91��ɫ-led findings show astronauts can safely assess distances in weightless environment

TORONTO, March 25 2024 – New research led by 91��ɫ finds .

The findings of the study, done in collaboration with the Canadian Space Agency and NASA, have implications for crew safety in space and could potentially give clues to how aging affects people’s balance systems here on Earth, says the study’s lead Faculty of Health Professor .

“It has been repeatedly shown that the perception of gravity influences perceptual skill. The most profound way of looking at the influence of gravity is to take it away, which is why we took our research into space,” says Harris, an expert on vision and the perception of motion who also heads up the Multisensory Integration Lab and is the former director of the at 91��ɫ.

“We’ve had a steady presence for close to a quarter century in space and with space efforts only increasing as we plan to go back to the moon and beyond, answering health-and-safety questions only becomes more important. Based on our findings it seems as though humans are surprisingly able to compensate adequately for the lack of an Earth-normal environment using vision.”

Harris and collaborators – who include Lassonde School of Engineering professors Robert Allison and Michael Jenkin, and two generations of 91��ɫ post docs and graduate students Björn Jörges, Nils Bury, Meaghan McManus and Ambika Bansal – studied a dozen astronauts aboard the International Space Station, which orbits about 400 kilometres from the Earth’s surface. Here, Earth's gravity is approximately cancelled out by centrifugal force generated by the orbiting of the station. In the resulting microgravity, the way people move is more like flying, says Harris.

“People have previously anecdotally reported that they felt they were moving faster or further than they really were in space, so this provided some motivation to actually record this,” he explains.

The researchers compared the performance of a dozen astronauts – six men and six women – before, during, and after their year-long missions to the space station and found that their sense of how far they travelled remained largely intact.

Space missions are busy endeavours and it took the researchers several days to connect with the astronauts once they arrived at the space station. Harris says that it’s possible their research was unable to capture early adaptation that may have occurred in those first few days, “it's still a good news message because it says that whatever adaptation happens, happens very quickly.”

Space missions are not without risk. As the ISS orbits the Earth it is sometimes hit with small objects that could penetrate the vessel requiring astronauts to move to safety.

“On a number of occasions during our experiment, the ISS had to perform evasive maneuvers,” recalls Harris. “Astronauts need to be able to go to safe places or escape hatches on the ISS quickly and efficiently in an emergency. So, it was very reassuring to find that they were actually able to do this quite precisely.”

The study, published recently in npj Microgravity, has been a decade in the making, and represents the first of three papers that will emerge from the research investigating the effects of microgravity exposure on different perceptual skills including the estimation of body tilt, travelled distance, and object size.

Harris says research shows exposure to microgravity mimics the aging process on a largely physiological level  – wasting of bones and muscles, changes in hormonal functioning and increased susceptibility to infection  – but this paper finds that self-motion is largely unaffected, suggesting the balance issues that frequently come from old age may not be related to the vestibular system.

“It suggests that the mechanism for the perception of movement in older people should be relatively unaffected, and that the issues involved in falling may not be so much in terms of the perception of how far they've moved, but perhaps more to do with how they're able to convert that into a balance reflex.”

About 91��ɫ

91��ɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91��ɫ’s fully bilingual Glendon Campus is home to Southern Ontario’s Centre of Excellence for French Language and Bilingual Postsecondary Education. 91��ɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contacts: Emina Gamulin, 91��ɫ Media Relations and External Communications, 437-217-6362, egamulin@yorku.ca

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TORONTO, May 10, 2017− No matter how slim, women and men have often looked at themselves in the mirror and wondered, 91��ɫ researchers at the Centre for Vision Research say this may be due to their perceptions of body image and not by what they physically see with their eyes.

New research out of the Faculty of Health by Sarah D’Amour, supervised by Professor Laurence Harris, director of 91��ɫ U’s Centre for Vision Research, is the first to provide direct evidence that what we see and think about the shape and size of our face does not necessarily reflect reality. This is the first time that this has been done using psychophysically robust measurements of how accurately healthy participants perceive the size of their face, revealing distortions of the implicit body representation.

In the paper titled, “Perceived face size in healthy adults,” published this week in the journal , researchers at 91��ɫ U’s Centre for Vision Research discovered that our representation of our face within our brains may not be the same as the face we see in the mirror.

“We have showed that neither healthy males nor healthy females are completely accurate at judging the length and width of their faces, and that accuracy changes depending on the orientation in which the face is viewed”, says Harris. “What we found was that people were not very accurate when they were judging their face in a normal view such as seen in a mirror. People tended to think their faces were wider or fatter than they really were and this was especially true for women. Women had larger errors than men.”

The study sought to explore face perception as a way to reveal how people judge their body dimensions and to gain insight into how body size and shape are processed and represented by the brain. The research findings reveal how accurately people are able to judge their body dimensions and provide insight into how body size and shape are processed and represented by the brain.

In the 91��ɫ U study, 40 participants were asked to complete a body shape questionnaire to assess their level of dissatisfaction with their bodies. They were then shown two life-size photographs; one that offered an accurate reference of their face and the other distorted in the horizontal or vertical dimension. The participants were asked to select the photograph that they perceived to be most like them.

“It’s a very unexpected finding. You would think that something you are used to looking at every day would be something you are very familiar with and that you would be accurate about its perception,” says Professor Harris. ��“However what it tells us is that what you see, including what you see in the mirror, is hugely affected not so much by information coming in from the retina, but from your perceptions, from your world view, or from your memory.”

