Motion Perception Research Articles

Human movements do not look the same in a tilted world: Gravitational constraints influence the perception of biological motion.

We investigated whether gravitational constraints influence the interaction of visual, proprioceptive and vestibular cues for Biological Motion Perception (BMP). Participants were asked to distinguish between plausible and random point-light movements, while passively placed in either an upright or a tilted body orientation. Manipulating the body orientation with respect to gravity leads to different gravitational signals transmitted by the visual, proprioceptive, and vestibular systems. Participants were overall faster in distinguishing plausible point-light movements than random movements. Critically, response times for biologically plausible point-light movements - but not for random movements - were significantly prolonged in the tilted body orientation. Our results suggest that BMP depends not only on the spatial-temporal cues embedded in point-light movements but also rely on the congruency between current gravitational signals detected by the sensory systems and our previous knowledge of terrestrial gravity. STATEMENT OF RELEVANCE: As humankind is preparing for a new space age, understanding how gravity influences behaviour and cognition has never been more pressing. All living organisms have evolved to survive in a terrestrial gravitational field. Although we cannot consciously feel gravity, it has an impact in our life: it affects how we move and interact with the external environment. The sensory signals from the vestibular system are continuously combined with visual and proprioceptive cues to help us in maintaining a stable representation of the world. Here we placed participants in a tilted body orientation and were able to determine that a conflict between prior gravitational knowledge and what was actively sensed about gravity affected human Biological Movement Perception. Humans suffer changes in perception under non-terrestrial gravity conditions that may potentially compromise performance during space exploration.

Auto-Tuning Parameters of the Offline Optimal Motion Cueing Algorithm with Mean-Variance Mapping Optimization

A motion cueing algorithm (MCA) not only maintains the simulator within its physical limits but also generates such movements of the driving simulator that the necessary motion cues of drivers on the realistic vehicle are equivalently reproduced. The offline optimal MCA focuses on finding the best combination of the translational acceleration and tilt angles of the motion platform to maintain drivers’ motion perception. However, the best combination depends on the MCA’s parameters, tuned mainly by trial and error with experts in the loop. Moreover, for different amplitude input signals, the parameters are accordingly modified. This manual tuning procedure is so time-consuming that the generic optimization, named Mean-Variance mapping optimization, was proposed to search the suitable parameters for the optimal algorithm. This tuning method uses the specific cost function of constraint conditions such as workspace limits, avoiding false cues, and improving motion fidelity to achieve the best parameters for optimal MCA with the particular input signals.

Porous Polydimethylsiloxane Elastomer Hybrid with Zinc Oxide Nanowire for Wearable, Wide-Range, and Low Detection Limit Capacitive Pressure Sensor.

We propose a flexible capacitive pressure sensor that utilizes porous polydimethylsiloxane elastomer with zinc oxide nanowire as nanocomposite dielectric layer via a simple porogen-assisted process. With the incorporation of nanowires into the porous elastomer, our capacitive pressure sensor is not only highly responsive to subtle stimuli but vigorously so to gentle touch and verbal stimulation from 0 to 50 kPa. The fabricated zinc oxide nanowire–porous polydimethylsiloxane sensor exhibits superior sensitivity of 0.717 kPa−1, 0.360 kPa−1, and 0.200 kPa−1 at the pressure regimes of 0–50 Pa, 50–1000 Pa, and 1000–3000 Pa, respectively, presenting an approximate enhancement by 21−100 times when compared to that of a flat polydimethylsiloxane device. The nanocomposite dielectric layer also reveals an ultralow detection limit of 1.0 Pa, good stability, and durability after 4000 loading–unloading cycles, making it capable of perception of various human motions, such as finger bending, calligraphy writing, throat vibration, and airflow blowing. A proof-of-concept trial in hydrostatic water pressure sensing has been demonstrated with the proposed sensors, which can detect tiny changes in water pressure and may be helpful for underwater sensing research. This work brings out the efficacy of constructing wearable capacitive pressure sensors based on a porous dielectric hybrid with stress-sensitive nanostructures, providing wide prospective applications in wearable electronics, health monitoring, and smart artificial robotics/prosthetics.

