Laurence R Harris

Laurence R Harris
York University · Department of Psychology

PhD

About

295
Publications
32,716
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4,816
Citations
Citations since 2016
67 Research Items
1766 Citations
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2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250

Publications

Publications (295)
Article
Full-text available
Self-motion perception (e.g., when walking/driving) relies on the integration of multiple sensory cues including visual, vestibular, and proprioceptive signals. Changes in the efficacy of multisensory integration have been observed in older adults (OA), which can sometimes lead to errors in perceptual judgments and have been associated with functio...
Article
Full-text available
Depth information is limited in a 2D scene and for people to perceive the distance of an object, they need to rely on pictorial cues such as perspective, size constancy and elevation in the scene. In this study, we tested whether people could use an object’s size and its position in a 2D image to determine its distance. In a series of online experi...
Article
Full-text available
Inaccurate perceptions, such as under- or over-estimation of body size are often found in clinical eating disorder populations but have recently been shown also in healthy people. However, it is not yet clear how body size perception may be affected when the internal body representation is manipulated. In this study, visual adaptation was used to i...
Article
Full-text available
Falls are a common cause of injury in older adults (OAs), and age-related declines across the sensory systems are associated with increased falls risk. The vestibular system is particularly important for maintaining balance and supporting safe mobility, and aging has been associated with declines in vestibular end-organ functioning. However, few st...
Article
Full-text available
Here, we investigate how body orientation relative to gravity affects the perceived size of visual targets. When in virtual reality, participants judged the size of a visual target projected at simulated distances of between 2 and 10 m and compared it to a physical reference length held in their hands while they were standing or lying prone or supi...
Article
Full-text available
Judging object speed during observer self-motion requires disambiguating retinal stimulation from two sources: self-motion and object motion. According to the Flow Parsing hypothesis, observers estimate their own motion, then subtract the retinal corresponding motion from the total retinal stimulation and interpret the remaining stimulation as pert...
Article
Full-text available
Background: Humans demonstrate many physiological changes in microgravity for which long-duration head down bed rest (HDBR) is a reliable analog. However, information on how HDBR affects sensory processing is lacking. Objective: We previously showed (25) that microgravity alters the weighting applied to visual cues in determining the perceptual...
Preprint
Full-text available
Falls are a common cause of injury in older adults (OAs), and age-related declines across the sensory systems are associated with an increased risk of falls. The vestibular system is particularly important for maintaining balance and supporting safe mobility, and aging has been associated with declines in vestibular end-organ functioning. However,...
Article
Objectives: Older adults with age-related hearing loss (ARHL) are at greater risk of falling and have greater mobility problems than older adults with normal hearing (NH). The underlying cause of these associations remains unclear. One possible reason is that age-related declines in the vestibular system could parallel those observed in the audito...
Article
Full-text available
Human perception is based on expectations. We expect visual upright and gravity upright, sensed through vision, vestibular and other sensory systems, to agree. Equally, we expect that visual and vestibular information about self-motion will correspond. What happens when these assumptions are violated? Tilting a person from upright so that gravity i...
Article
Full-text available
Vection is a perceptual phenomenon that describes the visually induced subjective sensation of self-motion in the absence of physical motion. Previous research has discussed the potential involvement of top-down cognitive mechanisms on vection. Here, we quantified how cognitive manipulations such as contextual information (i.e., expectation) and pl...
Article
Full-text available
An internal model of self-motion provides a fundamental basis for action in our daily lives, yet little is known about its development. The ability to control self-motion develops in youth and often deteriorates with advanced age. Self-motion generates relative motion between the viewer and the environment. Thus, the smoothness of the visual motion...
Article
Full-text available
Past studies have found poorer performance on vertical heading judgement accuracy compared to horizontal heading judgement accuracy. In everyday life, precise vertical heading judgements are used less often than horizontal heading judgements as we cannot usually control our vertical direction. However, pilots judging a landing approach need to cons...
Chapter
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Vestibular damage can be very debilitating, requiring ongoing assessment and rehabilitation to return sufferers to normal function. The process of rehabilitation can require an extended period of therapy during which patients engage in repetitive and often boring tasks to recover as much normal vestibular function as possible. Making these tasks mo...
Article
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The perception of an event is strongly influenced by the context in which it occurs. Here, we examined the effect of a rhythmic context on detection of asynchrony in both the auditory and vibrotactile modalities. Using the method of constant stimuli and a two-alternative forced choice (2AFC), participants were presented with pairs of pure tones pla...
