Learn why more humans are growing an extra artery; emotional hangovers; and the drawbacks of energy-efficient LED streetlamps. More humans are growing an extra artery, which shows we're still evolving by Cameron Duke Lucas, T., Kumaratilake, J., & Henneberg, M. (2020). Recently increased prevalence of the human median artery of the forearm: A microevolutionary change. Journal of Anatomy, 237(4), 623–631. https://doi.org/10.1111/joa.13224 McRae, M. (2021). More And More Humans Are Growing an Extra Artery, Showing We’re Still Evolving. ScienceAlert. https://www.sciencealert.com/more-humans-are-growing-an-extra-artery-in-our-arms-because-we-re-still-evolving Emotional Hangovers Are Real, And They're Not What You Think by Sam Suarez Waude, A. (2016, February 23). Emotion And Memory: How Do Your Emotions Affect Your Ability To Remember Information And Recall Past Memories? Psychologistworld.com; Psychologist World. https://www.psychologistworld.com/emotion/emotion-memory-psychology Mather, M., & Sutherland, M. (2012). The selective effects of emotional arousal on memory. Https://Www.apa.org. https://www.apa.org/science/about/psa/2012/02/emotional-arousal Tambini, A., Rimmele, U., Phelps, E. A., & Davachi, L. (2016). Emotional brain states carry over and enhance future memory formation. Nature Neuroscience, 20(2), 271–278. https://doi.org/10.1038/nn.4468 New York University. (2016, December 27). Is there such a thing as an emotional hangover? Researchers find that there is. PsyPost; PsyPost. https://www.psypost.org/2016/12/thing-emotional-hangover-researchers-find-46675 Energy-efficient LED streetlamps are bad news for insect populations by Cameron Duke Boyes, D. H., Evans, D. M., Fox, R., Parsons, M. S., & Pocock, M. J. O. (2021a). Street lighting has detrimental impacts on local insect populations. Science Advances, 7(35), eabi8322. https://doi.org/10.1126/sciadv.abi8322 Portree, D. S. F. (2002, October). Flagstaff’s Battle for Dark Skies. The Griffith Observer. http://www2.lowell.edu/users/wes/GriffithObserver1crop.pdf Sharon, W. (2007). STUDYING THE ECOLOGICAL IMPACTS OF LIGHT POLLUTION ON WILDLIFE. StarLight: A Common Heritage. https://www.researchgate.net/profile/Sharon-Wise-3/publication/242297944_STUDYING_THE_ECOLOGICAL_IMPACTS_OF_LIGHT_POLLUTION_ON_WILDLIFE_AMPHIBIANS_AS_MODELS/links/00b7d53bd619157183000000/STUDYING-THE-ECOLOGICAL-IMPACTS-OF-LIGHT-POLLUTION-ON-WILDLIFE-AMPHIBIANS-AS-MODELS.pdf Light Pollution Effects on Wildlife and Ecosystems - International Dark-Sky Association. (2016, September 12). International Dark-Sky Association. https://www.darksky.org/light-pollution/wildlife/ Main, D. (2019, February 14). Why insect populations are plummeting—and why it matters. Animals; National Geographic. https://www.nationalgeographic.com/animals/article/why-insect-populations-are-plummeting-and-why-it-matters?loggedin=true 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 why more humans are growing an extra artery; emotional hangovers; and the drawbacks of energy-efficient LED streetlamps.
More humans are growing an extra artery, which shows we're still evolving by Cameron Duke
Emotional Hangovers Are Real, And They're Not What You Think by Sam Suarez
Energy-efficient LED streetlamps are bad news for insect populations by Cameron Duke
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/your-extra-artery-emotional-hangovers-leds-are-bad-for-bugs
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 why more humans are growing an extra artery; why it might be a good thing if you have an “emotional hangover”; and the darker side of energy-efficient LED streetlamps.
CODY: Let’s satisfy some curiosity.
More humans are growing an extra artery, which shows we're still evolving by Cameron Duke (Ashley)
One big question we get on the show a lot is about whether humans are still evolving. The answer is yes, and today, I’ve got a perfect example of that happening. That is: more and more adult humans possess an extra artery that we didn’t have before.
The artery is called the median artery, and it tends to form while we are still in the womb. It runs down the center of our forearms to bring extra blood to our hands so they can get oxygen and nutrients while they’re developing. But it doesn’t last long. Like our baby fat and baby teeth, the median artery goes away pretty early in life. In fact, it typically disappears when we’re only eight weeks old, leaving the radial and ulnar arteries on either side to do the heavy lifting of supplying blood to the hands. These arteries are with you for your entire life.
At least, that’s what used to happen. A recent study found that more and more humans are holding onto their baby artery into adulthood. In other words, it isn’t going away anymore.
Here’s what I mean. Researchers have been watching how common this artery is since the 1880s. Back then, 90 percent of people would lose the median artery, and ten percent would maintain it throughout life.
Recently, a team of anatomy researchers examined the limbs of 80 cadavers, all from people of European descent who died recently. They found that 30 percent of those adults still had their median artery, roughly three times the rate from 100 years ago.
Just in case their data might be skewed because of their small sample size, the researchers searched through the literature for more data. They found consistent reports throughout the last century indicating that more and more adults possess median arteries.
Ok, but why are so many of us keeping this artery from infancy? Well, researchers don’t have a great answer at the moment. The team involved in the study thinks it might have to do with mutations of genes involved in artery development or health problems during pregnancy.