The reverse motion illusion in random dot motion displays and implications for understanding development.

Across two independent developmental labs, we have been puzzled by the observation that a small proportion of our child and adult participants consistently report perceiving motion in the direction opposite to that presented in random-dot motion displays, sometimes even when the motion is at 100% coherence. In this review, we first draw together existing reports of misperceptions of motion direction in random dot displays across observers in a small percentage of trials, before reporting evidence of consistent reverse motion perception in a minority of observers, including previously unreported observations from our own studies of visual development. We consider possible explanations for this reverse motion illusion, including motion induction, motion energy, correspondence noise and spatial undersampling. However, more work is required to understand the individual differences relating to this percept. We suggest that errors in perceived motion direction are likely to be more widespread than can be currently gleaned from the literature and explain why systematic study is needed, especially in children. Finally, we list some remaining open questions and call for collaborative efforts to document this phenomenon and stimulate future investigation.

Assessing the Effect of the Refresh Rate of a Device on Various Motion Stimulation Frequencies Based on Steady-State Motion Visual Evoked Potentials.

The refresh rate is one of the important parameters of visual presentation devices, and assessing the effect of the refresh rate of a device on motion perception has always been an important direction in the field of visual research. This study examined the effect of the refresh rate of a device on the motion perception response at different stimulation frequencies and provided an objective visual electrophysiological assessment method for the correct selection of display parameters in a visual perception experiment. In this study, a flicker-free steady-state motion visual stimulation with continuous scanning frequency and different forms (sinusoidal or triangular) was presented on a low-latency LCD monitor at different refresh rates. Seventeen participants were asked to observe the visual stimulation without head movement or eye movement, and the effect of the refresh rate was assessed by analyzing the changes in the intensity of their visual evoked potentials. The results demonstrated that an increased refresh rate significantly improved the intensity of motion visual evoked potentials at stimulation frequency ranges of 7–28 Hz, and there was a significant interaction between the refresh rate and motion frequency. Furthermore, the increased refresh rate also had the potential to enhance the ability to perceive similar motion. Therefore, we recommended using a refresh rate of at least 120 Hz in motion visual perception experiments to ensure a better stimulation effect. If the motion frequency or velocity is high, a refresh rate of≥240 Hz is also recommended.

Cognitive Dynamics: Additive or Multiplicative?

Introduction: Cognition is assumed to rely on distinct and additive substages such as perceptual encoding, memory, and motor control. Nevertheless, questions surrounding the assumptions of modularity and additivity persist. If a stable cognitive architecture exists, then repeatedly executing the same cognitive act should repeatedly engage the self-same structure. If discreet sub-acts behave in a manner consistent with a sum of independent random variables, then the assumption of additive and modular cognitive processes is reasonable. However, if they develop dependencies, then the assumption of additivity and modularity in cognition should be questioned. Methods: The study required participants (N = 180) to successively execute identical elementary cognitive acts in a stacked 1-word, 2-word, and 4-word lexical decision task. Correct response time was the primary dependent measure. Results: Statistical analyses revealed evidence for additivity in mean response time after a logarithmic transformation (r2 = .81, p < .05 & r2 = .74, p < .05). This pattern is consistent with multiplicative dynamics. Conclusions: The results indicate that variance grows multiplicatively as a function of the number of sub-acts. A straightforward way to generate this pattern of variability growth is to assume the sub-acts develop successive dependencies and combine multiplicatively.

Extension of Dancer's Legs: Increasing Angles Show Motion.

