Nikolaus Troje

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Verified

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• Professor
• Canada Reserach Chair at York University

Traditionally, perceptual spaces are defined by the medium through which the visual environment is conveyed (e.g., in a physical environment, through a picture, or on a screen). This approach overlooks the distinct contributions of different types of visual information, such as binocular disparity and motion parallax, that transform different visua...

Background The literature shows conflicting results regarding inter- and intra-rater reliability, even for the same movement screen. The purpose of this study was to assess inter- and intra-rater reliability of movement scores within and between sessions of expert assessors and the effects of body-shape on reliability during a movement screen using...

Previous research on attention to fear-relevant stimuli has largely focused on static pictures or drawings, and thus did not consider the potential effect of natural motion. Here, we aimed to investigate the effect of motion on attentional capture in spider-fearful and non-fearful participants by using point-light stimuli and naturalistic videos. P...

Visual perception in different contexts elicits different perceptual spaces with different perceptual geometry. While visual space emerges from perception in the physical environment, pictorial space arises when the observer looks into a picture. Although visual and pictorial space is suggested to be qualitatively different, observers can still rel...

Previous research on attention to fear-relevant stimuli has largely focused on static pictures or drawings, and thus did not consider the potential effect of natural motion. Here, we aimed to investigate the effect of motion on attentional capture in spider-fearful and non-fearful participants by using point-light stimuli and naturalistic videos. P...

The dynamics of head and eye gaze between two or more individuals displayed during verbal and nonverbal face-to-face communication contains a wealth of information and is used for both volitionary and unconscious signaling. Current video communication systems convey visual signals about gaze behavior and other directional cues, but the information...

Interacting with people and three-dimensional objects depicted on a screen is perceptually different from interacting with them in real life. This difference resides in their corresponding perceptual spaces: The former involves pictorial space, and the latter, visual space. Studies have examined the perceptual geometry of pictorial or visual space,...

Natural, dynamic eye contact behaviour is critical to social interaction but is dysfunctional in video conferencing. In analysing the problem, I introduce the concept of directionality and emphasize the critical role of motion parallax. I then sketch approaches towards re-establishing directionality and enabling natural, dynamic eye contact in vide...

We present ZeroEGGS, a neural network framework for speech‐driven gesture generation with zero‐shot style control by example. This means style can be controlled via only a short example motion clip, even for motion styles unseen during training. Our model uses a Variational framework to learn a style embedding, making it easy to modify style throug...

Life motion, the active movements of people and other animals, contains a wealth of information that is potentially accessible to the visual system of an observer. Biological-motion point-light displays have been widely used to study both the information contained in life motion stimuli and the visual mechanisms that make use of it. Biological moti...

Interacting with people and three-dimensional objects depicted on a screen is perceptually different from interacting with them in real life. This difference resides in their corresponding perceptual spaces: The former involves pictorial space, and the latter, visual space. Studies have examined the perceptual geometry of pictorial or visual space,...

We present ZeroEGGS, a neural network framework for speech-driven gesture generation with zero-shot style control by example. This means style can be controlled via only a short example motion clip, even for motion styles unseen during training. Our model uses a Variational framework to learn a style embedding, making it easy to modify style throug...

Previous research suggests that belief in free will correlates with intentionality attribution. However, whether belief in free will is also related to more basic social processes is unknown. Based on evidence that biological motion contains intentionality cues that observers spontaneously extract, we investigate whether people who believe more in...

The long-standing nativist vs. empiricist debate asks a foundational question in epistemology – does our knowledge arise through experience or is it available innately? Studies that probe the sensitivity of newborns and patients recovering from congenital blindness are central in informing this dialogue. One of the most robust sensitivities our vis...

Motor abnormalities occur in the majority of persons with schizophrenia but are generally neglected in clinical care. Psychiatric diagnostics fail to include quantifiable motor variables and few assessment tools examine full-body movement. We assessed full-body movement during gait of 20 patients and 20 controls with motion capture technology, symp...

Most listeners possess sophisticated knowledge about the music around them without being aware of it or its intricacies. Previous research shows that we develop such knowledge through exposure. This knowledge can then be assessed using behavioral and neurophysiological measures. It remains unknown however, which neurophysiological measures accompan...

Cybersickness is an enduring problem for users of virtual environments. While it is generally assumed that cybersickness is caused by discrepancies in perceived self-motion between the visual and vestibular systems, little is known about the relative contribution of active motion parallax and binocular disparity to the occurrence of cybersickness....

Large high-quality datasets of human body shape and kinematics lay the foundation for modelling and simulation approaches in computer vision, computer graphics, and biomechanics. Creating datasets that combine naturalistic recordings with high-accuracy data about ground truth body shape and pose is challenging because different motion recording sys...

