Researchers out of York University’s Faculty of Health have confirmed a new form of visual spatial attention that behaves like an “eye in the palm of your hand.”
The research project, which took more than two years to complete, shows that vision is enhanced in the region of space around the hand when the eyes are focused elsewhere.
“If we don’t want to hit our thumb with a hammer, then we keep our eye on it,” said Mazyar Fallah, associate dean of research and innovation at York. “But when driving a car and shifting gears, we can still accurately grab the gear shift … without looking directly at it.
“We’ve evolved the ability to look in one place and reach for something somewhere else.”
Doctoral student Carolyn Perry led the project and conducted the research in Fallah’s lab. Other contributors included Associate Professor Lauren E. Sergio and J. Douglas Crawford.
Findings of the study confirm that the mechanisms behind eye-related attention and hand-related attention work very differently, said Fallah.
“Normally, attention from the eyes is equivalent to shining a light on whatever you are looking at. It makes it brighter,” he said. “But hand attention brings things into a sharper focus.”
Perry’s research specifically shows that orientation selectivity improves when the hand is near an object that you are not looking at. This means that when you want to grab the handle on a mug, a tool, a gearshift or a bar, for instance, the visual system processes it more accurately when your hand is close to the object than it would in the periphery.
Hand attention is a function, Fallah said, that requires real-time processing; this is what makes it possible to successfully grasp objects in different orientations without looking at them. The hand effectively changes the way it rotates to match the orientation of the object it is reaching for.
Perry’s findings have been published in the Journal of Neurophysiology, and could offer valuable insight in other areas of research, such as distracted driving with respect to hand-held devices, and rehabilitation of stroke patients.
She has received funding from NSERC Alexander Graham Bell Canadian Graduate Scholarships at the master's (CGS-M) and PhD (CGS-D3) levels, an Ontario Graduate Scholarship at the PhD level and the Susan Mann Dissertation Scholarship.
The research will continue over the next year, and will explore what the specific signal is that enhances the special attention around the hand. Part of the process will be to cover the view of the hand to determine whether having the hand in sight is needed to improve hand attention.