How old is your brain? Traditionally, you’d just state your age like you would for the rest of your body. However, the results of a new study suggest that your brain actually has five truly different ages and stages that change at four different points of the average human lifespan. In fact, your brain wasn’t much different between 4th grade and your 32nd birthday.

Scientists at the University of Cambridge led by Dr. Alexa Mousley, used MRI topography to track how the brain’s nerve fibers grow, shift, and die throughout a person’s lifespan. They conducted this research through studying the MRIs of 3,800 “neurotypical” brains ranging from the age of infants to folks in their 90s. During this study, Mousley and her team found four major turning points in how a human brain changes shape: how it grows, peaks, and eventually declines within a person’s life. Roughly, based on the data, the human brain’s functions shift at ages nine, 32, 66, and 83.

“We know the brain’s wiring is crucial to our development, but we lack a big picture of how it changes across our lives and why,” said Dr. Mousley in a press release. “This study is the first to identify major phases of brain wiring across a human lifespan.”

The study shows that there are five stages or “epochs” of a human brain. From infancy to age nine, the brain is in “growth mode” in which billions of brain connections are made, strengthened, and pruned. From age nine to 32, the brain’s communications become more refined and efficient. The “prime” epoch of the brain is from age 32 to 66, when the brain stabilizes and its efficiency is at its peak while a person’s intelligence and personality stabilize along with it. At 66, the brain subtly shrinks and the networks in it gradually reorganize as blood flow decreases and disease risk increases. By age 83, there is a steeper decline with deeper reliance on specific brain regions as other regions fade.

What does this mean?

Interventional psychiatrist Dr. Grant Hilary Brenner told GOOD that he finds this research could open up other possibilities on how to approach brain health in his field.

“For healthspan, regenerative and anti-aging medicine, while further research and replication are necessary, the Mousley and colleagues study is intriguing,” said Dr. Brenner. “On a straightforward level, it may lay the groundwork for assessing brain health with more precision, based on network analysis.”

“A ‘brain age’ metric could be developed compared with an average curve, as we do with children’s growth curves,” he explained. “Early signs of cognitive decline can be detected with this, and related, research – including AIML (artificial intelligence machine learning) based models, which may be able to detect dementia non-invasively, for earlier intervention.”

“Given these findings, these present to us an opportunity to preserve the stage from 32 to 66 years of age where the least changes occur and this period of time coincides with the supposed “prime of one’s life” where one is most productive and where health is most optimal,” neurologist Dr. Jon Stewart Hao Dy tells GOOD.

How can we keep our brains “fit” for now?

Dr. Dy mentioned to GOOD that much of ensuring and protecting peak brain performance requires regularly exercising, having a healthy diet, and being in an environment with clean air and water. He also recommends “intentional learning” through taking classes, reading, and social interactions that keep a person cognitively stimulated throughout their life and lowers the risk of developing dementia as they age.

It will be interesting to see further studies and testing over time in order to better understand our brains and ourselves. Perhaps we’ll get to a point in which we use our brains to make the next generation’s brains “younger” for longer.

  • How D.C.’s ‘humanure’ fertilizer creates lush gardens and big profits while improving the environment
    Photo credit: CanvaWhat you flush away could help your garden grow.

    The District of Columbia Water and Sewer Authority—now known as D.C. Water—has long provided water and sewer services to Washington, D.C. But for the past decade, the utility has also had an unexpected side hustle: turning human wastewater into fertilizer with flourishing results.

    At most wastewater treatment plants, flushed water is cleaned, while the remaining solid matter is hauled away for disposal. Over time, transporting and disposing of that waste can cost millions of dollars while increasing carbon emissions from the trucks carrying it. A decade ago, however, D.C. Water decided to invest in transforming the solid waste into “humanure” rather than throwing it away.

