Brain Pickings

Posts Tagged ‘psychology’

04 SEPTEMBER, 2012

The Science of “Chunking,” Working Memory, and How Pattern Recognition Fuels Creativity


“Generating interesting connections between disparate subjects is what makes art so fascinating to create and to view… We are forced to contemplate a new, higher pattern that binds lower ones together.”

It seems to be the season for fascinating meditations on consciousness, exploring such questions as what happens while we sleep, how complex cognition evolved, and why the world exists. Joining them and prior explorations of what it means to be human is The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning (public library) by Cambridge neuroscientist Daniel Bor in which, among other things, he sheds light on how our species’ penchant for pattern-recognition is essential to consciousness and our entire experience of life.

The process of combining more primitive pieces of information to create something more meaningful is a crucial aspect both of learning and of consciousness and is one of the defining features of human experience. Once we have reached adulthood, we have decades of intensive learning behind us, where the discovery of thousands of useful combinations of features, as well as combinations of combinations and so on, has collectively generated an amazingly rich, hierarchical model of the world. Inside us is also written a multitude of mini strategies about how to direct our attention in order to maximize further learning. We can allow our attention to roam anywhere around us and glean interesting new clues about any facet of our local environment, to compare and potentially add to our extensive internal model.

Much of this capacity relies on our working memory — the temporary storage that holds these primitive pieces of information in order to make them available for further processing — and yet what’s most striking about our ability to build such an “amazingly rich” model of the world is that the limit of our working memory is hardly different from that of a monkey, even though the monkey’s brain is roughly one-fifteenth the size of ours: Experiment after experiment has shown that, on average, the human brain can hold 4 different items in its working memory, compared to 3 or 4 for the monkey.

What makes the difference, Bor argues, is a concept called chunking, which allows us to hack the limits of our working memory — a kind of cognitive compression mechanism wherein we parse information into chunks that are more memorable and easier to process than the seemingly random bits of which they’re composed. Bor explains:

In terms of grand purpose, chunking can be seen as a similar mechanism to attention: Both processes are concerned with compressing an unwieldy dataset into those small nuggets of meaning that are particularly salient. But while chunking is a marvelous complement to attention, chunking diverges from its counterpart in focusing on the compression of conscious data according to its inherent structure or the way it relates to our preexisting memories.

To illustrate the power of chunking, Bor gives an astounding example of how one man was able to use this mental mechanism in greatly expanding the capacity of his working memory. The man, an undergraduate volunteer in a psychology experiment with an average IQ and memory capacity, took part in a simple experiment, in which the researchers read to him a sequence of random digits and asked him to say the digits back in the order he’d heard them. If he was correct, the next trial sequence would be one digit longer; if incorrect, one digit shorter. This standard test for verbal working memory had one twist — it took place over two years, where the young man did this task for an hour a day four days a week.

Initially, he was able to remember roughly 7 numbers in the sequence — an average improvement over the 4-item limit that most people arrive at with a few simple and intuitive rehearsal strategies. But the young man was so bored with the experiment he decided to make it interesting for himself by doing his best to greatly improve his limit — which he did. By the end, some 20 months later, he was able to say back a sequence that was 80 digits long — or, as Bor puts it, “if 7 friends in turn rapidly told him their phone numbers, he could calmly wait until the last digit was spoken and then, from memory, key all 7 friends’ numbers into his phone’s contact list without error,” an achievement that would make Joshua Foer proud.

But how, exactly, was an average person capable of such a superhuman feat? Bor sheds light:

This volunteer happened to be a keen track runner, and so his first thought was to see certain number groups as running times, for instance, 3492 would be transformed into 3 minutes and 49.2 seconds, around the world-record time for running the mile. In other words, he was using his memory for well-known number sequences in athletics to prop up his working memory. This strategy worked very well, and he rapidly more than doubled his working memory capacity to nearly 20 digits. The next breakthrough some months later occurred when he realized he could combine each running time into a superstructure of 3 or 4 running times — and then group these superstructures together again. Interestingly, the number of holders he used never went above his initial capacity of just a handful of items. He just learned to cram more and more into each item in a pyramidal way, with digits linked together in 3s or 4s, and then those triplets or quadruplets of digits linked together as well in groups of 3, and so on. One item-space, one object in working memory, started holding a single digit, but after 20 months of practice, could contain as much as 24 digits.

