Speaker 1: Welcome to Stuff to Blow Your Mind, the production of
Speaker 1: My Heart Radio. Hey you welcome to Stuff to Blow
Speaker 1: your Mind. My name is Robert Lamb and I'm Joe McCormick.
Speaker 1: And today we're finally getting around to it. We wanted
Speaker 1: to talk about a few of the ig Nobel Prize
Speaker 1: winners from this year. Yes, we're a little late. The
Speaker 1: awards ceremony was in September of this year and we're
Speaker 1: just now getting to it. But you know, a lot
Speaker 1: of things are happening around the September October. It's a
Speaker 1: busy time for us. Yeah. I think we've covered the
Speaker 1: ig Nobels every year since we started covering them, and
Speaker 1: I'm not sure when that year was. Maybe it was
Speaker 1: like two thousand seven, two eight or something. I don't know,
Speaker 1: it's pretty early on. Um, we almost never cover them
Speaker 1: right away because, like you said, there's there's generally a
Speaker 1: lot going on. The awards usually come out during September
Speaker 1: or very early October, and so we're either wrapped up
Speaker 1: in Halloween stuff I then, or we're getting ready to
Speaker 1: do Halloween stuff or something like that. Uh, So we
Speaker 1: generally come in like late November or part of sometime
Speaker 1: in November or in this case, very early December. But
Speaker 1: I guess it's better late than never. And uh, I
Speaker 1: guess one of the cool things about this is is
Speaker 1: we kind of come in after the initial coverage and
Speaker 1: chew on them a bit more. So, if you're waiting
Speaker 1: on these episodes and you and you're inclined to complain,
Speaker 1: just don't stop. But if you're not familiar, the ig
Speaker 1: no Bells are a series of awards given out once
Speaker 1: a year by a scientific humor journal called the Annals
Speaker 1: of Improbable Research that's been edited for many years now
Speaker 1: by somebody named Mark Abraham's and the stated purpose of
Speaker 1: this of these awards is to quote honor achievements that
Speaker 1: first make people laugh and then make them think. So
Speaker 1: to give you an idea if if you haven't heard
Speaker 1: one of these episodes before and you've never read about
Speaker 1: the ig Nobels. Among the awards we covered last or
Speaker 1: there was a prize in the material science category for
Speaker 1: research into whether you could make a knife blade out
Speaker 1: of frozen feces. What was the verdict on that? I
Speaker 1: think it was no right that no matter how hard
Speaker 1: you freeze them, they just don't really cut. I believe
Speaker 1: so um, you know, it reminds me of Yeah. I
Speaker 1: think they think that the research ended up saying, yeah,
Speaker 1: like you, no matter how hard it gets, uh, you're
Speaker 1: still gonna have a certain amount of melting that's going
Speaker 1: to take place, right because the friction on the sharp
Speaker 1: end will will pretty quickly wear it away and then
Speaker 1: it's then it's blunt. Yeah, better to make it like
Speaker 1: a frozen poop warhammer, I think, so that could shatter.
Speaker 1: I don't know, we'll look into that in the future. Um,
Speaker 1: but then let's see what was One of the other
Speaker 1: ones we did last year was there was a prize
Speaker 1: in the acoustics category for a study that made alligators
Speaker 1: huff helium to see if it made their voices higher pitched.
Speaker 1: I remember that. Yeah. So occasionally the papers that get
Speaker 1: selected for these prizes are I think originally themselves intended
Speaker 1: to be satirical or funny. One example like that that
Speaker 1: comes to mind is, uh, there was a rayology study
Speaker 1: one year about whether cats should be considered a solid
Speaker 1: or a liquid. That that was a good one, but
Speaker 1: clearly there was a good bit of jokiness about the
Speaker 1: paper itself most of the time. Actually, this the research
Speaker 1: covered in in these prizes, is it's just straightforward research.
Speaker 1: They're they're straightforward experiments published in real scientific journals that
Speaker 1: happened to have some weirdly hilarious methodology or finding. Yeah.
Speaker 1: Either you know, it varies, but you know, sometimes it's
Speaker 1: it's just a particular experiment that is hilarious or giggle inducing. Um.
Speaker 1: Other times it's just the minutia of it, you know,
Speaker 1: one of those kind of a shrimp on a treadmill
Speaker 1: situation where it may it's still important work. It's all
Speaker 1: part of the general um, you know, expansion of scientific
Speaker 1: knowledge of of the universe, but it just in an
Speaker 1: area that we might not think about. Or sometimes it's
Speaker 1: just an important study that involves like pooper vomit or something,
Speaker 1: and therefore just by ver orteese or something, you know,
Speaker 1: just by virtue of the subject, kissing, yeah, is inherently funny. Now,
Speaker 1: in these episodes we're doing on on the Igno Bells,
Speaker 1: we're just going to pick out a few of the
Speaker 1: prizes to highlight because there was something about them that
Speaker 1: we wanted to talk about. We're not gonna have a
Speaker 1: chance to cover all of the winners, but if you
Speaker 1: want to read about those. You can go to the
Speaker 1: Annals of Improbable Research website at Improbable dot com and
Speaker 1: you can see the full list of the awards and
Speaker 1: click on links to to read about them. I mean,
Speaker 1: and not only the most recent awards, but you can
Speaker 1: go back through the entire history of the Igno Bells
Speaker 1: and just and explore them all. It's a very simple,
Speaker 1: easy to use website. Well, I am ready to get
Speaker 1: started if you are, Uh, let's do it, okay, Well,
Speaker 1: the first area I wanted to get into was actually
Speaker 1: this will be a pair of thematically linked prizes from this.
