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A record shark migration, metalhead woodpeckers and how the brain understands 'not'


It's time now for our regular science news roundup with our friends at NPR's Short Wave podcast, Emily Kwong and Regina Barber. Hey to both of you.



CHANG: OK, so how this works is you bring us three science stories that catch your attention week by week. What are they this week?

KWONG: OK. For you, we have a new study on how not to be misunderstood.

BARBER: A shark named Genie that makes a record migration.

KWONG: And some rocking metalhead woodpeckers.

CHANG: Metalhead woodpeckers. OK. Let's first start with this study about how not to be misunderstood, which is, I feel like, the story of my life. But how not to be misunderstood - not to be the grammar police, but...


CHANG: This is a double negative.

KWONG: Yeah. And I bet you feel totally lost by that, you know?

CHANG: I do not feel terribly found, but...

KWONG: (Laughter).

CHANG: Yeah.

KWONG: OK, even that sentence...

CHANG: (Laughter).

KWONG: ...Right there - you, Ailsa Chang, just used negation.

CHANG: Negation.

KWONG: It's this thing we do in linguistics all the time - right? - where we cancel out a word or part of a sentence to change its meaning.


KWONG: And neuroscientist Arianna Zuanazzi wanted to figure out how our brains process negation and published a study in the journal PLOS Biology all about it.

CHANG: Well, as someone who is in the business of communication, this is super fascinating already. How did Arianna study this?

KWONG: Yeah. When she was a postdoctoral fellow at NYU, she set up a study where participants sat in front of a computer monitor and read phrases with the words not and really next to adjectives like good, bad, hot, cold.

BARBER: Like the phrase, this coffee is not hot. Arianna would measure how participants interpreted that phrase through a computer task and neuroimaging to measure, like, electrical brain activity.

CHANG: Oh, cool. What did they find?

BARBER: So when a phrase with negation came up, participants took several milliseconds longer to interpret it, and their interpretation had this specific pattern to it.

KWONG: So, yeah, the not in, this coffee is not hot, merely reduced the temperature of the coffee in the minds of the participants. They didn't generally think the coffee is cold. So negation appears to mitigate meaning rather than invert meaning.

CHANG: That is interesting. But, I mean, I feel like linguists have known about this for a long time. Like, I can think of a bunch of people at NPR who would readily point out to you, oh, you just used a double negative.

KWONG: Yeah, for sure, for sure. But, you know, Arianna says this is one of the few negation studies using, like, neuroimaging of this type to maybe provide evidence for it. And that's important research because negation can be used to deliberately deceive people. Think about legal findings or advertising.

ARIANNA ZUANAZZI: For instance, if you say, oh, this product is not harmful to the environment, what does that mean? Is it safe, or is it not safe? So using negation sometimes...


ZUANAZZI: ...Introduces this level of confusion.

CHANG: Confusion, obfuscation.

BARBER: Yeah. Arianna wants this message to reach everyone who cares about language, from AI developers to writers to public speakers.

KWONG: We could all stand to communicate more clearly and maybe try not to use not as much.

CHANG: (Laughter) Deal. OK. Gina...


CHANG: Next up, you have a story about a shark named Genie.

BARBER: Yeah. Yes.

KWONG: (Laughter).

BARBER: Not Gina but Genie.

CHANG: (Laughter).

BARBER: So Genie is this 6-foot-long silky shark. And silky sharks are named after their smooth, silky skin.


BARBER: Yeah. And Genie was tagged in the Galapagos Marine Reserve and then traveled halfway to Hawaii twice and circled all over the place in the area in between.

KWONG: Ailsa, this journey by our girl Genie was epic. It turned out to be the longest silky shark migration on record. Genie traveled over 17,000 miles in a year and a half, an average of 31 miles per day. Researchers published the results in The Journal Of Fish Biology.

CHANG: Wait. Wait. Wait. Wait. Before we move on, why is this shark named Genie? Like, can you make a wish with it?

BARBER: I actually wish you could make a wish, but no.

CHANG: (Laughter).

BARBER: But it's a sweet story. The researchers behind the study, including the lead author, Pelayo Salinas de Leon - he named the shark after the late marine biologist Eugenie Clark. And here's Pelayo.

PELAYO SALINAS DE LEON: She was called the shark lady. And we wanted to acknowledge her career and, you know, all the great things she did for the field of shark ecology.