Usain Bolt’s Lightning Bolt pose, one arm highly extended to one side, suggests action. Likewise, static pictures of animals, legs extended, show animation. We tested a new cue for motion perception—extension—and in particular extension of dancer’s legs. An experiment with pictures of a dancer finds larger angles between the legs suggest greater movement, especially with in-air poses and in lateral views. Leg positions graded from simply standing to very difficult front and side splits. Liking ratings (a small range) were more related to Difficulty ratings (a large range) than Movement ratings (a moderate range).

Local motion pooling is continuous, global motion perception is discrete.

Perceiving the motion of an object is thought to involve two stages: Local motion energy is measured at each point in space, and these signals are then pooled across space to build coherent global motion. There are several theories of how local-to-global pooling occurs, but they all predict that global motion perception is a continuous process, such that increasing the strength of motion energy should gradually increase the precision of perceived motion directions. We test this prediction against the alternative that global motion perception is discrete: Motion is either perceived with high precision or fails to be perceived altogether. Data from human observers provides clear evidence that, whereas pooling local motion energy is continuous, the segmentation of local signals into coherent global motion patterns is a discrete process. This result adds motion perception to the growing list of processes that exhibit evidence of all-or-none visual awareness. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Sentire: A Participative Interactive Sound Performance

Sentire is both an artwork and a research project in which proximity and touch are sonified with the aim to enhance body perception and social interaction. Sentire uses a digital system that mediates body movements and musical sounds, using a Body-Machine-Interface that allows two (or more) people to interact with one an- other in a physical environment—rather than in a virtual environment. The artwork consists of a participatory performance, which has been presented at numerous events since 2016. Distance and touch between the users can be measured and mapped to an algorithmic sound environment in real time. Through this multi- modal experience, the awareness of the self and the other is enhanced on bodily, especially kinaesthetic levels, i.e. movement perception. Since 2019, Sentire has been also a research project at the Humboldt University of Berlin , with the aim to develop the system for therapeutic purposes.

Learning Dense and Continuous Optical Flow From an Event Camera.

Event cameras such as DAVIS can simultaneously output high temporal resolution events and low frame-rate intensity images, which own great potential in capturing scene motion, such as optical flow estimation. Most of the existing optical flow estimation methods are based on two consecutive image frames and can only estimate discrete flow at a fixed time interval. Previous work has shown that continuous flow estimation can be achieved by changing the quantities or time intervals of events. However, they are difficult to estimate reliable dense flow, especially in the regions without any triggered events. In this paper, we propose a novel deep learning-based dense and continuous optical flow estimation framework from a single image with event streams, which facilitates the accurate perception of high-speed motion. Specifically, we first propose an event-image fusion and correlation module to effectively exploit the internal motion from two different modalities of data. Then we propose an iterative update network structure with bidirectional training for optical flow prediction. Therefore, our model can estimate reliable dense flow as two-frame-based methods, as well as estimate temporal continuous flow as event-based methods. Extensive experimental results on both synthetic and real captured datasets demonstrate that our model outperforms existing event-based state-of-the-art methods and our designed baselines for accurate dense and continuous optical flow estimation.

The effect of long-term radiofrequency exposure on cognition in human observational studies: A protocol for a systematic review.