    Growin’ grass and makin’ gas

    At the end of the wastewater treatment process, the collected human waste solids are processed into biosolid fertilizer using technology developed by Norwegian company Cambi. The process doesn’t just produce high-quality fertilizer—it also generates biogas that can be put to good use.

    “So you get up to 40% more biogas,” Cambi CEO Eirik Fadnes said. “That biogas can be used to generate electricity to be used elsewhere in the wastewater-treatment plant or put on the grid and sold.”

    D.C. Water sells the biosolid fertilizer under the brand name Bloom, and it’s already proving to be a success. Bloom has been used throughout the Washington, D.C., area by customers including Catholic University, Mount Olivet Cemetery, and the Franciscan Monastery. It’s also used on numerous lawns, school grounds, community gardens, and golf courses.

    Success by the numbers

    The numbers underscore D.C. Water’s success. To date, nearly 400,000 tons of Bloom have been sold across Washington, D.C., Maryland, Pennsylvania, and Virginia, generating $13.6 million in revenue. D.C. Water originally estimated it would take 20 years for Bloom to pay off its investment. But thanks to strong demand from institutions, landscapers, and local garden centers, the utility is now on pace to recoup that investment in just 12 years.

    Bloom is also helping D.C. Water meet its environmental goals. By turning waste into a useful product instead of hauling it away for disposal, the utility has reduced its carbon footprint by roughly 50,000 metric tons of CO₂ emissions each year—the equivalent of taking more than 11,700 gas-powered cars off the road annually. The process also produces biogas, which can be converted into electricity to help offset the energy costs of wastewater treatment.

    Human waste works wonders

    None of this would matter if human biosolids weren’t effective at improving soil. “Humanure,” a term coined by Joseph Jenkins, refers to compost made from properly treated human waste. Because human feces can contain disease-causing pathogens, it must be handled carefully. After all, we call it “waste” for a reason.

    When human waste is composted correctly, naturally occurring microbes break down the organic material while generating enough heat to destroy harmful pathogens. Over time, the result is a nutrient-rich compost that can improve soil health. Some farmers even build specialized outdoor composting toilets to create humanure for use on their land.

    Should D.C. Water continue on this path of simultaneous profitability and environmental improvement, it’s likely other wastewater treatment plants will follow its lead.

  • A Spanish park has been free of wildfires for over a decade thanks to 18 donkeys
    Photo credit: CanvaDonkeys and other livestock could help prevent mass wildfires.

    According to NASA, wildfires have doubled worldwide due to climate change. Throughout the globe, governments and environmentalists have been trying to find ways to curb the fires. One particular national park in Spain has found a solution that has been keeping them fire-free for over a decade: donkeys.

    Since 2014, the Firefighting Donkey Battalion unit consisting of 18 donkeys has been preventing wildfires in Doñana National Park in Doñana, Spain. The mission these donkeys do is simple: eat the dry brush that usually sparks and fuels wildfires. The donkeys spend up to seven hours a day using their voracious appetites to graze and clear a 130 by 50 feet area of dried grass, scrub, and other vegetation.

    Why donkeys?

    While humans can do this type of clearing out of dry brush, using donkeys for this work is arguably more effective. While it is a slower process, it is consistent and thorough. Donkeys are able to quietly patrol in areas that are inaccessible to vehicles. In exchange for the feasting, the donkeys get about eight gallons of water and rest. No money or fuel needed.

    The donkeys’ bodies are also pretty much built for this kind of environmental work, too. Their stomachs are built to eat the same rough and dry grass repeatedly without issues. These daily grazings slowly but surely remove potential origin sources for fires. As a bonus, the donkeys are naturally disposing of the dried vegetation whereas humans would have to find a different way to dispose of it.

    Having donkeys or other livestock graze in such areas was once more common in agriculture prior to modern farming. Some argue that the machinization of farming and urbanization have reduced the number of grazing animals. This in turn allows more vegetation growth that become dry spots for more wildfires to occur.

