Today on Something You Should Know, Why If You're Holding a Grudge, You Really Need to Let It Go. Then, some interesting ways your thinking gets distorted that can lead to some bad outcomes. For example, there's this thing called the primacy effect, which is what people learn early on, they will hold on to despite evidence to the contrary.

This is probably the biggest, baddest cognitive property that we have love.

Also, how allergy medicines can make you fat. The world animals live in is so different than ours because of how they sense and perceive everything. For instance, catfish, they sense their world through taste, and they don't have a tongue, as you and I understand the tongue.

Their whole body is their tongue. All the flanks of their body are covered in taste buds.

All this today on Something You Should Know. As a listener to something you should know, I can only assume that you are someone who likes to learn about new and interesting things and bring more knowledge to work for you in your everyday life. I mean, that's what something you should know was all about. I want to invite you to listen to another podcast called Ted Talks Daily. Now, you know about Ted Talks, right? Many of the guests on something you should know have done Ted Talks. Well, you see, Ted Talks Daily Daily is a podcast that brings you a new TED Talk every weekday in less than 15 minutes. Join host Elise Hugh. She goes beyond the headlines, so you can hear about the big ideas shaping our future. Learn about things like sustainable fashion, embracing your entrepreneurial spirit, the future of robotics, and so much more. Like I said, if you like this podcast, Something You Should Know, I'm pretty sure you're going to like Ted Talks Daily. You get Ted Talks Daily wherever you get your podcast. Something You Should Know, fascinating intel, the world's top experts, and practical advice you can use in your life.

Today, Something You Should Now with Mike Carruthers. Hi, welcome to something you should know. I suspect all of us have, at some point in our lives, held a grudge against somebody. It's probably a good idea Well, not to hold on to that grudge very long. I remember hearing this quote a long time ago. It was from Dr. Judith Kuriansky, who wrote a book called The Complete Idiot's Guide to a Healthy Relationship. She says that holding a grudge is like drinking poison yourself and hoping it makes the other person sick. I always like that. The resentment you feel by holding a grudge can do some real damage to you, emotionally and physically. Not only does it interfere with your present pleasure and keep you focused on the pains of the past, it could also destroy a salvageable relationship. The physical pain can include a tight chest, tense muscles, upset stomach, headaches, and poor sleep. Letting go of a grudge isn't always easy, but it may be worth the effort. You might just try speaking up and let the other person know what they did that bothers you and try to offer a solution. If an apology from the other person is in order, you'll probably get one, and then you'll feel a whole lot better.

That is something you should know. Fractions Distort your Thinking. Now, marketers know this and use this. Perhaps the simplest example is gas prices. They're always expressed as a number and then nine-tenths of a cent to help make you think that it's actually costing less than it does. That's just one example. It does seem that the brain doesn't really grasp fractions very well without some considerable effort, and that can cause some trouble for all of us, according to my guest, James Zimring. He's Professor of Experimental Pathology at the University of Virginia School of Medicine and author of the book Partial Trufs: How Fractions Distored Our Thinking. Hey, James, welcome.

Hi there. Thanks for having me.

I think a good way to explain this rather than trying to explain the concept, just give an example of how fractions distorted our thinking?

A comical example is that in the 1980s, ANW fast food chain took on a gargantuan task, which was they were trying to unseat the Big Mac as the king of the burgers in America, which had been dominant since 1971. So they put together what they thought would be a much better burger. And by blinded tests, it tasted better, it was cheaper, and it was more meat. So they thought, wow, this is really going to do the trick. And when they released it on the market, it did not sell well at all. They had to pull it eventually. And when they did a market analysis after the fact, what they discovered was that many people thought a third pound less than a quarter pound because three is less than four.

Well, what seems weird to me about that is anybody who took arithmetic in grade school learned that a quarter of a pound is less than a third of a pound, a quarter of a cup is less than a third of a cup. I guess people just reflexively think four is more than three. What could A and W have done to avoid the confusion?

Well, that's a good question that I'm probably not qualified to answer. I guess they could have said the bigger burger or just explicitly stated that as a fact.

There's an obvious solution.

