Learn how weird dreams may help us in the real world; how we date dinosaurs; and why a healthy grip means a healthy body. A theory from AI says our weird dreams help us better perceive the world by Briana Brownell Our dreams’ weirdness might be why we have them, argues new AI-inspired theory of dreaming. (2021). EurekAlert! https://www.eurekalert.org/pub_releases/2021-05/cp-odw050621.php Hoel, E. (2021). The overfitted brain: Dreams evolved to assist generalization. Patterns, 2(5), 100244. https://doi.org/10.1016/j.patter.2021.100244 Paleontologists know how old dinosaurs were when they died because bones are like tree rings by Cameron Duke Anonymous. (2019, June 11). Which Dinosaur Bones Are “Real”? Field Museum. https://www.fieldmuseum.org/blog/which-dinosaur-bones-are-real Field Museum. (2020, November 25). Growth Rings From Fossil Bones Reveals T. rex Had Huge Growth Spurts, but Other Dinosaurs Grew “Slow and Steady.” SciTechDaily. https://scitechdaily.com/growth-rings-from-fossil-bones-reveals-t-rex-had-huge-growth-spurts-but-other-dinosaurs-grew-slow-and-steady/ Welsh, J. (2012, June 27). How Sweet! Dinosaurs May Have Been Warm-Blooded After All. Livescience.com; Live Science. https://www.livescience.com/21215-dinosaur-bones-warm-blooded.html Wits University. (2021, May 12). Southern African dinosaur had irregular growth. Phys.org; Phys.org. https://phys.org/news/2021-05-southern-african-dinosaur-irregular-growth.html A Healthy Grip Means a Healthy Body by Ashley Hamer Grip Strength Is Good Indicator of Overall Health - UConn Today. (2011, June 6). UConn Today. https://today.uconn.edu/2011/06/grip-strength-is-good-indicator-of-overall-health/# Sanderson, W. C., & Scherbov, S. (2014). Measuring the Speed of Aging across Population Subgroups. PLoS ONE, 9(5), e96289. https://doi.org/10.1371/journal.pone.0096289 Mukherjee, S., Clouston, S., Kotov, R., Bromet, E., & Luft, B. (2019). Handgrip Strength of World Trade Center (WTC) Responders: The Role of Re-Experiencing Posttraumatic Stress Disorder (PTSD) Symptoms. International Journal of Environmental Research and Public Health, 16(7), 1128. https://doi.org/10.3390/ijerph16071128 Follow Curiosity Daily on your favorite podcast app to learn something new every day withCody Gough andAshley Hamer. Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Learn how weird dreams may help us in the real world; how we date dinosaurs; and why a healthy grip means a healthy body.
A theory from AI says our weird dreams help us better perceive the world by Briana Brownell
Paleontologists know how old dinosaurs were when they died because bones are like tree rings by Cameron Duke
A Healthy Grip Means a Healthy Body by Ashley Hamer
Follow Curiosity Daily on your favorite podcast app to learn something new every day with Cody Gough and Ashley Hamer. Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/weird-dreams-might-be-a-brain-feature-not-a-bug
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about a theory from AI about why we have weird dreams; how paleontologists know how old dinosaurs are; and why a healthy grip means a healthy body.
CODY: Let’s satisfy some curiosity.
Artificial intelligence takes inspiration from the human brain. That means the more we know about our brains, the better AI can be. But AI can also teach us about our own brains. That’s why an AI researcher just published a theory for why we have such weird dreams: they might be the brain’s way of helping us perceive the world more accurately.
It has to do with how AI learns. Let’s say we wanted to teach an artificial neural network to look at images and tell us what they are. To do this, first, the artificial neural network needs to learn from examples of images labeled with what they are — usually millions of them.
Training an artificial neural network on labeled images might allow them to differentiate between a dog and a cat, for example, or to detect even more subtle differences like distinguishing between a cat and a cougar.
But the problem is, sometimes the data that an AI is trained on has quirks that let the AI learn the wrong thing. For example, if most of the images of a cougar are taken outdoors, it may learn that being on green grass is a particular characteristic of a cougar, and then fail to recognize one if, for instance, it ends up on your back deck. Yikes!
This error in generalizing data is called overfitting. Right now, one of the most common ways researchers avoid it is by using what’s called “dropout.” In the training data, scientists randomly block out parts of the image in the hopes that the neural network will learn to focus on the critical parts of the image rather than the specific quirks, like the grassy ground in an image of a cougar. This helps AI’s to do a better job of categorizing images it hasn’t seen before.
