The Half-Life of Facts (26 page)

As part of my scientific research, I’ve been part of a team that has developed software infrastructure for running online experiments to see how people cooperate in networks on Mechanical Turk. But due to this, I have also gained an appreciation for Mechanical Turk. To get a sense of people’s factual inertia, I thought it would be a good place to quickly survey a population about their beliefs and knowledge.

I decided to examine people’s knowledge of best practices when it comes to treating a nosebleed. I can distinctly remember a nosebleed of mine about ten years ago, when my nose started bleeding spontaneously one evening. With one hand holding a tissue to stanch the blood flow, I used the other hand to search online for how to properly treat it. Do I lean back? Do I lean forward? Where do I pinch my nose? I had heard so much competing information that I really didn’t remember the “right” thing to do any longer. Searching online mid-nosebleed was my only recourse.

So I put a similar question to my Turkers:

“If you have a nosebleed, what’s the best way to handle it?”

A. Lean your head back

B. Lie down

C. Lean your head slightly forward

D. Lean your head all the way forward

“And how would you hold your nose?”

A. Hold nose completely closed

B. Pinch bridge of nose

I asked for one hundred responses and offered five cents for each survey completion. Even with paying the overhead to Amazon, I was paying less than six dollars for new knowledge. I had my first response in less than a minute, and after a couple of days all the responses were in.

For the record, according to the medical site UpToDate and the Merck Manual, the proper procedure is to lean your head slightly forward and pinch your nose closed, so the correct answers should be C and A.

But how did my subjects respond? Here’s the breakdown for the Turkers:

“If you have a nosebleed, what’s the best way to handle it?”

Lean your head back: 50

Lie down: 14

Lean your head slightly forward: 31

Lean your head all the way forward: 5

“And how would you hold your nose?”

Hold nose completely closed: 17

Pinch bridge of nose: 83

From this, it’s clear that the Turkers do not know the proper position to assume during a nosebleed or how to stanch the flow of blood. Only about a third can correctly identify the way to position oneself and only one in six Turkers know that holding your nose completely closed is a good idea.

The results of this experiment are not terribly surprising. In addition to all of the cognitive biases that we are saddled with, it is difficult for us to keep abreast of all the information around us. When we are young, we are treated as little generalists, absorbing all manner of information. We learn geography, history, mathematics, how to read a map, and lots of science trivia. We are even able to learn entire languages relatively effortlessly.

But then, as we get older, a curious thing happens with our approach to education. In addition to no longer being compelled to learn all manner of things (because we are, after all, adults, and we really can’t be compelled to learn anything at all), if we do continue to educate ourselves, we focus. We choose a major and learn all that there is to learn about a single topic, such as biology. Then we become experts in that area, well aware of all of the nuances, debates, and changes in facts within that field. We learn more and more about less and less.

But all of our earlier knowledge remains in stasis. Instead of it all growing and developing in a rigorous fashion, like whatever we choose to make our careers in, it generally stays the same. Unless we happen to stumble upon an article in a magazine or newspaper about a certain scientific finding, or unless something is so important and earth shattering that we can’t help but remark upon this new fact’s novelty, we remain stuck at the factual level of our grade-school selves.

We continue to refer to different countries as First World, Second World, or Third World, not recognizing that these terms refer to alignments in the Cold War. Or our awareness of the periodic table remains stuck at high school levels, not realizing that the number of elements has grown a lot since we were in chemistry class.

But this description of how we learn things when we’re young,
and then stop learning, is a little too oversimplified and straightforward. It turns out that many of us do update these sorts of facts, but it often happens only in bursts. And these jumps occur at precise intervals: the length of a single human generation.

.   .   .

THE
science writer Brian Switek pointed out to me that when most people learn about a topic—we were chatting about dinosaurs, but it works for most anything—we learn it when young, in the time of our lives when obsessive knowledge-gathering is the default mode, and then we leave it aside as we turn to more mature topics, or simply other things that we are now interested in.

