Michael Gove’s bookcase has gained attention recently due to
some controversial books which appeared on its shelves. Inevitably some people expressed concern that he would own these books as they inferred he may share their
views. In response to this, some people suggested that just because he owns these
books, doesn’t mean he agrees with them.
Even though it seems like a disagreement, both of these statements are compatible with
each other. But to explain this, I am going to talk about a concept in economics
called “signalling”.
Signalling is when your action indicates to others some
information about you. Let’s think of a situation where an employer has two
candidates, one that went to university and one that didn’t. The candidate that didn’t go to university may actually be
smarter (and hence more employable) than the one that did, but just decided not
to go. However, the employer has no way of knowing this, and so must choose a
candidate that they believe is most likely going to be smarter than the other.
To do this, the employer reasons using conditional probability, sometimes referred
to as Bayesian probability after the mathematician. Personally, I prefer to
call it conditional probability as it helps people remember what it is: conditional
on x happening, what are the chances of y. So the question the employer must
ask is “given the condition that the person did or did not go to university, what
is the probably that they are smart?”
The way to think about this is to look at the two different types of groups.
Those what went to university have to be at least smart enough to meet the
entry requirements. Those that did not go, however, include people who are not
smart enough to meet the entry requirements.
Therefore even though it is possible
that the person who didn’t go to university is smarter than the person who did,
it is still more likely that the person we pick at random, who went to university,
is smarter. Therefore, one* reason why people may be tempted to go to
university is because that it acts as a signal to future employers that they
are smart.
Personally, I am really not a fan of how economics uses signalling a lot of the
time. It is not that I do not think people should use Bayesian reasoning, it is
that economists generally use signalling to find negatives in people. Telling some
academic economist about a hobby is tricky as in their minds you should always
be working on your research. Saying that I enjoy pottery acts as a signal to
them that I am not spending every waking moment on a new paper. However, I have
in fact started to tell economists about my hobbies. This is so that if they start
saying anything about my research I have a signal that they are, most likely,
assholes.
So what has all this got to do with Michael Gove’s
bookshelf? Is a bookshelf a signal or is it just a place to store books. I can
buy that some politicians may be sitting in front of their bookcases to appear
smart, even going so far as to choose the books that are on view. But even if they
were not consciously trying to signal something, we could still perform the
same sort of Bayesian reasoning on them.
To say that we cannot learn anything about a person by their
bookshelf is just silly. It either indicates they have read or are going to
read a book. You should be able to work out from my bookshelf that I have at
least studied economics given the amount of economic textbooks on my shelf. At
the same time, it is also true that just because you own a book does not mean
you agree with its views.
For example, owning a copy of Mein Kampf does not mean you are a Nazi. In fact, I am pretty sure
most people who own a copy of Mein Kampf are
not Nazis. However, if you do happen to be a Nazi, I think it is also quite
likely you would own a copy of Mein Kampf.
So if we were to pick a person at random who owns Mein Kampf, then we may be more likely to pick a Nazi then someone
who does not own Mein Kampf.** But importantly
here, even though we are more likely to pick a Nazi, it still pretty unlikely. This
is because the overall number of Nazis is quite low. For example, let us say the
probability of finding a Nazi, given that they own Mein Kampf, is 0.01%, whereas
the probability of finding a Nazi, given that they do not own Mein Kampf is 0.001%.
So yes, I think it is more likely that Michael Gove holds
these controversial views than people who do not own these books, but overall
pretty unlikely that he does hold these views. Whatever my views are on Michael
Gove as a politician, I tend not to think the worst in people in these sorts of
situation. This is because as I was told never to judge a book by its cover (unless
it’s a book about Beysian inference).
*I say ONE reason to go to university here, as I think it is
important (especially as an economist) to say there are many reasons to go to university
then just employability.
**It could be the case the owning a copy of Mein Kampf makes a random person less
likely to be a Nazi if we believe many Nazi’s don’t actually read that many
books.