Speaker 1: The first is the Physics Prize, which went to Alessandro Corbetta,
Speaker 1: Jasper Mayu, Sen Chung Min Lee, Roberto Benzi, and Federico
Speaker 1: Tashi quote for conducting experiments to learn why pedestrians do
Speaker 1: not constantly collide with other pedestrians. And then the second
Speaker 1: here is the Kinetics Prize, which went to his Sashimurakami,
Speaker 1: Claudio Feliciani, Utah Nishi Yama, and katsu Hero Nishi Nari.
Speaker 1: And this is quote for conducting experiments to learn why
Speaker 1: pedestrians do sometimes collide with other pedestrians. Uh, Rob, have
Speaker 1: you ever had a really memorable, just bodily head on
Speaker 1: with somebody. I was trying to remember if I had,
Speaker 1: and I could not bring any instances to mind. Though
Speaker 1: I have run into plenty of things in my life.
Speaker 1: I run into tree branches and sliding glass doors, but
Speaker 1: I can't really think of any head ons with humans
Speaker 1: except maybe while playing soccer. Yeah, thinking back, yes, certainly,
Speaker 1: I there have been more than a few low hanging
Speaker 1: branches that have have clipped the top of my head
Speaker 1: or tried to stab me in the eye, that sort
Speaker 1: of thing. But in terms of of running into people,
Speaker 1: um even in crowded cities, and like I was just
Speaker 1: in um in New Orleans, and you know, those are
Speaker 1: some crowded streets at times, and those are also some
Speaker 1: drunken streets at times. You know they're folks wandering around
Speaker 1: in various states of inebriation, and yet you don't see
Speaker 1: people just colliding with each other. I feel like I've
Speaker 1: had I can think maybe to some close calls in
Speaker 1: the past where you have that moment where you almost
Speaker 1: run into somebody and you both kind of acknowledge it
Speaker 1: and it's a little bit awkward, but still it's not
Speaker 1: like you see. I guess in a lot of like
Speaker 1: comedy films where people just plow into each other, knock
Speaker 1: their groceries down, and then they have a romantic moment
Speaker 1: as they pick up each other's groceries, that sort of thing. Yes,
Speaker 1: why is it romantic comedies where people plow into each other?
Speaker 1: I guess there's something metaphorical about that, about you know,
Speaker 1: the oh you came into my life like a like
Speaker 1: a large, massive meat slamming me in the face. Yeah.
Speaker 1: Because Yeah, in general, you don't see like fights breaking
Speaker 1: out because people ran into each other, or at least
Speaker 1: I don't think I've ever seen that occur. I mean
Speaker 1: it probably has occurred, but not with the regularity you
Speaker 1: might expect, given just how intense uh streets and sidewalks
Speaker 1: are at times. Yeah, and I think this is something
Speaker 1: we should keep in mind as we discussed this research.
Speaker 1: It's interesting how rare collisions are given how often huge
Speaker 1: masses of people are just criss crossing with each other
Speaker 1: all day. So to actually reference the two papers here,
Speaker 1: the first one was Corbetta at all. This was in
Speaker 1: Physical Review E in eighteen and it was called Physics
Speaker 1: based Modeling and Data Representation of pair wise interactions among pedestrians.
Speaker 1: And then the second paper the Kinetics Prize was called
Speaker 1: Mutual anticipation can contribute to self organization and human crowds.
