Rebecca Woods, University of Toronto

In just the last several months, de-extinction — bringing back extinct species by recreating them or organisms that resemble them — has moved closer from science fiction to science fact. Colossal Biosciences — an American for-profit de-extinction startup headed by geneticists George Church and Beth Shapiro — announced two major achievements almost back-to-back.

In the first, scientists spliced part of the woolly mammoth’s genome into mice to create “woolly mice,” incredibly cute pom-pom like rodents sporting coats that express the genes of long-extinct woolly mammoths.

Just a few weeks later, Colossal announced an even bigger achievement, claiming to have brought back the dire wolf, a contemporary of the woolly mammoth who, like their Ice Age proboscidean co-travellers, last roamed the Earth roughly 10,000 years ago.

Mammoth popularity

Woolly mammoths are at the forefront of these controversial de-extinction efforts. Despite a deep bench of more recently extinct species — the dodo, the moa, passenger pigeons, the bucardo, quagga, thylacine, aurochs and a whole host of others — readily available to take centre stage in de-extinction efforts, woolly mammoths figure prominently in de-extinction stories, both scientific and popular.

Woolly mammoths featured prominently in the imagery of Revive & Restore, a “genetic rescue” conglomerate of scientists and futurists headed by tech-guru Steward Brand; in 2021, Colossal “established ownership” over woolly mammoth revival. Colossal’s own logo visualizes CRISP-R, the gene-splicing technology that facilitates de-extinction, and the signature spiralled tusks of Mammuthus primigenius.

In popular culture, woolly mammoths have been a source of fascination for the last several centuries. Thomas Jefferson famously held out hope that live mammoths would be found beyond the frontier of American colonialism in the late-1700s, while early excavations of American mastodons were major events in the early 1800s. American painter Charles Willson Peale captured the first such excavation in oils, and later capitalized on that mastadon’s skeleton in his Philadelphia museum.

More recently, Manny the mammoth featured in the ongoing Ice Age animated film franchise, first launched in 2002.

Climate icons

At the same time, woolly mammoths have also become an emblem of the contemporary climate crisis. During the recent wave of defacing famous artwork in order to draw attention to the climate crisis, environmental activists painted the (fortunately artificial) tusks of the Royal B.C. Museum’s woolly mammoth model bright pink.

In a 2023 publicity stunt, the Australian cultured-meat startup, Vow, unveiled a mammoth meatball produced out of the woolly mammoth’s genome with sheep DNA as filler. Not for sale, the mammoth meatball was scorched before an audience at the Dutch science museum, Nemo.

The stunt was intended to call attention, again, to the plight of the Earth’s climate, the unsustainability of industrialized food systems and the potential for lab-grown meat to square this particular circle.

Model animals

For a creature that no human being has ever seen live and in the flesh, woolly mammoths certainly get a lot of media exposure. How did this long-extinct species become the emblem of contemporary extinction and de-extinction?

People have been interacting with the remains of woolly mammoths for hundreds of years. Dig a hole deep enough almost anywhere in the northern hemisphere, and you are apt to come across the bones or maybe the tusks of extinct mammoths or mastodons.

In early modern Europe, mammoth fossils were famously interpreted as the bones of unicorns and giants before being recognized as belonging to elephant-like creatures around 1700. Only around 1800 were mammoths recognized as a distinct and extinct species of proboscidea.

Elsewhere in Arctic regions, especially Siberia, Indigenous Peoples were familiar with mammoth remains preserved by permafrost. As rivers and their tributaries surged during annual thaws, whole carcasses of mammoths (and woolly rhinos) were sometimes exposed.

Local peoples who came across these remains, apparently recently dead but belonging to creatures they never saw walking the Earth’s surface, surmised that they were great burrowing rodent-like animals that tunnelled through the ground and perished if they accidentally came into contact with atmosphere.

Around the Arctic, including in Alaska, permafrost prevented the fossilization of mammoth tusks as well as bodies, and this ice ivory was — and remains — an important element of Arctic economies, carved locally and exchanged into historically regional, and now global, markets.

Continued relevance

Despite their association with the distant past, woolly mammoths have long resonated with modern human cultures as their fossilized or preserved body parts entered economic practices and knowledge systems alike. But as the extinction of once numerous species like the passenger pigeon, the American bison and African elephant began to loom over the late 19th century, woolly mammoths took on new meanings in the context of modern extinction and emergent understandings of human evolution.

Revolutions in geology, archeology, paleontology and related disciplines were changing long-held assumptions about the origin of humankind.

Narratives of the rise of “man the hunter” arose in natural history institutions such as the American Museum of Natural History and the Field Museum in Chicago. These origin stories were explicitly connected to the presumed extinction of woolly mammoths and their evolutionary relatives, the mastodons.

