22 April 2026

Today’s The Life Academic delves into how AI is shaping language in research papers. But first, catch up on the latest science news, including when crabs began walking weirdly and an ancient assembly line.

Evolution | eLife

Biology gone sideways

This brown land crab and its sideways relatives likely got their odd gait from a common ancestor about 200 million years ago. Tsubasa Inoue

Crabwalk competitions are a perfect activity for school field days or family reunions. But when, exactly, did crabs’ iconic sideways scuttle evolve?

To find out, researchers assessed 50 of the nearly 8000 species of true crabs. They began by recording 10 minutes of movement for each crab in a natural-seeming enclosure, classifying 35 as sideways movers and 15 as forward movers. Then, the team placed their crabs within a recently published phylogeny of hundreds of crab species. In a reviewed preprint, they report that the switch from forward to sideways walking occurred only once, about 200 million years ago, then got conserved across true crabs. The team thinks that sideways walking may have provided an advantage when escaping predators by moving unpredictably.

“This single event contrasts starkly with carcinization, which has occurred repeatedly across decapod species,” said author Yuuki Kawabata, referencing the often-joked-about phenomenon where different kinds of animals have evolved crablike body types. The team “makes a convincing case that sideways locomotion is not simply a trivial byproduct of a crablike body plan ,” wrote one of the reviewers. As Kawabata explained: “This highlights that while body shapes may converge multiple times, behavioral changes such as sideways walking can be rare.”

reviewed preprint

Archaeology | News from Science

An ancient assembly line comes to light

When it comes to ancient stone toolmaking, not all strategies were the same. Scientists believe that for millions of years our distant ancestors mostly grabbed rocks on the go while hunting and gathering, or migrating from place to place; they fashioned them into whatever was needed there on the spot. A different, arguably more advanced technique known as direct procurement—which involves humans seeking and repeatedly visiting choice rock outcrops for the specific purpose of obtaining materials—wasn’t thought to have arisen until much later, perhaps around 166,000 years ago.

A study out this month in Nature Communications suggests that timeline may need to be rewritten. Archaeologists excavating a site called Jojosi in South Africa’s eastern grasslands found rock fragments reflecting both the beginning and end products of the toolmaking process, in which makers chipped away small flakes to slowly shape and sculpt a smaller core. The abundance of these castoffs suggests the area was primarily a manufacturing site for “blanks,” of partially knapped stones that could later be refined into a multitude of different tools.

When the researchers dated the sediment layers in which these blanks were found, they discovered people visited the site frequently from about 220,000 years ago to 110,000 years ago, making it the earliest evidence of direct procurement yet uncovered. “The Jojosi research shows that humans were deliberate about their sourcing behaviors,” said archaeologist Matt Lotter. “This implies clear planning and intentionality.”

Read the full story

SPONSORED

Designing targeted therapies for cancer's next move

Targeted therapies are reshaping cancer care, but tumors evolve to resist them. In this Q&A, Jeff Settleman of Pfizer Oncology discusses strategies to anticipate resistance, target multiple pathways, and design more precise treatments.

The Life Academic

graph showing increase in use of the word underscore after 2022

This graph shows the percentage of PMC full-text publications mentioning underscore[s/d/ing] at least once (2021–2025) by main document type with 95% confidence intervals; ChatGPT was publicly released in November 2022. Kousha & Thelwall/Scientometrics (2026)

Large language models have a way with words

Unveiling the use of generative artificial intelligence in academic publications is sometimes a little bit too easy. A given paper might include smoking-gun phrases like “my knowledge cutoff,” fabricated citations, or, in one infamous case, horrifying illustrations of rats with giant penises.

Because authors who use generative AI have found increasingly innovative ways to cover their tracks, sleuths also keep an eye out for more subtle giveaways, such as telltale words that occur rarely in scientific writing but appear frequently in text generated by large language models. Researchers using this technique recently determined that a fifth of computer science papers may include AI-modified content, underscoring just how pervasive this practice has become.

