In my never-ending quest to find out how the human brain works, today I would like to talk about recency bias.

Recency bias is the tendency to weigh the latest information more heavily than older data. Sort of like this:

And this:

In the world of the stock market, investors often think the market will always look the way it does today, which results in an endless number of unwise decisions.

It’s not surprising why recency bias dominates our decision making. It forms the basis of our habits, which help us in our day-to-day lives. Recent events and trends are easier to remember than events in the distant past or unknown events that will occur in the future.

But, of course, recency bias means we tend to ignore the lessons of history.

This is a problem for people who work in ‘big data’. 90% of the world’s data has been created in the last few years – and that statement has been true pretty much every year for the last 30 years. Every two years, the amount of data in the world has increased by about 10 times. And so recency bias is sort of ‘built in’ to the system – there is too much recent stuff and not as much of the older stuff.

Anyway, we can’t really overcome recency bias – like all cognitive biases, it’s part of being human. But it is important to be aware of it. So the next time your crazy uncle tells you that global warming can’t be real because it’s been cold for 4 days, you can point him to this post.

 

It is time for a new series on the blog – a deep dive into the many different cognitive biases that exist in our world. Much like my train stories segment, I expect this one to finish in about 64 years.

I’ve always had an interest in human psychology. One of the best classes I took in college was called Organisational Behaviour (I took it while abroad in Sydney, hence the spelling). OB is the study of the way people interact, particularly in groups. And by understanding how people interact, and how we make decisions, we can become more conscious of others and more aware of our own behaviors.

And part of becoming more aware of our behavior is understanding cognitive biases. These biases are systematic patterns of deviation from norm or rationality in judgment, whereby inferences about other people and situations may be drawn in an illogical fashion. They prevent us from acting objectively. They are also present in all of us. It is a deeply flawed part of the human machine.

Today I would like to talk about one of the most well-known cognitive biases: confirmation bias.

Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms one’s preexisting beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities. It’s a fancy way of describing our human inclination to see what we want to see.

It is one of the *many* reasons why it’s so hard to have an open and intelligent conversation about politics, or the economy, or sports, or climate change, or basically everything ever. We surround ourselves in an echo chamber of agreement, through our friends and the news we watch and the social media accounts we follow. Everything is curated to agree with our own beliefs.

The problem with confirmation bias is that when we come across disconfirming evidence, we are more likely to dismiss it than critically evaluate it. The other day I was having an argument with someone about politics, which I really hate to do, but the person said something that was so blatantly wrong that I had to chime in. So, I did. I responded with a litany of data, all meticulously sourced, much of it recited by memory, because I am a robot. Didn’t matter. I got nowhere. Because when we want to believe something, we tend to only seek evidence that confirms our desired belief. We ignore the rest, even when presented with very honest facts.

The internet is a cesspool of confirmation bias. If I have a preconceived hypothesis about something – say, that Bigfoot is real – all I have to do is search for ‘Bigfoot sightings’ and I’m greeted with this:

Five hours of reading later, and I’ll be out in the street shouting HEY EVERYBODY, BIGFOOT IS REAL, OH GOD IT’S COMING FOR US and no one can convince me otherwise (to be clear, I don’t actually think Bigfoot is real).

I like to think of myself as a rational, critically thinking individual, but I am not above confirmation bias. No one is. It’s sort of hard-wired into us, part of an instinctual group mentality that has been passed down by our big dumb Australopithecus ancestors.

There are plenty of examples from my own life where my decision making, or general thoughts, were influenced by confirmation bias instead logic or reason or the truth. For example, when I was growing up, I was certain that the Yankees had the best fans in baseball, and they were revered across the country, and everyone who played on the Yankees was perfect, because that’s what I saw on TV. Every time I turned on the YES Network, I was inundated with messages about THE PRIDE OF THE YANKEES and TRADITION and THE POWER OF THE PINSTRIPES.

When I moved to Boston, I quickly realized that the Yankees, and their brand, are actually hated just about everywhere else in the country. It was a sobering discovery.

So, how do we get past confirmation bias? Well, according to the internet, just being aware that the bias exists is not enough (just like I know that too much ice cream is bad for me, but I DON’T CARE GIMME ICE CREAM, I WANT THE ICE CREAM). Here is what you should do:

1. Open your mind. Learn how to think of a few far-our alternatives and keep an eye out for evidence that supports any one of them.
2. But don’t abandon your first guesses too readily! Sometimes your initial expectation may be neither 100% right, nor 100% wrong.
3. Embrace surprises when they happen to you. When you feel that something didn’t go exactly as you expected, consider that you need to refine some hypotheses about how things are working.

