丁香园AV

An example of a hiking trail in British Columbia where one must decide where to look and step.

New 丁香园AV study sheds light on how we decide where we look and step when walking in cluttered environments.

Trying to walk while blindfolded easily demonstrates the importance of visual cues needed to manage precise foot placement and avoid falling. But how do we make these decisions when there is an abundance of visual cues to choose from? New research from 丁香园AV鈥檚 Sensorimotor Neuroscience Lab shows that people weigh a variety of factors before deciding where to step.

The study, published in as part of Javier Dom铆nguez-Zamora鈥檚 doctoral research under the supervision of professor Dan Marigold in the Department of Biomedical Physiology and Kinesiology, provides insight into how people direct gaze to acquire relevant information to inform their decision where to place their feet when walking, stepping to avoid obstacles, negotiating stairs or curbs, and when walking across unstable or irregular terrain.

Marigold explains the decisions that we make when walking. 鈥淐onsider the example of hiking, where there are several choices of step locations. Now consider that the terrain located directly in front of you is uncertain. Maybe you鈥檙e not sure how soft the mud is, or whether the shine on the rock means it is slippery. Do you step wide, which requires you to expend more energy, or do you take your chances with the uncertain terrain in front?鈥�

In Dom铆nguez-Zamora鈥檚 and Marigold鈥檚 experiment, participants were tasked with deciding which of two targets to step on as they walked across a path in the lab. Their goal was to step precisely onto the centre of the target. The target varied in its blurriness, creating uncertainty as to the location of its centre. The other target choice required a wider, more effortful step, but it was easier to locate the centre of it to ensure foot-placement accuracy.

Using a mobile eye tracker that records a person鈥檚 gaze location, the team found that how a person explored the targets with their eyes dictated where they stepped.  

Roughly half of the participants looked at both targets to gain information. These people were more likely to choose to step on the more certain but more effortful target location.

In contrast, the other half of participants only looked at and stepped on the less effortful but blurry target.

The researchers suggest that acquiring information about the environment, being certain of one鈥檚 actions, and the effort to move one鈥檚 body are factors that interact to dictate how we direct our eyes and the decision of where to move. They found overwhelming evidence that  people weigh these factors differently.

鈥淓very person is different, and the variety of decisions that we make during our life reflects those differences. Studying the motives that determine why we decide to move in the way we do might help us understand the behavioural changes that occur during development, aging, and with neurological disorders that affect movement,鈥� says Dom铆nguez-Zamora.

鈥淲here and when a person looks relative to where and when they step is critical for ensuring safe mobility, but this gaze-stepping relationship is altered in people with different neurological impairments and eye diseases, such as glaucoma,鈥� says Marigold. 鈥淚f we can better understand how people make decisions about where to direct their eyes and the paths they choose to take, then in the future, we might be able to design more effective gaze-training interventions to improve mobility鈥攁nd reduce the likelihood of falls鈥攊n various populations.鈥