Speaker 1: This was by more commy at all in one in
Speaker 1: Science Advances. Now, I was interested in this pair of
Speaker 1: findings not only because I was obviously amused by the
Speaker 1: image of people just absolutely eating each other's teeth in
Speaker 1: in high speed sidewalk collisions, but because this is one
Speaker 1: of those ignoble subjects where once you get beyond the
Speaker 1: mildly funny image it conjures, it actually raises quite i think,
Speaker 1: quite deep, mysterious, fascinating questions about the emergent mathematical properties
Speaker 1: of human behavior in groups. And it's also a subject
Speaker 1: that goes way beyond mere curiosity. Understanding the flow of
Speaker 1: crowds is a matter of life and death. It is
Speaker 1: a vitally important subject for all kinds of reasons. So
Speaker 1: this involves questions like how do masses of people move
Speaker 1: through space on foot? What rules govern their behavior both
Speaker 1: as individuals and as as a group, How can that
Speaker 1: behavior be influenced, and especially how does the built environment
Speaker 1: shape that behavior? Uh, you know, as you were alluding
Speaker 1: to a minute ago. I think it's actually kind of
Speaker 1: amazing how pedestrians can navigate through crowds without running into
Speaker 1: each other. It's one of those, you know, thousand little
Speaker 1: miracles of human human brain capacity that we don't usually
Speaker 1: notice or appreciate. But you can have huge crowds moving
Speaker 1: quickly and bi directionally mean running at cross directions, past
Speaker 1: each other, straight through each other, and uh and most
Speaker 1: of the time people are able to avoid human crashes. Yeah,
Speaker 1: and it it seems to be the case no matter
Speaker 1: where you go, even though I will say, and this
Speaker 1: is just uh my my observation. I don't know to
Speaker 1: what extent this this holds up to research, but it
Speaker 1: feels like in in some parts of the world, the
Speaker 1: the energy of love, say, the movement of crowds on
Speaker 1: a sidewalk can feel different, can a little bit different,
Speaker 1: you know, but it's still maintaining, you know, the same
Speaker 1: collision free experience. You know, like like maybe there's there's
Speaker 1: something slightly different going on there, there's some sort of
Speaker 1: there are different cultural norms in place regarding say, like
Speaker 1: what side of the sidewalk people moving this way should
Speaker 1: be on, or or so or so forth, or or
Speaker 1: even maybe you know how much space is permittable between
Speaker 1: you and the next person, but still people are managing
Speaker 1: not to blow into each other. Yeah. So to discuss
Speaker 1: a few of the details of these two studies, regarding
Speaker 1: the first one, Corbetta at all from from eighteen. I
Speaker 1: was reading about this uh in an article that had
Speaker 1: a few interview clips um from in l Times, and
Speaker 1: this was looking at Technical University Eindhoven researchers Federico Tashi
Speaker 1: and Alessandro Corbetta and uh so their study in particular
Speaker 1: was looking at the question of how pedestrians avoid running
Speaker 1: into each other when moving through the Eindhoven train station,
Speaker 1: and they did this by installing sensors under the plow
Speaker 1: forms of the train station which they used to track
Speaker 1: the movements of pedestrians across the platform. So this was
Speaker 1: an area of like twenty seven square meters and they
Speaker 1: tracked pedestrian movement within it for six months. This came
Speaker 1: out to measuring the movements about five million pedestrians total,
Speaker 1: and they found a few measurable quantities. So first of all,
Speaker 1: they said that people keep an average distance of about
Speaker 1: seventy five centimeters away from other people while moving through crowds,
Speaker 1: so that's about two and a half feet. And they
Speaker 1: said that about one out of every thousand people quote
Speaker 1: will turn around and go back the way they came
Speaker 1: to avoid bumping into somebody else. According to Alessandro Corbetta, quote,
Speaker 1: about eighty of the pedestrians actually collided with each other.
Speaker 1: The other pedestrians adjusted their walking route when they were
Speaker 1: at least a hundred and forty centimeters which is about
Speaker 1: four ft and seven inches apart, and thus managed to
Speaker 1: avoid a collision. And though I was wondering about that,
Speaker 1: so he gives the number eighty eight pedestrians collided. Does
Speaker 1: that mean eighty pedestrians total, meaning roughly forty collisions or
Speaker 1: is that like, uh, there were eighty collisions, which would
Speaker 1: make you think they'd be like at least a hundred
Speaker 1: and sixty people involved. I'm not sure. Well, it raises
Speaker 1: the question how many people are necessary to create a collision?
Speaker 1: Is it one? Or is it too it's at least two,
Speaker 1: I mean you could have more, I guess, But is
Speaker 1: it I guess it depends on like is it is
Speaker 1: it negligence on one person's part that leads to collision?
Speaker 1: Or negligence or distraction whatever on two people's parts. You know, Ah,
Speaker 1: well that will I will actually come up in the
Speaker 1: other study, I think. But what this study found is that, yeah,
Speaker 1: people are constantly monitoring for upcoming collisions and then adjusting
Speaker 1: their walking trajectories accordingly several meters in advance. So ultimately,
Speaker 1: the question here is it's not really relevant exactly how
Speaker 1: many people slammed faces, but how on average pedestrians adjust
Speaker 1: their courses to avoid collisions. What rules do they use
Speaker 1: to make those those evasions? And this just apparently happens constantly.
