Ranxiao Frances Wang’s research while affiliated with University of Illinois Urbana-Champaign and other places

Mind wandering is a common occurrence that can have serious consequences, but estimating when mind wandering occurs is a challenging research question. Previous research has shown that during meditation, people may spontaneously alternate between task-oriented and mind-wandering states without awareness (Zukosky & Wang, 2021, Cognition, 212, Article 104689). However, under what conditions such alternations occur is not clear. The present study examined the effects of task type on spontaneous alternations between task focus and mind wandering. In addition to a meditation task, participants performed either a scene-categorization-based CPT or a visual detection task while attentional orientation was assessed via self-monitoring and intermittent probes. The three tasks differ in the extent of their reliance on continuous monitoring (less required in the detection than meditation and CPT tasks) and attentional orientation (oriented internally in meditation task and externally in CPT and detection tasks). To overcome prior methodological challenges, we applied a technique designed to detect spontaneous alternations between focused and mind-wandering states without awareness, based on how the proportion of “focused” responses/ratings to intermittent probes changes during a focus-to-mind-wandering interval (i.e., the period from one self-report of mind wandering to the subsequent self-report). Our results showed that the proportion of “focused” responses to intermittent probes remained constant with increasing interprobe interval during meditation (consistent with previous work), but declined significantly in the CPT and detection tasks. These findings support the hypothesis that spontaneous alternations of attentional states without self-awareness occur during tasks emphasizing internally but not externally oriented attention.

This article examines how people respond to the presence of a flying robot under various operating conditions using traditional human physiological measures and a novel head movement measurement. A central issue to the integration of flying robotic systems into human-populated environments is how to improve the level of comfort and safety for people around them. Traditional motion control algorithms in robotics tend to focus on the actual safety of collision avoidance. However, people's perceived safety is not necessarily equivalent to the actual safety of the vehicle. Therefore flight control systems must account for people's perception of safety beyond the actual safety of the aerial vehicles in order to allow for successful interaction between humans and the unmanned aerial vehicles (UAVs). Across three experiments participants passively observed quadrotor trajectories in a simulated virtual reality environment. Quadrotor flight characteristics were manipulated in terms of speed, altitude, and audibility to examine their effect on physiological arousal and head motion kinematics. Physiological arousal was greater when the quadrotor was flying with the audio on than off, and at eye-height than overhead, and decreased over repeated exposure. In addition, head acceleration away from the UAVs indicating defensive behavior was stronger for faster speed and audible UAVs. These data suggest head acceleration can serve as a new index specific for measuring perceived safety. Applications intended for human comfort need to consider constraints from specific measures of perceived safety in addition to traditional measures of general physiological arousal.

A variety of reports suggest that rhythmic auditory stimulation can entrain visual perception, inducing perceptual oscillations as a function of time relative to the auditory rhythm. These effects have, to date, been reported only for stimulation frequencies at and below 3 Hz. Here we investigate the effects of rhythmic auditory stimulation on the detection of masked visual targets when this stimulation occurs at frequencies to which the visual system has been shown to entrain (8-12 Hz). Across four experiments, we found no consistent evidence of poststimulation modulations in performance induced by 8.5, 10.6, or 12.1 Hz auditory stimulation. This absence of a consistent auditory-to-visual effect was paralleled by an absence of unimodal effects (oscillations in auditory performance) following 12.1 Hz auditory stimulation. In a fifth experiment, we found that although auditory stimulation alone did not induce oscillations in visual performance, auditory stimulation did enhance the effects of concurrent visual stimulation. Notably, this enhancement did not require synchronous presentation of stimuli. These observations are consistent with recent reports that passive auditory stimulation beyond 5 Hz induces neither auditory perceptual oscillations nor visual cortical oscillations and suggest limits to the extent of cross-modal entrainment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Humans can learn spatial information through navigation in the environment. The nature of these spatial representations is constantly debated, including whether they conform to Euclidean geometry. The present study examined the types of Euclidean representations people may form while learning virtual wormhole mazes. Participants explored Euclidean or non-Euclidean tunnel mazes and drew maps of the landmark layout on a 2D canvas. The results showed that people have different, consistent strategies, some mainly preserving distance information while others mainly preserving turning angles. The straightness of the segments was mostly preserved. These results suggest that representations of non-Euclidean space may be highly variable across individuals, and possible Euclidean solutions need to be carefully examined before testing Euclidean vs alternative models.

Navigation and representations of the spatial environment are central to human survival. It has often been debated whether spatial representations follow Euclidean principles, and a number of studies challenged the Euclidean hypothesis. Two experiments examined the geometry of human navigation system using true non-Euclidean environments, i.e., curved spaces with non-Euclidean geometry at every point of the space. Participants walked along two legs in an outbound journey, then pointed to the direction of the starting point (home). The homing behavior was examined in three virtual environments, Euclidean space, hyperbolic space, and spherical space. The results showed that people's responses matched the direction of Euclidean origin, regardless of the curvature of the space itself. Moreover, participants still responded as if the space were Euclidean when a learning period was added for them to explore the spatial properties of the environment before performing the homing task to ensure violations of Euclidean geometry were readily detected. These data suggest that the path integration / spatial updating system operates on Euclidean geometry, even when curvature violations are clearly present.