They could have said 30% of a pound instead of 25% of a pound. But in this case, which is funny, A&W wasn't trying to deceive people. Actually, just the opposite. It's when people are trying to deceive us that it probably becomes much more problematic. For example, and Well, maybe this is intentional or not. If you look at mutual funds when they're first released for us to invest money in, if we have money to invest, that's a pretty serious thing. Mutual funds, people don't usually invest in them unless There's some track record of them, how they did, because who's the manager? What are they charging? How do they do in the stock market? Well, companies that release mutual funds often, not always, do something that's called pre-incubating their funds. So they'll have their funds running without public investment for a couple of years. And the ones that do really well, then they make available to the public. The ones that do really poorly, you never hear about. They never release them. They destroy them. Now, on the surface, that seems almost like good consumer advocacy. Why would you release to the public a product that you had not yet tested?

But what is really going on here, at least to some extent, is that Imagine if none of the funds, their strategy mattered, if none of the funds had the ability to really outperform the market average, but just by chance, some would and some wouldn't. So they're only showing you then the ones that just happen to do well. They're only showing you the top of the fraction, and they're selling you a false product. Now, how would we know if that was true? If that was true, then pre-incubated funds, as soon as they were released to the public, would stop performing well or as well as they had. And that is the case. That once pre-incubated funds that really outperform the market are released, they usually hit the market average. That may or may not be intentional, but that's a rather serious manifestation of how subtle fractional differentiations can have huge effects on people's livelihoods.

Well, I get what you're saying, but that is a little difficult to get your head around because it does seem that basically just testing out their strategy ahead of time before they release it to the public. What's maybe an easier to understand example of how this works?

Let's consider for a minute self-help books or books that are going to show you how to become rich. And they often have a title of something like The Five Habits of Self-Made Millionaires. And the implication is if you find the things that self-made millionaires do, and then you do those things, you're more likely to become a millionaire. Well, I can promise you that self-made millionaires have the following habits. They eat, they breathe, they sleep, they yawn. Obviously, you're not going to become a millionaire by doing those things. But the point I'm trying to make is it's not what do self-made millionaires do, it's what do self-made millionaires do that other people don't do? And that second part, that's the bottom of the fraction, it's seldom, if ever, contained in these seminars and books that you might buy. Ask that question. Go to a self-help seminar and they'll say, Well, these are the habits that highly disruptive startup companies do. And if you ask the question, Okay, that's interesting, but of of the companies that fail, of the companies that aren't disrupted that don't do well, do they have the same properties or not? And you usually won't get an answer.

So by just presenting part of what has the form of a fraction, you can distort the message you're making. Now, remember, nothing that's coming out of your mouth is untrue here. None of the numbers you're giving are incorrect. You're just presenting part of what has an underlying fractional form, and that can be very deceptive.

Yeah, I think that is so true. You have to be so on guard about what people say and then the evidence they use to support what they say, because on the surface, it might look right. But if you deeper, you go, Wait a minute. What's another example of that?

If you talk about claims that are made about products having some benefit to you, crystals having curative properties, It's not a question of whether somebody tried medicinal crystals and got better. Some people will try medicinal crystals, and they will get better, and that is evidence that they might work. The question is, do people who use medicinal crystals get got better more frequently or at a higher rate than people would have just gotten better on their own? So until you juxtapose with and without this thing, you can't tell. All you can tell is that you're cherry-picking an association. And again, this isn't necessarily some sinister plan to manipulate people because we do it to ourselves all the time. It's called the availability heuristic, where we replace what comes to mind easily for what we think is most likely or most probable. But again, it's also a way that people can purposely manipulate us if they want to.

You talk about, and I remember when this was a story about the Dungeons and Dragons and teenagers killing themselves and all that. Can you tell that story?

Yeah. In 1979, there was a gentleman, a young man named James Dallas-Eggbert. He went by the name Dallas. He was a child prodigy, brilliant kid. And he was at Michigan State University, and he was fairly troubled. And one of the things that he did was play Dungeons & Dragons. Now, at that time, D&D was a relatively new game. It was confusing to parents. There's this game, but there's no board. People sit around and they roleplay. It has demonic tones to it. And there was just a lot of confusion about it. And Dallas, as he went by, disappeared from Michigan University. He left a note, which seemed like a suicide note, but they weren't sure. And they launched an investigation to find him. And one of the detectives who was looking for him came up with the theory that he had killed himself in the steam tunnels under the Michigan State as part of a Dungeons & Dragons game that got out of control. Well, they searched the steam tunnels. They searched all around. The newspapers had headlines stating as a matter of fact that that was why he disappeared. Even 60 Minutes got involved in a segment with Gary Gygax, the inventor of Dungeons & Dragons.

