Brain Pickings

Posts Tagged ‘science’

16 NOVEMBER, 2012

Are We Nearing the Maximum Capacity of the Human Brain?


How “the cleverest organ in the known universe could suddenly become one of the dumbest.”

“If you ever feel lazy or dull,” neuroscientist David Eagleman wrote of the human brain, “take heart: you’re the busiest, brightest thing on the planet.” But are you, or at least are you for long?

Much has been said about the perils of information overload and what we can do about it. But what if the issue was not simply one of will over wiring? In The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning (public library) — which also gave us this fascinating look at the science of “chunking” and how pattern recognition fuels creativity — Cambridge neuroscientist Daniel Bor turns to the potential hard-wired limitations of our human brains as they grapple with the rapidly proliferating influx of available information:

Human eyes have around 100 million photoreceptors, each of which can pick up about ten visual events every second, so our eyes are effectively receiving a billion pieces of information each second. If you include the information pouring in from our other senses, that’s a staggering quantity of data for our brains to sift through every moment of our waking lives.


If we had an infinite resource of energy by which to crunch the numbers, and an infinitely fast brain by which to make the calculations, then there would be no problem, as we could analyze every scrap of data to its fullest capacity and never miss an opportunity or be caught by a threat. But, of course, in reality, it takes time to process anything, and human brains consume a frighteningly large proportion of our body’s total energy resources.

Computing pioneer Charles Babbage's brain

Public domain image

Then, Bor adds in a footnote:

Even though the human brain is a mere 2 percent of total body weight, in newborns this single organ requires a staggering 87 percent of the body’s total energy. A five-year-old has a brain that greedily guzzles nearly half of all the energy the child consumes, and even in adults this figure is at least a quarter, though that proportion can rise dramatically if we’ve had a mentally taxing day — for instance, when studying for exams. In fact, some biologists have suggested that the energy demands and complexity of a human brain are nearing the endpoint of what is biologically possible and that if you started trying to cram even more neuronal wires into the brain, the additional miniaturization that this would entail would turn all brain signal into random noise — and the cleverest organ in the known universe would suddenly become one of the dumbest.

Of course, for those of us who believe it’s less a matter of what machinery the skull houses and more a matter of how we use it, this is merely of curiosity rather than of concern.

Babbage’s brain image via Public Domain Review

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15 NOVEMBER, 2012

The Birth of Sound: Why the Big Bang Was Actually Silent


The science of why the wail of the baby Universe sounded like muffled highway traffic.

Questions of what sound is, why its digitization is a dangerous thing, and how it bleeds into other senses have long fascinated thinkers and listeners alike. In Discord: The Story of Noise (public library) from Oxford University Press, sound scholar Mike Goldsmith, former Head of the Acoustic Group at the UK National Physical Laboratory, explores the flipside of the cultural evolution of silence by tracing our relationship with noise, the history of sound, and where our auditory future might take us.

Among the many fascinating and counterintuitive facets of noise Goldsmith examines is the very dawn of sound, in a chapter titled A Silent Bang:

Despite a promising name, the Big Bang was silent — a sudden burst of energy in which time and space began, forming the Universe as it spread. With no space to expand into, there could be no medium around it into which sound waves could possibly propagate. But, in cosmic terms, the Universe was not silent for long — 380,000 years later (a mere 0.0003 per cent of its present age), it was filled with sound. And, this was not the random roar of white noise that one might perhaps expect — it was a sound with a pitch: it had a characteristic wavelength.

It would not, however, have been an audible sound to any eared creatures, could they have existed so far back in time, before even the stars were born: a vast objet like the Universe makes a very low sound indeed — about one trillionth of a hertz.

