The ideal of science is to respect the evidence — to take nobody’s word for it. But this cuts against our social instinct to pay deference to members of our tribe.

Blair Fix

If you ask the average person what 'science' is, they'll probably answer
something like 'it's what we know about the world'. To the lay person,
'science' is a body of facts.

To the trained scientist, however, 'science' means something different.
It's not a body of knowledge. It's a *method* for determining what's
true and what's not. To determine the way the world works, science
appeals to *evidence*.

The ideal of science is beautifully summarized by the motto of the Royal
Society: *nullius in verba*. It means *'take nobody's word for it'*. In
science, there is no authority. There are no gods, no kings, and no
masters. Only evidence.

In this post, I reflect on how *'taking nobody's word for it'* cuts
against some of our deepest instincts as humans. As social animals, we
have evolved to trust members of our group. Among these group members,
our instinct is to 'take their word for it'. I call this the 'tribal
instinct'.

When we do science, we have to fight against this tribal instinct. Not
surprisingly, we often fail. Rational skepticism gets overpowered by the
instinct to trust members of our group. If the group happens to be
powerful --- say it dominates academia in a particular discipline ---
then false ideas get entrenched as 'facts'.

This is a problem in all areas of science. But it's a rampant problem in
economics. The teaching of economics is dominated by the neoclassical
sect, which has managed to entrench itself in academia. Among this sect,
I believe, tribal instincts trump the rational appeal to evidence.

Recent empirical work highlights this fact. Neoclassical economists, it
seems, pay deference to fellow members of their sect. But before getting
to the fascinating empirical results, we'll take a brief foray into
evolutionary biology. This will help us understand why skepticism and
the rational appeal to evidence so often get trumped by the tribal
instinct to believe members of our group.

### Our evolved sociality

While economists like to pretend otherwise, humans are social animals.
We spend the vast majority of our lives in groups, and much of our time
is spent negotiating social relations. Like all other social animals,
we've evolved to behave this way. Sociality is an instinctual behavior.

In my opinion, the best explanation for the evolution of sociality comes
from [ 
multilevel selection
theory](https://en.wikipedia.org/wiki/Group_selection#Multilevel_selection_theory){target="_blank"
rel="noopener"}. Like orthodox Darwinism, multilevel selection theory
appeals to 'survival of the fittest'. The difference, however, is that
multilevel selection looks at many 'levels' of selection. Orthodox
Darwinism, in contrast, is concerned only with selection between
individuals. One individual out-reproduces another, and so passes more
of its genes to future generations.

Multilevel selection keeps this selection between individuals, but adds
other units of selection --- both smaller and larger. At the smaller
level, there is selection between cells *within* organisms. This
explains how multi-cellular organisms evolved in the first place. At the
larger level, there is selection *between* groups of organisms. This
explains how sociality evolves.

To explain the evolution of sociality, multilevel selection proposes
that there must be competition between groups. The fiercer this
competition, the stronger the selection for sociality. Like Darwin's
original theory of natural selection, the premise of this group
selection is simple. Here's how David Sloane Wilson and E.O. Wilson put
it:

> Selfishness beats altruism within groups. Altruistic groups beat
> selfish groups. Everything else is commentary.
> [(Source)](https://www.journals.uchicago.edu/doi/pdf/10.1086/522809){target="_blank"
> rel="noopener"}

If there is strong competition between groups (especially if larger
groups beat smaller groups), we expect sociality to evolve. The catch is
that strong selection at the group level seems to be rare. We infer this
because a minuscule fraction of all species are
[eusocial](https://en.wikipedia.org/wiki/Eusociality){target="_blank"
rel="noopener"} (or 'ultra-social').

Yet when group selection does happen, it produces potent results.
Ultra-social species may be rare (in terms of the number of species),
but they are spectacularly successful. In [The Social Conquest of the
Earth](https://www.goodreads.com/book/show/12918295-the-social-conquest-of-earth){target="_blank"
rel="noopener"}, evolutionary biologist E.O Wilson observes that the few
ultra-social species that do exist --- bees, ants, termites ... and
humans --- dominate the planet (in terms of biomass).

### Natural selection for tribalism: 'taking somebody's word for it'

With group selection in mind, let's think about how the human instinct
for tribalism --- 'taking somebody's word for it' --- might evolve.

Imagine that you're a member of a small tribe of hunter gatherers. A
member of your tribe returns from a scouting mission and warns that a
rival tribe is about to attack.

What do you do?

Do you take the scouts' word for it? Or are you skeptical until you see
the evidence first hand?

Let's imagine how these two options might play out.

If you (and every other member of the tribe) take the scout's word for
it, then you immediately prepare for battle. If the scout was lying, the
worst thing that could happen is that your tribe needlessly prepares for
battle. This wastes your time, but little else. But if the scout was
telling the truth, your tribe potentially avoids a devastating defeat
(worst-case scenario ... everyone dies).