And it turns out that Dallas ran away because he was so troubled and wound up. They found him about a month later in Morgan City, Louisiana, 1,100 miles away or so in an apartment where he was just being despondent. And eventually, he called the detectives. They didn't find him. He said, Please come get me. And they took him back to his parents. And this caused the light to shine on Dungeons and Dragons. And over the next five In a couple of years or so, there were 28 cases of murder or suicide by adolescents who were playing D&D. And the idea entered people's heads that this is a dangerous game and it's causing kids to kill themselves. And to be fair, that was a very appropriate concern. You have 28 suicides associated with this game, it's something that needs to be investigated. But when they investigated it, they found that at that time, there were already 3 million people playing Dungeons & Dragons across the country, basically 3 million adolescents, because that's where it was most popular. Now, the suicide rate at that time was 120 for every million adolescents, which is basically 360 suicides a year you would expect without any outside influence.

And so when you say, wow, there were 28 suicides playing Dungeons and Dragons, that seems like a really dangerous game. But when you consider that there were 28 suicides out of 3 million people playing, and the rate of suicides should have been 360 out 3 million anyway. If anything, the game had a protective effect instead of a damaging effect. And so this is what happens, again, if you look just at the numerator of the fraction and not the denominator. And this continues to play forward with these the terrible, tragic mass shootings that we've had by adolescents in recent decades and the claims that while they're playing violent video games or they're listening to certain types of music. They are. This is true. But that's not the question. The question is, are kids that carry out horrible acts exposed to these things more frequently than your average kid? Is there any association?

Well, I want to dig a little deeper into this Dungeons and Dragons thing in just a moment. First, my guest is James Imring, and he is author of the book Partial Truths: How Fractions Distort Our Thinking. James, it's almost human nature, it seems, that when there's a problem, we want to find the cause. We want to find the villain. In this case, it was the game Dungeons and Dragons. And let's just blame that. And then we can get on with our lives. It just seems right, even though there's no evidence to support it.

It really does seem right because it catches our attention. It's what comes to mind. People who want to go swimming in the ocean, especially in my generation, often say to themselves, I'm not sure I want to go in the ocean. I think I might get eaten by a shark. And the A whole series of Jaws movies came out when I was a kid. And every time someone gets eaten by a shark, it's all over the news, and it's all over the papers, and we see it, and it's available to our minds. Now, the truth is, a lot more people die in the ocean, drowning. From currents or riptides than ever get eaten by sharks, many more. But I don't remember Hollywood ever making a movie called Riptide. And I don't remember the news saying, unless it's a celebrity that drowned, oh, yes, another person drowned in a riptide today. And And so what becomes available to our mind as the most likely thing is whatever was sensationalized or caught our attention. But it causes us to make really bad choices all the time when we're trying to assess risk. Driving your car is hands down more dangerous than flying by every analysis.

But not many people are afraid of driving. A lot of people are afraid of flying, in part because you're not in control and it's unfamiliar, perhaps, but also because when plane crashes go down, it's such a big deal. And Hollywood has made horror films about it and all this stuff. So don't get me wrong, this thing, the availability heuristic, is very advantageous to us in many cases. I mean, a lot of times you see dangerous things and you know, I shouldn't be doing that. But the problem is, is they distort the real probabilities out there once you begin to investigate, and they do lead us to make quite bad choices.

Let's talk about how confirmation confirmation bias fits into all of this, and maybe start off by explaining what confirmation bias is.

Confirmation bias has several nuanced definitions, but in short, it is that Once you believe something, as you have new experiences, you will filter those experiences based upon your belief such that you will notice or emphasize things that support your belief, and you will discount or ignore entirely things that refute your belief such that it's not really that seeing is believing, it's believing is seeing.

And why do we do that? I mean, is that just human wiring? We're just built to do that?

Yeah, we always have to consider anthropological, cultural influences, but this seems to be everywhere. And it's really confusing when you think about why would a creature have this tendency that seems odd or not terribly clever. And there are some advantages to having it, to be sure, but the disadvantages are overwhelming. There was a wonderful study done where at a Department of Psychology at a University, you always have to say, well, are psychology students representative of all of us? But we're always stuck with that when they do psychology studies. And they took two groups of students who had opposite beliefs on whether the death penalty is a deterrent or not, which is a common debate. And they mixed them together, and then they presented a bunch of evidence to them based upon studies of this question. And then they separated them apart and talked to them. And what they found was that people with opposite beliefs who saw the very same evidence presented, both sides increased the belief in what they had believed at the beginning. So the same evidence polarized the beliefs even further, which if you look at some of the struggles of our society today, you can see this happening real-time.