Confirmation bias is just one of the many cognitive biases that exist in our stupid brains, and I look forward to covering the rest of them over the next several decades.

What’s the loudest sound you’ve ever heard? A canon? A gunshot? A fire alarm? The screeching of the subway?

Have you ever wondered about the loudest sound of all time? No? Just me? OK, that’s fine, but here are 700 words on it anyway.

The loudest sound of all time was the Krakatoa volcanic eruption of 1883, off the coast of Indonesia. The sound was so loud that it ruptured eardrums of people 40 miles away, traveled around the world four times, and was clearly heard 3,000 miles away:

Think, for a moment, just how crazy this is. If you’re in Boston and someone tells you that they heard a sound coming from New York City, you’re probably going to give them a funny look. But Boston is a mere 200 miles from New York. What we’re talking about here is like being in Boston and clearly hearing a noise coming from Dublin, Ireland. Travelling at the speed of sound (766 miles or 1,233 kilometers per hour), it takes a noise about 4 hours to cover that distance. This is the most distant sound that has ever been heard in recorded history.

The earth has not come close to replicating that type of sound since.

The island of Krakatoa was torn apart, and smoke rose 17 miles into the atmosphere, three times higher than Mt. Everest. The eruption also caused a tsunami with waves over 100 feet high. Between 36,000 and 120,000 people died instantly.

A guy named Norham Castle – what a great name – was on a ship 40 miles from the eruption. In his log, he wrote: So violent are the explosions that the ear-drums of over half my crew have been shattered. My last throughts are with my dear wife. I am convinced that the Day of Judgement has come.

The sound registed at 172 decibals … 100 miles away! Do you know how loud 172 decibels is? Here’s a breakdown:

95 decibals: jackhammer
100 decibals: motorcycle
115 decibals: loud rock concert
125 decibals: pain begins
140 decibals: jet engine
165 decibals: 12 gauge shotgun blast
170 decibals+: death of hearing tissue

At 172 decibals, you would be unable to breathe or see from the sound pressure. Glass would shatter. Water in the air would drop out of suspension. It is the same sound that a military stun grenade makes for a split second, if it was right next to your ear.

Again, the sound was 172 decibals not at the source or a mile away … but 100 miles away!

There is actually a limit to the loudest sound possible in Earth’s atmosphere. It’s 194 decibals. Any louder and the sound is no longer just passing through the air. It is pushing the air along with it, which creates a pressurized burst of moving air known as a shock wave. At Krakatoa, the sound was well over this limit.

Here is a video of a recent volcanic eruption in Papa New Guinea. It’s on a much smaller scale, but it gives you a sense of how powerful the shock wave can be from a distance.

In the year following the Krakatoa eruption, average Northern Hemisphere summer temperatures fell by as much as 2.2 °F. Weather patterns were chaotic for years, and temperatures did not return to normal until 1888. You might remember the famous “water year” from July 1883 to June 1884 when Los Angeles received 38.18 inches of rain. This was attributed to the Krakatoa eruption.

The eruption darkened the sky worldwide for years afterwards, and produced spectacular sunsets throughout the world for many months. A British artist named William Ashcroft  made thousands of color sketches of the red sunsets in the years after the eruption. Look at this!

The ash caused “such vivid red sunsets that fire engines were called out in New York, Poughkeepsie, and New Haven to quench the apparent conflagration.” The eruption also produced a Bishop’s Ring around the sun by day, and a volcanic purple light at twilight.

Now, I ask you, fellow blog readers: why is such a cataclysmic, literally earth-shattering event not common knowledge? Why isn’t this taught in schools? Like, why the heck do I have to spend half of my high school science career learning how to operate a frikkin’ Bunsen burner while the amazing story of Krakatoa goes untold?

Well, at least we have Squidward for that.

Last year I wrote a post about how the earth’s poles are switching. The few pieces of feedback I received were along the lines of:

Wtf are you talking about, Jeff? 

or

There is no way this is true and even if it is I don’t care, please go back to writing about baseball.

Even my grandmother got in on the action:

Well, it’s been a year, so I thought I would give an update.

As a reminder, the earth’s magnetic field can change at any time. On average, it happens about once every 500,000 years. The reversal itself isn’t the problem, it’s the transition. During the process of reversal, there is a stretch of time between 100 and 1,000 years where the magnetic field is reduced to about 5% of its normal strength. And since humans rely on the magnetic field for protection from solar radiation, this can … uh … be a problem. In fact, scientists believe that past flips have led to mass extinctions.

