Optical illusions are sometimes survival mechanisms, University of Idaho researcher Russell Jackson said.
Jackson, associate professor of psychology at UI, studies how evolution shaped the way humans navigate their environments and presented “Illusions and Mortality: The story of Evolved Navigation Theory” at the Malcom M. Renfrew Interdisciplinary Colloquium Tuesday. Jackson works with Eve Buck, an undergraduate research assistant, and Will Felton, a Ph.D. student.
He said a hidden cost of navigation for humans includes falling off things.
“Falling is a major source of selection in humans,” Jackson said. “It’s likely the primary accidental mortality and injury risk in human evolutionary history.”
This hasn’t changed.
He said workplace falls in the U.S. cost roughly $110 billion each year.
“There has been a drastic increase in investment in falling prevention in the last thirty years, but the rate of falling has increased over this same period,” Jackson said.
He said the danger of falling has shaped human perception.
“We overestimate vertical stuff,” Jackson said. “And sloped stuff.”
He said people estimate the length of a school bus accurately when it is horizontal, but they estimate the same distance vertically to be the height of a 5-story building.
However, he said people only significantly overestimate vertical distances if they feel they are at risk of falling.
To test this, Jackson removed falling risk from the situation by setting up virtual reality environments that are purposefully poorly immersive.
“Without the falling cost, people’s predictions became far more accurate,” Jackson said.
Eve Buck, an undergraduate researcher who works with Jackson, works with Jackson’s participants, who sign up through Sona.
“They look over different ledges and there are three dots in the environment,” Buck said. “Two are at the top of the distance and one is at the base. We move one dot horizontally until they tell us it looks the same distance as the one below them.”
She said Jackson started the research with a part of the lawn behind Life Sciences South that drops off to pavement and is as high as it is long. She said they recreated it in virtual reality to test the differences in how people react.
For the reverse, he used relatively immersive virtual reality situations that added falling risks to horizontal surfaces by putting the horizontal distance on narrow walkways or on cliffsides.
“Falling still kills tons of people,” Jackson said. “So I’m working on creating a falling risk inventory. This would be an assessment that predicts how likely it is someone will fall based on behaviors and distance perception.”
He said currently, age and known balance problems are the only predictors. For everyone else, he said there are no predictors of how likely they are to fall.
Jackson said his research is applicable for airplane pilots.
“The most dangerous parts of airplane flight are during takeoff and landing,” Jackson said. “Trained pilots fly drones and they fly them way differently than they fly real planes.”
Buck is also working with Jackson on an infant navigation study on evolved survival instincts in infants.
“He gives me a lot of hands-on experience,” Buck said.
Nishant Mohan can be reached at [email protected] or on Twitter @NishantRMohan