When observing point light walkers orthographically projected onto a frontoparallel plane, the direction in which they are walking is ambiguous. Nevertheless, observers more often perceive them as facing towards than as facing away from them. This phenomenon is known as the “facing-the-viewer bias” (FTV). Two interpretations of the facing-the-viewe...

This study compared how two virtual display conditions of human body expressions influenced explicit and implicit dimensions of emotion perception and response behavior in women and men. Two avatars displayed emotional interactions (angry, sad, affectionate, happy) in a “pictorial” condition depicting the emotional interactive partners on a screen...

Previous research suggests that belief in free will correlates positively with intention perception. However, whether belief in free will is also related to more basic social processes is unknown. Based on evidence that biological motion is an intention-carrier, we investigate if belief in free will and related two beliefs, namely belief in dualism...

Developing computational methods for bodily expressed emotion understanding can benefit from knowledge and approaches of multiple fields, including computer vision, robotics, psychology/psychiatry, graphics, data mining, machine learning, and movement analysis. The panel, consisting of active researchers in some closely-related fields, attempts to...

There has been accumulating evidence of human social chemo-signaling, but the underlying mechanisms remain poorly understood. Considering the evolutionarily conserved roles of oxytocin and vasopressin in reproductive and social behaviors, we examined whether the two neuropeptides are involved in the subconscious processing of androsta-4,16,-dien-3-...

We sought to understand the spatiotemporal characteristics of biological motion perception. We presented observers with biological motion walkers that differed in terms of form coherence or kinematics (i.e., the presence or absence of natural acceleration). Participants were asked to discriminate the facing direction of the stimuli while their magn...

We present a probabilistic framework to generate character animations based on weak control signals, such that the synthesized motions are realistic while retaining the stochastic nature of human movement. The proposed architecture, which is designed as a hierarchical recurrent model, maps each sub‐sequence of motions into a stochastic latent code...

Visual input during the first years of life is vital for the development of numerous visual functions. While normal development of global motion perception seems to require visual input during an early sensitive period, the detection of biological motion (BM) does not seem to do so. A more complex form of BM processing is the identification of huma...

We present a probabilistic framework to generate character animations based on weak control signals, such that the synthesized motions are realistic while retaining the stochastic nature of human movement. The proposed architecture, which is designed as a hierarchical recurrent model, maps each sub-sequence of motions into a stochastic latent code...

Gait recognition, referring to the identification of individuals based on the manner in which they walk, can be very challenging due to the variations in the viewpoint of the camera and the appearance of individuals. Current methods for gait recognition have been dominated by deep learning models, notably those based on partial feature representati...

Movement screens are frequently used to identify differences in movement patterns such as pathological abnormalities or skill related differences in sport; however, abnormalities are often visually detected by a human assessor resulting in poor reliability. Therefore, our previous research has focused on the development of an objective movement ass...

Advances in virtual reality technology have made it a valuable new tool for vision and perception researchers. Coding virtual reality experiments from scratch can be difficult and time-consuming, so researchers rely on software such as Unity game engine to create and edit virtual scenes. However, Unity lacks built-in tools for controlling experimen...

Advances in virtual reality (VR) technology have made it a valuable new tool for vision and perception researchers since it offers a critical depth cue, active motion parallax. Coding VR experiments from scratch is difficult and time-consuming so researchers rely on software such as Unity game engine to create and edit virtual scenes. However, Unit...

An essential difference between pictorial space displayed as paintings, photographs, or computer screens, and the visual space experienced in the real world is that the observer has a defined location, and thus valid information about distance and direction of objects, in the latter but not in the former. Thus egocentric information should be more...

Stereopsis and motion parallax provide depth information, capable of producing more realistic user experiences after being integrated into a flat screen (e.g. immersive virtual reality). Extensive research shows that stereoscopic screens increase realism, while few studies have investigated users' responses to parallax screens without stereopsis. I...

Animated virtual characters are essential to many applications. Little is known so far about biological and personality inferences made from a virtual character’s body shape and motion. Here, we investigated how sex-specific differences in walking style relate to the perceived attractiveness and confidence of male and female virtual characters. The...

Human movements are both an area of intense study and the basis of many applications such as character animation. For many applications, it is crucial to identify movements from videos or analyze datasets of movements. Here we introduce a new human Motion and Video dataset MoVi, which we make available publicly. It contains 60 female and 30 male ac...

The sense of presence is defined as a subjective feeling of being situated in an environment and occupying a location therein. The sense of presence is a defining feature of virtual environments. In two experiments, we aimed at investigating the relative contribution of motion parallax and stereopsis to the sense of presence, using two versions of...

