The most famous New York City subway map is the one New Yorkers rejected. That would be Massimo Vignelli’s system map from 1972 . Vignelli’s modernist design stressed visual clarity over geographical precision; all the lines ran vertical or horizontal, for instance, and rectangular Central Park was rendered as a square. Public pressure led subway officials to replace the map in 1979 with one much less distorted in style but also far more cluttered to the eye.

The quicker people process information on a subway or bus map, the easier their lives will be.

Transit maps have a considerable impact on the everyday lives of people in cities. Traveling in and around busy urban environments can be tough for anyone–from the tourist visiting for the first time to the native heading into an unfamiliar part of town. So establishing whether a map like Vignelli’s has merit despite its detractors is a matter of real consequence: the quicker people process information on a subway or bus map, the easier their lives will be.

Recently, some vision scientists at MIT developed a remarkably direct way to perform just this type of map evaluation. The research team, led by Ruth Rosenholtz of the Computer Science and Artificial Intelligence Laboratory, devised a computer model capable of determining how well people will comprehend a subway map (or any other complex diagram) in a single glance. The model spits out alternate visualizations called “mongrels”–twisted images that represent how our brains actually process the maps in front of our eyes.

The MIT mongrels draw on new scientific insights into peripheral vision. Research by Rosenholtz and others has suggested that peripheral vision operates by pooling together information outside a person’s direct line of sight. These peripheral pools sacrifice detail for overall impression to reduce the amount of data we process; they’re a little like a low-resolution JPEG in that sense. So the mongrels effectively show what visual elements–color, text, space, line orientation, among them–have been condensed into pools during the map’s journey from eye to brain.

“What these mongrels try to capture is this qualitative information about what you lose in the periphery,” Lavanya Sharan, a postdoc who collaborated on the work, tells Co.Design. “Looking at these mongrels is a way of confirming the designer’s intuition.”

Being located in Boston, the researchers took a particular interest in the Massachusetts Bay Transportation Authority’s recent contest to redesign the subway map. Earlier this month, the M.B.T.A. announced the winning entry, designed by Michael Kvrivishvili, which will begin to appear in stations next year. Rosenholtz, Sharan, and graduate student Shaiyan Keshvari created mongrels of both the current map and the contest winner to see whether or not the city was getting a visual upgrade.

Here’s the current M.B.T.A. subway map: