Learning to Read as an Adult Changes Deep Regions of the Brain

iStock
iStock

In the evolutionary history of humans, reading and writing are relatively new functions. As a result, in order to read written language, human brains have had to recruit and adapt parts of the visual system to interface with language centers. This is a process researchers have long believed occurred primarily in the cerebral cortex, the outer layer of the brain. But in a new study where illiterate people in their thirties were trained to read over six months, researchers have discovered that reading actually activates much deeper brain structures as well, opening doors to a better understanding of how we learn, and possible new interventions for dyslexia. Their results were recently published in the journal Science Advances.

In order to learn to read, "a kind of recycling process has to take place in the brain," Falk Huettig, one of the collaborating researchers at Max Planck Institute for Human Cognitive and Brain Sciences, tells Mental Floss by email. "Areas evolved for the recognition of complex objects, such as faces, become engaged in translating letters into language.”

To study this process in the brain, researchers selected participants from India, where the literacy rate is about 63 percent, a rate influenced by poverty, which limits educational access, especially for girls and women. Most of the participants in this study were women in their thirties who came into the study unable to read a single word.

They divided the participants into a group that received reading training intervention and a control group that was not trained. Both groups underwent functional magnetic resonance imaging (fMRI) brain scans before and after the six-month study. Some participants were excluded due to incomplete scanning sessions, leaving a total of 30 participants in the final analysis.

They were taught to read Devanagari, the script upon which Hindi and some other languages of South Asia are based. It's an alpha-syllabic script composed of complex characters that describe whole syllables or words.

The instructor was a professional teacher who followed the locally established method of reading instruction. During the first month of instruction, the participants first were taught to read and write 46 primary Devanagari characters simultaneously. After learning the letters and reading single words, they were taught two-syllable words. In all, they studied approximately 200 words in the first month.

In the second month, the participants were then taught to read and write simple sentences, and in the third month, they learned more complex, three-syllable words. Finally, in the second half of the program, participants learned some basic grammar rules. "For example, the participants learned about the differences between nouns, pronouns, verbs, proverbs, and adjectives, and also about basic rules of tense and gender," Huettig says.

Within six months, participants who could read between zero and eight words even before the training had reached a first-grade level of reading, according to Huettig. "This process was quite remarkable," Huettig says. "Learning to read is quite a complex skill, as arbitrary script characters must be mapped onto the corresponding units of spoken language."

When the researchers looked at the brain scans taken before and after the six-month training, Huettig says they expected to simply replicate previous findings: that changes are limited to the cortex, which is known to adapt quickly to new challenges.

What they didn't expect was to see changes in deeper parts of the brain. "We observed that the learning process leads to a reorganization that extends to deep brain structures in the thalamus and the brainstem." More specifically, learning to read had an impact on a part of the brainstem called the superior colliculus as well as the pulivinar, located in the thalamus, which "adapt the timing of their activity patterns to those of the visual cortex," Heuttig explains.

These deep brain structures help the visual cortex filter important information from the flood of visual input—even before we consciously perceive it. "It seems that these brain systems increasingly fine-tune their communication as learners become more and more proficient in reading," he says.

In essence, the more these participants read, the better they became at it. The research also revealed that the adult brain is more adaptable than previously understood. "Even learning to read in your thirties profoundly transforms brain networks," Huettig says. "The adult brain is remarkably flexible to adapt to new challenges."

Even more promising, these results shed new light on a possible cause of dyslexia, a language-processing disorder, which researchers have long attributed to dysfunctions of the thalamus. Since just a few months of reading training can modify the thalamus, Huettig says, "it could also be that affected people show different brain activity in the thalamus, just because their visual system is less well-trained than that of experienced readers."

Huettig feels that the social implications of this kind of research are huge, both for people effected by dyslexia as well as the hundreds of millions of adults who are completely or functionally illiterate around the world. Huettig says the new findings could help "put together literacy programs that have the best chance of succeeding to help these people."

Lost Your Wallet? You Might Be More Likely to Get It Back If There's Cash Inside

iStock/tzahiV
iStock/tzahiV

Few things can incite more panic than discovering you’ve lost a wallet or purse containing money, identification, credit cards, and/or keys. You wonder if anyone will find it—and if they do, whether they’ll decide to retain your cash using the playground ethics of the "finders keepers" rule.