Developing computational methods for bodily expressed emotion understanding can benefit from knowledge and approaches of multiple fields, including computer vision, robotics, psychology/psychiatry, graphics, data mining, machine learning, and movement analysis. The panel, consisting of active researchers in some closely-related fields, attempts to...

Correctly perceiving the movements of opponents is essential in everyday life as well as in many sports. Several studies have shown a better prediction performance for detailed stimuli compared to point-light displays (PLDs). However, it remains unclear whether differences in prediction performance result from explicit information about articulatio...

Objectives The current study sought to examine the relative contributions of kinematic and situational probability information to anticipation using different levels of disguised kinematics. More specifically, it was tested whether the weighting of the informational sources (kinematic vs. probabilistic) shifts relative to the certainty of the avail...

Optical marker-based motion capture is a vital tool in applications such as motion and behavioural analysis, animation, and biomechanics. Labelling, that is, assigning optical markers to the pre-defined positions on the body is a time consuming and labour intensive postprocessing part of current motion capture pipelines. The problem can be consider...

Optical marker-based motion capture is a vital tool in applications such as motion and behavioural analysis, animation, and biomechanics. Labelling, that is, assigning optical markers to the pre-defined positions on the body, is a time consuming and labour intensive post-processing part of current motion capture pipelines. The problem can be consid...

Large datasets are the cornerstone of recent advances in computer vision using deep learning. In contrast, existing human motion capture (mocap) datasets are small and the motions limited, hampering progress on learning models of human motion. While there are many different datasets available, they each use a different parameterization of the body,...

The individual shape of the human body, including the geometry of its articulated structure and the distribution of weight over that structure, influences the kinematics of a person's movements. How sensitive is the visual system to inconsistencies between shape and motion introduced by retargeting motion from one person onto the shape of another?...

The detection performance of a walk-through metal detector (WTMD) is affected not only by the electromagnetic properties and size and shape of the test objects, but potentially also by the type of motion of the test object through the portal of the WTMD. This motion, it has been argued, can contribute to the uncertainty in detecting threat objects...

Avatars are important for games and immersive social media applications. Although avatars are still not complete digital copies of the user, they often aim to represent a user in terms of appearance (color and shape) and motion. Previous studies have shown that humans can recognize their own motions in point-light displays. Here, we investigated wh...

Can cognition penetrate action-to-perception transfer? Participants observed a structure-from-motion cylinder of ambiguous rotation direction. Beforehand, they experienced one of two mechanical models: An unambiguous cylinder was connected to a rod by either a belt (cylinder and rod rotating in the same direction) or by gears (both rotating in oppo...

Anticipating the outcome of an opponent’s action is an important skill for coping with temporal demands in competitive sport. Research has shown that athletes make use of both kinematic and situational probability information when anticipating action outcomes. However, there has been relatively little empirical work to identify the relative contrib...

Use of virtual reality (VR) technology is often accompanied by a series of unwanted symptoms, including nausea and headache, which are characterised as ‘simulator sickness’. Sensory mismatch has been thought to lie at the heart of the problem and recent studies have shown that reducing cue mismatch in VR can have a therapeutic effect. Specifically,...

Using fMRI and multivariate analyses we sought to understand the neural representations of articulated body shape and local kinematics in biological motion. We show that in addition to a cortical network that includes areas identified previously for biological motion perception, including the posterior superior temporal sulcus, inferior frontal gyr...

Depth-ambiguous point-light walkers are most frequently seen as facing-the-viewer (FTV). It has been argued that the FTV bias depends on recognising the stimulus as a person. Accordingly, reducing the social relevance of biological motion by presenting stimuli upside down has been shown to reduce FTV bias. Here, we replicated the experiment that re...

Introduction: Movement screens are frequently used to identify abnormal movement patterns that may increase risk of injury or hinder performance. Abnormal patterns are often detected visually based on the observations of a coach or clinician. Quantitative, or data-driven methods can increase objectivity, remove issues related to inter-rater reliab...

Significance Impaired visual processing of biological motion (BM) is inextricably linked to compromised social cognitive abilities in autism spectrum disorder (ASD). Using behavioral genetic methodology, we demonstrate that genes contribute to interindividual variation in BM perception abilities and autistic traits. More importantly, the ability to...

The present study tested whether or not functional adaptations following congenital blindness are maintained in humans after sight-restoration and whether they interfere with visual recovery. In permanently congenital blind individuals both intramodal plasticity (e.g. changes in auditory cortex) as well as crossmodal plasticity (e.g. an activation...

Stabilization of the head in animals with limited capacity to move their eyes is key to maintain a stable image on the retina. In many birds, including pigeons, a prominent example for the important role of head stabilization is the characteristic head-bobbing behavior observed during walking. Multimodal sensory feedback from the eyes, the vestibul...