    The method expands

    This method has been so successful that other areas of Spain have adopted it. In 2020, Tivissa launched the Burros Bomberos project with three donkeys to so much success they’ve expanded. They now have 40 donkeys grazing and clearing nearly 400 hectares of land.

    The Andrea Association in Allariz uses a team of donkeys to clear and maintain nearly 1,000 hectares of a biosphere reserve. Using GPS to monitor the donkeys’ activity, the group of grazers travel 19 kilometers per day to feed. Similar initiatives have since started in Basque Country, Catalonia, and Galicia, too.

    Other ways to combat wildfires

    In the United States, California has been using goats in a similar function. The group Fire Grazers Inc. has been contacted throughout California to bring hundreds of goats to eat dried vegetation. Much like donkeys, goats are built to eat rough and dry brush. This includes certain plants such as star thistle that are painful for human hands to grab.

    It’s important to note that donkeys or other animals that eat dry scrub are the primary solution to wildfires. The same folks behind these initiatives also advocate proper forest planning and land management. This includes reducing the amount of easily flammable species of plants and trees such as pine. It takes thought, care, work, and maybe a bunch of donkeys to make a difference.

  • Spanish zoo study suggests that giraffes can do basic math
    Photo credit: CanvaA study is showing giraffes could be using math.
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    Spanish zoo study suggests that giraffes can do basic math

    These hoofed mammals can understand addition.

    The results of an experiment done in a Barcelona zoo suggest that giraffes are capable of doing basic mathematics.

    A group of researchers from the University of Leipzig, the Max Planck Institute for Evolutionary Anthropology, and the University of Barcelona published their study observing four giraffes at the Barcelona Zoo. The experiment involved the giraffes observing containers that had different amounts of carrot pieces inside.

    How did this experiment work?

    The researchers showed each giraffe the two yellow containers and the amount of carrots within each one. After a few seconds, they closed the containers, keeping the carrots out of sight. They then showed each giraffe a green container which had extra carrots inside. Researchers took the carrot pieces from the green container and placed them into one of the closed yellow containers. They then let each giraffe independently choose which of the two closed yellow containers they preferred, without them seeing the total number of carrot pieces within each box.

    The results found the giraffes would choose the container that had the most carrot pieces around 68% of the time. This suggests to the scientists that the giraffes were mentally adding the carrots up in each container before making their choice. After all, there have been past studies suggesting that other hoofed mammals, such as horses, had similar capability of basic quantity tracking.

    The researchers did the experiment again. Only this time they subtracted the amount of carrots in each container. The giraffes were mostly unsuccessful at finding the container with the most pieces. So while giraffes showed signs of knowing addition, they don’t quite process all forms of arithmetic.

    Math = Survival

    Scientists believe that this understanding of addition helped giraffes survive in the wild. They cite that acacia trees, a dietary staple for wild giraffes, can be spread far apart in Africa. Being able to figure out which area has the most trees and the most leaves can help them decide where to graze next.

    Giraffes also live in flexible groups that often change in size. One grouping can mix in with another group and then branch off or away. This means that the giraffes often have to keep track of those currently within their group and surroundings to survive.

    Can other animals do math?

    Giraffes are just the latest animal species known to have some form of mathematical skill. Chimpanzees displayed similar abilities to count as giraffes in a similar experiment that involved them picking the bowl with the most chocolate pieces rather than carrots. Chickens and black bears also showed aptitude in quantity tracking, too. 

    Scientists theorize that most of the animals that can do this basic math through evolutionary survival. After all, the animal that can deduce where more food is tends to live longer.

    One species that displays remarkable mathematical ability are Tunisian desert ants. An observation of their navigational skills of finding their way to food and back to their nest suggests they use the sun as a compass in combination with mentally keeping track of the number of steps they take in a three-dimensional space. In short, these desert ants possess basic geometric and trigonometry skills.

    While you wouldn’t want wild animals to calculate your taxes, it’s interesting to see how rudimentary math is a language that goes beyond species.

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