So what actually causes these reverals? Here’s a quick explanation:

The Earth’s magnetic field is generated by the movement of molten iron in its outer core, through what’s known as the dynamo theory. We won’t know for sure until we actually get down there and do some investigating, but as far as scientific theories go it’s pretty well grounded.

Due to reasons we don’t fully understand, something causes the movement of the molten core to change — and thus the north and south poles switch. The most likely reason for the reversal is simply the general interaction and chaos of the massive dynamic forces at play — but there are some other hypothesized triggers, such as massive impacts, or significant plate tectonic shifts.

Now that you are thoroughly scared, let’s look at the facts.

It is true that the earth’s magnetic field  – which extends 370,000 miles above the surface – is already starting to weaken, particularly over the Western hemisphere. However, it is also true that the field is strengthening in other parts, particularly over the southern Indian Ocean. Still, data suggests that the total field is weakening at about 5% per decade, a lot faster than previously thought.

It is not necessarily true that this will lead to mass extinction and certain death for the human race. While there seems to be a correlation to past extinctions, it could also be true that those extinctions were caused by something else – an asteroid impact, a nearby supernova, a gamma ray burst*, a solar flare, a black hole, aliens.

*A gamma ray burst is one of the most powerful events that can occur in the universe. It happens when a star’s core fuses into heavier elements until it eventually cant fuse anymore. And then what happens? Well, it collapses into a black hole, of course. In the process, it releases more energy in a few seconds than the sun will over its 10-billion-year lifetime. Gamma ray bursts are rare – in our galaxy, they’ll only happen in a few times in a million years – but it could really ruin our day if it happens to be pointed in our direction.

So … with regard to the poles, has anything changed in the past year? Eh, not really. Scientists still believe we are in the process of a magnetic reversal. Scientists are still unsure whether the result will be catastrophic (mass extinctions) or hardly noticeable (power grids are slightly affected).

It is pretty amazing that the universe allows us to live, considering everything that could go wrong. No black holes or asteroids or gamma ray bursts or solar flares in recent memory. No super-volcano eruptions that have caused a nuclear winter. No alien abductions. No super-viruses. No nuclear warfare. And for that I say: well done, everyone. Let’s keep it going for as along as possible.

 

If you don’t like numbers, please don’t read this post. PLEASE. I’m begging you. Get out while you can.

I think about numbers a lot, because they’re fascinating. A lot of times I think about them in the context of sports, or science, or finance. Numbers are just cool. They are an exclusively human creation, and yet they appear all the time throughout nature. This world we live in has inherent mathematical properties, and we are lucky to be conscious and intelligent and aware to discover them for ourselves.

And each time I try to learn something new, I inevitably travel down a rabbit hole that forces me to write blog posts like this.

**

You’ve probably heard of the Fibonacci sequence. You start with two consecutive 1’s, and then each number after that is the sum of the two numbers that precede it.

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, …

The Fibonacci sequence appears in many biological settings: branching in trees, arrangement of leaves on a stem, the fruitlets of a pineapple, the flowering of artichoke, an uncurling fern, the arrangement of a pine cone, and the family tree of honeybees.

In fact, the spiral of hurricanes match the Fibonacci sequence. It’s pretty extraordinary.

**

Here’s an odd quirk of math. Take the number 1. Then add 2. Then add 3. Then repeat this forever:

1 + 2 + 3 + 4 + 5 + 6 + … + ∞ = ?

What’s the result? Infinity, right? No! The answer is not infinity. It is -1/12. That doesn’t look right. How can the sum of all positive integers equal a negative number? And why the heck is it -1/12? I cannot answer that. But I can link you to the absolutely ridiculous proof. I advise not to read through for fear of a massive migraine.

The YouTube channel Numberphile also did a video on this seemingly impossible answer. They break it down into (somewhat) understandable chunks.

(EDIT: As my friend Dan points out, -1/12 may be incorrect. It is hotly debated.)

—

Have you ever heard of Graham’s number? It is a number so big, so frikkin’ big, that it holds the record for the largest number ever used in a serious mathematical proof.

Literally, no one has ever used a larger number.

It’s difficult to visualize how big this number is, but here is an attempt. Let’s start with the smallest measurable unit – the Planck volume. It is 1.616199×10⁻³⁵ meters, which is about 10⁻²⁰ times smaller the diameter of a proton. A proton. So, yes, the Planck volume is small. You could fit a lot of those in the observable universe, about 10¹⁸⁵ of them. That’s how many of the smallest thing (Planck units) you can fit in the biggest thing (universe).

Graham’s number is WAY bigger than that.

Calculating Graham’s number requires tetration and hyperoperations and it’s pretty much the most complicated thing ever. I recommend this post and then I recommend taking a break from the internet.

