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This is the Guardian.
Hear that? No?
Well, according to scientists, that definitively proves you are not a hedgehog.
The revelation that these sweet, spiky creatures pick up sounds well into the ultrasonic range
opens up the possibility of better understanding hedgehog communication
and how we can make use of it to slow or reverse their drastic declines.
As well as exploring new ways to converse with the hedgehogs,
researchers have been investigating one of the new ways we converse with each other
with the aid of AI autocomplete. It's certainly changing how we write,
but could it also change how we think?
A much more low-tech and simple approach for positively influencing the mind
is exercise. And scientists this week have been probing the possible reasons why working out
appears to be good for our body and brain.
So today I sit down with my co-host and science editor, Ian Sample,
to discuss the stories you need to know about this week.
From the Guardian, I'm Madeline Finley, and this is Science Weekly.
Ian, our first story today is about the link between exercise and the brain.
There is a fair bit of research that links exercise and brain function,
but the mechanisms behind all of it are still quite murky.
So what has this group at UCL done to try and clear this up?
You're right, there's been an awful lot of work looking at exercise and brain function,
and I would say a lot of that researchers have pretty mixed results.
What this group at UCL was doing was they wanted to look at exercise and brain function,
but as a potential mechanism for that, they wanted to look at blood levels of a protein
called brain-derived neutrophic factor. We can call that BDNF for short.
It's often referred to as fertiliser for the brain. It's actually a protein that's produced in
the brain, and crucially, it helps protect neurons. It helps to drive the growth of fresh neurons,
and also helps in the formation of new connections between brain neurons.
So really this study, it's exploratory. It's really sensitive research, but they wanted to look at
is there some kind of mechanism going on here, which is linking exercise and brain function
through the release of this neuron nurturing protein?
Very intriguing. So what did they do? How did they look at this?
So for the study, they recruited people who were unfit and sedentary. These people weren't
getting much exercise. They had high BMI's, and they divided them into two groups. So first
we had a control group, and for them, it's just carry on as normal. The interesting part of this is
the intervention group, and they were put on an exercise program, which involved going on an
exercise bike at a gym, whereby the intensity of the exercise increased over 12 weeks, and throughout
the study, they're giving blood so that the researchers can measure their blood levels of BDNF,
and they're also testing them for their attention, their focus, for their memory, and their reaction
times, things like that. And they're also using a technique to look at their brain activity while
all this is going on to see if they can see any changes in how their brains are behaving.
Right, so what did they find? So it's worth saying straight up, they didn't see any improvement in
how people performed on the cognitive tasks after doing the exercise. They also didn't see any
rise in the resting level of BDNF in people's blood. But what was interesting, and I think this
is really just one of those studies which says, okay, there might be something interesting here to
go and look at properly, was the people got fitter after this 12 week exercise regime,
that increase in fitness was linked to a BDNF response. So let me sort of unpack that.
Once these people have finished that 12 week exercise program, if you then got them to do 15
minute bouts of really intense exercise, the amount of BDNF they produced really spiked,
they produced more than they would have done when they were less fit. So what the study's really
doing is it's saying that if you're fitter, then you seem to produce more of this BDNF when you
have a sort of sharp, sharp bout of exercise. And they also see that even though people weren't
doing better on the cognitive tasks, some of the brain imaging they were doing suggests that the
prefrontal cortex, that part of the brain where you're making decisions and all sorts of things
like that, they thought the activity there looked as if they had seen some changes that were
beneficial. So Ian, if we were going to try and interpret this, as you said it's exploratory,
but it sounds like the idea would be, once you get fit, if you keep exercising, you might potentially
have some kind of brain benefit. I think that is the hope. This is all part of this broader feel
to try and understand whether exercise is really benefiting the brain in terms of cognition,
and if it is how it's doing that. And I guess a good thing is the participants in this got fit,
the very least. Absolutely, it's only three months and there's a pretty good commitment,
you know, four times a week, but their improvement in their fitness was pretty impressive. So I think
that should at least give everybody hope. Maddie, you've got a story about hedgehogs and what they
can hear. What's all this about? Yeah, so researchers have found that hedgehogs can hear in the
ultrasound and they hope that this might lead to more effective hedgehog deterrence. Now why would
you want to deter a hedgehog because they're the most wonderful creatures? It's because, unfortunately,
in Europe, particularly there has been a drastic decline in hedgehogs. We'll probably both be
old enough to remember the road safety TV ads with the parent and child hedgehog giving advice
about how to cross the road. That was very pertinent because actually it's been estimated that one
in three hedgehogs are killed by vehicles. I've seen numbers around 335,000 hedgehogs dying on
the road every year and that isn't even their only threat. The use of pesticides and the huge
drop in insect numbers we've seen habitat loss and fragmentation and then there's also them getting
other injuries from things like streamers or robotic lawn mowers. In the UK, it's been estimated
that there might be up to a 75% decline in their numbers in rural areas since the start of the 2000s.