And when they interviewed the people after the fact, they realized that what had happened was they all saw the same data. But the people who saw data that supported their belief rated that as high-quality data and the data against their belief as poor-quality data. And so they're stuck, all of us, in a certain belief construct based upon how we experience the world.

Well, that certainly seems problematic because it It almost doesn't matter what the truth is. You believe what you believe. And even if you're wrong, and I show you evidence that you're wrong, you'll still believe it's true. That doesn't seem like a good thing.

Correct. Now, there's this thing called the primacy effect, which is whatever you happen to believe first, then immediately attaches, and even gives you evidence that persists if your original evidence is removed. So there was this great study done by Bruner and Potter, where they showed people pictures that were out of focus so that you could not discern what the picture was and ask people to guess what it was a picture of. And then they showed them a series of the same the picture slowly coming into more and more focus. And people stuck with their original guesses as to what the picture was, even when it became so much in focus that it was obviously something else that people who had never made a guess could easily discern. So we talk about debates of what are in our primary education textbooks, what our children are exposed to when they're young, and we talk about it for a number of reasons. But this is a big part of that, because what people learn early on, they will hold on to despite evidence to the contrary. And so this is probably the biggest, baddest cognitive property. I'm going to call it a property because it's not always a defect.

That we have, and it explains a lot of what human society holds.

But people do change their minds. One thing I've noticed, and I think it frustrates people, they'll argue hoping to change the other person's mind. People, when they do change their mind, change their mind over time. It takes time. It isn't like, Oh, God, now I see what an idiot I was. I'll believe you now. It really takes time to change your mind.

It is going to take time and reflection. One of the most interesting developments in education around these areas, at least most interesting to me that I've read recently, is the difference between justifying a position with reasons as opposed to mechanism. And what I mean by that is if you say to someone, Give me 10 reasons why you believe this, they will usually give you 10 reasons, and it will enforce their belief even more because look at all the reasons they have. But if you ask to say to someone, Okay, the reasons you have to believe this, how exactly would that work? What is the mechanism by which your reasons justify your claim? Then usually their belief becomes a little bit less extreme. It doesn't go away, but it forces them to think through the internal implications of their belief construct, as opposed to just repeating over and over again a matter that they hold as fact. And so when you ask, is there hopes here? Yes, I think there is. I think that when we engage reflective debate about mechanisms and justifications, people become much less polarized and can understand the nuances of an issue better.

When we just pound, you should believe this for this reason, louder and louder and louder and with great repetition, things become pretty extreme. So how you ask the question, how you approach the problem, can have a big effect.

Well, not only is this conversation interesting, but it helps you think differently. I think it makes you a more critical thinker, and only good can come from that. James Zimring has been my guest. He is a professor of experimental pathology at the University of Virginia School of Medicine and author of the book Partial Truths: How Fractions Distort Our Thinking. There's a link to the book at Amazon in the show notes. Thanks, James.

I'm grateful for your time and your help, and thanks for doing your podcast.

Just as we humans have our senses to help us navigate and perceive the world, Other creatures have their senses, and they don't necessarily work the same as ours do. Some of them have senses that work a whole lot better than ours. Perhaps there are things we can learn from those creatures that can help us better understand and how we function. Jackie Higgins is a writer, producer, and director of films about animals, and she has a book out called Sentient: How Animals Illuminate the Wonder of Our Human Senses. Hi, Jackie. Welcome.

Thanks for having me on, Mike.

To give people a sense of what we're talking about here, let's start by discussing the Peacock Mantis shrimp and their sense of sight and their sense of color.

Yes. So this creature has a dizzying array of color sensors in its eyeball. So when scientists looked at its eyeball, they found 12 different color sensors in their eyes. And to put things in perspective, we have three different color sensors. So we're known as trichromats, and from that, we see millions of colors, whereas they're dodechachromats. So scientists envisioned or imagined that these creatures could see a million times a million, et cetera, et cetera, septillion. I mean, it's such a large number of colors with so many zeros on the end that we can't quite compute how many colors they see. The thing with our senses is that they circumscribe every waking moment. So they're the most mundane. We forget about them. We take them for granted. There's this quote I use. I go from Aristotle to Da Vinci, Leonardo da Vinci. He had this amazing quote saying that the typical person Looks without seeing and listens without hearing, touches without feeling, eats without tasting, exhales without awareness of odor or fragrance. So the idea of looking at the shrimp and understanding what it might be able to see gives us some distance on ourselves for us to realize how extraordinary our color site is and that we do see millions of colors.

