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Dogs seem to agree with humans that 'bouba' is round and 'kiki' is spiky

2026-10-18T01:38:08+00:00

Picture a shape called 'Bouba'. What features does it have? Is it angular, rounded, soft, hard? What about a shape called 'Kiki'?

There's no correct answer to this – the words are made up. But for some strange reason, most people who are asked this question – regardless of the language or alphabet they use to speak or write – agree that Kiki is spiky, and Bouba is round.

This fascinating psychological experiment was first conceived in the 1920s, and it suggests there may be something universal about the way we humans connect visual information, like shapes, with sounds.

Now, a new study published in Proceedings of the Royal Society B: Biological Sciences suggests even our canine companions might follow this trend.

The shapes used in the 'bouba/kiki' experiments. (Andrew Dunn/Wikimedia Commons/CC BY-SA 3.0)

Animal behaviorist Eleonora Biffi at the University of Parma in Italy led the research.

She and her team recruited 70 domestic dogs to participate in two almost identical experiments.

The first experiment involved 51 dogs and their owners. Each dog/owner pair entered a room set up with a screen and a speaker to the left, and another screen and speaker to the right.

After giving the dog an opportunity to explore the room and get settled in, the owner sat with them, facing the middle of the setup while the screens and speakers played.

Over roughly 15 minutes, the screens and speakers alternated through different combinations of a human saying either 'Bouba' or 'Kiki' over the speakers, and the two shapes above swapping between the left and right screens.

Meanwhile, a GoPro recorded each dog during the trials. The researchers later fed these videos into an AI designed to track where the dogs' heads were pointing, a stand-in for where they were looking, so they could check for any statistically significant patterns that might occur above random chance.

The second experiment, which involved 19 other dogs, was identical in design except that the owners wore headphones playing rock music to stop them from hearing the 'Bouba' and 'Kiki' sounds. The idea here was to remove any owner cues the dogs might have been following.

Setup of the experiment with the two screens, and steps of the computational analyses with dog's head detection and angular vision detection. (Biffi et al., Proc. R. Soc. B, 2026)

Overall, "dogs looked significantly more at the rounded shape while 'Bouba' was played, and they looked at and explored the spiky shape when 'Kiki' was played," Biffi and team report.

The main difference between the two experiments was that dogs in study 1 showed a general bias toward looking at the spiky shapes. That bias disappeared in study 2, when their owners were wearing headphones.

"It could be hypothesized that the dogs were influenced by the owners' unintentional cues. However, since humans typically show a stronger preference for rounded or curved shapes rather than spiky ones, this is unlikely," the authors write.

"Another possible explanation could be that, in the case of dogs, animals' facial configuration, especially when considering ancient dogs and wolves, is characterized by more angular, 'spiky' features, which contrasts with the round facial morphology typical of human infants and could plausibly contribute to an opposite bias."

There's still a lot more research to be done before scientists can definitively say dogs associate 'Bouba' with round shapes and 'Kiki' with sharp ones.

But these results are an interesting starting point for exploring bigger questions, like why dogs are quick to pick up on human language, and how they came to be our close companions in the first place.

The research has been published in Proceedings of the Royal Society B: Biological Sciences.

This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.

New 'super ice' 10 times stronger, bringing it close to the strength of concrete

2026-10-13T21:42:38+00:00

During the Second World War, the British Royal Navy experimented with the idea of using ice reinforced with wood pulp to build an aircraft carrier.

The composite material, known as Pykrete, was apparently as strong as concrete, as long as it could be kept frozen.

The ship would've effectively been a floating, custom-made, strengthened iceberg for planes to take off from and land on – but with rising costs and better options becoming available, the project was eventually abandoned.

Now researchers led by a team from the Hebrew University of Jerusalem in Israel have extended that idea from the 1940s to create what they're calling BioPykrete.

By adding plant-based crystals and a bespoke protein to ice, they've created something that's 10 times stronger than regular ice and able to absorb 70 times more energy before breaking.

A study of the new material has been published in Colloids and Surfaces B: Biointerfaces, and the team behind it hopes that it may one day be used as a building material.

A sample of the new ice. (Chen Adar)

"We wanted to go beyond simply mixing fibers into ice and instead control how the different materials connect at the molecular level," says biochemist Ido Braslavsky, from the Hebrew University of Jerusalem.

"The result changes not only how strong the ice is, but also how it breaks. Instead of suddenly shattering, it can absorb much more energy and deform gradually."

The intended application isn't for aircraft carriers this time, but rather for construction projects in remote, cold areas where conventional building methods aren't easy to apply – like the Arctic and Antarctic.

With no concrete or steel required, and with ice and plant-based cellulose as the main ingredients, this could be a building material with a low carbon footprint that's also biodegradable.

"While the construction industry is a cornerstone of the global economy, it remains one of the most significant environmental polluters, responsible for substantial carbon emissions and massive resource depletion," write the researchers in their published paper.

"Biotechnology offers a transformative pathway to mitigate this impact by developing novel, sustainable biomaterials."

It's going to be a while before BioPykrete can be used as a construction material, however. This study was a small-scale proof-of-concept test, and further research will be needed to look at how BioPykrete stands up over long periods and under changing conditions.

Instead of wood pulp's larger, disordered fibers, the researchers used cellulose nanocrystals here.

Cellulose is the main structural material in plants, and in nanocrystal form, it can act as a microscopic strengthening agent for other materials, including ice – essentially stopping cracks from spreading easily.

The protein used here was called CBM3a-AFPIII, a combination of an antifreeze protein (AFP) and a carbohydrate-binding module (CBM). Its job was to act like glue, keeping the cellulose nanocrystals and ice bonded together.

Scanning electron microscope images of freeze-dried samples reveal the network formed by tiny cellulose crystals. The top row shows the material magnified 40 times, and the bottom row 90 times. (Yulia Baron and Dr. Liat Bahari)

It's a clever approach, and the researchers think that by tweaking their ingredients and methods, they might be able to improve their 'super ice' even further.

"Optimizing solidification kinetics and freezing protocols, alongside developing diverse AFP-CBM variants, could yield even higher-strength composites," write the researchers.

Besides further tests of the durability of the material, the researchers are also keen to take a closer look at how cracks propagate through BioPykrete, to confirm that the underlying strengthening mechanisms are what they think they are.

Further down the line, this approach could open up a whole new landscape for materials used in packaging, construction, and more: Using a custom protein to bring two unlikely compounds (ice and cellulose) together.

"By bridging the gap between recombinant protein design and structural engineering, we have developed a high-performance material specifically engineered for the rigors of the world's most extreme environments," write the researchers.

The research has been published in Colloids and Surfaces B: Biointerfaces.

This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.