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What Really Made Humans Smart?
A noted neuroscientist's new study illuminates what remarkable invention made our brains the largest of all the primates.
Why are we the smartest of all the animals? A new study led by a noted neuroscientist has the answer - it’s not just the size of our brains but the total number of neurons inside it.
Vanderbilt University’s neuroscientist Suzana Herculano-Houzel, who led the study, explained:
"People need to drop the idea that the human brain is exceptional. Our brain is basically a primate brain. Because it is the largest primate brain, it does have one distinctive feature: It has the highest number of cortical neurons of any primate. Humans have 16 billion compared with 9 billion in gorillas and orangutans and six-to-seven billion in chimpanzees. It is remarkable, but it is not exceptional.”
The neurons in question are located in the prefrontal cortex, which appears responsible for for our personality, abstract thinking and decision making.
How did our brain grow larger than the brains of gorillas and orangutans, whose bodies are bigger than ours? It’s because of cooking!
In her book The Human Advantage: A New Understanding of How Our Brain Became Remarkable, Herculano-Houzel explained it this way:
“Our big brains are very costly. They use 25 percent of all the energy the body needs each day. Cooking allowed us to overcome an energetic barrier that restricts the size of the brains of other primates."
How did cooking allow us to get past this barrier? The neuroscientist goes back to the beginning for an explanation, tying the discovery of tools and the invention of cooking to the growth of the human brain.
"Those early tool makers had brains about the same size as gorillas. But, beginning about 1.8 million years ago, the brains of our ancestors began growing steadily, tripling in size over the next 1.5 million years.”
What happened to make their brains grow so rapidly? They figured out how to slice and dice, how to start fire and, ultimately, how to cook.
“Take a single carrot. If you eat it raw, it will take 10 to 15 minutes of vigorous chewing and your digestive system will only capture about one third of the calories. But, if you cut the carrot up and cook it for a few minutes, it takes only a few minutes to consume and your body gets 100 percent of the calories."
Cooking thus allowed us to prepare and consume a meal high in calories efficiently. And we needed more calories to grow our energy-hungry brains. If we couldn’t cook and ate the food raw, we would have had to spend 9.5 hours every day foraging for and eating food. Basically, doing nothing else.
Herculano-Houzel sees the role of cooking in our evolution rather poetically -
"It's amazing that something we now take for granted, cooking, was such a transformational technology which gave us the big brains that have made us the only species to study ourselves and to generate knowledge that transcends what was observed firsthand; to tamper with itself, fixing imperfections with the likes of glasses, implants and surgery and thus changing the odds of natural selection; and to modify its environment so extensively (for better and for worse), extending its habitat to improbable locations."
You can read the Herculano-Houzel’s study “No relative expansion of the number of prefrontal neurons in primate and human evolution” here.
You can also check out this TED talk by the neuroscientist on “What is So Special about the human brain?”
The team caught a glimpse of a process that takes 18,000,000,000,000,000,000,000 years.
- In Italy, a team of scientists is using a highly sophisticated detector to hunt for dark matter.
- The team observed an ultra-rare particle interaction that reveals the half-life of a xenon-124 atom to be 18 sextillion years.
- The half-life of a process is how long it takes for half of the radioactive nuclei present in a sample to decay.
A study looks at the ingredients of a good scare.
Catching fear in a bottle<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYyNzg1Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyOTQwMTcyMn0.WtpJ1E_dhK2o09fBpKARynj4_p5NXeklgsXsbd7xr9w/img.jpg?width=980" id="8ff51" class="rm-shortcode" data-rm-shortcode-id="f10dd9188b173f4a36e85e9325507c6b" data-rm-shortcode-name="rebelmouse-image" />
Credit: Photo Boards/Unsplash<p>Previous studies have tracked physiological signs of fear arousal, but none have established a one-to-one correlation between that arousal and specific, actual fear events.</p><p>Andersen says that much of the research has been conducted in lab settings with weak fear stimuli, observing subjects as they experience things like scary videos. Scares in these situations tend to be weak and difficult to measure. Even harder to track in these situations is the link between enjoyment and fear. </p>
Eyes everywhere<iframe src="https://player.vimeo.com/video/109695164" width="100%" height="480" frameborder="0" scrolling="no" class="rm-shortcode" data-rm-shortcode-id="267ba87cfb8591ed5830499574d2272a"></iframe><p>Andersen and his colleagues conducted their experiments at <a href="https://dystopia.dk" target="_blank" rel="noopener noreferrer">Dystopia</a> Haunted House, a commercial attraction in Vejle, Denmark constructed in an old, run-down factory. The Recreational Fear Lab has a long-standing partnership with the spook shack.</p><p>They outfitted 100 volunteers with heart monitors and sent them on their terrifying way through the 50-room horror mansion. The facility incorporates a number of fright mechanisms including frequent jump scares in which a sudden threat takes a visitor by surprise.</p><p>Researchers surreptitiously observed their participants on closed-circuit video as they made their way through the attraction. They tracked each individual's scares, scoring them for intensity according to their visible reactions. After exiting the attraction, individuals self-reported their experiences in the haunted house.</p><p>Combining these self-reports with observer notes and each participant's heart-rate data gave the researchers subjective, behavioral, and physiological insights into the ways in which fear is experienced, and when it's a good thing or not.</p>
A pair of inverted U-shapes<p>In analyzing their data, the researchers saw two separate inverted u-shape curves. One depicted participants' enjoyment based on their self-reports and observed behavior. A similar u-curve was detected in their heart rates showing that just the right amount of heartbeat acceleration is associated with fun, but too much is too much. It's the terror Goldilocks zone.</p><p>Says Andersen, "If people are not very scared, they do not enjoy the attraction as much, and the same happens if they are too scared. Instead, it seems to be the case that a 'just-right' amount of fear is central for maximizing enjoyment."</p><p>The research suggests that being scared is enjoyable when it represents just a quick minor physiological deviation from one's normal state. When it goes on too long, however, or triggers too severe a physiological change, it becomes disturbing. Game over.</p><p>Andersen notes that this is not dissimilar to the factors known to make interpersonal play enjoyable: just the right amount of uncertainty and surprise. These are, maybe not coincidentally, also the ingredients of a successful joke.</p>
A meteorite that smashed into a frozen lake in Michigan may explain the origins of life on Earth, finds study.
- A new paper reveals a meteorite that crashed in Michigan in 2018 contained organic matter.
- The findings support the panspermia theory and could explain the origins of life on Earth.
- The organic compounds on the meteorite were well-preserved.
Meteor streaks through Michigan sky<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="80b7f30820153b35fc515592d7475f53"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/EPu2qnqMYBo?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
The meteorite that smashed into Strawberry Lake carried pristine extraterrestrial organic compounds.
Credit: Field Museum