We see millions of colors, but they're all shades of a couple. I mean, there's really only a handful of colors. Does that shrimp actually see a color that we couldn't even imagine?

Well, that was the notion, yes. And then through that, I introduced a scientist who was searching for the first human tetrachromat. So there is evidence to suggest that some women are walking around with four different types of color cones in their eyes, and so they are able to see colors that most of us can't see. I suppose one easy way of thinking about it is if you think of color blindness. So there are some people who only have two different types of cone, and they see red-green. You've heard of red-green color blindness. So they cannot see colors that I know that I can see. So yes, this shrimp, the idea would be that this shrimp can see many more colors than we could imagine.

So our sense of taste, and you talk about the Goliath catfish, how does this all come together?

So catfish, basically, they sense their world through taste, and they don't have a tongue, as you and I understand the tongue. Their body, their whole body is their tongue. The flanks and the feelers of their little whiskers, their catfish whiskers, but all the flanks of their body are covered in taste buds. And so I chose the Goliath catfish because this fish is enormous, possibly more than many meters long, that swims through soupy Amazonian waters where there isn't much light. And the taste buds on the outside of its skin enable it to track its prey. So it sees the world through taste. But what's extraordinary, or I find extraordinary, well, I understand it, but I love all these connections, is that the catfish, the taste buds that are on the outside of the catfish, are incredibly similar to the taste buds on our tongue. Proof, yet again, of this deep evolutionary past we share with fish. All life, all vertebrate life on this planet comes originally from fish and the Devonian seas when the first tetrapod crawled out the land millions of years ago. By studying these fish and these taste buds, we can better understand our sense of taste and how it works.

And so let's talk about the sense of hearing and the great gray owl. I find this interesting. Can you talk about that?

Yes. We all think of owls as having incredible eyesight, which they do. But the great A gray owl does this rather wonderful thing. From 30 meters away, it can hear a mouse or a vole underneath the mound of snow. So it's not seeing them, it's not sensing their heat, it's hearing them. And the way that it does this is it uses both its ears So like we have stereo vision using two eyes to get a sense of depth and position, these owls use stereotyoscopic hearing, and they use these two ears to map their environment. This is an aspect of hearing I was fascinated by, this idea that sound creates a landscape around us, and it's something that we, as humans, use all the time. John Hull wrote a wonderful book called Notes on Blindness, about his experience of losing his eyesight. And he talks about this idea of geographic sound. He has these wonderful... He's got an amazing turn of phrase, and he talks about thunder putting a roof over his head, or when it rains, suddenly the contours of the world world become apparent to him. He can grasp topography again, things beyond what he can feel with his fingers, which is another way in which he could grasp topography.

But he can hear the topography of a landscape in the distance that he can't see. It's an aspect of sound that we don't necessarily notice. I talk about echolocation and how we're all using echolocation to some degree.

So when you say echolocation, I When you think of bats, like sonar. Is that what you mean, echolocation?

So echolocation, we always think of bats. You send out ultrasonic peeps that then basically bounce off the surface, and they then listen to the reflections of these ultrasonic sounds, and that enables them to map the topography of their world, map their landscape. I was walking down the corridor with a scientist talking about this idea that we use this sense of echolocation sublimit me without really noticing it. I could hear our feet hit the floor surface. And the scientist said to me, You probably noticed that we're about to run into a wall because we were chatting to one another. I could hear the fact that a wall was coming up because of the reflections of the echoes that my feet were making, because we're attuned to using and hearing these kinds of sounds.

You see, that's really interesting to me because I know exactly what you mean about how sound guides us like it did you in the hallway there. And yet we never think about it. We never consciously say, Oh, well, I can hear that the wall is coming up. You just know it is and you turn right. You would turn.