Article
Full-text available
The perception of the body and its parts has traditionally been studied using the conscious body image. Here, we determine the implicit representation of the hand. Participants were sequentially shown two life-size images of either the dorsal or palmar surface of their hand. In one interval either the horizontal or vertical dimension of the image w...
Article
Full-text available
Forward models can predict sensory consequences of self-action, which is reflected by less neural processing for actively than passively generated sensory inputs (BOLD suppression effect). However, it remains open whether forward models take the identity of a moving body part into account when predicting the sensory consequences of an action. In th...
Article
Full-text available
Perceived body size is a fundamental construct that reflects our knowledge of self and is important for all aspects of perception, yet how we perceive our bodies and how the body is represented in the brain is not yet fully understood. In order to understand how the brain perceives and represents the body, we need an objective method that is not vu...
Article
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Our recent work demonstrated that vision can recalibrate the vestibular signal used to re-establish equilibrium following a platform perturbation. Here, we investigate whether vision provided during a platform perturbation can recalibrate the use of vestibular reafference during the dynamic phase of the perturbation response. Dynamic postural respo...
Article
Full-text available
Our visual system maintains a stable representation of object size when viewing distance, and thus retinal size, changes. Previous studies have revealed that the extent of an object's representation in V1 shows systematic deviations from strict retinotopy when the object is perceived to be at different distances. It remains unknown, however, to wha...
Poster
Updating egocentric positions of surrounding objects during self-motion is fundamental to our ability to navigate around the world. However, past studies have shown that people make systematic errors in the direction of the movement when updating positions during lateral self-motion. To determine the source of these errors, we measured errors in re...
Poster
Full-text available
Updating egocentric positions of surrounding objects during self-motion is fundamental to our ability to navigate around the world. However, past studies have shown that people make systematic errors in the direction of the movement when updating positions during lateral self-motion. To determine the source of these errors, we measured errors in re...
Conference Paper
Maintaining orientation in an environment with non-Earth gravity (1 g) is critical for an astronaut's operational performance. Such environments present a number of complexities for balance and motion. For example, when an astronaut tilts due to ascending or descending an inclined plane on the moon, the gravity vector will be tilted correctly, but...
Article
Full-text available
Passive rotation has been shown to alter temporal-order judgments for tactile stimuli delivered to the hands giving an advantage to the leading hand. Here we measure thresholds for detecting stimulus onset asynchrony for touches on the hands during tilt to the left or right and during galvanic vestibular stimulation (GVS) that evoked illusory tilt....
Article
Full-text available
INTRO Females are influenced more than males by visual cues during many spatial orientation tasks; but females rely more heavily on gravitational cues during visual-vestibular conflict. Are there gender biases in the relative contributions of vision, gravity and the internal representation of the body to the perception of upright? And might any suc...
Conference Paper
Females are influenced more than males by visual cues during many spatial orientation tasks; but females rely more heavily on gravitational cues during visual-vestibular conflict. Are there gender biases in the relative contributions of vision, gravity and the internal representation of the body to the perception of upright? And might any such bias...
Article
Full-text available
Objective: Perceived upright depends on three main factors: vision, graviception, and the internal representation of the long axis of the body. We assessed the relative contributions of these factors in individuals with sub-acute and chronic stroke and controls using a novel tool; the Oriented Character Recognition Test (OCHART). We also considere...
Poster
Full-text available
INTRODUCTION The perceived distance to objects in the environment needs to be updated during self-motion. Such updating needs to be overridden if the object moves with the observer (such as when reading a phone while walking). Errors in updating could lead to errors in perceived distance and, because of size/distance invariance, to errors in percei...
Article
Full-text available
Vestibular-somatosensory interactions are pervasive in the brain but it remains unclear why. Here we explore the contribution of tactile flow to processing self-motion. We assessed two aspects of self-motion: timing and speed. Participants sat on an oscillating swing and either kept their hands on their laps or rested them lightly on an earth-stati...
Article
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A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
Article
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In the absence of visual feedback, the perceived orientation of the fingers is systematically biased. In right-handers these biases are asymmetrical between the left and right hands in the horizontal plane and may reflect common functional postures for the two hands. Here we compared finger orientation perception in right- and left-handed participa...