Now imagine your tribe is filled with skeptical scientists. You (and
every other member of the tribe) take nobody's word for it. Seeking
first-hand evidence that a rival tribe is actually approaching, each
tribe member leaves the camp undefended. If the scout was lying, you
avoid needlessly preparing for battle. But if the scout was telling the
truth, your tribe potentially gets massacred by its rival. Viola, your
tribe of skeptics is eliminated from the gene pool.

If we repeat this scenario a few hundred thousand times, we can see how
selection for trust of group members would occur. The groups that follow
the ideals of science --- 'taking nobody's word for it' --- slowly get
wiped out. The groups that reject the ideals of science and 'take a
tribe-member's word for it' win out.

The point I want to make with this parable is that in many situations,
trust of group members is a more adaptive trait than rational
skepticism. This is certainly the case with warfare --- violent
competition between groups. And as Peter Turchin [convincingly
argues](http://peterturchin.com/ultrasociety/){target="_blank"
rel="noopener"}, warfare may have been the driving force behind human
sociality. Warfare rewards groups that are able to function
collectively, and punishes those that are not.

### Tribalism in science

In light of the evolution of sociality, it's not surprising that humans
have an instinct to 'take the word' of fellow group members. What is
surprising is our capacity for rational skepticism. Clearly we do have
the ability to 'take nobody's word for it'. Science depends on this
ability. But it's by no means our dominant instinct.

Doing science, I argue, is a precarious act. The scientist must foster
rational skepticism and suppress the instinct to conform to the ideas of
the group. At the same time, testing scientific theories often requires
large-scale cooperation. Experiments in particle physics, for instance,
involve the cooperation of thousands of people. These scientists must
maintain skepticism while simultaneously having faith in the actions of
fellow group members.

This balancing act can easily veer in the wrong direction. Thus we
should not be surprised when tribalism prevails, and false ideas get
ensconced as 'facts'. And we should celebrate (because of its
improbability) when the rational appeal to evidence wins the day.

### Measuring tribalism in science

Here's a fun idea: what if we scientifically studied tribalism in
science? It would be quite simple to do. To study tribalism, we'd
measure the degree to which scientists hold the following ideals:

**Ideal of Tribalism**: Take group members' word for it.

**Ideal of Science**: Take nobody's word for it.

Of course, we can't directly ask scientists which ideal they hold.
They'll almost certainly respond that they respect the ideals of
science. The problem of tribalism, I suspect, is an unconscious one.
Scientists know (or at least profess to know) that they should respect
evidence. But tribal instincts get in the way. For instance, a scientist
might selectively interpret evidence (or even ignore it entirely) based
on the ideas of his/her group. In most cases, the scientist will be
unaware of what's going on.

To test for tribalism, we need to measure unconscious bias. Here's one
way we could do it. We test if scientists' agreement with a given
statement is affected by its attribution.

If tribalism dominates, we expect scientists to agree with a statement
if it is attributed to a member of their tribe. Conversely, they should
disagree with the same statement if it is attributed to a non-member of
their tribe.

Here's a fun example applied to the most tribal of human activities ---
organized religion. Suppose we asked American Christians if they agree
with the following statements.

"God is great." --- Pope Francis

"God is great.' --- Osama Bin Laden

My guess is that agreement would drop precipitously when the statement
is attributed to Osama Bin Laden. His 'God', after all, is not the
Christian God.

Conversely, suppose we asked physicists if they agree with the following
statements:

"The Earth is round." --- Stephen Hawking

"The Earth is round.' --- Donald Trump

Because there's overwhelming evidence that the Earth is round, we expect
100% agreement with both statements. In other words, the evidence trumps
physicists' loathe for Trump (who is clearly not a member of their
physics tribe).

These are toy examples, meant to illustrate the extreme between
tribalistic and scientific ideals. But they illustrate a point. If the
ideals of science dominate a discipline, attribution shouldn't affect
scientists' agreement with a statement. Conversely, if the ideals of
tribalism dominate a discipline, attribution should strongly affect
agreement with a statement. Scientists should be more likely to agree
with a statement if it's attributed to a member of their tribe.

### Measuring tribalism in economics

This brings us to the results that you've been waiting for --- the
evidence of tribalism in economics.

Mohsen Javdani and Ha-Joon Chang recently [conducted a survey of
economists](https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3356309){target="_blank"
rel="noopener"} that mirrors the logic described above. Javdani and
Chang asked economists if they agreed with a given statement. With one
exception, the statements came from members of the mainstream tribe in
economics (the neoclassical sect). But unbenounced to the economists,
Javdani and Chang randomly switched the attribution of the statement
from its original (neoclassical) source to a heterodox (non-mainstream)
source. Javdani and Chang then tested how this change in attribution
affected economists' agreement with the statement.

Before getting to the results, let me frame my expectations. After
studying economics for a decade, I've come to believe that the field is
incredibly tribal. It's dominated by a sect of neoclassical economists.
Among these economists, deference to authority (prestigious members of
the tribe) is everything. Evidence is an afterthought. In-house critic
Paul Romer [puts it this
way](https://paulromer.net/trouble-with-macroeconomics-update/WP-Trouble.pdf){target="_blank"
rel="noopener"}:

> Progress in the field \[of economics\] is judged by the purity of its
> mathematical theories, as determined by the authorities.