Absolutely. And there are many of these senses that work like that. Our sense of body, our sense of proprioception. This sense that if you close your eyes, I hope, Mike, you know where your body is to the point that you can Take your finger with your eyes closed and touch your nose. So this, again, is one of these senses. Without this sense, it's impossible to move. It's impossible to sit up and to walk. It's one of these senses that is so familiar and automatic that we just don't notice it. Often, the way one notices these things is if you lose them. And I met an extraordinary man called Ian Waterman, who, back in the 1970s, contracted a nasty virus, and it completely interfered with the senses that enabled this sense to exist, the senses in his muscle. All the nerves back to his brain were essentially cooked by this virus. They were wiped out. And so he had lost his sense of body. So when he came around from his feverish dreams in the hospital, he could not feel his body from the neck down. So it was as if when he first was grappling with this new way of being, he said he felt disembodied.

So if he closed his eyes, it wasn't like his body had been anesetized. We still have a sense of our flesh and our presence if we're anesetised. If you're going to the dentist and your gums being anesetised or your side of your cheek, you still feel these things. You still feel its presence. He felt nothing. It was like everything had disappeared. It's back to that Leonardo da Vinci quote. We're using them all the time without appreciating them. And some of them are working secretly beneath our conscious radar, which makes it even more difficult to appreciate them.

Was he paralyzed or he just couldn't sense his body, but he could use his body?

So he couldn't sense his body, and He couldn't use his body because he couldn't control it, but he wasn't paralyzed. So he found his arms would be off moving, but he didn't know that they were moving. I mean, he joked that one was saying hello to a nurse in an inappropriate way, but he didn't know. He didn't know that that's what his arm was doing. He could only gather control and master his body again by allowing his sense of vision to step in for this lost sense of print perception. So if he looked at his hand and knew where it was, then he could control it. And so Ian, more than any other person, perhaps, had to break down every single motion. He had to relearn how to master his body and relearn how to move. He had to break down the simple action of sitting up into the many different components, which you talk about things that happen automatically. It wasn't happening automatically for him, so he had to break it down and basically, sew his body back together with his sense of sight.

But if you touched him, would he feel it?

No, he also is touch-blind. He's And this is where touch... I think touch was one of the most interesting senses. Often when people say, what's the sense you'd least like to use? We often say vision, but touch. Touch is so complicated. There are many different senses in our skin. And if you stroke his arm, he can't feel it, but he can feel hot and cold. That's because temperature sensors are different sensors within our skin to the ones that your body registers if you're being stroked, or the sensors that you're using. He also can't feel the topography of the world. So you've got many different sensors, for example, in your fingertips and in your skin that enable you to detect texture, shape, size. He's lost all of that. So there are certain dimensions of his touch that he has, and very few, temperature, essentially, but everything else was wiped out alongside this muscular sense, this deep a sense of body, the sense of proprioception.

I've never heard of that. That is so strange. That is so-He's unique, almost.

There's been a couple of other cases like him, but he It's such a rarity, such a rarity. The fact that he was able then to walk again and to master his body, I think makes him exceptional and unique. He's a properly amazing man.

Now that he can walk again, and he figured out how to walk again, is it very deliberate where he has to watch himself walking, or does he now do it automatically?

No, every moment he has to watch himself. He talks about his daily marathon If the lights go out and he's unable to see his body, he falls like a rag doll. Even if he's watching fireworks, and you know that momentary blackness you get after a bright light has just gone off in front of your eyes, even When that short loss of contact between his body, he staggers. So when power cuts have happened in his house, he's been at the mercy of just... He can't move. He can only move when he watches himself and he engages with that movement. So for him, a walk in the countryside is not enjoying the view, listening to the bird song. He has to really focus on what it is he's doing, and he might be able to continue the conversation at the same time, but not with the same level of concentration or focus that you and I could give it because it's such a mental feat just to walk.

So talk about our sense of pleasure and pain Because I don't think people really think of those things as senses, but you talk about the common vampire bat. So talk about that. Yes.

The vampire bat has these little sensors in its nose that enable it to detect the tiniest variations in temperature so that if it's landed on its prey's hide, it can detect where the vein is pulsing beneath the skin from the heat that emanates. So these little trip sensors are much the same as what is found in our skin. David Julius, who's this extraordinary scientist who was awarded the Nobel Prize for Physiology and medicine this year, is in the book, and he studied the vampire bat, and he also studied trip sensors in us. And these trip sensors in us give us a sliding scale of temperature, and a sliding scale of... Sometimes boiling hot water will trigger pain, or incredibly cold things will also be painful. So sliding scale of temperature alongside a sliding scale of pain. And the vampire bat on pleasure and pain, there were so many sensors within our skin that scientists are just beginning to understand, not simply the trip sensors, but this incredible sensor that they found in our skin a few decades ago, but they're only just beginning to map out. And this is a sensor that fires if you lightly touch your skin, so with very little pressure, and then you move it at a speed between three and five centimeters a second.