Speaker 1: We're usually not even aware of it. But you know,
Speaker 1: I can recall, like moving through an airport or something,
Speaker 1: you are just doing a delicate dance for for several
Speaker 1: minutes of a time at a time, often you know,
Speaker 1: just dodging dodging, dodging, dodging, and you don't even really
Speaker 1: think about it. It's a process that can be be
Speaker 1: oddly captivating, I find, you know, especially if I'm on
Speaker 1: my own, I don't have to worry about anyone else,
Speaker 1: you know, traveling with me. Uh, you know, cutting a
Speaker 1: swath for them to travel through, you know, checking back
Speaker 1: on how they're doing it. It's just me cutting through, um,
Speaker 1: like a reasonable sized crowd or a reasonable flow of
Speaker 1: pedestrian traffic. Uh, it feels kind of empowering. Well, yeah
Speaker 1: it is, and I think that highlights one of the
Speaker 1: interesting features there, which is that, um, so when you're
Speaker 1: moving through a crowd, you are making individual decisions, like
Speaker 1: and those decisions are being driven by different things. Like,
Speaker 1: on one hand, you've got your basic propulsive drive, like
Speaker 1: you have where you need to be and the course
Speaker 1: you think you need to take to get there. And
Speaker 1: then probably the second main thing governing your movement is
Speaker 1: what these researchers would refer to as social forces, which
Speaker 1: would be things like the taboo against touching other people
Speaker 1: while you're walking, or basically the force that keeps you
Speaker 1: separate from other people and makes you want to avoid
Speaker 1: running into them or touching them in some other way. Yeah,
Speaker 1: because there's a physical risk to actually running into somebody,
Speaker 1: and there is like a social risk to not only
Speaker 1: running into somebody, but even almost running into somebody, yeah,
Speaker 1: even getting too close exactly. But so while those forces
Speaker 1: are are guiding your decision making as an individual, you
Speaker 1: are a thinking person and you you know there are
Speaker 1: cognitive inputs, like you are moving through this crowd as
Speaker 1: an individual. It's strange that take thousands of people and
Speaker 1: they're all making these individual decisions based on these types
Speaker 1: of forces, you know, their drive forces, and their and
Speaker 1: their restrictive social forces. And yet when you look at
Speaker 1: them as a group, they seem to behave in ways
Speaker 1: that are predictable. Even though they're making in these individual decisions,
Speaker 1: they behave in ways that can quite well be modeled
Speaker 1: and predicted and understood by things that are that are
Speaker 1: like physics models the way the same way that you
Speaker 1: would model, say, the movements of a fluid, you know,
Speaker 1: a gas or a liquid through a container than and
Speaker 1: so the authors of this first study you're saying, well,
Speaker 1: by studying the natural movement patterns of pedestrians and trying
Speaker 1: to model them in in terms of the language of
Speaker 1: physics on a large scale, Uh, this can be useful
Speaker 1: in terms of things like architecture and design. You know,
Speaker 1: you can design better spaces for people to walk, both
Speaker 1: in terms of efficiency the throughput how many people can
Speaker 1: move through them quickly, but also in terms of safety
Speaker 1: because as we know, and as I'll talk about in
Speaker 1: a bit, UH, crowds can become quite dangerous when when
Speaker 1: density gets too high. Now, I was also reading an
Speaker 1: article that that had a few uh quotes from these researchers,
Speaker 1: And this was an article for Physics, the magazine of
Speaker 1: the American Physical Society by Michael scherber Uh. And this
Speaker 1: one also discussed the second winner, the winner of the
Speaker 1: Kinetics Prize, the paper that was by Murakami at all.
Speaker 1: And this study was interesting too. So it instead of measuring,
Speaker 1: you know, putting sensors under a floor and measuring natural movement,
Speaker 1: it's staged experiments. So this study asked volunteers to walk
Speaker 1: by directionally, so imagine people crossing each other, walking in
Speaker 1: opposite directions the way they would say, like a crowded
Speaker 1: crosswalk in the street. And then it tried to see
Speaker 1: what happens when when people walk by directionally under normal circumstances,
Speaker 1: and then what happens when some of those people are distracted, specifically,
Speaker 1: what happens when they're trying to do calculations on their phones.
Speaker 1: And the purpose of this experiment was to interfere with
Speaker 1: people's ability to see collisions coming and avoid them. Now,
Speaker 1: it probably won't come as a big surprise that pedestrians
Speaker 1: who were distracted by phones made more navigation mistakes, leading
Speaker 1: to a number of near collisions. But even when not distracted,
Speaker 1: people sometimes had difficulty and uh. One of the implications
Speaker 1: of this experiment is that avoiding collisions is a collaborative effort.
Speaker 1: It requires awareness and coordination of multiple parties, both looking
Speaker 1: at each other and trying to assess what paths they're
Speaker 1: about to take, and then adjusting their own paths in accordingly.
Speaker 1: And this becomes difficult when even just one of these
Speaker 1: parties is distracted, especially if multiple parties are distracted. I
Speaker 1: was also reading an interview with one of the researchers
Speaker 1: from the second study, the coninectics ees UM. This was
Speaker 1: on a Swiss news site swiss Info dot c H
Speaker 1: and it was an interview by Zeno Soccatelli with a
Speaker 1: researcher named Claudio Feliciani who works at the University of
Speaker 1: Tokyo but who originally hails from Switzerland. And so Feliciani
Speaker 1: mentioned a few interesting things in this interview. One is that, okay,
Speaker 1: so when you when you have people not distracted, UM,
Speaker 1: how do they tend to move in groups when they're
Speaker 1: moving by directionally, like you imagine people crossing each two
Speaker 1: crowds at at a busy crosswalk trying to go past
Speaker 1: each other. How do they normally move? And Feliciani says
Speaker 1: that what tends to happen is people automatically self organize
Speaker 1: into lines. People tend to naturally follow the person directly
Speaker 1: in front of them, and simply by obeying this rule,
Speaker 1: the moving crowd naturally forms into lanes or lines of people.
Speaker 1: And so they were trying to understand the mechanisms that
Speaker 1: make these lines form and how they work. Of course,
Speaker 1: you know one way understand how something works is to
Speaker 1: see if you can break it. Um So, Feliciani says,
Speaker 1: quote specifically, we caused some of the pedestrians to be distracted,
Speaker 1: asking them to walk while solving simple calculations on their phones.