These led to some of the most powerful expressions of mammoths in visual form, like the frescoes and paintings produced by renowned paleoartist Charles R. Knight.

At the same time, cave paintings in France, Spain and elsewhere came to light in the early 20th century. For example, the 40,000-year-old frescoes at Rouffignac, France clearly depicting woolly mammoths were interpreted as further evidence of this deep and powerful historical connection.

It is this connection — the association of the rise of modern humankind with the decline and extinction of the woolly mammoth — that feeds today’s continued fascination. Notions of human complicity in extinction stories have long been embedded in modern scientific understandings of woolly mammoths. It is no accident that woolly mammoths are so central to de-extinction projects and climate activism alike.

Rebecca Woods, Associate Professor, Institute for the History & Philosophy of Science & Technology, University of Toronto

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Marcus Pearce, Queen Mary University of London

Many of us have got into the habit of listening to podcasts, audiobooks and other online content at increased playback speeds. For younger people, it might even be the norm. One survey of students in California, for instance, showed that 89% changed the playback speed of online lectures, while there have been numerous articles in the media about how common speedy viewing has become.

It is easy to think of some advantages to watching things more quickly. It can let you consume more content in the same amount of time, or go through the same piece of content a couple of times to get the most out of it.

This could be particularly useful in an educational context, where it might free up time for consolidating knowledge, doing practice tests and so forth. Watching quickly is also potentially a good way of making sure you sustain your attention and engagement for the entire duration to avoid the mind wandering.

But what about the disadvantages? It turns out that there are one or two of those as well.

When a person is exposed to spoken information, researchers distinguish three phases of memory: encoding the information, storing it and subsequently retrieving it. At the encoding phase, it takes the brain some time to process and comprehend the incoming speech-stream. Words must be extracted and their contextual meaning retrieved from the memory in real-time.

People generally speak at a rate of about 150 words per minute, though doubling the rate to 300 or even tripling it to 450 words per minute is still within the range of what we can find intelligible. The question is more about the quality and longevity of the memories that we form.

Incoming information is stored temporarily in a memory system called working memory. This allows chunks of information to be transformed, combined and manipulated into a form that is ready for transfer to the long-term memory. Because our working memory has a limited capacity, if too much information arrives too quickly it can be exceeded. This leads to cognitive overload and loss of information.

Speedy viewing and information recall

A recent meta analysis in this area examined 24 studies of learning from lecture videos. The studies varied in their design but generally involved playing a video lecture to one group at original speed (1x) and playing the same video lecture to another group at a faster speed (1.25x, 1.5x, 2x and 2.5x).

Just like in a randomised controlled trial used to test medical treatments, participants were randomly assigned to each of the two groups. Both groups then completed an identical test after watching the video to assess their knowledge of the material. The tests either required them to recall information, used multiple choice questions to assess their recall, or both.

The meta-analysis showed that increasing playback speed had increasingly negative effects on test performance. At speeds of up to 1.5x, the cost was very small. But at 2x and above, the negative effect was moderate to large.

To put this in context, if the average score for a cohort of students was 75% with a typical variation of 20 percentage points in either direction, then increasing the playback speed to 1.5x would bring down the average person’s result by 2 percentage points. And increasing the playback speed to 2.5x would lead to an average loss of 17 percentage points.

Older people

Interestingly, one of the studies included in the meta-analysis also investigated older adults (aged 61-94) and found that they were more affected by watching content at faster speeds than younger adults (aged 18-36). This may reflect a weakening of memory capacity in otherwise healthy people, suggesting that older adults should watch at normal speed or even slower playback speeds to compensate.

However, we don’t yet know whether you can reduce the negative effects of fast playback by doing it regularly. So it could be that younger adults simply have more experience of fast playback and are therefore better able to cope with the increased cognitive load. Similarly, it means we don’t know whether younger people can mitigate the negative effects on their ability to retain information by using faster playback more often.

Another unknown is whether there are any long-term effects on mental function and brain activity from watching videos at increased playback speeds. In theory, such effects could be positive, such as a better ability to handle increased cognitive load. Or they could be negative, such as greater mental fatigue resulting from increased cognitive load, but we currently lack the scientific evidence to answer this question.

A final observation is that even if playing back content at, say, 1.5 times the normal speed doesn’t affect memory performance, there is evidence to suggest the experience is less enjoyable. That may affect people’s motivation and experience at learning things, which might make them find more excuses not to do it. On the other hand, faster playback has become popular, so maybe once people get used to it, it’s fine – hopefully we’ll understand these processes better in the years to come.

Marcus Pearce, Reader in Cognitive Science, Queen Mary University of London

This article is republished from The Conversation under a Creative Commons license. Read the original article.