This young man had, essentially, mastered exponential chunking. But, Bor points out, chunking isn’t useful only in helping us excel at seemingly meaningless tasks — it is integral to what makes us human:

Although [chunking] can vastly increase the practical limits of working memory, it is not merely a faithful servant of working memory — instead it is the secret master of this online store, and the main purpose of consciousness.


There are three straightforward sides to the chunking process — the search for chunks, the noticing and memorizing of those chunks, and the use of the chunks we’ve already built up. The main purpose of consciousness is to search for and discover these structured chunks of information within working memory, so that they can then be used efficiently and automatically, with minimal further input from consciousness.

Perhaps what most distinguishes us humans from the rest of the animal kingdom is our ravenous desire to find structure in the information we pick up in the world. We cannot help actively searching for patterns — any hook in the data that will aid our performance and understanding. We constantly look for regularities in every facet of our lives, and there are few limits to what we can learn and improve on as we make these discoveries. We also develop strategies to further help us — strategies that themselves are forms of patterns that assist us in spotting other patterns, with one example being that amateur track runner developing tactics to link digits with running times in various races.

But, echoing Richard Feynman’s eloquent lament on the subject, Bor points to a dark side of this hunger for patterns:

One problematic corollary of this passion for patterns is that we are the most advanced species in how elaborately and extensively we can get things wrong. We often jump to conclusions — for instance, with astrology or religion. We are so keen to search for patterns, and so satisfied when we’ve found them, that we do not typically perform sufficient checks on our apparent insights.

Still, our capacity for pattern-recognition, Bor argues, is the very source of human creativity. In fact, chunking and pattern-recognition offer evidence for the combinatorial nature of creativity, affirm Steve Jobs’s famous words that “creativity is just connecting things”, Mark Twain’s contention that “all ideas are second-hand”, and Nina Paley’s clever demonstration of how everything builds on what came before.

The arts, too, generate their richness and some of their aesthetic appeal from patterns. Music is the most obvious sphere where structures are appealing — little phrases that are repeated, raised a key, or reversed can sound utterly beguiling. This musical beauty directly relates to the mathematical relation between notes and the overall logical regularities formed. Some composers, such as Bach, made this connection relatively explicit, at least in certain pieces, which are just as much mathematical and logical puzzles as beautiful musical works.

But certainly patterns are just as important in the visual arts as in music. Generating interesting connections between disparate subjects is what makes art so fascinating to create and to view, precisely because we are forced to contemplate a new, higher pattern that binds lower ones together.

What is true of creative skill, Bor argues, is also true of our highest intellectual contribution:

Some of our greatest insights can be gleaned from moving up another level and noticing that certain patterns relate to others, which on first blush may appear entirely unconnected — spotting patterns of patterns, say (which is what analogies essentially are).

Best of all, this system expands exponentially as it feeds on itself, like a muscle that grows stronger with each use:

Consciousness and chunking allow us to turn the dull sludge of independent episodes in our lives into a shimmering, dense web, interlinked by all the myriad patterns we spot. It becomes a positive feedback loop, making the detection of new connections even easier, and creates a domain ripe for understanding how things actually work, of reaching that supremely powerful realm of discerning the mechanism of things. At the same time, our memory system becomes far more efficient, effective — and intelligent — than it could ever be without such refined methods to extract useful structure from raw data.

Though some parts of The Ravenous Brain fringe on reductionism, Bor offers a stimulating lens on that always fascinating, often uncomfortable, inevitably alluring intersection of science and philosophy where our understanding of who we are resides.

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21 AUGUST, 2012

What Actually Happens While You Sleep and How It Affects Your Every Waking Moment


“We are living in an age when sleep is more comfortable than ever and yet more elusive.”