Speaker 1: With just three out of fifty four people focused on
Speaker 1: something else, rows formed much less quickly, especially if the
Speaker 1: distracted people were at the front of the group, and
Speaker 1: the increased attention of the non distractors is not enough
Speaker 1: to make up for the lack of attention of the
Speaker 1: three who are distracted. And then on this website there
Speaker 1: is actually video I could watch maybe you want to
Speaker 1: take a look, rob But there's video that shows how
Speaker 1: people move in these lines under normal conditions, and then
Speaker 1: what it looks like when just a few of them
Speaker 1: are distracted. So not everybody is trying to do math
Speaker 1: on their phone. Just a few people, just a few
Speaker 1: people out of the fifty four completely screw things up
Speaker 1: and everybody gets jammed up. The lanes stone form naturally.
Speaker 1: Uh So it seems like its navigating through crowds by directionally.
Speaker 1: It has this tendency to for you know, self organizing
Speaker 1: emergent structures to form, but that requires everybody to be
Speaker 1: paying attention and monitoring each other and sort of communicating
Speaker 1: nonverbally about where they're headed. This is interesting. I mean,
Speaker 1: of course, this has huge ramifications on a are already
Speaker 1: you know, near ubiquitous use of smartphones and the fact
Speaker 1: that people will have them out while they're walking around.
Speaker 1: But it also makes me wonder about, you know, the
Speaker 1: more we push into this idea of augmented reality, of
Speaker 1: of having some sort of you know, a metaverse that
Speaker 1: is digitally imposed on the world around us. Uh, you know,
Speaker 1: what's what's that going to do? Or does it make
Speaker 1: it easier? I don't know like I can. Maybe you
Speaker 1: imagine the case being made that like, well, you're not
Speaker 1: looking at your screen, You're looking at the world around
Speaker 1: you for this information, which you were probably already doing
Speaker 1: and potentially distracted by, just as a normal pedestrian pre smartphone. Well,
Speaker 1: I mean it is yet another one of those things
Speaker 1: are we have surprisingly powerful capacities, you know, like we
Speaker 1: can do things that are kind of amazing if you
Speaker 1: sit and think about them, like walking through crowds without
Speaker 1: collisions or driving a car, but we also fail to
Speaker 1: have the metacognitive recognition of how much attention it takes
Speaker 1: to do that correctly. So you have people not realizing
Speaker 1: how impaired they are when they're texting while driving, or uh,
Speaker 1: not quite appreciating how quickly this entire crosswalk will get
Speaker 1: jammed up if just a couple of people are distracted
Speaker 1: while they're walking. But anyway, I just got really interested
Speaker 1: in the subject of the the modeling of the flow
Speaker 1: of human crowds. Um uh. Like one idea that that
Speaker 1: I found very sticky is I was looking at a
Speaker 1: paper from two thousand three in the Annual Review of
Speaker 1: Fluid Mechanics by Roger L. Hughes, who is who worked
Speaker 1: in the Department of Civil and Environmental Engineering at the
Speaker 1: University of Melbourne, and the paper is called the Flow
Speaker 1: of Human Crowds, and he was discussing the idea that
Speaker 1: human movements could be modeled like like the flow of
Speaker 1: of non human substances, you know, just like molasses flowing
Speaker 1: out of a jar, or like the way particles of
Speaker 1: gas move around in a container. But of course it's
Speaker 1: complicated by the fact that there are social inputs on
Speaker 1: the movement, even if the movement can be modeled like
Speaker 1: the movement of a physical substance at the large scale. Uh.
Speaker 1: And he ended up characterizing crowds as the field of
Speaker 1: quote thinking fluids, which is just wonderful. Uh. And so
Speaker 1: this isn't related to either of the prize winners I
Speaker 1: was just talking about, but I was also I ended
Speaker 1: up reading another really interesting article on the subject of
Speaker 1: physical and mathematical modeling of crowdflow. And this was an
Speaker 1: article in Smithsonian Magazine from January by Evelyn Lamb. It
Speaker 1: was called how fluid dynamics can help You Navigate crowds
Speaker 1: And so the premise of this article is that because
Speaker 1: the of human crowds can be modeled like the flow
Speaker 1: of physical substances. Physics modeling can also offer suggestions to
Speaker 1: individual members of crowds for how to move through them
Speaker 1: in the safest and best way, at least potentially. I mean,
Speaker 1: there's a lot of uncertainty. Uh this, I guess it's
Speaker 1: kind of a young scientific field right now, but um
Speaker 1: that it could potentially offer individual advice in addition to
Speaker 1: the stuff we already talked about, like informing how to
Speaker 1: better design spaces for people to walk through and uh so,
Speaker 1: of course, this article mentioned some of the same research
Speaker 1: we already talked about, such as the the idea that
Speaker 1: moving crowds tend to form the self organizing natural lanes
Speaker 1: or lines, often just by a rule as simple as
Speaker 1: you directly follow the person ahead of you. But then
Speaker 1: this article goes on to side a few researchers offering
Speaker 1: some other observations. So one thing is that it cites
Speaker 1: a researcher named Dirk Helping, who is at the Swiss
Speaker 1: Federal Institute of Technology and Zurich and who studies computation
Speaker 1: all social science. Um, I just noticed, I wonder if
Speaker 1: there's like a big center of crowdflow study in Switzerland,
Speaker 1: because several of these uh of these papers have had
Speaker 1: Swiss connections of one kind or another, so springing off
Speaker 1: of some stuff that that helping says here, Lamb actually
Speaker 1: highlights a couple of the main governing forces that appear
Speaker 1: to drive the individual behaviors of people within crowds, and
Speaker 1: I think they actually they sort of line up with
Speaker 1: what we're talking about a minute ago. So on one hand,
Speaker 1: you've got a force that propels the person towards their goal.
