Why Are Pseudo Personality Tests So Popular?
Throughout this text, we have emphasized the value of critical thinking, which
requires that we recognize our personal biases and analyze data for value and
content. By carefully evaluating the evidence and credibility of the source,
critical thinkers recognize appeals to emotions and faulty logic. When we look
at the various problems with pseudo personality evaluations like the one in our
introductory incident, we can identify at least three different logical
fallacies: the Barnum effect, the fallacy of positive instances, and the selfserving bias.
The Barnum Effect
The first reason we often accept pseudo personality descriptions and horoscope
predictions is that we think they are accurate. We tend to believe these tests
have somehow tapped into our unique selves, when in fact they are ambiguous,
broad statements that fit just about anyone. Being so readily disposed to accept
such generalizations is known as the Barnum effect - after P. T. Barnum, the
legendary circus promoter who said, ‘Always have a little something for
everyone” and “There’s a sucker born every minute.” Reread the bogus personality
profile in the introductory incident. Can you see how “You have a strong need
for other people to like you and admire you” fits almost everyone? Do you know
anyone who doesn’t “at times have serious doubts whether [they’ve] made the
right decision or done the right thing”?
The Fallacy of Positive Instances
Now look again at the personality profile and count the number of times both
sides of a personality trait are given (“You have a strong need for other people
to like you” and “You pride yourself on being an independent thinker.”)
According to the fallacy of positive instances, we tend to notice and remember
events that confirm our expectations and ignore those that are nonconfirming. If
we see ourselves as independent thinkers, for example, we ignore the “needing to
be liked by others” part. Similarly, horoscope readers easily find “Sagittarius
characteristics” in a Sagittarius horoscope but fail to notice when Sagittarius
predictions miss or when the same traits appear for Scorpios or Leos.
The Self-Serving Bias
Now check the overall tone of the personality description. Note how the traits
are generally positive and flattering Ñ or at least neutral. According to the
self-serving bias, we tend to prefer information that maintains a positive selfimage (Brown & Rogers, 1991; Gifford & Hine, 1997). In fact, research shows that
the more favorable a personality description, the more people believe it, and
the more likely they are to believe it is unique to themselves (Guastello,
Guastello, & Craft, 1989). (The self-serving bias might also explain why people
prefer pseudo personality tests to bona fide tests – they’re generally more
flattering.)
Taken together, these three logical fallacies help explain the belief in “pop
psych” personality tests and newspaper horoscopes. They offer “something for
everyone” (the Barnum effect); we pay attention only to what confirms our
expectations (the fallacy of positive instances); and we like flattering
descriptions (the self-serving bias).