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How Did Human Language Evolve? Scientists Still Don’t Know

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Human language adaptations first appeared in our ancestors

Most scientists think language emerged in stages, as our ancestors evolved the necessary adaptations for speech. (Credit: Sergey Uryadnikov/shutterstock)

Humans have language and other animals don’t. That’s obvious, but how it happened is not. Since Darwin’s time, scientists have puzzled over the evolution of language. They can observe the present-day product: People today have the capacity for language, whether it be spoken, signed or written. And they can infer the starting state: The communication systems of other apes suggest abilities present in our shared ancestor.

But the million-dollar question is what happened in between. How did we transition from ape-like communication to full-fledged human language?

Most scientists think this happened in stages, as our ancestors evolved the adaptations needed for language. In earlier stages, human ancestors would have used a kind of protolanguage — more complex than ape communication, but lacking elements of modern language.

But what exactly was this protolanguage like? That’s where we hit considerable debate. Some researchers argue that our ancestors sang before they spoke. Others claim protolanguage was dominated by pantomimed gestures — a society built on charades.

Here, I’ll do my best to summarize prevailing models for language origins, drawing largely from a 2017 academic review by evolutionary biologist W. Tecumseh Fitch.

But first…

What Makes Language, Language

Before trying to explain how language evolved, we need to clarify exactly what evolved. We must define what language is and how it differs from the communication abilities of our closet evolutionary relatives, the great apes.

In human language, arbitrary sounds and signs represent specific words, which can be learned, invented and infinitely combined within grammatical structures. We can talk about anything we can think — plans, pancakes, politics — including what is not the case: “I have no plans to make pancakes or enter politics.” And many statements have specific meanings that are context dependent. For instance, “How are you?” can be a greeting, not a genuine inquiry. Language allows us to bond with others, or to deceive them. And although our native tongue is not innate, toddlers pick it up without conscious effort.

These qualities make language an extraordinary communication system found exclusively in humans. But the system can be dissected into components, or traits necessary for language. And these emerged at different times in our evolutionary past. Traits shared with other apes likely existed millions of years ago in our common ancestor. The traits we don’t see in other apes probably only emerged in hominins, the evolutionary branch that includes humans and our extinct relatives.

There are at least three elements of language only present in hominins:

First, is a fine-control over our vocal tracts. Other apes are likely born with a more limited repertoire of vocalizations. The difference comes down to how our brains are wired: Humans have direct connections between the neurons controlling our voice box and the motor cortex, the region of our brain responsible for voluntary movements. Brain scans show these connections are lacking in other primates.

Next is our tendency to communicate for the sake of communicating. To encapsulate this, biologist Fitch used the German word Mitteilungsbedürfnis, “the drive to share thoughts.” Whereas chimps use a finite set of calls and gestures to convey the essentials — food, sex and danger — humans talk to bond and exchange ideas, and strive to ensure we’re understood. Most researchers attribute this difference to an idea called “theory of mind,” the understanding that others have thoughts. Chimps demonstrate more limited theory of mind, whereas humans know that other humans think things — and we’re constantly using language to uncover and influence those thoughts.

The last difference is hierarchical syntax. Phrases and sentences have nested structure and these provide meaning beyond the simple sequence of words. For instance, take the sentence: “Chad, who was out to lunch with Tony, was late to the meeting.” Hierarchical syntax processing allows us to correctly interpret that Chad was late to the meeting, even though “Tony” is closer to the verb “was late.” Over 60 years ago and still today, linguist Noam Chomsky proposed hierarchical syntax as the key to language.

So hypotheses for language origins must explain (at least) these three traits: precise vocal learning and control, overtly social communication and hierarchical syntax.

Leading Views on Language Evolution

Now for the fun part: How did these components emerge, and eventually converge, to constitute language?

There are several prevailing views, which differ in terms of the evolutionary pressures favoring language adaptations, the order these adaptations arose and the nature of protolanguage along the way.

Some believe precise vocal control and learning was the first language trait to emerge in hominins — and not for speaking, but for singing. This idea of musical protolanguage comes from Darwin himself and has been modified over the years by different researchers. During this hypothetical singing stage of human evolution, our ancestors’ survival and/or reproductive success would have depended on serenading, in the context of maintaining social bonds, attracting mates or soothing infants. (Given my repulsion for acapella, I’d be evolutionarily unfit for this phase).

An alternate view envisions protolanguage characterized by gesture and pantomime. In this case, syntax and social communication would have preceded vocal prowess. The strength of the gestural hypothesis is that our closest relatives, chimpanzees, exhibit more controlled and variable gestures (over 70 and counting) than calls (4 types and more hard-to-distinguish subtypes). The weakness of this view is, it’s unclear why or how language became so speech-dominate.

Others, convinced that hierarchical syntax emerged last, propose a protolanguage with symbolic words, but no complex, nested sentences. According to this view, our pre-linguistic ancestors talked more like babies — “Water! Thirsty!” — or pop-culture’s image of cavemen — “Me hunt mammoth. Me want sex.”

These models aren’t mutually exclusive. Some researchers integrate them into successive stages, associated with different hominin species. Perhaps between 2 and 4 million years ago, Australopiths like Lucy were gifted singers. By 1.9 million years ago Homo erectus combined gestures and expressive vocalizations into group rituals. And hierarchical syntax only emerged some 200,000- 300,000 years ago with the appearance of our species, Homo sapiens.