Speaker 1: They're they're trying to get somewhere, and then second you've
Speaker 1: got the social forces that prevent them from doing something,
Speaker 1: mostly prevent them from colliding with with other people in
Speaker 1: the crowd. And regarding that second force, the social force,
Speaker 1: I thought this was really interesting. The article makes the
Speaker 1: case that it is similar to the repulsive force that
Speaker 1: keeps particles from colliding, like physical particles, and in the
Speaker 1: case of physic goal like atoms and molecules, this would
Speaker 1: be the electromagnetic force. Electrons of course repel one another.
Speaker 1: They've got like charges, they push back against each other,
Speaker 1: and in the case of particles, you can actually calculate
Speaker 1: the strength of the repulsive force via what's known as
Speaker 1: the inverse square law. So the inverse square law is
Speaker 1: a very important mathematical principle that applies throughout physics. Basically,
Speaker 1: it applies to any quantity of energy or force propagating
Speaker 1: out from a central source in three dimensions, and it
Speaker 1: says that the that quantity will decrease, not just in
Speaker 1: a linear way as you move away from the source,
Speaker 1: but it will decrease according to the square of the
Speaker 1: distance between you and the source. So a simpler way
Speaker 1: to conceptualize this is that when you're thinking about light intensity,
Speaker 1: or gravity or electromagnetic repulsive forces between particles, proximity really matters,
Speaker 1: and a force that is almost undetectable at a distance
Speaker 1: can become very strong as you can close. So this
Speaker 1: is true of particles avoiding collisions in flowing masses of
Speaker 1: liquid or gas. But it's also true of humans moving
Speaker 1: in a crowd, uh, though in a slightly different way.
Speaker 1: And then the article calls attention to a paper that
Speaker 1: made a really interesting discovery back in so this paper
Speaker 1: was by Johannis Karamutzas, Brian Skinner, and Stephen Jay Guy
Speaker 1: and Physical Review letters called universal power law governing pedestrian interactions,
Speaker 1: and the author summarize their findings like this, They say, quote,
Speaker 1: here we introduce a novel statistical mechanical approach to directly
Speaker 1: measure the interaction energy between pedestrians. This analysis, when applied
Speaker 1: to a large collection of human motion data, reveals a
Speaker 1: simple power law interaction that is based not on the
Speaker 1: physical separation between pedestrians, but on their projected time to
Speaker 1: a future collision, and it's therefore fundamentally anticipatory in nature.
Speaker 1: So this really got me. So so there is a
Speaker 1: rule in operation just automatically in moving human crowds that
Speaker 1: works somewhat like the inverse square law for the repulsion
Speaker 1: between particles in a fluid, but it's a repulsion based
Speaker 1: not just on physical proximity. It's based on the anticipation
Speaker 1: of movement pathways. So you can think about it this way.
Speaker 1: If you're in a big crowd of people and you're
Speaker 1: moving along on the sidewalk, you can actually be very
Speaker 1: close to another person. So you can be walking beside
Speaker 1: somebody parallel, side by side, or you can even be
Speaker 1: pretty close to the person ahead of you or behind
Speaker 1: you walking in the same direction, where you have to
Speaker 1: adjust your path to avoid a collision is when you
Speaker 1: notice that your path is about to cross somebody else's.
Speaker 1: And we calculate these adjustments not purely in terms of distance,
Speaker 1: but in terms of time. That like, the variable is
Speaker 1: time to collision based on the current speed of your movement,
Speaker 1: and people are typically anticipating about one to three seconds
Speaker 1: into the future, depending on the characteristics of the crowd.
Speaker 1: Thank so, people use these rules pretty reliably to move
Speaker 1: in crowds, and as we've said already, they can usually
Speaker 1: avoid collisions. But there are some situations where the rules
Speaker 1: stop working, particularly as the density of the crowd increases.