The reason that there was such a vast deep tone in the infancy of space and time is closely connected to one of the most mysterious and important aspects of the Universe’s history: structure, of which sound is a signpost. If the Universe had remained as it began, a completely homogenous, smoothed-out volume of energy, then galaxies, stars, and people could not exist today. But, for reasons that are still unclear, there was a clumpiness in the early Universe — some areas were a little denser than others, and it was these denser areas that would eventually become stars and galaxies. Density means gravity, and gravity attracted nearby matter (then in the form of plasma — a ‘gas’ of ions). he motion of that matter caused compression, heating the plasma, which in turn increased its output of radiation. The force of this radiation counteracted the gravitational force, and so the compression became an expansion — and it is this cycle of compression and expansion that formed the primordial sound waves.

But that early sound of was unlike what we typically think of as “sound,” not only because of its physical nature, but also because it fell on deaf — or, rather, non-existent — ears:

The wavelengths of the wail of the baby Universe — measured in hundreds of thousands of light years — were limited by the speed with which the pull of gravity travelled from one region to another, which is the speed of light. So, there was an ever-falling lowest possible pitch to the Universe, and consequently a gradually descending tone marked its growth.

The variation in pressure of the sound was around 1 per cent, or 11 dB, the kind of level that would be associated with motorway traffic a few metres away and over thirteen billion years later.

In the early Universe, as new generations of stars formed using the nuclear reaction products of the old, planets like ours formed with them — and sound waves surged and echoed through their structures and their atmospheres and, later, their hydrospheres too. But, as far as we know, for ten billion years there was nothing to hear them.

Though life on Earth began some four billion years ago in the ancient seas, it wasn’t until about 400 million years ago that the first amphibians crawled onto land, equipped with complex structures that could not only detect sound waves both underwater and in air, but could also estimate their strengths, pitches, and directions. So “sound” itself, or at least our conception and experience of it, is a property of evolution rather than of the physical environment.

The rest of Discord goes on to examine everything from the basic nature of sound to the war on noise pollution to scientific advances harnessing the power of sound in medicine.

Complement with Jad Abumrad’s fantastic talk on sound, science, and mystery.

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13 NOVEMBER, 2012

An Animated Open Letter to President Obama on the State of Science Education


Reigniting the spark of physics in an education ethos stuck 150 years in the past.

Many of us living in the United States have recently taken a massive exhale at the triumphant news of four more years of sanity and progress. But it isn’t all unicorns and rainbows for President Obama, who will have to address some serious challenges. The fine folks of MinutePhysics — who have previously explained why the color pink doesn’t exist, why the past is different from the future, and why it’s dark at night — have zoomed in one of them in this animated open letter to the President, addressing an astonishing gap in physics education: Namely, the fact that most high school curricula cover none of the physics breakthroughs that have taken place in the past 150 years, including “the topic of every single Nobel Prize in physics since…always.” MinutePhysics advises the President to take a cue from Carl Sagan, Richard Feynman, and Neil deGrasse Tyson — men “committed 100% to the dissemination of the awesomeness of the universe” — and reignite the educational spark of physics.

The United States: A country with 5,000 nuclear weapons, birthplace of the world’s computing and telecommunications industry, home of the first atomic clock, and creator of the Global Positioning System. Chances are, if you just took regular American high school physics, you don’t know one iota behind the science behind those things. … That’s because high school physics students across most of America are not required to learn about pretty much any physical phenomena discovered or explained more recently than 1865. Yes, 1865. That’s the year the Civil War ended and well over a decade before Albert Einstein was even born.

Sadly, even if modern physics were required in high school, the question of how much that would actually promote an understanding of physics is a different matter — you needn’t look further than the latest data on state science standards to sigh in desperation:

Luckily, though certainly no substitute for formal education, the internet offers a worthy complement to what the classroom leaves out. To inject your daily information diet with some science-plus magic and wisdom, follow Neil deGrasse Tyson on Twitter, read Joe Hanson’s fantastic It’s Okay To Be Smart and Ed Yong’s Not Exactly Rocket Science (and consider the occasional donation — they’re that good), and peruse the Brain Pickings science archive.

Brain Pickings has a free weekly newsletter and people say it’s cool. It comes out on Sundays and offers the week’s best articles. Here’s what to expect. Like? Sign up.