The evolution of the human brain

Why human brains were bigger 3,000 years ago

Our modern civilisation may be the most advanced to ever exist on Earth, but around 100 generations ago, our ancestors had brains that were larger than our own.

The role of fire in the evolution of humanity's big brains

Roughly 1.5 million years ago, the brain size of our hominin ancestors exploded. To understand why, Richard Wrangham posited the cooking hypothesis, arguing the adoption of fire as a means to cook food had a lasting impact on our ability to digest...

Why humans survived and smarter species did not

This interview with Joseph Henrich, a renowned professor of human evolutionary biology, unpacks human history. Henrich shares interesting information about why humans succeeded as a species (the answer isn't IQ), how cultural evolution works, why the human brain is shrinking, and how the Catholic Church played a role in the Industrial Revolution. Listen and watch for a deep dive into human evolution.

An interesting perspective on whether (and how) brain size matters in cognitive ability

Some brains are bigger than others, but what is the relevance, if any, to brain size and intelligence? This Scientific American article explores the question and offers examples. It also visually compares frontal slices of several mammals' brains, showing that humans don't necessarily have the biggest cerebrums on the block.

How humans evolved from single-cell organisms

Humans have had a long history. 3.8 billion years in the making, to be precise. From the primordial puddle to the modern day, here's how humans have evolved from the first life.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

Human origins 101

Learn about the over 20 early human species that belong in our family tree and how the natural selection of certain physical and behavioral traits defined what it means to be human.

Three examples of how humans are still evolving

For much of nature, natural selection and "survival of the fittest" still play a dominant role; only the strongest can survive in the wild. As little as a few hundred years ago, the same was true for humans, but what about now?

Like fingerprints, brain anatomy is unique too

Researchers have discovered that a combination of experiences and genetic factors shape the anatomy of the human brain. They found even quick experiences affect the brain’s genetic makeup, which—over time—means every person develops a completely unique brain anatomy. While brain imaging could be used to identify individuals, it remains much more expensive than fingerprinting for now. Read to found out more about this study from the University of Zurich.

Is human evolution speeding up or slowing down?

In the past 3,000 years, many populations have evolved genetic adaptations to their local environments. People in Siberia and the high arctic are uniquely adapted to survive extreme cold. The Bajau people can dive 70 meters and stay underwater for almost 15 minutes. So what are other recent changes? And will our technological innovations impact our evolution?

Why do humans have such long childhoods?

Humans have over twice as long childhoods than other animals with similar lifespans like whales and elephants. A human child can grow for nearly 20 years before they become a reproducing adult. Researchers believe there's a connection between long childhoods and human's unusually large brain size, though the science is not totally clear. Dive into what scientists know here.

Where are humans on the evolutionary tree?

This interactive tree-shaped map explores the evolutionary connections between more than two million species. According to this map, humans are on the same branch as great apes, tarsiers, and treeshrews. That branch then splits into even smaller branches, with humans appearing on the same twig-like branch as chimpanzees and bonobos.

Your brain appears to age in five distinct stages, with the pattern of connections inside your brain shifting, on average, around ages 9, 32, 66, and 83.

A beginner's guide to the brain

Small but powerful, the brain constitutes only about 2 percent of the human body. However, it runs jus about everything, day and night, all year round. Learn about the different parts of the human brain, as well as its unique defenses, like the blood brain barrier in this four-minute video.

Language is evolution's great mystery

What we call language is something more specific than communication. Language is about sharing what's in our minds: stories, opinions, questions, the past or future, imagined times or places, ideas. So what does language mean for humanity, and how did we come to have it? Watch this brief video to discover more.

Human anatomy provides evidence for evolution

Throughout history, scientists have used anatomy to support the Theory of Evolution in three main ways. Homologous structures, or similar physical features in organisms that serve different functions, can help scientists understand common ancestors....

Explore the human family tree

This interactive human family tree shows the various species that constitute the human evolutionary family. Click on each species or group image to learn more.