A pivotal study published last month in Scientometrics delved into the impacts these tools are having on the language of academic papers. The authors meticulously tracked a dozen words associated with LLMs across six major scholarly databases from 2015 to 2024. To explore changes in the frequency of these words before and after the release of ChatGPT, the team also analyzed full texts from more than 2.5 million open-access PubMed Central publications.

The team’s commendable effort revealed that, between 2022 and 2024, the words “delve,” “underscore,” and “intricate,” drastically increased in frequency across all databases. Some words were more likely to show up in paper titles or abstracts, while others were used more broadly across sections. The increase in LLM-associated term usage was more enhanced in STEM fields than in the realms of social sciences, arts, and humanities. The researchers also looked at the interplay between different terms, finding that the use of one LLM-associated word often fostered the use of others: A publication that includes the word “underscore,” for example, is more likely to also use “pivotal” and “delve.”

Overall, the results showcase how AI influences the language of academic writing styles and bolsters the idea that LLM-associated words are now being used much more frequently in academic writing. In response, some institutions are making an effort to crack down on the use of generative AI in academic papers. Certain journals have developed intricate policies outlining acceptable uses of this technology, for example, while the preprint server arXiv has heightened its scrutiny of manuscripts from first-time posters.

But, as the authors of the crucial new study argue, the issue may be more nuanced than it appears. The increasing prevalence of LLM-associated language in full texts “may be a welcome development overall,” they write, since it suggests that these tools “are reducing the language barrier to academic publishing for non-English speakers and hence partly addressing the current unacceptable level of global inequality in science publishing.”

This story was intentionally written by a human to contain 18 words that frequently appear in LLM-generated texts. Can you spot them all?

Read the paper

Et Cetera

Home safe home

Simple design choices can make homes safer for kids in Africa. In a randomized controlled trial, children that lived in specially built homes suffered less often from malaria, diarrhea, and respiratory infections than those living in traditional mud-and-thatch houses in the same villages. “This exciting finding shows the potential of novel house designs to improve children’s health and survival on a wide scale,” one expert said.

Nature Medicine Paper | Read more at News from Science

A battery of lies

The Finnish startup Donut Lab’s claim that they have developed a remarkable solid-state battery appears to be full of holes. “The information that I have says that the battery is not in the state that Marko Lehtimäki announced in January,” said the chief commercial officer of Nordic Nano, an R&D company collaborating with Donut that has filed a criminal complaint.

Read more at ScienceInsider

Martian organics

3.5-million-year-old Martian sandstones contain more than 20 organic molecules, according to analyses conducted by the Curiosity rover. “The story our findings tell is that there is complex organic carbon preserved in the very near subsurface of Mars, where we thought radiation would have destroyed all of that,” said one of the research team members. “The organics that rained down on Mars might have been present very early on in Mars’s history, even at the time when life was originating on Earth.”

Nature Communications Paper | Read more at Chemistry World

I no longer trust myself to continue this work without accommodating changes that I believe are fundamentally at odds with its purpose.
—Mike Reid

News from Science | 21 April 2026 | John Travis

Reid resigned from his post this week as Chief Science Officer for the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR) in protest of the Trump administration’s global health policies.

Last but not least

Happy Earth Day! Today, I’m appreciating the wonder all around us all the time, if we make the effort to look a little closer. I mean, have you ever watched a spider’s heart beat?

Christie Wilcox, Editor, ScienceAdviser

With contributions from Michael Price, Hannah Richter, and Phie Jacobs

Do you have a burning science question you can’t seem to find a good answer for? Submit it to Ask Science! Selected questions will receive responses from Science editors right here in ScienceAdviser.

Have feedback on this newsletter? Let us know what you think using this form or drop us a note at ScienceAdviser@aaas.org.

Want more? Catch up on past issues of ScienceAdviser.

If you were forwarded this newsletter by a friend, you can subscribe for free here.

To ensure ScienceAdviser lands in your inbox, consider taking a moment to add scienceadviser@aaas.sciencepubs.org as a trusted sender or contact in your email client. These instructions provide more information on whitelisting ScienceAdviser based on email client.