The Ancient Greeks believed that one fell asleep when the brain filled with blood and awakened once it drained back out. Nineteenth-century philosophers contended that sleep happened when the brain was emptied of ambitions and stimulating thoughts. “If sleep doesn’t serve an absolutely vital function, it is the greatest mistake evolution ever made,” biologist Allan Rechtschaffen once remarked. Even today, sleep remains one of the most poorly understood human biological functions, despite some recent strides in understanding the “social jetlag” of our internal clocks and the relationship between dreaming and depression. In Dreamland: Adventures in the Strange Science of Sleep (public library), journalist David K. Randall — who stumbled upon the idea after crashing violently into a wall while sleepwalking — explores “the largest overlooked part of your life and how it affects you even if you don’t have a sleep problem.” From gender differences to how come some people snore and others don’t to why we dream, he dives deep into this mysterious third of human existence to illuminate what happens when night falls and how it impacts every aspect of our days.

Most of us will spend a full third of our lives asleep, and yet we don’t have the faintest idea of what it does for our bodies and our brains. Research labs offer surprisingly few answers. Sleep is one of the dirty little secrets of science. My neurologist wasn’t kidding when he said there was a lot that we don’t know about sleep, starting with the most obvious question of all — why we, and every other animal, need to sleep in the first place.

But before we get too anthropocentrically arrogant in our assumptions, it turns out the quantitative requirement of sleep isn’t correlated with how high up the evolutionary chain an organism is:

Lions and gerbils sleep about thirteen hours a day. Tigers and squirrels nod off for about fifteen hours. At the other end of the spectrum, elephants typically sleep three and a half hours at a time, which seems lavish compared to the hour and a half of shut-eye that the average giraffe gets each night.


Humans need roughly one hour of sleep for every two hours they are awake, and the body innately knows when this ratio becomes out of whack. Each hour of missed sleep one night will result in deeper sleep the next, until the body’s sleep debt is wiped clean.

What, then, happens as we doze off, exactly? Like all science, our understanding of sleep seems to be a constant “revision in progress”:

Despite taking up so much of life, sleep is one of the youngest fields of science. Until the middle of the twentieth century, scientists thought that sleep was an unchanging condition during which time the brain was quiet. The discovery of rapid eye movements in the 1950s upended that. Researchers then realized that sleep is made up of five distinct stages that the body cycles through over roughly ninety-minute periods. The first is so light that if you wake up from it, you might not realize that you have been sleeping. The second is marked by the appearance of sleep-specific brain waves that last only a few seconds at a time. If you reach this point in the cycle, you will know you have been sleeping when you wake up. This stage marks the last drop before your brain takes a long ride away from consciousness. Stages three and four are considered deep sleep. In three, the brain sends out long, rhythmic bursts called delta waves. Stage four is known as slow-wave sleep for the speed of its accompanying brain waves. The deepest form of sleep, this is the farthest that your brain travels from conscious thought. If you are woken up while in stage four, you will be disoriented, unable to answer basic questions, and want nothing more than to go back to sleep, a condition that researchers call sleep drunkenness. The final stage is REM sleep, so named because of the rapid movements of your eyes dancing against your eyelids. In this stage of sleep, the brain is as active as it is when it is awake. This is when most dreams occur.

(Recall the role of REM sleep in regulating negative emotions.)

Randall’s most urgent point, however, echoes what we’ve already heard from German chronobiologist Till Roenneberg, who studies internal time — in our blind lust for the “luxuries” of modern life, with all its 24-hour news cycles, artificial lighting on demand, and expectations of round-the-clock telecommunications availability, we’ve thrown ourselves into a kind of circadian schizophrenia:

We are living in an age when sleep is more comfortable than ever and yet more elusive. Even the worst dorm-room mattress in America is luxurious compared to sleeping arrangements that were common not long ago. During the Victorian era, for instance, laborers living in workhouses slept sitting on benches, with their arms dangling over a taut rope in front of them. They paid for this privilege, implying that it was better than the alternatives. Families up to the time of the Industrial Revolution engaged in the nightly ritual of checking for rats and mites burrowing in the one shared bedroom. Modernity brought about a drastic improvement in living standards, but with it came electric lights, television, and other kinds of entertainment that have thrown our sleep patterns into chaos.