This might all sound like speculation (and some scientists dismiss it as such, e.g. this commentary or Chomsky’s quote here). But many researchers beg to differ: Scientific models of language evolution derive from evidence gathered in comparative biology, neuroscience, genetics, linguistics and paleoanthropology. This includes data on how animals communicate, the brain and gene systems underlying language, the complexity of artifacts in the archaeological record and changes in anatomy and brain size, preserved in fossils. Most importantly, the models make predictions for future research — what should be found if that’s really how language origins went down.

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Ecology

Today’s letters: ‘Visionary’ plans don’t always work in Ottawa

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The opinion piece written by Tobi Nussbaum, CEO of the NCC, declares that a “bold, visionary transit plan” would showcase the capital.

As a long-term resident of Ottawa, I’ve had it with visionary plans. In the 1950s, the streetcars serving Ottawa so well were sent to the scrapyards. In the early ’60s, Queensway construction bulldozed established neighbourhoods and ripped the city apart. Later in the decade, the downtown railway station, which could have formed the hub of a commuter network, was relocated to the suburbs. These actions, in the name of “progress,” were undertaken with the “vision” to make Ottawa a car-reliant city.

Now we have an LRT, built just in time for most people to realize that they do not have to go downtown as they can work from home.

Current thinking is pushing a new “link” between Ottawa and Gatineau, with yet more expensive and disruptive infrastructure projects being touted, including a tramway or another tunnel under the downtown core.

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Ecology

That was then: Biggest earthquake since 1653 rocked Ottawa in 1925

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A regular weekly look-back at some offbeat or interesting stories that have appeared in the Ottawa Citizen over its 175-year history. Today: The big one hits.

The Ottawa Senators were playing a Saturday night game against the Montreal Canadiens at the Auditorium, the score tied 0-0 halfway through the second period. Sens’ rookie Ed Gorman and the Habs’ Billy Boucher had just served penalties for a dustup when the building began to make “ominous creaking sounds.” A window crashed to the ground.

Nearby, at Lisgar Collegiate, all eyes were on teenager Roxie Carrier, in the role of Donna Cyrilla in the musical comedy El Bandido. She had the stage to herself and was singing “Sometime” when the building rocked, the spotlight went out, and someone in the audience yelled “Fire!”

At a home on Carey Avenue, one woman’s normally relaxed cat suddenly arched its back, rushed around the room two or three times, spitting angrily, and climbed up the front-window curtains.

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Ecology

Ottawa delays small nuclear reactor plan as critics decry push for new reactors

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TORONTO — Canadians will have to wait a little while longer to see the federal government’s plan for the development of small nuclear reactors, seen by proponents as critical to the country’s fight against global warming.

Speaking at the opening of a two-day virtual international conference on Wednesday, the parliamentary secretary to the minister of natural resources said the plan will lay out key actions regarding the reactors. Its launch, Paul Lefebvre said, would come in the next few weeks.

“We’re still putting the finishing touches on it,” Lefebvre said. “The action plan is too important to be rushed.”

Small modular reactors — SMRs — are smaller in size and energy output than traditional nuclear power units, and more flexible in their deployment. While conventional reactors produce around 800 megawatts of power, SMRs can deliver up to 300 megawatts.

Proponents consider them ideal as both part of the regular electricity grid as well as for use in remote locations, including industrial sites and isolated northern communities. They could also play a role in the production of hydrogen and local heating.

“SMRs will allow us to take a bold step of meeting our goal of net-zero (emissions) by 2050 while creating good, middle class jobs and strengthening our competitive advantage,” said Lefebvre.

Natural Resources Minister Seamus O’Regan had been scheduled to speak at the conference but did not due to a family emergency.

Industry critics were quick to pounce on the government’s expected SMR announcement. They called on Ottawa to halt its plans to fund the experimental technology.

While nuclear power generation produces no greenhouse gas emissions, a major problem facing the industry is its growing mound of radioactive waste. This week, the government embarked on a round of consultations about what do with the dangerous material.

Dozens of groups, including the NDP, Bloc Quebecois, Green Party and some Indigenous organizations, oppose the plan for developing small modular reactors. They want the government to fight climate change by investing more in renewable energy and energy efficiency.

“We have options that are cheaper and safer and will be available quicker,” Richard Cannings, the NDP natural resources critic, said in a statement.

Lefebvre, however, said the global market for SMRs is expected to be worth between $150 billion and $300 billion a year by 2040. As one of the world’s largest producers of uranium, Canada has to be part of the wave both for economic and environmental reasons, he said.

“There’s a growing demand for smaller, simpler and affordable nuclear technology energy,” Lefebvre said.

Joe McBrearty, head of Canadian Nuclear Laboratories, told the conference the company had signed a host agreement this week with Ottawa-based Global First Power for a demonstration SMR at its Chalk River campus in eastern Ontario. A demonstration reactor will allow for the assessment of the technology’s overall viability, he said.

“When talking about deploying a new technology like an SMR, building a demonstration unit is vital to the success of that process,” McBrearty said. “Most importantly, it allows the public to see the reactor, to kick the tires so to speak, and to have confidence in the safety of its operation.”

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