If you read
someone a list of ten or twenty items that could be bought at a supermarket,
that person will remember only a few. If you recite the list repeatedly, the
person’s recall will improve. But what really helps is if the items are
mentioned within the categories they fall into—for example, vegetables, fruits,
and cereals. Research suggests that we have neurons in our prefrontal cortex
that respond to categories, and the list exercise illustrates the reason:
categorization is a strategy our brains use to more efficiently process
information.
**
Every object and
person we encounter in the world is unique, but we wouldn’t function very well
if we perceived them that way. We don’t have the time or the mental bandwidth
to observe and consider each detail of every item in our environment. Instead,
we employ a few salient traits that we do observe to assign the object to a
category, and then we base our assessment of the object on the category rather
than the object itself. By maintaining a set of categories, we thus expedite
our reactions. If we hadn’t evolved to operate that way, if our brains treated
everything we encountered as an individual, we might be eaten by a bear while
still deciding whether this particular furry creature is as dangerous as the
one that ate Uncle Bob. Instead, once we see a couple bears eat our relatives
the whole species gets a bad reputation. Then, thanks to categorical thinking,
when we spot a huge, shaggy animal with large, sharp incisors, we don’t hang
around gathering more data; we act on our automatic hunch that it is dangerous
and move away from it.
**
Thinking in terms
of generic categories helps us to navigate our environment with great speed and
efficiency; we understand an object’s gross significance first and worry about
its individuality later. Categorization is one of the most important mental
acts we perform, and we do it all the time.
**
But the arrow of
our reasoning can also point the other way. If we conclude that a certain set
of objects belongs to one group and a second set of objects to another, we may
then perceive those within the same group as more similar than they really
are—and those in different groups as less similar than they really are. Merely
placing objects in groups can affect our judgment of those objects. So while
categorization is a natural and crucial shortcut, like our brain’s other
survival-oriented tricks, it has its drawbacks.
**
In another study,
researchers found that if you ask people in a given city to estimate the
difference in temperature between June 1 and June 30, they will tend to
underestimate it; but if you ask them to estimate the difference in temperature
between June 15 and July 15, they will overestimate it.4 The artificial
grouping of days into months skews our perception: we see two days within a
month as being more similar to each other than equally distant days that occur
in two different months, even though the time interval between them is
identical.
In all these
examples, when we categorize, we polarize. Things that for one arbitrary reason
or another are identified as belonging to the same category seem more similar
to each other than they really are, while those in different categories seem
more different than they really are. The unconscious mind transforms fuzzy
differences and subtle nuances into clear-cut distinctions. Its goal is to
erase irrelevant detail while maintaining information on what is important.
When that’s done successfully, we simplify our environment and make it easier
and faster to navigate. When it’s done inappropriately, we distort our
perceptions, sometimes with results harmful to others, and even ourselves.
That’s especially true when our tendency to categorize affects our view of
other humans—when we view the doctors in a given practice, the attorneys in a
given law firm, the fans of a certain sports team, or the people in a given
race or ethnic group as more alike than they really are.
**
Remember that the
propensity to categorize, even to categorize people, is for the most part a
blessing. It allows us to understand the difference between a bus driver and a
bus passenger, a store clerk and a customer, a receptionist and a physician, a
maître d’ and a waiter, and all the other strangers we interact with,
without our having to pause and consciously puzzle out everyone’s role anew
during each encounter. The challenge is not how to stop categorizing but how to
become aware of when we do it in ways that prevent us from being able to see
individual people for who they really are.