So that's essentially a stroke, and it will ping only if whatever is touching it is bodily temperature. So the scientists have called it the caress sensor. So we've just discovered a sensor in our skin that is activated when we're strokeed.

Quickly, because we're almost out of time here, but I wanted to talk about our sense of direction, because, again, I don't think people think of that as a sense. They think of it as Really, almost an innate ability. You're either good at your sense of direction or you're not, but it doesn't feel like a sense.

We know that birds are able to sense the magnetic field. So they have this compass sense that enables them to navigate. So they navigate by looking at the stars, and they navigate by listening to infrasound and it bouncing off mountains. But when it's dark at night and there are no stars because it's cloudy, these birds use the magnetic field that surrounds the Earth to navigate. And Joe Kirschvink at Caltech is convinced that humans are also able to use this magnetic field. Now, the mystery at the moment is figuring out where these sensors are. And there's some extraordinary science being done. And there are two theories. One is the quantum compass, whereby quantum changes happen in these little cryptochromes in eyes, in the bird's eyes, for example, that enable them perhaps even to see that magnetic field. But Joe thinks that what is the sensor are these tiny magnetite crystals that basically swivel like the little needles of the compass that enable us to know where north So it's a really fascinating possibility that humans might be able to have this sense of direction. And he's hoping, being funded by NASA, he's hoping to go out to Australia and study the indigenous tribes there who do have an exceptional sense of direction and to find out whether they are using somehow this magnetic field.

Well, I always wondered why there's a What's the difference between people who really do have a good sense of direction and those who don't? Because there are people that have a very good sense of direction.

Sense of direction. Or maybe people, if we are... He's In these experiments where he has in his basement at Caltech, he's let people sit in a chair and he's removed all sensory information. So people are relaxed, their eyes are closed, they're not hearing anything, they're not feeling things. And he's changed the magnetic field about their heads and looked for the brain, looked at the brain and found differences in brainwave patterns. So if we are sensing these changes, maybe these people that you talk about are just more tuned to that somehow. But it's an if, it's an if.

It would seem that our sense of balance is one of those senses that you don't really notice it unless you don't have it. And if you lost it and you couldn't stand up and and balance yourself, that you would really notice that. But imagine that. Imagine if you lost your sense of balance.

There was this wonderful quote from Brian Day who studied how we walk, for example, and he talks of walking as one of the most daring balancing acts in the animal kingdom, which is wonderful. We're inherently unstable on two feet, and each time we lift our leg and step forward, that's a tip into the unknown. So yes, I use It is very much a sense, and our body is adjusting according to what information is being sensed in terms of gravity. And we use our vision to balance ourselves, and we use that sense I talked earlier about proprioception, all of them key and all of them senses.

Well, what's interesting about this discussion is it makes you realize that your world, what you perceive as your world, the colors, the taste, the sights, the things that you see may be very different than another person, certainly other creatures. Even though we're all in the same world, the way we take it in is all unique. I've been talking with Jackie Higgins, who is a writer, producer, and director of Films About Animals, and she is author of the book Sentient: How Animals Illuminate the Wonder of Our Human Senses. You will find a link to that book in the show notes. Thank you for being here, Jackie.

The It's a pleasure, Mike, and thank you very much for having me on.

One way to deal with allergy symptoms is to take antihistamines. But what you may not realize is that those types of medications can promote weight gain in a lot of people. There have been a couple of studies that have shown that people who took common allergy medications like Allegra or Xertek or Claritin showed a roughly 10% increase in body weight. Now, the connection between antihistamines and body weight is not new. Some older antihistamines have actually been prescribed in the past to help underweight children increase their appetite so they would eat more and put on some pounds. But how it works exactly to cause weight gain, no one's really sure. But be aware that if you take these drugs to make allergy symptoms more manageable, your weight It may suffer if you're not careful. And that is something you should know. If you found something useful or interesting in this podcast, like the fish whose whole body is covered in taste buds, come on, that was pretty interesting. Tell someone you know about something you should know so they can hear it, too. I'm Micah Brothers. Thanks for listening today to Something You Should Know. The Bigger Pockets portfolio of podcasts are worthy of your investment.

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