From Wikipedia:

Using Knuth’s up-arrow notation, Graham’s number G is:

where the number of arrows in each layer, starting at the top layer, is specified by the value of the next layer below it; that is:

and where a superscript on an up-arrow indicates how many arrows there are. In other words, G is calculated in 64 steps: the first step is to calculate g1 with four up-arrows between 3s; the second step is to calculate g2 with g1 up-arrows between 3s; the third step is to calculate g3 with g2 up-arrows between 3s; and so on, until finally calculating G =g64 with g63 up-arrows between 3s.

Equivalently,

And there you have it. Graham’s number.

**

One of the hardest concepts I learned in finance was the Black-Scholes model*, a mathematical model of a financial market containing certain derivative investment instruments. The model was first published by Fischer Black and Myron Scholes in their 1973 paper, The Pricing of Options and Corporate Liabilities.

*Business Week recently named the Black-Scholes model the 60th most disruptive idea in the last 85 years, right between “the sharing economy” and cable news. It was ranked higher than: YouTube, OPEC, and the bar code. And yet most people have no idea what it is (for good reason, probably).

Let us take a look at the formula:

 

I spent many nights trying to uncover the mystery of this Black-Scholes formula. It didn’t make much sense when I learned it in college, and it doesn’t make much sense now, but there’s no doubt that it was a breakthrough:

Now the formula is used everywhere. If you have a mortgage, your right to prepay is an option. Your right to default and turn over the house to the lender if it’s underwater is an option. Every simple mortgage has these two options embedded in it. Seven hundred trillion dollars of this stuff is sloshing around the earth.

The key idea behind the model is this: you hedge an option by buying and selling the underlying asset in just the right way and you can eliminate risk. This type of hedging is called delta hedging and is the basis of more complicated hedging strategies that our friends in investment banks and hedge funds use.

I’m not sure if I explained that well enough. But, uh, let’s move on.

**

It is always in your favor to order a larger pizza. Even if you are not hungry. Again, this is because of math.

Let’s take a small 10 inch pizza and a large 16 inch pizza. And let’s assume that the price of the small is $10 and the price of the large is $16. It looks like you’re paying the same price for the same amount of pizza, but, well, you’re not.

We all know the formula for the area of a circle: πr². Right? This is a thing we still know? So, let’s take a look at the area of each pizza:

10 inch pizza = π * (5)² = 78 square inches
16 inch pizza = π * (8)² = 201 square inches

So, in this scenario, you are paying 60% more money but you’re actually getting almost three times as much pizza. And so you are paying much less per square inch.

10 inch pizza = $10 = 78 square inches = 12.8 cents per square inch of pizza
16 inch pizza = $16 = 201 square inches = 8.0 cents per square inch of pizza

And this is one of the many excuses  for why I always order the large.

**

I once had a theory that everyone in the world could get rich.

You start with person A. Let’s call him Edgar. Edgar has 1 dollar. He sells that dollar to Sally for 2 dollars. Sally then sells that dollar to Johan for 3 dollars. You repeat this forever. Each time, a different person is getting $1 richer. Go around the world one million times, and everyone makes one million dollars, right? Right? Did I just find a loophole?

No, what I inadvertently discovered was a ponzi scheme.

**

The difference between 1 million and 1 billion is just insanely large. We look at $1 million and we think: Wow, that’s a lot of money. Then we look at $1 billion and think: Wow, that’s really a lot of money! But the two numbers are nowhere close to each other.

If you were to count to 1 million, it would take you about 12 days. This is assuming you didn’t sleep, but I urge you to sleep, because I don’t want another Russian Sleep Experiment fiasco on my hands.

If you were to count to 1 billion, it would take you THIRTY ONE YEARS. This is, again, assuming you didn’t sleep. Put another way: the difference between 1 and 1 million is the difference between now and two weeks ago (can’t wait for Thanksgiving!). The difference between 1 and 1 billion is the difference between now and 1983, when the top song was Every Breath You Take and swatches were a thing.

**

In conclusion, I like numbers.

Our universe is big. Like, really big. Like so big that it is impossible for the human mind to comprehend how big it us. If you were to travel from Earth to Pluto, and let’s say you were in a massive spaceship that could travel 40,000 miles per hour, it would take you over 20 years to get there. Pluto isn’t even at the end of the solar system – it goes on quite a ways beyond the former planet. And, our solar system contains just one star. There are over 200 billion stars in the Milky Way Galaxy. That’s just OUR GALAXY. And the Hubble Space Telescope site estimates there are hundreds of billions of galaxies in the universe. Some scientists estimate that there are over 10,000 galaxies for every grain of sand on Earth. So, yeah, pretty big.