The new research from Erik Hoel at Tufts University suggests that human brains may overfit too. Dreams — especially weird ones — might help the brain to generalize experiences, just like they might for artificial intelligence. Seeing your mom’s face on an elephant’s body or feeling the sidewalk turn into quicksand might be the brain’s version of adding black boxes to our training data.
We know a little bit about what can prompt dreams in humans, and one trigger is performing a new task over and over. The research suggests that the reason this triggers dreams is because the brain realizes it is in danger of overfitting… so it uses dreams to compensate.
So it might just be that the bizarre nature of a dream world helps us cope in the hard reality of the real world. Thanks, brain!
CODY: Here’s a question: when a paleontologist discovers a new dinosaur fossil, how do they know whether it’s an adult or a baby? I mean, if they don’t know how big it’s supposed to be, how do they know how old it was when it died? Answer? They look at the rings. Yep, kinda like how you’d age a tree.
Despite the impression you might get from museums, fossilization is pretty rare. Most things die and decompose in a way that doesn't leave remains to be found millions of years later. That means that paleontologists often have very little to work with. As a result, the majority of known skeletons are incomplete. Sue the T. Rex, whose fossil stands in the Field Museum in Chicago, is the most complete T. Rex skeleton ever found. And even she is missing more than 100 of the approximately 380 bones that should be there.
So when a new species is discovered, often one skeleton tells us everything we know about the species. That’s why it’s important that paleontologists have a way to know whether an animal was fully grown. Knowing that would tell us a lot about how it lived. But that can be tough when there aren’t other members of the same species to compare with.
So the way they do this is by cutting open a bone — usually a long bone, like the femur (or thigh bone). Just like cutting down a tree reveals growth rings in its trunk, cutting across a femur reveals growth rings in the bone.
Of course, dinosaurs aren’t trees, so their rings appear for a slightly different reason. It’s because wild animals grow more rapidly in the spring and summer, when the climate is warmer and there’s more food available. This rapid growth causes the bone to produce a layer of capillaries that help it get the extra nutrients it needs. Each summer, a new layer of capillaries is created, and these are fossilized as rings — one ring for every year.
From this data, scientists not only learn how old the dino was when it met its unfortunate end — they can also learn about its growth patterns. For example, by analyzing the varying thicknesses of growth rings in T. Rex skeletons, scientists learned that teenage tyrannosaurus had huge growth spurts just like humans.
ASHLEY: HOST 1: So that must be why there aren’t any single T. rexes. [HOST 2: ...wait, why?] HOST 1: Because they all put a ring on it.
How good is your grip? Can you open a jar unassisted? What about something as simple as taking the trash to the curb? It turns out that your grip strength has a strong connection to your overall health — and if it’s lacking, you may want to step up your exercise routine.
When researchers behind a 2014 study set out to measure how fast different groups of people tend to age, they didn’t look at their number of gray hairs or wrinkles. They didn’t even look at medical measures like blood pressure or cholesterol. Instead, they measured the strength of each person’s grip. Researchers and physicians rely on this easy measurement because evidence shows that a weak grip predicts all sorts of things, from longer hospital stays to disability and early death.
Of course, simply working out your hands won’t guarantee survival. Grip strength is predictive because it’s a sign of health in other parts of your body: frail muscles in your hands probably mean frail muscles elsewhere, and an inability to close your hand fully could signify neurological issues. One study of 9/11 first responders even found that those with PTSD and depression had a weaker grip than those with better mental health.
But despite the fact that it’s a canary in the coal mine for other health problems, grip strength itself is still important in old age. After all, that’s when the ability to grasp a countertop while walking or grab the arm of a chair while sitting can mean the difference between a safe arrival and a broken hip. To measure grip strength, experts use a specialized device called a dynamometer, but you can use something as simple as an analog bathroom scale to watch for differences in your strength from month to month. Weightlifters and other athletes have targeted exercises to build hand musculature, but for the rest of us, getting enough exercise is one of the best ways to maintain strength into old age.
Let’s recap today’s takeaways
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ASHLEY: Today’s writers were Briana Brownell and Cameron Duke.
CODY: Our managing editor is Ashley Hamer, who was also a writer on today’s episode.
ASHLEY: Our producer and audio editor is Cody Gough.
CODY: Get a grip! Then, join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!