Given my experience in economics, I wasn't surprised when I read Javdani
and Chang's results. They found that agreement with a given statement
strongly depended on its attribution. Economists were more likely to
agree with a statement if it was attributed to a mainstream source
versus a heterodox source. Here's their results:

<figure id="attachment_713" class="wp-caption alignnone"
aria-describedby="caption-attachment-713" style="width: 680px">
<img
src="https://i0.wp.com/economicsfromthetopdown.com/wp-content/uploads/2019/08/javdani_chang.png?resize=680%2C479&amp;ssl=1"
class="alignnone size-full wp-image-713" loading="lazy" decoding="async"
data-attachment-id="713"
data-permalink="https://economicsfromthetopdown.com/javdani_chang/"
data-orig-file="https://i0.wp.com/economicsfromthetopdown.com/wp-content/uploads/2019/08/javdani_chang.png?fit=680%2C479&amp;ssl=1"
data-orig-size="680,479" data-comments-opened="1"
data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}"
data-image-title="javdani_chang" data-image-description=""
data-image-caption="&lt;p&gt;Evidence for tribalism in economics.&lt;/p&gt;
"
data-medium-file="https://i0.wp.com/economicsfromthetopdown.com/wp-content/uploads/2019/08/javdani_chang.png?fit=300%2C211&amp;ssl=1"
data-large-file="https://i0.wp.com/economicsfromthetopdown.com/wp-content/uploads/2019/08/javdani_chang.png?fit=680%2C479&amp;ssl=1"
data-recalc-dims="1" width="680" height="479" alt="javdani_chang" />
<figcaption> 
Evidence for tribalism in economics. This chart shows
the difference in economists’ agreement with a statement when
attribution was changed from a mainstream to a non-mainstream source.
The table below shows the economists to which each statement was
attributed. The first name is the actual source. The bold name is the
non-mainstream economist. Source: <a
href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3356309"
target="_blank" rel="noopener">“Who Said or What Said?”</a> by Mohsen
Javdani and Ha-Joon Chang. 
</figcaption>
</figure>

To interpret this chart, look at the sign of the plotted point. If it's
positive, agreement increased when the statement was attributed to a
non-mainstream source. If it's negative, agreement decreased. All but
one points are negative, meaning economists agree more with a statement
if it is attributed to a mainstream economist.

These results nicely demonstrates how tribalism dominates economics.
Most economists are members of the neoclassical tribe. And rather than
'take nobody's word for it', economists preferentially take fellow
tribe-members word for it.

### Rationalizing tribalism

Perhaps even more interesting than Javdani and Chang's results, is
neoclassical economists *reaction* to these results. I recently
[posted](https://twitter.com/blair_fix/status/1161468719840710656){target="_blank"
rel="noopener"} the above figure on Twitter, causing a bit of a
firestorm. Here are some of the reactions:

> Many of the heterodox economists listed are ... known to not know much
> of value so brand name capital is either minimal or negative. Real
> finding of paper is there aren't ten heterodox economists that are
> even well known. 
> ([Source](https://twitter.com/JimRose69872629/status/1161942161144762368){target="_blank"
> rel="noopener"})

> The Econ Nobel is a good indicator of being within the scientific
> consensus, if anything it's less of an appeal to authority than
> trusting a random heterodox academic on economic\[s\] because "they're
> an economist".
> ([Source](https://twitter.com/davidmonington/status/1162000063847002114){target="_blank"
> rel="noopener"})

> I'm ... not sure that reliance on authority is necessarily fallacious
> if authority only granted on basis of expertise and judgment earned
> through years of careful study.
> ([Source](https://twitter.com/IlliniBizDean/status/1162027229427195904){target="_blank"
> rel="noopener"})

Rather than refute the study's findings, these reactions demonstrate
that mainstream economists know little about the ideals of science.
Among members of the tribe, deference to authority is the 'rational'
course of action. And we all know how neoclassical economists worship
rationality.

### A broader problem?

Lest we be too hard on economics, I think Javdani and Chang's findings
would probably replicate in other social sciences, and to a lesser
extent in the natural sciences. But I suspect that the results would be
less spectacular. My experience is that economics is far and away the
most tribal of disciplines.

I'd like to see this type of research extended to all disciplines, and
studied over time. Given our evolutionary heritage, we should expect to
find tribal instincts at work in science, even when scientists profess
to respect only the evidence.

The ideal of science --- to take nobody's word for it --- contradicts
our social instincts. It's far easier to believe people we trust ---
members of our tribe. That science works at all is something we should
marvel at. And when we fall short of the ideals of science, we shouldn't
obfuscate. We should admit that we've given in to base urges, and that
we need to do better.

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If you ask the average person what ‘science’ is, they’ll probably answer something like ‘it’s what we know about the world’. To the lay person, ‘science’ is a body of facts. To the trained scientist, however, ‘science’ means something different. It’s not a body of knowledge. It’s a

 method

for determining what’s true and what’s not.

Messaggi di Rogue Scholar

Tribalism in Science (and Economics)