The long term effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) for frequencies from 100 kHz to 300 GHz on cognitive performance are best assessed using observational studies. In recent years, the use of mobile (cell) phones has been the main source of RF EMF exposure to the brain, although other sources of exposure may be significant. Cognitive function includes various mental and psychological abilities, which can be measured in a range of domains, such as learning, memory, reasoning, problem solving, decision making and attention. Although effects on cognitive function may be most evident later in life, in the experimental setting acute and immediate effects can only be studied. Observational studies are needed when effects are observed after months or years following short or long-term exposure. The importance of the effects of exposure on children has also been recently identified. To assess the long-term effects of RF EMF local and whole-body exposure compared to no or a lower level of exposure on indicators of cognition, including complex attention, executive function, learning and memory, perceptual motor ability and social cognition, but excluding cognitive effects caused by neurodegenerative diseases or neurodevelopmental disorders, and to assess if there is evidence of a dose response relationship. We will include observational studies that have evaluated cognitive effects of RF energy including a comparator group with a different level of exposure. Studies must report at least one validated measure of cognitive function, including global or domain specific measures, or cognitive impairment, with a minimum follow-up of 6 months. Cohort or case-control studies published in the peer review literature in any language are eligible. We will exclude cross-sectional studies and any that only report brain structure or biomarkers. We will conduct searches of PubMed, Embase, PsycINFO and the EMF-Portal. At least two authors will independently screen the titles/abstracts of all records, with any conflicts resolved by a third reviewer. Full-text screening will also be conducted independently by two authors with conflicts resolved by consensus. Data will be extracted from the studies included, such as identifiers and characteristics of the study design, exposure and comparator groups, participants, outcomes assessed and results. Risk of bias will be assessed with the Office of Health Assessment and Translation (OHAT) tool. We will conduct a meta-analysis of similar studies with a random effects model in STATA or similar software, if two or more studies are available for a given exposure-outcome combination. Confidence in the body evidence will be judged using GRADE methods as adapted by OHAT for reviews of environmental exposures.

他者接近に対する運動知覚と自閉症スペクトラム特性との関係

他者接近に対する運動知覚と自閉症スペクトラム特性との関係

Backward Illusory Line Motion: Visual Motion Perception Produced by Retrospective Attention

Backward Illusory Line Motion: Visual Motion Perception Produced by Retrospective Attention

Supplemental Material for Local Motion Pooling Is Continuous, Global Motion Perception Is Discrete

Supplemental Material for Local Motion Pooling Is Continuous, Global Motion Perception Is Discrete

Dorsal visual stream activity during coherent motion processing is not related to math ability or dyscalculia

Math disability (MD) or developmental dyscalculia is a highly prevalent learning disability involving deficits in computation and arithmetic fact retrieval and is associated with dysfunction of parietal and prefrontal cortices. It has been suggested that dyscalculia (and other learning disabilities and developmental disorders) can be viewed in terms of a broader ‘dorsal stream vulnerability,’ which could explain a range of dorsal visual stream function deficits, including poor coherent visual motion perception. Behavioral evidence from two studies in typical children has linked performance on visual motion perception to math ability, and a third behavioral study reported poorer visual motion perception in a small group of children with MD compared to controls. Visual motion perception relies on the magnocellular-dominated dorsal stream, particularly its constituent area V5/MT. Here we used functional MRI to measure brain activity in area V5/MT during coherent visual motion processing to test its relationship with math ability. While we found bilateral activation in V5/MT in 66 children/adolescents with varied math abilities, we found no relationships between V5/MT activity and standardized math measures. Next, we selected a group of children/adolescents with MD (n = 23) and compared them to typically developing controls (n = 18), but found no differences in activity in V5/MT or elsewhere in the brain. We followed these frequentist statistics with Bayesian analyses, which favored null models in both studies. We conclude that dorsal stream function subserving visual motion processing in area V5/MT is not related to math ability, nor is it altered in those with the math disability dyscalculia.

Cerebellar Contribution to Emotional Body Language Perception.

Body language is a powerful form of non-verbal communication providing important information about the emotions and intentions of others. The ability to infer other's emotions from their bodily movements and postures recruits an extended network in the brain that encompasses both cortical and subcortical regions. In this chapter, we review recent evidence suggesting that the cerebellum is a critical node of this network. Specifically, we present convergent findings from patients', neuroimaging and non-invasive brain stimulation studies that have shown that the cerebellum is involved in both biological motion perception and in discrimination of bodily emotional expressions. We discuss the potential underlying mechanisms that drive the recruitment of the sensorimotor (anterior) and cognitive (posterior) cerebellum in inferring others' emotions through their bodily movements and postures and how the cerebellum may exert these functions within different cortico-cerebellar and limbic-cerebellar networks dedicated to body language perception.

