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 window‑mounted heat pumps can give tenants efficient heating and cooling
    Photo credit: Spencer Platt/Getty ImagesMany U.S. apartments have individual heating and cooling systems that are less efficient than current technology.

    People who rent their homes, or don’t have enough money to make major upgrades to their homes, have for many years been left out of a major shift in heating and cooling technology that can improve efficiency, save money and be better for the global climate: heat pumps.

    Heating and cooling buildings consumes 35% of all the energy used in the United States each year. Many homes and businesses are converting their fossil fuel-powered heating and cooling systems to electric-powered heat pumps, which use electricity not to generate hot or cold air but to move heat into spaces needing warmth and out of spaces needing cooling.

    Until recently, that process has required a significant amount of sizable and expensive equipment to be permanently installed in a building, which needs a professional contractor and can cost as much as US$10,000 just for the installation – in addition to the actual equipment. Often called mini-splits, these systems usually have a condenser outside the building that exchanges heat with the outdoor air and an evaporator inside that exchanges heat with the indoor air.

    A woman stands in a room looking at a boxy piece of equipment in her window.
    The New York City Housing Authority has been installing window-mounted heat pumps in apartments, like this one in Queens. AP Photo

    But now window heat pumps are becoming available in the U.S. Much like a window air conditioner, these self-contained devices can be installed without professional help and plugged into a wall outlet. Unlike window air conditioners, though, they can provide heat as well as cooling. They cost much less than a permanent system – between $3,000 and $4,000 – and can be moved to a new property if the owner relocates.

    There aren’t many options commercially available yet, and those on the market can’t heat or cool very large spaces on their own. And they work less efficiently when heating homes in places with extremely cold outdoor temperatures. A few models are available on the market that are even cheaper, but they don’t have efficiency ratings, don’t work when outdoor temperatures are very cold, and are louder when running.

    I have designed and evaluated a wide range of building energy efficiency technologies; here’s how these window heat pumps work, and why they may allow apartment dwellers and residents of older houses to easily and relatively inexpensively make significant improvements to their homes’ heating and cooling systems. Federal subsidies for this type of equipment expired in 2025, but some utility companies, states and local governments may still offer money to help pay the costs.

    Two window heat pumps available now are very similar

    Moving heat from one place to another

    Heat pumps use a reversible refrigeration cycle and can provide similar heating and cooling as electric-powered space heaters, furnaces and baseboard heaters, while using less than half the electricity.

    The most common heat pumps transfer heat between air indoors and outdoors, but other systems can exchange heat with the ground or with bodies of water, such as lakes.

    Heat pumps’ capacities are defined by the amount of heat they can transfer in a particular period of time. A heat pump serving an entire home may need a capacity of 12,000 to 60,000 British thermal units (about 12,660 to 63,300 kilojoules) – but the window units’ capacities are much lower, getting up to only about 9,000 Btu (9,500 kJ).

    Performance varies based on the conditions outdoors, where the unit is either sending excess heat to cool the indoors or gathering heat to warm the indoors. In cooling mode, heat pumps are rated by their seasonal energy efficiency ratio, a figure that indicates how much cooling is achieved per unit of electricity used. The corresponding measurement for heating is called heating seasonal performance factor. In general, the larger these numbers are, the better they will perform. The U.S. Department of Energy has established minimum standards for those figures.

    While these units operate even when outdoor temperatures are -13 degrees Fahrenheit (-25 degrees Celsius), their heating output is reduced to almost half of its rated capacity, and their energy efficiency falls to one-third of its rated performance at that temperature.

    Apartment climate control costs less with a window unit

    In addition to their low cost compared to conventional split heat pumps, packaged window heat pumps meet heating and cooling needs with lower energy demands and costs. But each window unit serves just one room, while a more common split unit can serve multiple rooms.

    Packaged window heat pumps are easy and inexpensive to install and offer all-in-one heating and cooling options for apartments and older homes, with higher energy efficiency performance than traditional systems. Their main limitations include their low capacities and reduced energy efficiency in extremely cold climates or conditions.

    This article originally appeared on The Conversation. You can read it here.

  • Solar-powered boat feasts on trash and could solve the ocean’s plastic waste problem
    Photo credit: Ocean Cleanup on YouTubeThe Interceptor boat-barge could significantly clean our waters.

    Our oceans have a plastic problem. While it’s difficult to put a 100% accurate number on it, scientists estimated about 4.8 to 12.7 million metric tons of plastic waste entered the ocean in 2010 alone according to the journal Science. This issue has caused scientists and engineers to create a boat-barge in Los Angeles that skims the oceans to gobble up the plastic we leave behind.

    Devised by the non-profit Ocean Cleanup organization, the garbage-gulping Interceptor boat-barge is actually a smaller platform nestled within a larger boat. A floating barrier moves collected trash into the device onto a conveyor belt. An automatic shuttle then collects the trash from the conveyor to send it to a separate barge where there are six dumpsters to hold it. The solar-powered system can hold up to 20,000 lbs. of garbage. The trash is then separated into different categories (plastics, metal, etc.) so they can be disposed of responsibly.