This article describes the motion database for a large sample (n = 2400) of 7-m penalty throws in team handball that includes 1600 disguised throws. Throws were performed by both novice (n = 5) and expert (n = 5) penalty takers. The article reports the methods and materials used to capture the motion data. The database itself is accessible for down...

The individual shape of the human body, including the geometry of its articulated structure and the distribution of weight over that structure, influences the kinematics of a person's movements. How sensitive is the visual system to inconsistencies between shape and motion introduced by retargeting motion from one person onto the shape of another?...

This study examined the kinematic characteristics of disguised movements by applying linear discriminant (LDA) and dissimilarity analyses to the motion data from 788 disguised and 792 non-disguised 7-m penalty throws performed by novice and expert handball field players. Results of the LDA showed that discrimination between type of throws (disguise...

Visual illusions cut across academic divides and popular interests: on the one hand, illusions provide entertainment as curious tricks of the eye; on the other hand, scientific research related to illusory phenomena has given generations of scientists and artists deep insights into the brain and principles of mind and consciousness. Numerous thinke...

Anticipation is an important skill for coping with the challenges in competitive sport. Quite frequently, athletes attempt to deceive their opponents in order to manipulate anticipatory processes. Real and deceptive actions typically display a degree of spatiotemporal dissimilarity in terms of motion trajectories and temporal dynamics. Until now,...

This study examined the kinematic characteristics of disguised movements by applying linear discriminant (LDA) and dissimilarity analyses to the motion data from 788 disguised and 792 non-disguised 7-m penalty throws performed by novice and expert handball field players. Results of the LDA showed that discrimination between type of throws (disguise...

Entegra Corporation, in collaboration with NIST and the BioMotion Lab at Queen’s University in Ontario, has written new control software for the Cartesian Robot used by the Security Technologies Group at NIST for testing walk-through, handheld, and hand-worn metal detectors. The former control software produced rectilinear motion whereas the new co...

Visual illusions explore the limits of sensory processing and provide an ideal testbed to study perception. Size illusions – stimuli whose size is consistently misperceived – do not only result from sensory cues, but can also be induced by cognitive factors, such as social status. Here we investigate, whether the ecological relevance of biological...

(Open Access article: http://booksandjournals.brillonline.com/content/journals/10.1163/22134808-00002545) Studies of the illusory sense of self-motion elicited by a moving visual surround ('vection') have revealed key insights about how sensory information is integrated. Vection usually occurs after a delay of several seconds following visual motio...

Re­cent re­sults have shown that the way we cat­e­go­rize space varies as a func­tion of the frame of ref­er­ence. If the ref­er­ence frame (RF) is an­other per­son vs. an ob­ject, the dis­tance is judged as re­duced. It has been sug­gested that such an ef­fect is due to the spon­ta­neous pro­cess­ing of the other's mo­tor po­ten­tial­i­ties. To in...

Pecking at small targets requires accurate spatial coordination of the head. Goodale (1983a) suggested that planning of the peck happens during two distinct stop phases, but although this idea has now been around for a long time, the specific functional roles of these stop phases remain unsolved. Here, we investigated the characteristics of the two...

The illusory sense of self-motion that can occur when the visual field moves coherently ('vection') has revealed key insights into how sensory information is integrated. In the natural environment, moving through space generates an immediate perception that we are in motion. In the case of illusory self-motion, there are delays in the region of 5-1...

Perceiving the weight of a lifted object from visual displays of the lifting person is a non-trivial task. Runeson and Frykholm (1981), who worked with biological motion point-light displays, attributed the ability to estimate the weight of a lifted box to what they called the Kinematic Specification of Dynamics. The KSD assumes that dynamics are i...

Size perception is distorted in several illusions, including some that rely on complex social attributes: for example, people of higher subjective importance are associated with larger size. Biological motion receives preferential visual processing over non-biological motion with similar low-level properties, a difference presumably related to a st...

We report on a study conducted to extend our knowledge about the process of gaining a mental representation of music. Several studies, inspired by research on the statistical learning of language, have investigated statistical learning of sequential rules underlying tone sequences. Given that the mental representation of music correlates with distr...

Behavioural data and participant descriptives

Further descriptives of sample

A closed-loop teleprompter system was used to isolate and manipulate social interactivity in the natural courtship interactions of pigeons Columbia livia. In Experiment 1, a live face-to-face real-time interaction between 2 courting pigeons (Live) was compared to a played back version of the video stimulus recorded during the pairs Live interaction...

Athletes are often asked to adapt their behavior to constantly changing environmental conditions. Action prediction can make it easier to achieve such behavioral goals. However, in many situations, athletes attempt to manipulate this process in order to deceive their opponent. Nonetheless, opponents can detect the actor’s intention by observing the...