Speaker 1: The higher the density, the more your collision avoidance skills
Speaker 1: are overwhelmed and different principles take over. And sometimes, unfortunately,
Speaker 1: these situations can turn very dangerous. Uh. You know, people
Speaker 1: are killed in crowds all the time, at everything from
Speaker 1: music festivals to religious events. And I think a lot
Speaker 1: of times when people read reporting about about deaths through
Speaker 1: through crowd crush and crowd dynamics, I think a lot
Speaker 1: of times people fail to understand exactly what's happening in
Speaker 1: these situations, Like they sometimes seem to imagine that this
Speaker 1: must result from the crowds being somehow evil like violent
Speaker 1: or malicious or chaotic, or at least the news reporting
Speaker 1: on these events sometimes has that kind of tone, and
Speaker 1: this is not necessarily the case at all. People in
Speaker 1: large crowds can easily be injured or killed simply by
Speaker 1: the uncontrollable flow of human bodies through space. Like you
Speaker 1: don't have to imagine people in the crowd wanting to
Speaker 1: trample each other. There there are irresistible physical forces at work,
Speaker 1: like you could you could essentially have a large mass
Speaker 1: of people attending a rally about the importance of crowd
Speaker 1: safety and if we're not managed properly, it could result
Speaker 1: in injury. Right. Yeah, So say maybe you're trying to
Speaker 1: quickly move a huge, massive people and they're moving through
Speaker 1: a corridor that's originally a hundred meters wide and then
Speaker 1: suddenly it narrows to five ms wide. Uh, this could
Speaker 1: this could spell disaster. And you can also imagine scenarios where,
Speaker 1: you know, especially at events that are attracting big crowds,
Speaker 1: non crowdflow dynamics can can have exactly the wrong incentives
Speaker 1: for how to shape those spaces, right, Like maybe at
Speaker 1: a big music festival or something, you want to have
Speaker 1: choke points that control access to spaces, maybe so that
Speaker 1: you can check for tickets or who knows what UM.
Speaker 1: But but it's exactly at areas where there are there
Speaker 1: are things like bottlenecks where suddenly the density of the
Speaker 1: crowd increases dramatically and unexpectedly, that things can really get dangerous.
Speaker 1: And researchers in this field studying crowdflow have actually uh
Speaker 1: looked at a lot of video documentation to come up
Speaker 1: with models to try to understand what happens when crowdflow
Speaker 1: becomes deadly. And the article here discusses a few observations
Speaker 1: in this area. Though it's quick to caveat and I
Speaker 1: guess we should too, that we we we we can't
Speaker 1: give you, you know, the hard and fast rules to
Speaker 1: follow that will always keep you safe, because there's still
Speaker 1: a lot that's not known about exactly how this happens.
Speaker 1: But there are a few things that seem probably true.
Speaker 1: One of them, again, obviously, is that density seems to
Speaker 1: be a major contributor to when when crowds get dangerous.
Speaker 1: That you know, if a pathway suddenly narrows at a
Speaker 1: tunnel or a bridge or something um and the article
Speaker 1: describes how increasing density and these types of areas can
Speaker 1: lead to something called stop and go waves, where people
Speaker 1: can no longer keep moving continuously forward. They're moving, they're
Speaker 1: used to walking, and then they eventually reach a point
Speaker 1: where the crowd is so dense that even at low speeds,
Speaker 1: they can't keep moving forward, so they stop. And then
Speaker 1: once they're stopped, they move forward, but of course people
Speaker 1: are still trying to move in behind them. Uh, so
Speaker 1: they're stopped, people are advancing behind them, and they tend
Speaker 1: to move forward into any gaps as soon as they appear. Uh.
Speaker 1: Stop and go waves are not always necessarily dangerous, but
Speaker 1: they can be an indication that crowd density is getting
Speaker 1: too high. And then, to read from Lamb's description of
Speaker 1: what happens after this here quote, things get really dangerous
Speaker 1: if the crowd continues to get denser or people make
Speaker 1: unexpected movements. At that point, the crowd can become turbulent
Speaker 1: and chaotic, with people being pushed randomly in different directions.
Speaker 1: Disasters can break out when say, one person stumbles, causing
Speaker 1: someone else to be pushed into their place and either
Speaker 1: trampling them or stumbling themselves, and this whole can have
Speaker 1: a kind of gravitational effect pulling in more and more people,
Speaker 1: which in terms of the physical dynamics, this is similar
Speaker 1: to how the flow of physical substances like water behave
Speaker 1: when they're funneled into narrower and narrower places. Like I
Speaker 1: think about how some of the world's most dangerous whirlpools
Speaker 1: seem to occur in bottlenecks for the flow of water,
Speaker 1: where for example, the tide is pushing a huge amount
Speaker 1: of water through a narrow, straight or your This can
Speaker 1: lead to rushing and turbulence. It's chaotic flow and unpredictable
Speaker 1: directions which can sometimes create these whirlpools. Anyway, back to
Speaker 1: the article, it mentions a couple of other UH seeming
Speaker 1: risk factors for for when this happens UH. In addition
Speaker 1: to the high density another one is bidirectional or multidirectional flow.
Speaker 1: So things can get more dangerous if you have high
Speaker 1: density and people trying to move in different directions UM.
Speaker 1: And then finally, lambsites The researcher Juannas Kara Mutzis, who
Speaker 1: was one of the authors on that paper from feen
Speaker 1: I mentioned a minute ago saying that in large enclosed spaces.
Speaker 1: For some reason, the sides of the space seemed possibly
Speaker 1: to be more dangerous than the middle, though there isn't
Speaker 1: enough research to be sure of that or to explain
Speaker 1: why it happens. So obviously, understanding the flow of crowds
Speaker 1: goes way beyond just just being a kind of interesting
Speaker 1: little curiosity and like looking at how people move. It
Speaker 1: is something that is of critical importance in managing, you know,
Speaker 1: large masses of people, and in designing spaces for them
Speaker 1: to move through, and in planning events and all kinds
Speaker 1: of things like that. I mean, this is like one
Speaker 1: of those things that starts off being really funny but
Speaker 1: is in fact a critically important subject. Yeah, I mean absolutely,
Speaker 1: they're they're just going to be more and more office
Speaker 1: and these uh, these large events of of you know,
Speaker 1: varying genres are going to continue to be a part
Speaker 1: of our lives. This actually got me wondering about something,
Speaker 1: which is um why doesn't anything like like uncontrollable crowdflow
Speaker 1: with with actual like pressing against one another happen with cars.