So as soon as I heard about this story, I got in touch with the lead researcher Dr. Sophie
Lund Rasmussen. She's from the University of Oxford and I wanted to ask her, was there any reason
why she thought that hedgehogs might hear in the ultrasound in the first place? So I've often
been wondering about hedgehog communication because they don't have that many sounds and I think
it's a bit strange because you can tell when they meet each other in the garden that they are
communicating, they are interacting somehow but no noise is coming out of them. So to actually
investigate their ability to hear ultrasound was pretty obvious I think because I was just sure
that something was going on. But Maddie, how did they test the hedgehogs hearing to find out that
they can hear in the ultrasonic? So there were two parts to this study. One part was they did CT
scans of a euthanised hedgehog who had been injured. They built a 3D model of the middle
and inner ear and in doing that they found structures that basically showed them that hedgehogs
can process high pitch sounds very efficiently and they found structures that very similar to what
you might see in other animals that use ultrasound like echolocating bats. And then in the other part
of this study they took 20 rehabilitated hedgehogs from wildlife rescue centres and they gave
them a small amount of anesthesia and they put electrodes just under the skin to measure the
brain activity and then they played them different frequencies of ultrasound. Now when I was reading
about this I couldn't stop thinking that this is like you know when people describe being abducted
by aliens what's happened to them. I feel like these poor hedgehogs you know when they came round
must have felt the same way anyway. What these scientists were doing is they were looking for the
auditory brain stem response. So electrical signals that are travelling between the inner ear and
the brain in response to these different sound frequencies. What they found was that hedgehogs
hear sounds from around four kilohertz up to at least 85 kilohertz and they seem to have peak
sensitivity around 40 kilohertz so this is well into the ultrasonic range it's into a range that
humans can't hear and actually Sophie told me that now they're trying to understand a bit more
about how hedgehogs use ultrasound themselves to communicate. If they hear best at 40 kilohertz
there's a great likelihood that they also communicate around 40 kilohertz. So we've already started
testing this and we've been recording a lot of interactions between hedgehogs to detect whether
they are communicating it ultrasound and I'll be happy to share the results when we know what we
found. And you said that the researchers thought this discovery could be useful for designing more
effective hedgehog deterrence. Yeah one thing that occurred to me when I read this study was
cars and garden streamers are really loud and there's lots of vibrations but clearly that's not
a deterrent right because so many are dying on our roads so maybe the hedgehogs would react more
to the peak of where they hear. Scientists and conservationists might be able to design something
that works better that perhaps you put on the front of your car you put on your lawn mower and
it was something that Sophie was really really keen on it. I mean ultimately to her this was the
point of the research. How does one design a sound repellent that is efficient? Which sounds
actually scare hedgehogs? Perhaps it's a pulsating sound perhaps it's a deep vibration we don't know
that yet but we also have to make sure that the sound repellents are only efficient when they're
running. I don't want to risk evicting hedgehogs from gardens causing the hedgehogs to
not cross the roads altogether. We also have to be aware that bats and mice can hear in the
same frequency range and what happens if they're scared it takes a lot of thorough solid research to
develop these sound repellents and I'm hoping that the kind industry would want to support this
research and save thousands of hedgehog lives and hopefully turn this massive and worrying decline
around and ensure that our grandchildren get this wonderful nature experience it is to meet a
hedgehog in the garden at night. I don't suppose she had any thoughts on ways that you might use
ultrasound to attract hedgehogs into your garden for anyone who might be interested in doing that.
Do you know what? She was just talking about deterrence but Ian I think you've come up with a great
idea there you've got a business plan on your hands because I can't imagine anyone who wouldn't
want hedgehogs in your garden I mean that they eat slugs and snails that's so handy.
Coming up, can AI assistance change our minds?
