During the last election, we heard lots of generic
statements about political parties. Ads
told us that Democrats want to allow the government to intrude on the rights of
individuals. We heard that Republicans
want to take away funding for key social services. We were told that the Tea Party was racist.
These kinds of statements are called generics. A generic
statement is one that makes a blanket statement about the members of a
category. We use these kinds of sentences
all the time, even when we are not trying to be persuasive. For example, the simple sentence “Cardinals
are red” is a generic. We often use
sentences like this when teaching people about the properties of objects.
It turns out, though, that the psychology of generic
statements is quite interesting, and that it has important implications for how
we use them to persuade people. The
psychology of these generics was explored in a paper in the November, 2010
issue of Cognitive Science by Andrei
Cimpian, Amanda Brandone, and Susan Gelman.
They explored two facets of generics. The first is the number of members of a
category that have to have a property in order for us to be willing to use the
generic statement. For example, most of
us would be willing to say that cardinals are red, even though only about half
of cardinals (the males) are actually red.
Female cardinals are a dull color that helps them hide from predators. The second facet is our belief about what
proportion of category members people believe have a property when they hear a
generic statement.
These researchers had people do one of two tasks. In one condition, they described novel
animals that live on a fictitious island.
People were told about a property that the animal has. Some of the animals had particularly
distinctive or dangerous properties, while others had properties that did not
distinguish them from other animals.
They were also told what percentage of the animals of that type had the
property. These percentages varied from
10% to 100%.
One group was asked
whether a generic statement (like “Morseths have silver fur”) was appropriate to describe the
animals. People asked this question felt
that generic statements were most appropriate to use when the property was distinctive. That is, people feel that generic sentences
are less appropriate for describing properties of objects that are common to
lots of different things than for those properties that are distinctive. Of particular interest, though, people were
often willing to accept the generic statement even if only 50% of the animals
had the property.
A second group was asked to predict how many members of a
category were likely to have a property given a generic statement. If people heard a statement like “Morseths
have silver fur” they believed that about 90% of them actually had the
property.
Think about this. It
means that people are willing to use generic sentences to describe a category
when only 50% of the category members have that property. But, when people hear a sentence with a
generic in it, they assume that almost all of the category members have that
property.
These results really matter.
They mean that when we hear an ad with a generic statement in it, we
assume that it applies to almost all of the members of the category being
described. Hearing an ad that mentions
Democrats, Republicans, or the Tea Party can be misleadingly persuasive by
making people believe that almost all of them have a common set of
beliefs.
What can you do about this?
When you hear an ad that uses generic statements, think about how many
members of a category you really think it applies to. It will take a little work on your part, but
it can ultimately help you to make better decisions.