Work has morphed into a twenty-four-hour fact of life, bringing its own set of standards and expectations when it comes to sleep … Sleep is ingrained in our cultural ethos as something that can be put off, dosed with coffee, or ignored. And yet maintaining a healthy sleep schedule is now thought of as one of the best forms of preventative medicine.

Reflecting on his findings, Randall marvels:

As I spent more time investigating the science of sleep, I began to understand that these strange hours of the night underpin nearly every moment of our lives.

Indeed, Dreamland goes on to explore how sleep — its mechanisms, its absence, its cultural norms — affects everyone from police officers and truck drivers to artists and entrepreneurs, permeating everything from our decision-making to our emotional intelligence.

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17 AUGUST, 2012

Goethe on the Psychology of Color and Emotion


“Colour itself is a degree of darkness.”

Color is an essential part of how we experience the world, both biologically and culturally. One of the earliest formal explorations of color theory came from an unlikely source — the German poet, artist, and politician Johann Wolfgang von Goethe, who in 1810 published Theory of Colours (public library; public domain), his treatise on the nature, function, and psychology of colors. Though the work was dismissed by a large portion of the scientific community, it remained of intense interest to a cohort of prominent philosophers and physicists, including Arthur Schopenhauer, Kurt Gödel, and Ludwig Wittgenstein.

One of Goethe’s most radical points was a refutation of Newton’s ideas about the color spectrum, suggesting instead that darkness is an active ingredient rather than the mere passive absence of light.

…light and darkness, brightness and obscurity, or if a more general expression is preferred, light and its absence, are necessary to the production of colour… Colour itself is a degree of darkness.

But perhaps his most fascinating theories explore the psychological impact of different colors on mood and emotion — ideas derived by the poet’s intuition, which are part entertaining accounts bordering on superstition, part prescient insights corroborated by hard science some two centuries later, and part purely delightful manifestations of the beauty of language.

Color wheel designed by Goethe in 1809


This is the colour nearest the light. It appears on the slightest mitigation of light, whether by semi-transparent mediums or faint reflection from white surfaces. In prismatic experiments it extends itself alone and widely in the light space, and while the two poles remain separated from each other, before it mixes with blue to produce green it is to be seen in its utmost purity and beauty. How the chemical yellow develops itself in and upon the white, has been circumstantially described in its proper place.

In its highest purity it always carries with it the nature of brightness, and has a serene, gay, softly exciting character.

State is agreeable and gladdening, and in its utmost power is serene and noble, it is, on the other hand, extremely liable to contamination, and produces a very disagreeable effect if it is sullied, or in some degree tends to the minus side. Thus, the colour of sulphur, which inclines to green, has a something unpleasant in it.

When a yellow colour is communicated to dull and coarse surfaces, such as common cloth, felt, or the like, on which it does not appear with full energy, the disagreeable effect alluded to is apparent. By a slight and scarcely perceptible change, the beautiful impression of fire and gold is transformed into one not undeserving the epithet foul; and the colour of honour and joy reversed to that of ignominy and aversion. To this impression the yellow hats of bankrupts and the yellow circles on the mantles of Jews, may have owed their origin.


As no colour can be considered as stationary, so we can very easily augment yellow into reddish by condensing or darkening it. The colour increases in energy, and appears in red-yellow more powerful and splendid.

All that we have said of yellow is applicable here, in a higher degree. The red-yellow gives an impression of warmth and gladness, since it represents the hue of the intenser glow of fire.


As pure yellow passes very easily to red-yellow, so the deepening of this last to yellow-red is not to be arrested. The agreeable, cheerful sensation which red-yellow excites increases to an intolerably powerful impression in bright yellow-red.

The active side is here in its highest energy, and it is not to be wondered at that impetuous, robust, uneducated men, should be especially pleased with this colour. Among savage nations the inclination for it has been universally remarkedy and when children, left to themselves, begin to use tints, they never spare vermilion and minium.