Speaker 1: You can see some of the characteristics happen with cars
Speaker 1: because you can get traffic back up when there's a
Speaker 1: bottleneck in the highway, maybe seven lanes suddenly go down
Speaker 1: to one, and this will cause a huge traffic jam.
Speaker 1: But you don't usually have the problem with like cars
Speaker 1: pushing each other and and pressing against one another and
Speaker 1: leading to this bill up of uncontrollable forces. I was
Speaker 1: wondering why that is. Maybe it's because I'm just guessing.
Speaker 1: I wonder if it's because it's never considered acceptable for
Speaker 1: cars to touch each other at all. Uh. And people,
Speaker 1: of course mostly avoid try to avoid touching one another
Speaker 1: in crowds, but in some situations, maybe it just seems
Speaker 1: like there's no avoiding it, so you just sort of
Speaker 1: resign yourself to touching and then that and then that
Speaker 1: can build up. Maybe I'm not sure, you know, that's
Speaker 1: a good point. Yeah, because even though some drivers do
Speaker 1: like to come as close as possible to touching your car, uh,
Speaker 1: which is something I've never been able to understand, just
Speaker 1: given how dangerous it actually is to you know, to
Speaker 1: to you know, to pull up right behind somebody will
Speaker 1: at high speeds on the interstate. Uh. Yeah, yeah, to
Speaker 1: your point, they you're not actually supposed to ram into
Speaker 1: them even a little bit. And and while you know,
Speaker 1: certainly pile ups do occur. You do have acts density,
Speaker 1: do have cars crashing into one another and then multiple
Speaker 1: car pile ups occurring. Um, yeah, I wonder if this
Speaker 1: stricter no touch policy with cars has some sort of
Speaker 1: influence on us. Well yeah, maybe another thing is I'm
Speaker 1: not conceptualizing it right, And maybe the crowd dynamics I
Speaker 1: was talking about are more analogous to just actual like
Speaker 1: pile up crashes, I guess, which I wasn't thinking about
Speaker 1: in a similar way because those happen at higher speeds.
Speaker 1: I wonder what would we would see in something that's
Speaker 1: halfway between if what would be between a car and
Speaker 1: a person if we were to say, look at a
Speaker 1: bicycle traffic in very congested bicycle situations, say a city
Speaker 1: where there's a high number of bicycle riders or something,
Speaker 1: or bicycle races. Because I feel like one of the
Speaker 1: things with people is that yeah, it's like, yeah, maybe segways,
Speaker 1: but I feel like one of the things with people,
Speaker 1: like you've already mentioned, is when you're pushed forward, you
Speaker 1: may be pushed into that hole that you could not
Speaker 1: otherwise occupy or wouldn't occupy socially. But now you know,
Speaker 1: if you're being pushed. I guess that's where I'm going. Um,
Speaker 1: so there's just more nooks and crannies for for human beings.
Speaker 1: Um and then with with cars less so. But perhaps
Speaker 1: if you're looking at bicycles, like maybe maybe we see
Speaker 1: something that's more like the human scenario. It'd be interested
Speaker 1: to hear from some of our bicyclists out there, like
Speaker 1: what are the social laws of crowded bicycle scenarios? How
Speaker 1: close can you get to another bicyclist while moving while
Speaker 1: stationary while sort of you know, uh, tiptoeing along. I'd
Speaker 1: be interested a year, Yeah, totally, I mean especially yeah,
Speaker 1: like it seems a key difference is is the the
Speaker 1: the balancing act that's necessary on a bicycle? Yeah? Well, anyway,
Speaker 1: I want to say about these two subjects, the physics
Speaker 1: and kinetics price this year. This definitely did, uh did
Speaker 1: achieve the desired intent. It made me laugh a little
Speaker 1: bit and then did make me think it was not
Speaker 1: I will I will grant it did not make me
Speaker 1: laugh hilariously, so it was a mild chuckle, but then
Speaker 1: it got really interesting to me. Yes, all right, we're
Speaker 1: gonna go and close this episode out, but we will
Speaker 1: be back. Um, I'm going to talk about the Biology Prize.
Speaker 1: We're gonna get into some other prizes from the Igno
Speaker 1: Bells this year, so just tune into that in the
Speaker 1: next Core episode of Stuff to Blow Your Mind. To
Speaker 1: remind everybody, Stuff to Blow Your Mind. The podcast feed
Speaker 1: can be found wherever you get your podcasts. Core episodes
Speaker 1: come out on Tuesdays and Thursday's Monday is listener Mail,
Speaker 1: Wednesday is a short form artifact episode, and on Friday's
Speaker 1: we do Weird House Cinema. That's our time to set
Speaker 1: aside most serious concerns and just focus on a weird film.
Speaker 1: Huge thanks as always to our excellent audio producer Seth
Speaker 1: Nicholas Johnson. If you would like to get in touch
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