    Catching ocean trash from the source

    Ocean Cleanup hopes to make a dent cleaning the Great Pacific Garbage Patch in the Pacific Ocean. However, they decided to first attack the plastic ocean problem at its source: rivers. When it rains, a lot of trash from the hills and valleys washes down into the nearest river. While there is significant ocean trash taken from beaches, they have found that the lion’s share of garbage that floats into our oceans actually comes from rivers and tributaries that lead into it. Essentially, the plan is to get ocean trash before it even enters the ocean.

    “We have to turn the faucet off before we can scoop the ocean, or else all we’re doing is taking out legacy trash to replace it with new trash,” James Patterson, the operations manager of Ocean Cleanup said to The Guardian. “Before you can clean out the Great Pacific Garbage Patch, you really need to turn off the source.”

    How the Interceptor is helping Los Angeles and beyond

    There is an Interceptor already doing its work at the mouth of Ballona Creek in Culver City, California. Since 2025, the Interceptor has prevented 143,710 lbs. of trash from entering the ocean via the creek. As a bonus, the Interceptor’s trash sweeping has lowered government budgets for beach grooming. Since there is less trash, the beach doesn’t need to be cleaned as often.

    There are two more Interceptors planned to be at the mouths of the San Gabriel River and the Los Angeles River. This can help clean up the rivers for the upcoming 2028 Summer Olympics for aquatic events.

    There are currently 21 Interceptor systems throughout the globe. Countries using them include Indonesia, Vietnam, Jamaica, Guatemala, the Dominican Republic, and Malaysia.

    If this is an issue that speaks to you, you can help even if you don’t live near an ocean. There may be a nearby river or creek that could benefit from volunteer cleanups. Do some research to find an organization near you to volunteer. If you can’t locate one, groups like River Cleanup can help you organize your own group. Much like how a small drop contributes to a large ocean, a small pick-up can make a big difference.

  • A bonobo’s make-believe tea party has scientists rethinking whether imagination belongs only to humans
    Photo credit: CanvaAn adorable baby bonobo.

    Childhood activities like playing house, superheroes and villains, the floor is lava, and the classic tea party all involve imagination. We create stories and worlds with rules and roles to play.

    Humans want to believe that our creativity and art make us unique. But a bonobo named Kanzi was part of research that has scientists wondering how different we really are. In three evolving experiments, Kanzi correctly identified pretend objects, demonstrating that he could understand and engage in make-believe situations.

    primate research, behavior, bonobo study
    Kanzi associates words and symbols with Sue Savage-Rumbaugh.
    Photo by William H. Calvin, Phd/ Wikimedia Commons (Cropped)

    Kanzi has a make-believe tea party

    Researchers developed a simple setup using cups, a pitcher, and actions that began as real pouring and gradually shifted into pretend play. The first experiment used real liquids. The second had a combination of real and pretend liquids. The final scenario had no real liquids and relied entirely on imagination.

    The scientists used gestures and make-believe to see if Kanzi would react differently depending on what he was being shown. He didn’t react the same way in each setup. His responses showed he was paying attention to more than just the objects, but also to the way the situation was presented.

    bonobo play, animal imagination, Kanzi bonobo, apes
    Kanzi participates in an indoor test.
    Photo by William H. Calvin, Phd/ Wikimedia Commons (Cropped)

    Animals engaging in fantasy

    The experiment revealed that non-human animals can understand and follow along with imaginary situations.

    “[It] shows that animals are capable of understanding pretence in a controlled experimental setting, which hadn’t been done before,” Dr. Amalia Bastos, first author of the research from the University of St Andrews, told The Guardian.

    Scientists involved in the research are careful about how they describe it. They don’t treat it as proof that bonobos imagine things the same way humans do. Instead, they suggest that animals are capable of responding to situations where meaning is implied rather than directly shown.

    Why scientists care about pretend play

    Albert Einstein, one of the greatest scientific minds in history, is often credited with the idea that logic gets you from A to B, but imagination can take you everywhere. This study suggests that the more we learn about animals, the more it seems the difference between us may not be as great as we once thought.

    Developmental research credits early social and cognitive growth in human children to imagining situations that aren’t physically present. A 2024 meta-analysis found that make-believe is not just entertainment but also directly linked to social understanding and real-world interpretation.

    Researchers now describe animal play as more flexible than once believed. A 2025 study of ravens revealed that play included the manipulation of sticks, stones, and other items, suggesting social awareness and responsiveness to context rather than simple instinctive behavior.

    Play and imagination may be versatile behaviors no longer seen as uniquely human traits. A broader cognitive toolkit shared across multiple species suggests the gap between humans and animals may be smaller than it once seemed. Things we’ve long believed to be uniquely human may instead exist along a spectrum of abilities expressed in different ways.

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