In looking steadfastly at a perfectly yellow-red surface, the colour seems actually to penetrate the organ. It produces an extreme excitement, and still acts thus when somewhat darkened. A yellow-red cloth disturbs and enrages animals. I have known men of education to whom its effect was intolerable if they chanced to see a person dressed in a scarlet cloak on a grey, cloudy day.

The colours on the minus side are blue, red-blue, and blue-red. They produce a restless, susceptible, anxious impression.


As yellow is always accompanied with light, so it may be said that blue still brings a principle of darkness with it.

This colour has a peculiar and almost indescribable effect on the eye. As a hue it is powerful — but it is on the negative side, and in its highest purity is, as it were, a stimulating negation. Its appearance, then, is a kind of contradiction between excitement and repose.

As the upper sky and distant mountains appear blue, so a blue surface seems to retire from us.

But as we readily follow an agreeable object that flies from us, so we love to contemplate blue — not because it advances to us, but because it draws us after it.

Blue gives us an impression of cold, and thus, again, reminds us of shade. We have before spoken of its affinity with black.

Rooms which are hung with pure blue, appear in some degree larger, but at the same time empty and cold.

The appearance of objects seen through a blue glass is gloomy and melancholy.

When blue partakes in some degree of the pltis side, the effect is not disagreeable. Sea-green is rather a pleasing colour.


We found yellow very soon tending to the intense state, and we observe the same progression in blue.

Blue deepens very mildly into red, and thus acquires a somewhat active character, although it is on the passive side. Its exciting power is, however, of a different kind from that of the red-yellow. It may be said to disturb, rather than enliven.

As augmentation itself is not to be arrested, so we feel an inclination to follow the progress of the colour, not, however, as in the case of the red-yellow, to see it still increase in the active sense, but to find a point to rest in.

In a very attenuated state, this colour is known to us under the name of lilac; but even in this degree it has a something lively without gladness.


This unquiet feeling increases as the hue progresses, and it may be safely assumed, that a carpet of a perfectly pure deep blue-red would be intolerable. On this account, when it is used for dress, ribbons, or other ornaments, it is employed in a very attenuated and light state, and thus displays its character as above defined, in a peculiarly attractive manner.

As the higher dignitaries of the church have appropriated this unquiet colour to themselves, we may venture to say that it unceasingly aspires to the cardinal’s red through the restless degrees of a still impatient progression.


Whoever is acquainted with the prismatic origin of red will not think it paradoxical if we assert that this colour partly actu, partly potentia, includes all the other colours.

We have remarked a constant progress or augmentation in yellow and blue, and seen what impressions were produced by the various states; hence it may naturally be inferred that now, in the junction of the deepened extremes a feeling of satisfaction must succeed ; and thus, in physical phenomena, this highest of all appearances of colour arises from the junction of two contrasted extremes which have gradually prepared themselves for a union.

As a pigment, on the other hand, it presents itself to us already formed, and is most perfect as a hue in cochineal ; a substance which, however, by chemical action may be made to tend to the plus or the minus side, and may be considered to have attained the central point in the best carmine.

The effect of this colour is as peculiar as its nature. It conveys an impression of gravity and dignity, and at the same time of grace and attractiveness. The first in its dark deep state, the latter in its light attenuated tint; and thus the dignity of age and the amiableness of youth may adorn itself with degrees of the same hue.

History relates many instances of the jealousy of sovereigns with regard to the quality of red. Surrounding accompaniments of this colour have always a grave and magnificent effect. The red glass exhibits a bright landscape in so dreadful a hue as to inspire sentiments of awe.


If yellow and blue, which we consider as the most fundamental and simple colours, are united as they first appear, in the first state of their action, the colour which we call green is the result.

The eye experiences a distinctly grateful impression from this colour. If the two elementary colours are mixed in perfect equality so that neither predominates, the eye and the mind repose on the result of this junction as upon a simple colour. The beholder has neither the wish nor the power to imagine a state beyond it. Hence for rooms to live in constantly, the green colour is most generally selected.

Though hardly a work of science, Theory of Colours stands as an absorbing account of the philosophy and artistic experience of color, bridging the intuitive and the visceral in a way that, more than two hundred years later, continues to intrigue.

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