BARBER: So Eugenie spent her whole life studying sharks and trying to improve their public reputation.

CHANG: Oh, OK - rehabilitate the public image of sharks.




CHANG: So you mentioned that this is the longest silky shark migration on record, which is a really specific record.


CHANG: But were scientists surprised that the shark traveled so far?

BARBER: Yeah. It actually kind of was a surprise. So Genie was tagged in a marine reserve with, like, lots of food. So why leave? And other sharks that fed there, like tiger sharks - they don't travel that far.

KWONG: Yeah. Researchers have three hypotheses as to what Genie might have been up to. It could have been to find better food or to mate or to give birth. We still don't know a lot about how silkies reproduce. But this tracking system could help researchers one day answer that question.

CHANG: OK, cool. But beyond that, like, why is it important to know where they are going?

BARBER: So yeah. To protect them, we need to know where they are. Because of a poor public image, the shark fin trade and habitat loss, these sharks are considered a vulnerable species, and they're declining in number.

DE LEON: We cannot, as a society, allow for them to be systematically killed and overfished.

KWONG: And if silkies are swimming really far and spending most of their time in international waters, nations will have to work with each other to manage these waters and better protect Genie and other sharks.

CHANG: OK, well, from silky sharks to metalhead woodpeckers now. What are we talking here - like, headbanging birds? Yeah?


KWONG: Ailsa, before we proceed, I just want you to listen to a little clip.


CHANG: (Laughter) Oh, my God. What is that? Is that a bird or a...


CHANG: ...Construction site (laughter)?

BARBER: Yeah. So, Ailsa...

KWONG: That's a bird.

BARBER: This is the sound of a woodpecker drumming away recently on our NPR colleague Sacha Pfeiffer's metal chimney cap.

CHANG: Oh, my God, Sacha. I'm so sorry. That's terrible (laughter).

BARBER: It's so frustrating. I've heard it so many times outside of my house in the Pacific Northwest when I lived there. It sounded like a jackhammer outside my house.

CHANG: Yeah.

KWONG: And Sacha wanted to know, like, why are these woodpeckers pecking on metal and not wood?

CHANG: Oh, good point - seems kind of counterproductive.

KWONG: Yeah. So she spoke to an ornithologist at the Cornell Lab of Ornithology, Kevin McGowan. He said woodpeckers want to make the biggest noise they possibly can when making a home, marking territory or when finding a mate.


KWONG: And springtime is mating season for woodpeckers.

KEVIN MCGOWAN: Basically summarized as, all other guys, stay away. All the girls, come to me. And the bigger the noise, the better.

CHANG: Wait. But does banging your head on something really, really hard a bunch of times - I mean, doesn't that hurt them?

BARBER: Yeah. So Kevin said woodpeckers are really just trying to drum enough sound to make a big noise, not enough for it to hurt. They adjust their force, and they'll change how hard they're drumming based on the material.


BARBER: And in fact, he told Sacha that, over time, some urban woodpeckers learned that metal, like chimney caps on Sacha's roof, make a much louder, more reverberant sound than wood. And woodpeckers in the cities have access to tons of metal. Like, think about vent pipes, gutters, traffic signs...


BARBER: ...Metal ladders...


KWONG: It is all prime real estate for woodpeckers looking to claim some territory or couple up.

CHANG: I mean, but it sounds really annoying, so can people do anything who live near these metal surfaces to stop these woodpeckers?

BARBER: So woodpeckers are covered by the Migratory Bird Treaty Act, so capturing them requires federal permission. But people can scare them off with, like, noise deterrence, like recordings of screeching hawks, or physical deterrence, like balloons or pinwheels.

CHANG: That's incredible. OK, I guess I'll keep my screeching hawk recordings handy if I hear any woodpeckers.

BARBER: I'll loan you some.

CHANG: OK. Oh, thank you. That is Regina Barber and Emily Kwong from NPR's science podcast, Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Thanks to both of you.

BARBER: Thank you.

KWONG: Thanks, Ailsa.

(SOUNDBITE OF LOLA YOUNG SONG, "CONCEITED" ) Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Regina Barber
[Copyright 2024 WSKG]
Emily Kwong (she/her) is the reporter for NPR's daily science podcast, Short Wave. The podcast explores new discoveries, everyday mysteries and the science behind the headlines — all in about 10 minutes, Monday through Friday.
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