The messy story of humanity's genealogical past

For decades, scientists viewed the human fossil record and concluded Neanderthals, an early hominin, came before homo sapiens, or modern humans. The story became more complicated as technology advanced and ancient DNA samples were analyzed. This video breaks down the evidence, concluding the development of humanity was a lot messier than previously believed.

How do brain scans work?

There's only one thing in our solar system sophisticated enough to study itself: the human brain. But this self-investigation is challenging because a living brain is shielded by skull, swaddled in tissue, and made up of billions of tiny cells. How do we study living brains without harming their owners? Two experts explain how the various techniques like EEGs, fMRIs, and PETs work in this TedEd talk.

Why humans evolved single-child pregnancies

While birthing twins has been a rare occurrence for humans, research suggests that twins were actually the norm much further back in primate evolution. It’s proposed that single-childbearing turned out to be critical for the evolution of larger babies with larger heads. Discover more about the shift that gives insight into primate evolution.

Were humans the only hominin to walk upright?

When you imagine the line human evolution has taken, you might picture the March of Progress, an image of several chimp-like ancestors marching toward the implied final form: the upright bipedal Homo sapiens. Turns out this image, popularized in the...

The archaeological discovery that shifted scientists' understanding of human evolution

In 2003, archaeologists in Indonesia uncovered the remains of a 3-foot-tall skeleton that appeared to belong to a new type of human. Read this article to learn how the discovery of this 50,000-year-old skeleton upended the idea that human evolution...

Explore an interactive 3D model of the brain

The brain contains about 86 billion neurons—nervous system cells—and controls vital bodily functions via electrochemical signals. Neurons form circuits through axons, and different brain regions use these circuits to perform specific tasks.

The Paranthropus genus, our mysterious extinct cousins

In the last century, skull and jaw fragments have been discovered in East Africa suggesting an ancient hominin species lived, evolved, and died alongside humanity's ancestors. With large, broad skulls and strong jaws, the Paranthropus genus—which includes several related species—is an absorbing case of the effects of niche partitioning, where species coexist by adapting differently to the environment. Paranthropus died out and human ancestors endured. Find out why here.

A brief history of artificial intelligence

The concept of artificial intelligence and what it may mean for humanity has evolved as computer technologies have grown increasingly powerful through the decades. Beginning with the first (massive) computers in the 1940s, scientists have sought to make the machines as intelligent as humans. But it wasn't until computing power made exponential gains have computers begun to imitate human behavior.

Even in recent history, adaptations to the environment drove human evolution

Through genetics, environmental pressures, and cultural influences, humans have evolved to tolerate lactose, develop varying skin pigmentation, and acquire genetic resistance to diseases like bubonic plague. The metabolic and digestive systems of Indigenous peoples have adapted to their diet, which is influenced by the availability of food and water.

The debate on why humans are conscious—and what that means

Understanding what consciousness is, and why and how it evolved, is perhaps the greatest mystery known to science. Watch interviews with the world's leading experts on what it is and whether we'll ever know.

Neanderthals 101

Who were the neanderthals? Do humans really share some of their DNA? Learn facts about Neanderthal man, the traits and tools of Homo neanderthalensis, and how the species fits into our evolution story.

Interactive human migration map

Using archeological, genetic, and climate data, scientists have pieced together an outline of the human odyssey—the journey that took our species from Africa to all corners of the globe. Experience this 200,000-year migration using an interactive human migration map.

A timeline of human fossil discoveries

A key part of writing a coherent story about our origins is finding and identifying the remains of our ancestors and understanding their significance. Scientists will not always agree on identifications and opinions will change as new find are made and new ways of studying them are developed.

Studies estimating the number of years between human generations suggest there have been approximately 10,000 to 12,000 generations of humans.

Two scientists argue consciousness evolved through 'unlimited associative learning,' the ability to learn almost any new pattern during a lifetime.

Here's how early humans lived

Explore the evidence of early human behavior—from ancient footprints to stone tools and the earliest symbols and art – along with similarities and differences in the behavior of other primate species.