Study participants were unable to determine which photo best represented their face. The findings were true for both males and females, differing only in the magnitude of their errors. The errors in perception were consistent when the images were viewed both in the upright and upside down orientation. In all cases, face width was overestimated and face length was underestimated. The largest errors were found in the orientations that match our natural face shape, such as when looking in a mirror. Surprisingly, the errors disappeared when the face was viewed tilted by 90 degrees.

“Curiously, the largest errors were found in the most familiar orientations, whereas participants were accurate when the face was viewed in the unfamiliar sideways orientation,” says Harris.

Previous studies on body size perception have focused on the entire body or particular body parts, such as the belly, thighs or upper arms, all areas of the body with higher concentrations of fat. The studies were aimed at assessing distortions that happen in clinical populations, such as those individuals with eating disorders, and have tended to ignore the role of the face in healthy people’s self-perception. The role of the face is unique because it has internal features and it cannot be viewed directly and requires the use of mirrors. Face perception is a critical aspect of self-awareness.

“What we’re doing here is part of a larger research program where we’re hoping to alter people’s perception of their bodies by giving them various experiences, says Harris. “So if we can develop a way to alter body perception in healthy people, we may be able to alter it in other people, people who have issues with their own body.”

Click to watch video of Professor�� Laurence Harris explaining the research.

��is known for championing new ways of thinking that drive teaching and research excellence. Our students receive the education they need to create big ideas that make an impact on the world. Meaningful and sometimes unexpected careers result from cross-discipline programming, innovative course design and diverse experiential learning opportunities. 91��ɫ students and graduates push limits, achieve goals and find solutions to the world’s most pressing social challenges, empowered by a strong community that opens minds. 91��ɫ U is an internationally recognized research university – our 11 faculties and 26 research centres have partnerships with 200+ leading universities worldwide. Located in Toronto, 91��ɫ is the third largest university in Canada, with a strong community of 53,000 students, 7,000 faculty and administrative staff, and more than 295,000 alumni. 91��ɫ U's fully bilingual Glendon campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education.��

Media Contact:
Janice Walls, 91��ɫ Media Relations, 416-455-4710 wallsj@yorku.ca

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TORONTO, April 25, 2017– An international research collaboration between Canada and Japan with 91��ɫ Faculty of Health’s Professor Laurence Harris has discovered that our perception of self-motion has a previously unknown safety feature. Their discovery involves tactile flow, the tactile stimulation provided as you push through leaves in the undergrowth or rub your hands along a wall, and its predominant role in enhancing our sense of self-motion, overriding the information provided by vision and the balance-and-movement system contained within the inner ear.

“When you move around you have visual information that tells you how you’re moving and when you walk around the information flows past you”, says Harris. “If you’re touching something stationary as you move, such as a wall or the bannisters then that information, that tactile information, will also flow over your skin."

Harris, who is the director of the Centre for Vision Research at 91��ɫ, was invited to the Tohoku Gakuin University (TKU) in Sendai, Japan. There he collaborated with TKU Professor Kenzo Sakurai and researcher William Beaudot. “It was very unexpected,” says Harris. “Instead of simply combining with other sensory information about the movement in the same way as for example visual and acceleration cues combine, tactile flow actually dominated perceived self-motion."�� The addition of tactile information seems to provide a sort of emergency override, says Harris, making people feel they are going faster than they really are –something he says that may contribute to the "thrill of sliding down the banisters".

In their experiments they measured the perception of self-motion; how fast a person was going and how the perceived timing of the motion was impacted by the addition of tactile flow. Harris adds that there are special receptors in skin that are specialized to respond to something moving over the skin.

“We had people sitting on a swing that could move from side to side. Participants rested their fingertips on a flat piece of wood that was stationary. As they moved from side to side, they could feel the motion on their fingertips,” says Harris. “We discovered that this made them feel they were moving faster than when they were not feeling the tactile flow at the same time.”

The importance of this newly discovered role of touch in our sense of self-motion may account for why we reach for something to stabilize ourselves to prevent a fall if we miss a step. Holding on to something provides stability and provides a tactile cue about what is happening, overriding other available cues. The discovery also has ramifications for designing systems to provide artificial tactile cues to motion to enhance the experience of virtual reality or to help pilots monitor the movement of their aircraft.

“Artificial tactile stimulation might be a powerful aid to provide self-motion information in virtual environments or in situations where accurate knowledge about self-motion is critical, such as when flying a high-performance plane,” says Harris. “In people who are at risk of balance problems, such as older or blind individuals, or people who have had damage to the vestibular system, this information could provide an additional motion cue for them to help create tools for them.”

The researchers used TKU’s parallel swing, a specialized apparatus that moves a person from side to side. In their study, they had test subjects swing with and without tactile clues (created by running finger tips along a stationary surface).
The research Tactile flow overrides other cues to self-motion appears in the journal Scientific Reports and appears on nature.com.

Watch Prof. Laurence explain the findings here in this video:

91��ɫ is known for championing new ways of thinking that drive teaching and research excellence. Our students receive the education they need to create big ideas that make an impact on the world. Meaningful and sometimes unexpected careers result from cross-discipline programming, innovative course design and diverse experiential learning opportunities. 91��ɫ students and graduates push limits, achieve goals and find solutions to the world’s most pressing social challenges, empowered by a strong community that opens minds. 91��ɫ U is an internationally recognized research university – our 11 faculties and 26 research centres have partnerships with 200+ leading universities worldwide. Located in Toronto, 91��ɫ is the third largest university in Canada, with a strong community of 53,000 students, 7,000 faculty and administrative staff, and more than 295,000 alumni. 91��ɫ U's fully bilingual Glendon campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education.

Media Contacts:
Anjum Nayyar, 91��ɫ Media Relations, 416-736-2100 ext. 44543 anayyar@yorku.ca

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