An ambitious new study in the journal Science has provided at least a partial answer. If your wallet has cash inside, it’s actually more likely for people to return it than if it didn’t have any.

Researchers at the University of Michigan conducted an exercise in civic honesty, dispatching 13 assistants to 355 cities in 40 countries across the globe. At each destination, the assistants were armed with clear wallets that held things like grocery lists and business cards along with an email address. Some wallets had no money inside. Others contained about $13.45 in the local currency. The assistants gave the wallets to employees at banks, hotels, post offices, museums, and police stations, explaining they had “found” the wallet and were in too big of a hurry to contact the owner themselves. They passed the responsibility to the person receiving the wallet. All told, 17,303 wallets were left as proverbial bait to see what the employees might do.

Of the wallets without cash inside, researchers received an email seeking to return roughly 40 percent of them. About 51 percent of the employees attempted to return the wallets containing $13.45 in cash.

These percentages fluctuated by country. In Denmark, 82 percent of wallets with cash were returned. In the United States, the figure was 57 percent. When researchers upped the stakes by including $94.15 in wallets for areas in the U.S., Britain, and Poland, the return rate went up to 72 percent.

It’s difficult to infer motivations for why people returned wallets with more money than less, or none. In a survey, researchers found that people in general described wanting to avoid feeling like a thief by keeping the money. (Respondents were different than the employees who were left with the wallet.) That would explain why returns increased as the dollar amount went up.

The study was limited by the fact that the wallets were left with people who could have presumably been held accountable for not returning them. The research assistant could have returned to inquire about the wallet’s status, while no such concern exists for people finding a wallet in the street. Still, it does indicate that people feel a measure of sympathy for—and moral obligation to—lost money and will make an effort to see it returned.

[h/t Science News]

Some Fish Eggs Can Hatch After Being Pooped Out by Swans

iStock/olaser
iStock/olaser

A question that’s often baffled scientists is how certain species of fish can sometimes appear—and even proliferate—in isolated bodies of water not previously known to harbor them. A new study has demonstrated that the most unlikely explanation might actually be correct: It’s possible they fell from the sky.

Specifically, from the rear end of a swan.

A study in the journal Ecology by researchers at the Unisinos University in Brazil found that killifish eggs can, in rare cases, survive being swallowed by swans, enduring a journey through their digestive tracts before being excreted out. This kind of fecal public transportation system explains how killifish can pop up in ponds, flood waters, and other water bodies that would seem an unlikely place for species to suddenly appear.

After discovering that some plants could survive being ingested and then flourish in swan poop, researchers took notice of a killifish egg present in a frozen fecal sample. They set about mixing two species of killifish eggs into the food supply of coscoroba swans living in a zoo. After waiting a day, they collected the poop and dug in looking for the eggs.

Of the 650 eggs they estimated to have been ingested by the swans, about five were left intact. Of those, three continued to develop. Two died of a fungal infection, but one survived, enduring 30 hours in the gut and hatching 49 days after being excreted.

Because killifish eggs have a thick outer membrane, or chorion, they stand a chance of coming through the digestive tract of an animal intact. Not all of what a swan ingests will be absorbed; their stomachs are built to extract nutrients quickly and get rid of the whatever's left so the birds can eat again. In rare cases, that can mean an egg that can go on to prosper.

Not all fish eggs are so durable, and not all fish are quite like the killifish. Dubbed the "most extreme" fish on Earth by the BBC, killifish have adapted to popping up in strange environments where water may eventually dry up. They typically live for a year and deposit eggs that can survive in soil, delaying their development until conditions—say, not being inside a swan—are optimal. One species, the mangrove killifish, can even breathe through its skin. When water recedes, they can survive on land for over two months, waddling on their bellies or using their tails to "jump" and eat insects. A fish that can survive on dry land probably doesn't sweat having to live in poop.

The researchers plan to study carp eggs next to see if they, too, can go through a lot of crap to get to where they’re going.

[h/t The New York Times]

SECTIONS

arrow
LIVE SMARTER