But we do return to the subject, if only when our own children have reached the same point. Rather than seeing these mesofacts change slowly, in a relatively smooth advancement of knowledge, you only encounter them in bursts, when the next generation does, such as when your child comes home and informs you that dinosaurs were warm-blooded and looked like birds. This
generational knowledge
appears staccato, even though the knowledge changes and accretes steadily.

Whatever doesn’t conform to your childhood, and especially when it comes to dinosaurs, often seems wrong. Just as shifting baseline syndrome makes us assume that whatever state of affairs we were born into is the normal one, we don’t often confront changing facts until another generation grows up with a different baseline. We are then forced to confront the difference between them.

This is true of what’s currently happening with Pluto. If you ask young children in 2012 to name the planets, they go up to Neptune, and they finish by saying that Pluto is a dwarf planet, or distinguish Pluto in some other way. But this is likely a temporary condition. Those teaching want these kids to know about Pluto and its curious status. But soon enough, it will just fade away into a strange footnote, paralleling what happened back in the nineteenth century: Just as Ceres and the other large asteroids were
once counted as planets (marked as such on charts and taught to schoolchildren for decades) until the discovery of the abundant minor planets of the asteroid belt, Pluto’s special place will likely fade away.

Of course, what
generation
means needn’t be literal, although it is often the case that the facts in our brain—and their lifetime—are tied to childbirth. We can also understand what a generation is more figuratively. For example, when it comes to university-specific knowledge, a generation time is far closer to four years than multiple decades, due to the turnover of students. Institutional memory, and its attendant facts and knowledge, are only as permanent as its generation time.

This was made clear to me when reading an essay by Michael Chabon. He was bemoaning the recent commercialization and corruption of the purity that is LEGO. He began with noting how the LEGO sets that children have nowadays are fraught with pieces of every color of the rainbow: pink, purple, sky blue, and more. Furthermore, there are themed sets, from Harry Potter and
Star Wars
, replete with specialized pieces. But back in his day—and I read this approvingly—there were only a small handful of colors: red, blue, green, black, white, and yellow.

Then he continued by lamenting the cause of the downfall from LEGO’s pristine nature: the minifigure. Those small people with the yellow faces and simple grins, who, as Chabon argued, have constituted nothing more than a bastardization of the LEGO aesthetic.

Suddenly I was no longer in agreement with the essay. This was wrong. While I don’t care for the themed and specialized sets, which even include a set that seems to revolve around alien abduction, I grew up with these minifigs. They were a part of my childhood! How dare Chabon view these elemental little men as a corruption of the LEGO ideal? They are part of LEGO’s nature.

And this is precisely the problem. We both were simply rejecting anything newer than our own childhood. Just as many of us only view “technology” as anything invented after we were born,
we took our baseline—when we started playing with LEGO—as the way things should be in the realm of LEGO.

But is it always this simple? Are we forever mentally stuck in whatever state of the world we were born into? Or can we change the knowledge in our heads, even if it’s a bit harder?

.   .   .

IN
chapter 5
, I explored how knowledge spreads and diffuses. But even if it spreads rapidly, what about the speed with which it comes to be accepted? Just as there are phase transitions when it comes to what we know, there can also be phase transitions in how knowledge is accepted and assimilated. Because even when facts spread, sometimes they take time to actually fix in our minds. And this is just as true in the realm of the scientist as it is in the world of the layman.

Clearly, science is not an abstract venture that is done in isolation from everyday human issues. It is not some endeavor immune to passions and biases. Science is an entirely human process. Science is done through hunches and chance recognition of relationships, and is enriched by spirited discussion and debate around the lab. But science is also subject to our baser instincts. Data are hoarded, scientists refuse to collaborate, and grudges can play a role in peer review.