The history of the gene: an interactive timeline

Humans didn’t need modern technology to figure out that kids tend to look like their parents. But what did humans believe about genetics before we knew about DNA or cells in general? Explore this interactive timeline to see how philosophers and scientists throughout the ages tried to explain how traits are passed from generation to generation.

Paul Broca, a French brain researcher in the 19th century, hypothesized that humans evolved to trade in our "bestial sense" of smell for higher brain capacity.

Human ancestors: a guide

Modern humans are not the only creatures classified as part of the Homo genus. This article examines the eight other humans that fall under the Homo umbrella.

The human brain only uses 5% more energy during active tasks versus resting

Despite only being 2% of the weight of a human body, the average adult brain consumes 20% of its energy, with the majority of it spent on maintaining homeostasis—the stable equilibrium conditions of temperature, acidity, blood sugar, and other properties in the body. For infants, the consumption is closer to 50%.

A historical tree of technological advancement

Starting from stone tools millions of years ago and culminating in today's cutting-edge tech, this thorough genealogy lays out how humanity has progressed in its use of tools over thousands of years. See descriptions, links to further info, and how each tech fits in the larger tree.

Explore the independent lines of evidence behind the theory of evolution

Gradual changes in organisms have been directly observed through artificial selection—humans purposely selecting organisms to breed to pass on specific traits—and in organisms with short lifespans, such as insects and microbes. Analyses of DNA and anatomical structures across different species, as well as fossil records, also reveal ancient shared ancestry consistent with natural selection.

Watch the history of human migration that led to civilizations

Starting in Africa where they hunted with spears and fires, humans would gradually move out of the continent over thousands of years as they navigated crossing deserts, rivers, uneven terrain, and shifting climates. Development of technology, language, farming, and other societal structures helped build up the first civilizations.

Behind the fascinating disguising mechanism of camouflage

Camouflage—nature's master game of hide-and-seek—is more complex than simply how things look. The disguising process required millions of years of evolution that have programmed how our brains take shortcuts. Watch this video to see examples of camouflage and understand how we process it.

How aging degrades neural functioning in the brain over time

Aging affects the brain perhaps more than any other organ in the body. Throughout life, the brain experiences radical shifts in the number of neurons, synaptic connections between neurons, and hormone levels that regulate our mood and processing.

Everything scientists could learn by looking at your skull

Our skulls are all unique, but they also share characteristics across groups of people. In the absence of fingerprints, forensic scientists can learn a lot about you just from your skull.

Grief rewires the human brain

The human brain handles stress and emotional traumas similarly. In response to the emotional stress of a situation like the death of a loved one, divorce, or abuse, the brain may strengthen or weaken connections between nerves to form new neural connections. Over time, chronic stress can diminish brainpower, reducing overall nerve growth and memory to shift resources to enable elevated fear responses and enable humans to survive.

See a timeline of landmark discoveries in the field of genetics to gain a better understanding of more than a century of advances.

How can octopuses and MDMA help scientists understand the human brain?

Research shows that psychedelics may induce something called "critical periods" in the adult brain, which can make our brains more open to learning and changing, like they once were back in early childhood. Psychedelics similarly change how social creatures like octopuses behave, which demonstrates that these animals could help us better understand our own neurobiology.

A pregnant woman's brain sheds gray matter, perhaps explaining 'baby brain.'

Humans won't develop more than 5 fingers because it would impact too many body parts

All modern animals have five or fewer digits on each of their limbs. Roughly 348 million years ago, at least two species had eight: the Ichthyostega and the Acanthostega. According to Dollo's law, complex evolved features are very unlikely to recur in evolution. Researchers believe humans won't develop more than five digits because it would impact other body parts too much.

Mapping how human population has grown throughout history

It took 200,000 years for our human population to reach 1 billion—and only 200 years to reach 7 billion. When will our global population peak? And how can we minimize our impact on Earth's resources, even as we approach 11 billion?

Examine this captivating animation 'building' a human—illustrating the roughly 40 weeks of fetal development.