The cover illustration of The New Yorker’s March 29, 1976, issue depicted a “view of the world from 9th Avenue,” starring a massive Manhattan that dwarfed not only other U.S. cities but entire countries, reducing the Pacific Ocean to a band of water not much wider across than the Hudson River.
But New Yorkers aren’t the only ones with a skewed perception of scale or an idiosyncratic sense of geography and place. Humans and other animals behave in ways that suggest they’re mapping out their view of the world by emphasizing the information they find valuable.
Two studies appearing in Science last week show how deep that bias runs. Both research teams observed how the neurons that compile mental maps of physical space reprogram themselves to better reflect our experiences, activities, and priorities. The findings also offer evidence for a link that other scientists have started to uncover: The brain’s way of encoding positional information might extend to the way it organizes volumes of other information to be navigated, including varieties of sounds and abstract concepts such as social hierarchy.
To help mammals keep track of where they are within their physical surroundings, their brains have developed two types of specialized cells. Place cells in the hippocampus fire when an animal is in a particular location—for example, near a recognizable landmark. Grid cells in the entorhinal cortex, a region that abuts the hippocampus, fire when the animal passes through some set of positions arranged like the vertices of a hexagon; collectively, these hexagons overlap to tile over a terrain, like a grid (hence the neurons’ name).