In psychology, illusory correlation is the phenomenon of perceiving a relationship between variables (typically people, events, or behaviors) even when no such relationship exists. A false association may be formed because rare or novel occurrences are more salient and therefore tend to capture one's attention. This phenomenon is one way stereotypes form and endure. Hamilton & Rose (1980) found that stereotypes can lead people to expect certain groups and traits to fit together, and then to overestimate the frequency with which these correlations actually occur.
History
"Illusory
correlation" was originally coined by Chapman and Chapman (1967) to
describe people's tendencies to overestimate relationships between two
groups when distinctive and unusual information is presented. The concept was used to question claims about objective knowledge in clinical psychology through Chapmans' refutation of many clinicians' widely used Wheeler signs for homosexuality in Rorschach tests.
Example
David
Hamilton and Robert Gifford (1976) conducted a series of experiments
that demonstrated how stereotypic beliefs regarding minorities could
derive from illusory correlation processes.
To test their hypothesis, Hamilton and Gifford had research
participants read a series of sentences describing either desirable or
undesirable behaviors, which were attributed to either Group A or Group
B.
Abstract groups were used so that no previously established stereotypes
would influence results. Most of the sentences were associated with
Group A, and the remaining few were associated with Group B. The following table summarizes the information given.
| Behaviors | Group A (majority) | Group B (minority) | Total |
|---|---|---|---|
| Desirable | 18 (69%) | 9 (69%) | 27 |
| Undesirable | 8 (30%) | 4 (30%) | 12 |
| Total | 26 | 13 | 39 |
Each group had the same proportions of positive and negative
behaviors, so there was no real association between behaviors and group
membership. Results of the study show that positive, desirable behaviors
were not seen as distinctive so people were accurate in their
associations. On the other hand, when distinctive, undesirable behaviors
were represented in the sentences, the participants overestimated how
much the minority group exhibited the behaviors.
A parallel effect occurs when people judge whether two events,
such as pain and bad weather, are correlated. They rely heavily on the
relatively small number of cases where the two events occur together.
People pay relatively little attention to the other kinds of observation
(of no pain or good weather).
Theories
General theory
Most explanations for illusory correlation involve psychological heuristics: information processing short-cuts that underlie many human judgments. One of these is availability:
the ease with which an idea comes to mind. Availability is often used
to estimate how likely an event is or how often it occurs.
This can result in illusory correlation, because some pairings can come
easily and vividly to mind even though they are not especially
frequent.
Information processing
Martin
Hilbert (2012) proposes an information processing mechanism that
assumes a noisy conversion of objective observations into subjective
judgments. The theory defines noise as the mixing of these observations
during retrieval from memory.
According to the model, underlying cognitions or subjective judgments
are identical with noise or objective observations that can lead to
overconfidence or what is known as conservatism bias—when asked about
behavior participants underestimate the majority or larger group and
overestimate the minority or smaller group. These results are illusory
correlations.
Working-memory capacity
In an experimental study done by Eder, Fiedler and Hamm-Eder (2011), the effects of working-memory
capacity on illusory correlations were investigated. They first looked
at the individual differences in working memory, and then looked to see
if that had any effect on the formation of illusory correlations. They
found that individuals with higher working memory capacity viewed
minority group members more positively than individuals with lower
working memory capacity. In a second experiment, the authors looked
into the effects of memory load
in working memory on illusory correlations. They found that increased
memory load in working memory led to an increase in the prevalence of
illusory correlations. The experiment was designed to specifically test
working memory and not substantial stimulus memory. This means that
the development of illusory correlations was caused by deficiencies in
central cognitive resources caused by the load in working memory, not selective recall.
Attention theory of learning
Attention
theory of learning proposes that features of majority groups are
learned first, and then features of minority groups. This results in an
attempt to distinguish the minority group from the majority, leading to
these differences being learned more quickly. The Attention theory also
argues that, instead of forming one stereotype regarding the minority
group, two stereotypes, one for the majority and one for the minority,
are formed.
Effect of learning
A
study was conducted to investigate whether increased learning would
have any effect on illusory correlations. It was found that educating
people about how illusory correlation occurs resulted in a decreased
incidence of illusory correlations.
Age
Johnson and
Jacobs (2003) performed an experiment to see how early in life
individuals begin forming illusory correlations. Children in grades 2
and 5 were exposed to a typical illusory correlation paradigm to see if
negative attributes were associated with the minority group. The authors
found that both groups formed illusory correlations.
A study also found that children create illusory correlations.
In their experiment, children in grades 1, 3, 5, and 7, and adults all
looked at the same illusory correlation paradigm. The study found that
children did create significant illusory correlations, but those
correlations were weaker than the ones created by adults. In a second
study, groups of shapes with different colors were used. The formation
of illusory correlation persisted showing that social stimuli are not
necessary for creating these correlations.
Explicit versus implicit attitudes
Two
studies performed by Ratliff and Nosek examined whether or not explicit
and implicit attitudes affected illusory correlations. In one study,
Ratliff and Nosek had two groups: one a majority and the other a
minority. They then had three groups of participants, all with readings
about the two groups. One group of participants received overwhelming
pro-majority readings, one was given pro-minority readings, and one
received neutral readings. The groups that had pro-majority and
pro-minority readings favored their respective pro groups both
explicitly and implicitly. The group that had neutral readings favored
the majority explicitly, but not implicitly. The second study was
similar, but instead of readings, pictures of behaviors were shown, and
the participants wrote a sentence describing the behavior they saw in
the pictures presented. The findings of both studies supported the
authors' argument that the differences found between the explicit and
implicit attitudes is a result of the interpretation of the covariation
and making judgments based on these interpretations (explicit) instead
of just accounting for the covariation (implicit).
Paradigm structure
Berndsen
et al. (1999) wanted to determine if the structure of testing for
illusory correlations could lead to the formation of illusory
correlations. The hypothesis was that identifying test variables as
Group A and Group B might be causing the participants to look for
differences between the groups, resulting in the creation of illusory
correlations. An experiment was set up where one set of participants
were told the groups were Group A and Group B, while another set of
participants were given groups labeled as students who graduated in 1993
or 1994. This study found that illusory correlations were more likely
to be created when the groups were Group A and B, as compared to
students of the class of 1993 or the class of 1994.