Chicago 2011 a cop is murdered police and prosecutors swear they have the trigger man
he swears he didn't do it how far will each side go to prove their right like it's just one
bombshell after another you know where you're like what what the story of a playstation
a brain eating amoeba and the relentless pursuit of justice off duty coming soon listen wherever you
get your podcast. So Ian our third and final story for today is about AI and how it can
influence what we think we've heard about how chat bots can be persuasive but this research is
looking at something a little more subtle isn't it? That's right so I'm sure pretty much everyone
by now has come across these sort of AI writing assistance where whether you want them to or not
they will start completing your sentence for you before you've managed to complete it yourself
often with some sort of banal suggestion of how you might want to communicate with someone else
and what these researchers from Cornell University in New York wanted to do was to see whether
those suggestions which obviously cause they're coming from an AI can easily have inherent biases
actually shifted people's attitudes about issues so it's not only would they have an influence
on obviously what they're writing but does it actually affect how they do things afterwards?
This is so interesting because when I see auto complete I immediately am thinking to myself well
I'm not going to say that because you've suggested it but how did the researchers actually go about
testing this? So they had a couple of really large-scale experiments they involved more than two
and a half thousand people and in the first one people were asked to write a short essay four
or a gates standardized testing and education and as they went about the task some of the people
taking part saw these auto complete suggestions so these are AI powered suggestions of how they
might want to write that sentence but these suggestions came from an AI assistant that they had
engineered to give a sort of slightly biased view on the topic. In the second experiment they
had a similar number of people but they were asked to write about things like the death penalty
fracking genetically modified organisms and voting rights for criminals so all really quite
sort of sensitive public issues and again the AI was prompted to give slightly biased suggestions
in its corrections and what they wanted to do in that second study in particular was they had
got people to fill out a quiz about their views beforehand and then they got them to fill out the
same quiz afterwards to see if there was any shift in their attitudes. I would imagine that no
one would want to think that they could be biased by an AI but what did the researchers find?
What's really interesting in the results is that not only did their actual attitudes to issues
change in the same direction that the AI was biased they were unaware of this that they didn't
appreciate that that is what happened and I think even more sort of devastating is that even when
they were told beforehand that the AI would be biased or afterwards it didn't mitigate the effect
they still express this shift in attitudes so by being exposed to these auto completions it wasn't
just changing what they wrote it was shifting their attitudes about the issues that they were
writing about. I mean I find these results quite troubling because we know that AI can be biased
and you look at a system like Grock and what that's come out with why would this be happening though
why is it making us sort of think differently? Well one question that came to my mind when I was
reading this paper was okay you're seeing a shift in people's expressed attitudes immediately
after they've done this task but I'm kind of interested in whether that effect would really hold
if you gave them the same questionnaire a week two weeks three weeks down the line is this just
the kind of effect where you might have a conversation with someone who has slightly
different views to you you hear the logic of what they're saying it might seem reasonable
for about five minutes until you go for walk and realise actually no it's not what I believe
but I think it's really interesting why this particular sort of mode is affecting people's
attitudes that it's affecting them when it's completing their sentences in another part of this
study they actually gave people instead of having the AI auto complete their sentences they were
given some similarly biased sentences that have been generated by the AI but just as text to have
while they wrote if you have that same biased information but not presented to you as sort of
completing your sentences the shift in your attitude was much less which suggests that there is
something particularly going on when the AI is trying to complete a sentence as you're writing it
and I don't know why that is and I don't think the scientist know why that is but you can imagine
if you're writing something you're thinking it through and these answers are pouring out on the
screen in front of you as you're typing it's probably quite easy for you to be fooled that this
is how you're thinking again maybe until you've had time to reflect and think about whether this
really gels with your core values. Gosh the implementation of all these systems is just really a
big experiment on us isn't it? I think it really is and Lord knows how many emails and documents
are written using these auto complete writing assistance but I'm sure there is another bunch of
people I think journalists are some of them where as soon as they see these suggestions they bristle
and will go out of their way to write anything else. And for those that aren't resistant Ian I've
got a business idea for you a Guardian AI auto complete bot so that we can really sell our pro hedgehog
pro fermented food pro wild swimming agenda. My thanks again to Ian and to Dr Sophie
Rasmussen you can find the article about her research on the Guardian.com and before you go I'd
like to recommend the latest episode of the Guardian Long Read where writer and academic Ariane
Chavezi describes her happy childhood holiday spent in Iran. She paints a portrait of everyday life
in the country behind today's headlines. Just search for audio long read wherever you're listening to this.
And that's it for today. This episode was produced by Ellie Sands. It was sound designed by Joel
Cox and the executive producer is Ellie Beary. We'll be back on Tuesday. See you then.
This is the Guardian
Science Weekly