The human aspect of science plays an important role when it comes to the acceptance of new knowledge. We don’t always weigh the evidence for and against a new discovery or theory and then make our decision, especially if it requires a wholesale overhaul of our scientific worldview. Too often we are dragged, spouting alternative theories and contradictory data, to the new theoretical viewpoint. This can be very good. Having more than a few contrarians keeps everyone honest. But it can also be very bad, as when people irrationally hold onto ideas for too long, refusing to admit the errors of their ways. But eventually, in the face of overwhelming evidence, the majority will generally accept the new theory, before their recalcitrance becomes too counterproductive.

Lant Pritchett, a professor of international development at Harvard’s Kennedy School of Government, is all too aware of this. In the field of international development there are many sacred cows, and challenges to them are not met with as much cool and calculating logic as one might wish. Pritchett recently proposed an intriguing idea to help developing countries: create lots of guest worker programs. But is everyone simply weighing its merits? Not exactly. Pritchett argues that a more apt way to describe how these ideas are adopted is that they often follow this trajectory: “Crazy. Crazy. Crazy. Obvious.”

Plot that on a graph, and you’ve got a phase transition, but this time it’s one about how ideas are accepted and adopted. Thomas Kuhn, a physicist turned historian of science, also discussed how such rapid transitions occur in his celebrated book,
The Structure of Scientific Revolutions
. Kuhn used the term
paradigm
to refer to a holistic worldview or theory that can be used to explain our surroundings. (While Kuhn did not invent the word
paradigm
, he used it so much and so often that he is credited with its popularization.) For example, Newtonian gravitation is a very good theory, and has a great deal of explanatory power. But while Newtonian mechanics is actually still used for a large number of engineering applications, it has since given way to the theoretical worldview put forth by Albert Einstein. This change in perspective was termed a
paradigm shift
by Kuhn.

Kuhn argued that switching from one paradigm to another is a messy process and often involves scientists digging in their heels to the extent that their retirement or death—with their attendant replacement by younger and more open minds—might be required for the new paradigm to become accepted.

Max Planck, another physicist, codified this in a maxim: “New scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”

This seems intuitively obvious. Due to science being the biased
and human affair it is, we can’t expect the old stalwarts of science to change their minds when a new idea comes along. We just have to wait for them to die.

However, Planck’s Principle turns out to be wrong.

This can be seen through a careful examination of the work of Charles Darwin. The quintessential phase transition in science, and paradigm shift, is that of the theory of evolution by natural selection. Everything in biology prior to evolution was sophisticated stamp collecting, ordering the living world around us and exploring its wonders. With the advent of evolution, biologists finally had a conceptual framework to make sense of the facts surrounding them. But the acceptance of evolution wasn’t immediate. While
On the Origin of Species
was a bestselling book, it did not find universal agreement within the Victorian populace.

The same was true of the scientists themselves. David Hull, a philosopher of science, examined many of Darwin’s well-known contemporaries to see who eventually accepted the theory of natural selection, and how long it took them to do so. Hull, along with two graduate students, Peter Tessner and Arthur Diamond, examined sixty-seven British scientists from Darwin’s time. They found that only about three quarters of them had accepted Darwinian evolution ten years after
On the Origin of Species
was first published in 1859. So evolution was
not
the rapid phase transition of knowledge acceptance we thought it might have been.

But is this due to the vast majority of the holdout scientists being older? Were Darwin’s ideas rapidly accepted by the younger generation, and was age simply masking what was in fact a phase transition among the younger scientists? It is true that the average age of those who accepted evolution was younger than those who still rejected it after ten years. But there are some complications. Age explains only about 5 percent of the variation of acceptance or rejection of this theory. The younger scientists didn’t necessarily accept it rapidly; they accepted it at a rate similar to the older scientists who accepted it, over the course of a decade. More recent research into Planck’s Principle has generally confirmed Hull’s
initial insight: Planck’s Principle doesn’t hold. Younger scientists aren’t necessarily more likely to accept new ideas, and new ideas don’t spread through a population as rapidly as we might expect.