Potentially, the trait might be related to giving us more dexterous fingers, but it may also come with an increased risk of carpal tunnel syndrome, so that benefit is complicated.
The point is, this trait is rapidly changing in humans for some reason. The researchers expect the trend to continue into the future. They predict that by 2100, the majority of adults will have a median artery. It’s not exactly evolving wings, but it’s something.
Emotional Hangovers Are Real, And They're Not What You Think by Sam Suarez (Cody)
Usually, we think of emotional hangovers as a bad thing: you get in a fight with a friend or receive a piece of bad news, and days later you’re still feeling down in the dumps. But according to neuroscientists, emotional leftovers can also be a good thing. The effects of an emotional experience can sharpen your memory — even for things unrelated to that experience.
In a study, researchers from New York University had one group of volunteers look at a series of emotional images and a second group look at non-emotional, neutral images while their brains were scanned via fMRI and their skin conductance was measured. Around 10 to 30 minutes after the first viewing, the groups were switched: participants in the first group viewed non-emotional images and those from the second group looked at the emotional ones. Six hours later, both groups took a memory test to see how well they could recall the images.
Results showed that the group who viewed the emotional images first could better remember the images they saw second, compared to the people who saw the non-emotional images first. This suggested that strong emotions may have affected the way participants remembered later events. The fMRI scans seemed to support this: the regions of the brain that were active in response to the emotional images were still active up to 30 minutes later when the participants saw the second set of neutral images.
Essentially, the brain seems to be "charged" by emotional experiences, and that sets the stage for future memories to form more vividly.
If you've ever had an intensely emotional experience, you’re probably familiar with this phenomenon. It's the way you don't just remember the car wreck; you also vividly remember the color of the pen you used to exchange insurance information. You don't just remember winning the volleyball championship; you remember the taste of the sports drink you had right after. The question is, could you use emotional experiences to your advantage — say, watch a dramatic movie before studying for a test? There's only one way to find out.
Energy-efficient LED streetlamps are bad news for insect populations by Cameron Duke (Ashley)
Sometimes, attempts to fix one problem end up making another problem worse. That’s exactly what’s happening when it comes to efforts to be more energy-efficient. Cities are installing LED street lamps that use less energy — but it turns out that they also damage insect populations. Luckily, there may be an easy fix.
There’s no getting around it: fossil fuels are bad for the planet, and they’re largely what drive the electricity that powers our streetlights. So, like I said, many cities have started swapping out old sodium street lamps with more energy-efficient LEDs, which have the added bonus of emitting a pleasing white light instead of the yellow glare of their predecessors.
But this swap ignores another ongoing threat to the planet: light pollution. As more and more cities electrified around the turn of the last century, the planet got brighter. That brightness has its obvious benefits, but it also has costs. For one, electric lighting has completely changed human sleep cycles, and we might not be better off for it.
Those effects extend to wildlife, too. Just as our lamps and screens keep us awake at night, nighttime lighting changes the way wildlife species sleep, hunt, mate, and hide from predators.
So it may not be a coincidence that insect populations are in decline right as nighttime lighting is on the rise. A recent study in the UK confirmed this connection. At 26 different sites, scientists counted the number of caterpillars in bushes under different lighting. There were fewer
caterpillars in LED-illuminated bushes than in those illuminated by traditional sodium bulbs or left dark. It wasn’t by a little bit, either. The LED-illuminated bushes had roughly 50 percent fewer insects than the unlit ones.
This is a huge problem because drops in insect populations can have ripple effects for the rest of the ecosystem. As insect populations drop, so will the number of birds and amphibians that rely on these insects as a food source. So, an effort to be more environmentally friendly might not be panning out the way we hoped.
But it’s not all bad news. LEDs do have one thing over their traditional lighting competitors: it’s a lot easier to adjust their brightness and color. Energy efficiency is a worthwhile goal, but finding an ecologically beneficial brightness level for our LED street lights would benefit us all.
For a brighter future, maybe we should dim the lights a little.
RECAP
Let’s recap what we learned today to wrap up. Starting with
1. CODY: More and more humans are reaching adulthood with an extra artery that adult humans of the past didn’t have. That’s the median artery, and it usually just helps out with hand development in the womb and goes away when we’re about two months old. But the number of adults who have hung onto this artery has tripled since the 1800s, and scientists predict that by 2100, most adults will have it. This is a perfect example of how humans are still evolving.
2. ASHLEY: An emotional event could sharpen your memory. Studies have found that not only do emotional memories stick better in your mind, but that memory superpower extends to non-emotional information you encounter after the emotional event. Whether that means watching a horror movie before studying will help you pass a test is anyone’s guess.
3. CODY: Our cities’ attempts to be more energy efficient may be hurting the ecosystem: a study found that LED street lights are leading to lower insect populations. That has ripple effects for the whole ecosystem, since fewer insects means less food for birds and amphibians. The good news? LEDs are really easy to adjust, so it should be simple enough to find the right brightness and hue to keep insects healthy.
[ad lib optional]
ASHLEY: Today’s writers were Cameron Duke and Sam Suarez.
CODY: Our managing editor is Ashley Hamer.
ASHLEY: Our producer and audio editor is Cody Gough.
CODY: [AD LIB SOMETHING FUNNY] Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!