Music in the Human Brain

Introduction: The idea to develop this topic came to us while analyzing our own observation of how music helped us to realize a large amount of intellectual work in a short period of time. Aim: Our aim was to study the influence of music on various aspects of brain activity. Tasks: Our task was to support our thesis that music has an effect on the brain through which it provokes an increase in cognitive and perceptual motor impulse, causing higher functional and structural plasticity of the brain. Materials and Methods: For the realization of this task, we used the method of observation and analysis of the experimental productions available in the scientific literature, conducted in some of the leading neurolinguistic centers in the world . Results and Discussion: Our personal result was that in the background of musical works or alternating musical activities with our main intellectual activity, we were able in a short period of time to summarize and structure a large volume of activity, while at the same time, in this work pattern our body and mind did not feel exhausted and for a long time we kept our motivation to work and our concentration on the detail. Conclusion: Our work came to the conclusion, which are in support of the influence of music on the speed of concentration, strengthening the selective processes of attention, the speed of associative processes in the brain, quick analysis of cognitive and emotional aspects, faster and more efficient memorization.

Supplemental Material for The False Aperture Problem: Global Motion Perception Without Integration of Local Motion Signals

Supplemental Material for The False Aperture Problem: Global Motion Perception Without Integration of Local Motion Signals

How do humans group non-rigid objects in multipleobject tracking?: Evidence from grouping by self-rotation.

Previous studies on perceptual grouping found that people can use spatiotemporal and featural information to group spatially separated rigid objects into a unit while tracking moving objects. However, few studies have tested the role of objects' self-motion information in perceptual grouping, although it is of great significance to the motion perception in the three-dimensional space. In natural environments, objects always move in translation and rotation at the same time. The self-rotation of the objects seriously destroys objects' rigidity and topology, creates conflicting movement signals and results in crowding effects. Thus, this study sought to examine the specific role played by self-rotation information on grouping spatially separated non-rigid objects through a modified multiple object tracking (MOT) paradigm with self-rotating objects. Experiment 1 found that people could use self-rotation information to group spatially separated non-rigid objects, even though this information was deleterious for attentive tracking and irrelevant to the task requirements, and people seemed to use it strategically rather than automatically. Experiment 2 provided stronger evidence that this grouping advantage did come from the self-rotation per se rather than surface-level cues arising from self-rotation (e.g. similar 2D motion signals and common shapes). Experiment 3 changed the stimuli to more natural 3D cubes to strengthen the impression of self-rotation and again found that self-rotation improved grouping. Finally, Experiment 4 demonstrated that grouping by self-rotation and grouping by changing shape were statistically comparable but additive, suggesting that they were two different sources of the object information. Thus, grouping by self-rotation mainly benefited from the perceptual differences in motion flow fields rather than in deformation. Overall, this study is the first attempt to identify self-motion as a new feature that people can use to group objects in dynamic scenes and shed light on debates about what entities/units we group and what kinds of information about a target we process while tracking objects.

Acuity and summation strategies differ in vinegar and desert fruit flies

SummaryAn animal's vision depends on terrain features that limit the amount and distribution of available light. Approximately 10,000 years ago, vinegar flies (Drosophila melanogaster) transitioned from a single plant specialist into a cosmopolitan generalist. Much earlier, desert flies (D. mojavensis) colonized the New World, specializing on rotting cactuses in southwest North America. Their desert habitats are characteristically flat, bright, and barren, implying environmental differences in light availability. Here, we demonstrate differences in eye morphology and visual motion perception under three ambient light levels. Reducing ambient light from 35 to 18 cd/m2 causes sensitivity loss in desert but not vinegar flies. However, at 3 cd/m2, desert flies sacrifice spatial and temporal acuity more severely than vinegar flies to maintain contrast sensitivity. These visual differences help vinegar flies navigate under variably lit habitats around the world and desert flies brave the harsh desert while accommodating their crepuscular lifestyle.