaces. ADFS is compatible with commercial atomic force microscopes and we anticipate its wide-spread use in taking AFM toward quantitative microscopy

Distance dependence of force and dissipation in non-contact atomic force microscopy on Cu(100) and Al(111)

The dynamic characteristics of a tip oscillating in the nc-AFM mode in close vicinity to a Cu(100)-surface are investigated by means of phase variation experiments in the constant amplitude mode. The change of the quality factor upon approaching the surface deduced from both frequency shift and excitation versus phase curves yield to consistent values. The optimum phase is found to be independent of distance. The dependence of the quality factor on distance is related to 'true' damping, because artefacts related to phase misadjustment can be excluded. The experimental results, as well as on-resonance measurements at different bias voltages on an Al(111) surface, are compared to Joule dissipation and to a model of dissipation in which long-range forces lead to viscoelastic deformations

Phase Transitions of an Oscillator Neural Network with a Standard Hebb Learning Rule

Studies have been made on the phase transition phenomena of an oscillator network model based on a standard Hebb learning rule like the Hopfield model. The relative phase informations---the in-phase and anti-phase, can be embedded in the network. By self-consistent signal-to-noise analysis (SCSNA), it was found that the storage capacity is given by $\alpha_c = 0.042$, which is better than that of Cook's model. However, the retrieval quality is worse. In addition, an investigation was made into an acceleration effect caused by asymmetry of the phase dynamics. Finally, it was numerically shown that the storage capacity can be improved by modifying the shape of the coupling function.Comment: 10 pages, 6 figure

Motivation moderates gender differences in navigation performance.

Gender differences in navigation performance are a recurrent and controversial topic. Previous research suggests that men outperform women in navigation tasks and that men and women exhibit different navigation strategies. Here, we investigate whether motivation to complete the task moderates the relationship between navigation performance and gender. Participants learned the locations of landmarks in a novel virtual city. During learning, participants could trigger a top-down map that depicted their current position and the locations of the landmarks. During testing, participants were divided into control and treatment groups and were not allowed to consult the map. All participants were given 16 minutes to navigate to the landmarks, but those in the treatment group were monetarily penalized for every second they spent completing the task. Results revealed a negative relationship between physiological arousal and the time required to locate the landmarks. In addition, gender differences in strategy were found during learning, with women spending more time with the map and taking 40% longer than men to locate the landmarks. Interestingly, an interaction between gender and treatment group revealed that women in the control group required more time than men and women in the treatment group to retrieve the landmarks. During testing, women in the control group also took more circuitous routes compared to men in the control group and women in the treatment group. These results suggest that a concurrent and relevant stressor can motivate women to perform similarly to men, helping to diminish pervasive gender differences found in the navigation literature