Well, that’s a lot of data points to work with. Why we haven’t found life yet? Surely based on the laws of probability and chance, ONE of those galaxies has to contain life.

This is what puzzled Enrico Fermi. Fermi, you might know, was a 20th century scientist who popularized the apparent contradiction between:

high estimates of the probability of the existence of extraterrestrial civilization

and

humanity’s lack of contact with, or evidence for, such civilizations.

Somewhere out there, there should have been a civilization as intelligent as Earth that was able to colonize the galaxy, or at least have the capability to visit Earth or send satellite signals. And yet, here we are, still alone.

A few weeks ago I read a blog post on Wait But Why that explains the Fermi Paradox and the way scientists grapple with it.

One possibility is that there is no other intelligent life in the universe. This is a comforting thought – hey, we’re special! – but it also suggests that there is something that prevents truly intelligent life, something called The Great Filter. There is a wall that all life hits.

This means one of three things:

1) We made it! We are the only civilization that survived The Great Filter.

2) We made it! But we aren’t the only civilization that survived The Great Filter. Perhaps we’re just the first.

3) We’re doomed. The Great Filter is ahead of us.

Another possibility is that there is other intelligent life out there, but we haven’t heard from them for any number of reasons:

– Super-intelligent life could very well have already visited Earth, but before we were here.
– The galaxy has been colonized, but we just live in some desolate rural area of the galaxy.
– The entire concept of physical colonization is a hilariously backward concept to a more advanced species.
– There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location.
– There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things.
– We are receiving contact from other intelligent life, but the government is hiding it.
– Higher civilizations are aware of us and observing us (AKA the “Zoo Hypothesis”).
– Higher civilizations are here, all around us. But we’re too primitive to perceive them.
– We’re completely wrong about our reality.

But the scariest possibility is this one: There is only one instance of higher-intelligent life,  a “superpredator” civilization. They are far more advanced than everyone else. They keep it that way by exterminating any intelligent civilization once they get past a certain level.

Wait But Why explains:

This would suck. The way it might work is that it’s an inefficient use of resources to exterminate all emerging intelligences, maybe because most die out on their own. But past a certain point, the super beings make their move – because to them, an emerging intelligent species becomes like a virus as it starts to grow and spread. This theory suggests that whoever was the first in the galaxy to reach intelligence won, and now no one else has a chance. This would explain the lack of activity out there because it would keep the number of super-intelligent civilizations to just one.

OK, I have to say, I love this stuff. No, I don’t love the possibility of being wiped out by a superpredator civilization once we invent hoverboards, but I love thinking about any of the above possibilities. It makes for a great conversation.

Any evidence of intelligent life would be the single most important discovery of mankind. And any type of communication with intelligent life would be the single most important moment in our history. And once we make that step, there is no coming back.

I’ve got three sciencey-type posts coming this week. Because science is awesome. Today we’re talking about the poles.

Some call it the polar flip. Others call it a geomagnetic reversal. In any event, the north and south poles are in the process of switching magnetic direction. It is not the first time this has happened* (the poles switch every 100,000 to 1 million years), but it is the first time it has happened while humans have had any sort of infrastructure that relies on the earth’s magnetic field.

*The last one, the Brunhes–Matuyama reversal, occurred 780,000 years ago.

I first heard about this story in my high school physics class. My teacher mentioned it offhandedly – please turn to page 78 in your textbook, hey did you guys know that the poles are switching, anyway today we’ll be discussing Newton’s third law of thermodynamics – and, I, uh, couldn’t just let that go. The freakin’ poles are switching, how cool is that?!?

I have tried to follow any developments in the decade or so since.

Well, earlier this month data collected by a European satellite array suggested that the Earth’s magnetic field is shifting and weakening at a greater pace than previously thought. Previously, researchers estimated that the earth’s magnetic field was weakening at 5 percent per century, but the new data reveals that the field is weakening at 5 percent per decade. Which means we’re less than 200 years away from the full flip.

So, what does this mean?

**BEST CASE SCENARIO**

Historically, there is no evidence that magnetic field reversals result in any mass extinctions or radiation damage. The worst that happens is that a compass points south instead of north.

**WORST CASE SCENARIO**

All power grids and communication systems fail. The magnetic fields that protect us from radiation weaken to the point where radiation damage is a serious threat. Navigation systems that rely on the magnetic field are no longer accurate. Compasses are rendered moot. Human sacrifice, dogs and cats living together, mass hysteria.

Personally, I think this could be a real boon to the magnetic compass industry. Imagine the type of demand they’ll see if all compasses have to be re-calibrated. Gold, Jerry! Gold!