The shortest distance between two points is in a straight line, but walking down the street is not always possible, so how do you choose the best path?
well, according to a study of Massachusetts Institute of Technology (MIT), in the US, our brain is not prepared to calculate the shortest path, but the most ‘pointer‘.
Based on information provided by cell phones of more than 14,000 people anonymous, the team found that pedestrians tend to choose paths that appear to be pointing in a straight line more direct towards your destination, even if these routes turn out to be longer. It’s what they call the “most avant-garde path”.
This strategy, known as vector navigation, has also been observed in animal studies, from insects to primates.
Pedestrians tend to choose paths that seem to point most directly to their destination, even if those paths turn out to be longer.
In his study, published yesterday in Nature Computational Science, the MIT team suggests that navigation based on vector —Which requires less brain energy than calculating the shortest path—may be a evolutionary consequence so that the brain devotes more energy to other tasks.
“It seems like there’s a trade-off that allows us to use our brain’s computing power for other things: 30,000 years ago, to avoid a lion, or now, to avoid a dangerous SUV,” he explains. Carlo Ratti, urban technology teacher in the Department of Urban Studies and Planning at MIT.
And although vector-based navigation doesn’t reach the shortest path, “it’s quite close and it’s very easy to calculate,” argues the researcher.
One way to go and a different way to come back
Ratti began ruminating on this study as an undergraduate at Cambridge. Every day he walked the path between the housing development and the university until one day he realized he was actually following two different routes: one going to university and another a little different in the back. Years later, he wanted to know why.
To find out, he used the mobile data of more than 14,000 people who lived in urban environments, GPS signal data which contained more than 550,000 trips performed by pedestrians as they walked through Boston and Cambridge (Massachusetts) over the course of a year.
Their analysis showed that instead of choosing routes shorter, pedestrians chose slightly longer routes, but minimized their angular deviation As for the destination, that is, they opted for paths that would allow them to face the final point more directly when starting the route, although a path that left or right could be shorter.
The study used data from GPS signals that contained more than 550,000 trips made by pedestrians while walking through Boston and Cambridge in the United States.
“Instead of calculating the minimum distances, we found that the most predictive model was not the one that looked for the shortest path, but the one that tried to minimize the angular displacement, that is, point directly to the destination as far as possible while traveling at larger angles it’s actually more efficient,” he says. Paolo Santi, researcher of the Italian National Research Council and co-author of the study.
The analysis found that this behavior was repeated both for pedestrians in Boston and Cambridge, which have a complicated street network, and for those in San Francisco, which have a grid-shaped street layout.
They also noted that people tend to choose different routes when they made a round trip between two destinations, just as Ratti did in his student days.
“When we make decisions based on the angle to the destination, the road network takes you down an asymmetrical path. Based on thousands of pedestrians, it is very clear that I am not the only one: the human being is not a great navigator”, concludes Ratti.
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