Detective Pikachu, the first live-action film inspired by the classic Nintendo game Pokémon, hits theaters on May 10. So it's timely that a new paper has just appeared in Nature Human Behavior, concluding that people who avidly played the game as children have developed a unique cluster of brain cells devoted to recognizing the hundreds of different Pokémon species.

It's well known that human beings are remarkably adept at visually recognizing faces, words, numbers, places, colors, and so forth thanks to a constellation of regions—small clusters of neurons about the size of a pea—in the temporal lobe, located just behind the ears. Those regions show up in the same place in most people, despite differences in age, sex, or race. There's even a so-called "Jennifer Aniston neuron," (aka the "grandmother cell") discovered by a UCLA neuroscientist in 2005, whose primary purpose seems to be to recognize images of the famous actress. Similar neurons have also been found for other celebrities like Bill Clinton, Julia Roberts, Halle Berry, and Kobe Bryant.

"This is quite remarkable, and it's still an open mystery in neuroscience why these regions appear exactly where they do in the brain," said co-author Jesse Gomez, a postdoc at the University of California, Berkeley, who conducted the experiments while a grad student at Stanford University. One way to answer this question, and determine which of several competing theories is correct, is to study people who, as children, had a unique experience with a new type of visual stimulus. If those people were shown to have developed a new brain region dedicated to recognizing that new object class, that would offer useful insight into how the brain organizes itself.

"The game rewards kids for individuating between hundreds of similar-looking Pokémon."

The catch: it would take many hours of laboratory practice with any new visual stimulus for there to be any measurable effect. But "I realized that the 1990s had already done it for me," said Gomez. "I grew up playing Pokémon. The game rewards kids for individuating between hundreds of similar-looking Pokémon." The game is also played primarily during childhood, a "critical window" period where the brain is especially plastic and responsive to experience. He reasoned it might be possible that passionate Pokémon players like his childhood self would have developed a new brain region in response to that experience. So he applied for a seed grant to test that hypothesis.

His advisor, Stanford psychology professor Kalanit Grill-Spector, was initially skeptical about the proposed experiment. "I was uncertain that childhood experience playing a video game for several hours would be sufficient to generate a new representation in the brain," she said. "While some representations in the brain—like representations of words—are clearly learned during childhood, learning these stimuli involves many hours of daily experience that extend from childhood throughout adulthood."

YouTube/Stanford University

YouTube/Stanford University

YouTube/Stanford University

Grill-Spector cites two factors that quelled her skepticism. First, when she saw the handheld Nintendo Gameboy device and the small black-and-white pixelated Pokémon characters, she realized the game really would provide a "unique, yet consistent, visual experience to children," she said—sufficient to test current theories of brain development. And then Gomez showed her the first results from subjects scanned under the seed grant, all who had played many hours of Pokémon as children. "In each, there was a clear pattern of activity to Pokémon characters in a similar location in the brain," she said.

Gomez recruited 11 Pokémon experts for his experiment (mean age 29.5 years), along with 11 Pokémon novices who had never played the game, for comparison. While undergoing fMRI, the subjects were shown images of faces, animals, cartoons, bodies, words, cars, corridors, and Pokémon. The Pokémon experts responded more strongly to images of the Pokémon characters than the control group.

When they analyzed the data, Gomez et al. found that, as hypothesized, there was a new region of the brain that formed in the subjects, dedicated to recognizing Pokémon characters, in the same location across the Pokémon-playing subjects. According to Gomez, this supports a theory called "eccentricity bias." It holds that it's the way we look at visual stimuli—specifically, whether we use central or peripheral vision—and how much of our visual field a given object takes up, that determines the location for a dedicated brain region for that stimulus.

"Because Pokémon are very small and viewed with our central vision most of the time, they occupy a small portion in the central retina when we're looking at them," said Gomez. "Faces are a bit bigger, so they occupy a slightly larger portion of the central retina. Scenes, as we navigate through them, are very large and extend all the way into our peripheral vision." So the information from each type of stimulus ends up being sent to slightly different locations in the brain.

"These findings suggest that our brain is capable of developing more specialized brain regions for recognizing objects than we previously thought," said Gomez. "So we're likely not limited by our brain, but instead by how much we can experience in childhood."

For the benefit of parents who might be concerned that playing such games is "rewiring" children's brains, Gomez emphasizes that any substantial experience we have will affect the brain; it's designed to be adaptive to accommodate new experiences, especially when we're young. In fact, "Most of the Pokémon experts I scanned are getting their PhDs in science or working at companies like Google, so there's no evidence to suggest being a Pokémon expert had any adverse impact," he said. "They're all doing very well."

DOI: Nature Human Behavior, 2019. 10.1038/s41562-019-0592-8 (About DOIs).

Listing image by YouTube/Stanford University