It's a common assumption that people's mental state timeline can be divided into a sequence of focus-mind wandering episodes, each comprises a focusing stage followed by a mind wandering stage. Accordingly, probability of being in a focus state should be high early in an episode and decrease overtime. We investigated the dynamics of shifting between meditation and off task thoughts by systematically probing participants at various time points during a focus-mind wandering episode. Contrary to predictions of the two-stage model, there's no significant decrease in probability of focus state during a focus-mind wandering episode. Simulations matching parameters of each participant suggest that the lack of this negative trend was not due to statistical power. Instead, people may have multiple spontaneous alternations between meditation and off task thoughts before they are able to catch themselves mind wandering. Based on this Multiple Sub-event Model, a novel method was developed to estimate the number of sub-events during a focus-mind wandering episode.

Objective To examine the hypothesis that constant speed is more comfortable than variable speed profiles and may minimize cybersickness. Background Current best practices for virtual reality (VR) content creation suggest keeping any form of acceleration as short and infrequent as possible to mitigate cybersickness. Methods In Experiment 1, participants experienced repetitions of simulated linear motion, and in Experiment 2, they experienced repetitions of a circular motion. Three speed profiles were tested in each experiment. Each trial lasted 2 min while standing. Cybersickness was measured using the Simulator Sickness Questionnaire (SSQ) and operationally defined in terms of total severity scores. Postural stability was measured using a Wii Balance Board and operationally defined in terms of center of pressure (COP) path length. Postural measures were decomposed into anterior-posterior and medial-lateral axes and subjected to detrended fluctuation analysis. Results For both experiments, no significant differences were observed between the three speed profiles in terms of cybersickness or postural stability, and none of the baseline postural measures could predict SSQ scores for the speed profile conditions. An axis effect was observed in both experiments such that normalized COP movement was significantly greater along the anterior-posterior axis than the medial-lateral axis. Conclusion Results showed no convincing evidence to support the common belief that constant speed is more comfortable than variable speed profiles for scenarios typical of VR applications. Application The present findings offer guidelines for the design of locomotion techniques involving traversal in VR environments.

Animal communication impacts many kinds of behavior including mating and courtship, escaping from predators and foraging activity. In this article, our investigation focuses primarily on how alarm communication impacts foraging activity, using individual based computer simulations. We used this approach to help resolve a debate in the literature between the risk-allocation hypothesis, which predicts that over time, animals become habituated to alarm communication versus the hypothesis that alarm communication consistently decreases foraging activity to avoid predators. We found that in most cases, alarm communication did indeed decrease foraging activity whereas in other cases, alarm communication resulted in habituation and a gradual increase in foraging activity, suggesting that there is some truth to both hypotheses. Moreover, it is possible that a decrease in foraging as well as habituation in response to alarm communication both contribute to fitness, or more generally, that alarm communication contributes to fitness as opposed to non-communication. Among the communication runs, we found that although there were higher levels of fitness compared with non-communication runs, fitness was higher when communication results in decreased foraging activity vs. runs where communication results in increased foraging activity. Finally, we used a variational autoencoder based estimation of distribution algorithms in conjuction with C4.5 decision trees as a wrapper to discern the features that distinguish communication runs from non-communication runs. In general, communication runs tend to have relatively low population densities, whereas non-communication runs tend to have relatively high population densities, suggesting that the ability to communicate fear obviates the need for prey to stay in close proximity to one another in order to defend against predators. Also a high level of reproductive urgency was observed in individuals with communication ability when the level of fear of predators was low.

In this article, we present a preliminary motion planning framework for a cyber-physical system consisting of a human and a flying robot in vicinity. The motion planning of the flying robot takes into account the human’s safety perception. We aim to determine a parametric model for the human’s safety perception based on test data. We use virtual reality as a safe testing environment to collect safety perception data reflected on galvanic skin response (GSR) from the test subjects experiencing a flying robot in their vicinity. The GSR signal contains both meaningful information driven by the interaction with the robot and also disturbances from unknown factors. To address the issue, we use two parametric models to approximate the GSR data: (1) a function of the robot’s position and velocity and (2) a random distribution. Intuitively, we need to choose the more likely model given the data. When GSR is statistically independent of the flying robot, then the random distribution should be selected instead of the function of the robot’s position and velocity. We implement the intuitive idea under the framework of hidden Markov model (HMM) estimation. As a result, the proposed HMM-based model improves the likelihood compared to the Gaussian noise model, which does not make a distinction between relevant and irrelevant samples due to unknown factors. We also present a numerical optimal path planning method that considers the safety perception model while ensuring spatial separation from the obstacle despite the time discretization. Optimal paths generated using the proposed model result in a reasonably safe distance from the human. In contrast, the trajectories generated by the standard regression model with the Gaussian noise assumption, without consideration of unknown factors, have undesirable shapes.