Article
Full-text available
Forming a coherent percept of an event requires different sensory inputs originating from the event to be bound. Perceiving synchrony aids in binding of these inputs. In two experiments, we investigated how voluntary movements influence the perception of simultaneity, by measuring simultaneity judgments (SJs) for an audiovisual (AV) stimulus pair t...
Article
Full-text available
Self-motion information can be used to update spatial memory of location through an estimate of a change in position. Viewing optic flow alone can create Illusory self-motion or ''vection.'' Early studies suggested that peripheral vision is more effective than central vision in evoking vection, but controlling for retinal area and perceived distanc...
Article
Full-text available
Perceptual body size distortions have traditionally been studied using subjective, qualitative measures that assess only one type of body representation–the conscious body image. Previous research on perceived body size has typically focused on measuring distortions of the entire body and has tended to overlook the face. Here, we present a novel ps...
Data
Data. The percentage difference from accurate where 0 = accurate and negative means thinner or shorter than accurate. (XLSX)
Article
Full-text available
The importance of multisensory integration for perception and action has long been recognised. Integrating information from individual senses increases the chance of survival by reducing the variability in the incoming signals, thus allowing us to respond more rapidly. Reaction times (RTs) are fastest when the components of the multisensory signals...
Article
Full-text available
Visuo-vestibular recalibration, in which visual information is used to alter the interpretation of vestibular signals, has been shown to influence both oculomotor control and navigation. Here we investigate whether vision can recalibrate the vestibular feedback used during the re-establishment of equilibrium following a perturbation. The perturbati...
Article
Full-text available
Going into space is a disorienting experience. Many studies have looked at sensory functioning in space but the multisensory basis of orientation has not been systematically investigated. Here, we assess how prolonged exposure to microgravity affects the relative weighting of visual, gravity, and idiotropic cues to perceived orientation. We separat...
Article
Full-text available
Predictive mechanisms are essential to successfully interact with the environment and to compensate for delays in the transmission of neural signals. However, whether and how we predict multisensory action outcomes remains largely unknown. Here we investigated the existence of multisensory predictive mechanisms in a context where actions have outco...
Data
Table A, Table B, Fig A, Fig B. (DOCX)
Article
Full-text available
In the absence of visual feedback, the perceived position of the hands is systematically biased towards the plausible manual task space. Here we tested whether perceived orientation of the finger is similarly misperceived in right-handed individuals. Participants’ index fingers were passively rotated about the middle joint to a range of test angles...
Article
Full-text available
Seeing our body from a 'self' perspective while performing a movement improves our ability to detect asynchrony between the visual and proprioceptive information concerning that movement: a signature of enhanced body ownership referred to as the 'self-advantage'. We consequently experience no self-advantage when seeing our body from an 'other' pers...
Article
Full-text available
The perception of body size has traditionally been studied using subjective, qualitative measures that assess only one type of body representation - the conscious body image. Previous research has typically focused on measuring the perceived size of the entire body rather than individual body parts, such as the face and arms. Here, we present a nov...
Article
Full-text available
Right-handed people show an advantage in detecting a delay in visual feedback concerning an active movement of their right hand when it is viewed in a natural perspective compared to when it is seen as if viewing another person's hand (Hoover and Harris in Exp Brain Res 233:1053-1060, 2012. doi: 10.1007/s00221-014-4181-9 ; Exp Brain Res 222:389-397...
Article
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Animals try to make sense of sensory information from multiple modalities by categorizing them into perceptions of individual or multiple external objects or internal concepts. For example, the brain constructs sensory, spatial representations of the locations of visual and auditory stimuli in the visual and auditory cortices based on retinal and c...
Article
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Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, usually using stimuli that are close together to reveal local interactions. Masking effects have also been demonstrated in which a tactile stimulus alters the perception of a touch at a distant locati...
Article
Full-text available
Long-range tactile masking has been reported between mirror symmetric body locations. This suggests a general principle of contralateral inhibition between corresponding points on each side of the body that may serve to enhance distinguishing touches on the two halves of the body. Do such effects occur before or after posture is added to the body s...
Article
The ‘stream/bounce’ illusion refers to the perception of an ambiguous visual display in which two discs approach each other on a collision course. The display can be seen as two discs streaming through each other or bouncing off each other. Which perception dominates, may be influenced by a brief transient, usually a sound, presented around the tim...