Judgment and Decision
Making, vol. 2, no. 1, February 2007, pp. 48-53.
Susceptibility to anchoring effects: How
openness-to-experience influences responses to anchoring cues
Todd McElroy1
and Keith Dowd
Department of Psychology
Appalachian State University
Abstract
Previous research on anchoring has shown this heuristic to be a very
robust psychological phenomenon ubiquitous across many domains of human
judgment and decision-making. Despite the prevalence of anchoring
effects, researchers have only recently begun to investigate the
underlying factors responsible for how and in what ways a person is
susceptible to them. This paper examines how one such factor, the
Big-Five personality trait of openness-to-experience, influences the
effect of previously presented anchors on
participants' judgments. Our findings indicate that
participants high in openness-to-experience were significantly more
influenced by anchoring cues relative to participants low in this
trait. These findings were consistent across two different types of
anchoring tasks providing convergent evidence for our hypothesis.
Keywords: anchoring, openness, personality, judgment, Big-5.
1 Introduction
The anchoring effect (e.g., Lichtenstein & Slovic, 1971; Tversky
& Kahneman, 1974; Wilson, Houston, Etling, & Brekke, 1996)
refers to the adjustment of one's assessment, higher or lower,
based upon previously presented external information or an
"anchor." The anchoring heuristic appears to be prevalent
throughout human decision processes and has been shown to
reliably influence judgments in a variety of domains including
probability estimates (Plous, 1989; Tversky n& Kahneman, 1974),
negotiation (Neale & Bazerman, 1991; Ritov, 1996), legal
judgments (Chapman & Bornstein, 1996), and general knowledge
(Chapman & Johnson, 1999; Jacowitz & Kahnman, 1995; Wilson,
Houston, Etling, & Brekke, 1996). Further, anchoring effects
appear viable across most situations for both novices and experts
(Northcraft & Neale, 1987) and seem to be effective under
conditions of monetary incentives (Chapman & Johnson, 1999;
Wilson, Houston, Etling, & Brekke, 1996; Wright & Anderson,
1989) and in real-world settings (Northcraft & Neale, 1987;
Cervone & Peak, 1986).
Anchoring thus appears to be a very robust psychological phenomenon.
However, not all individuals may be equally influenced by anchoring
cues. Identification of factors that influence how and in what ways a
person is susceptible to this heuristic should further the
understanding of the process. One avenue of approach is to investigate
the role of individual difference factors.
Tversky and Kahneman (1981) pointed to the important role of
"personal characteristics" of the
decision maker in risky choice situations. Later work by Stanovich and
West (1998; 2000) suggested that intellectual traits influence decision
making and consequential choice preference. Recently, individual
differences have been found in numerical reliance (Bartels, 2006;
McElroy & Seta, 2003; Peters, Vastfall, & Slovic, 2006; Simon, Fagley,
& Halleran, 2004), ambiguity (Lauriola & Levin, 2001; Nowlis, Kahn,
& Dhar, 2002), preference for actions or inactions (Baron & Ritov,
2004) and the optimistic bias (Buehler & Griffin, 2003). The Big-Five
personality traits (Lauriola & Levin, 2001; Levin, Gaeth, &
Schreiber, 2002) have proven to be important individual difference
factors for understanding decision choices. Further, attesting to the
importance of individual differences, Levin and Hart (2003)
demonstrated that individual differences in preference appear to
originate at a very early age. Taken together, these findings suggest
that the impact of individual difference factors on decision-making is
both profound and pervasive.
The purpose of the current study is to investigate how one individual
difference factor may influence the strength of the anchoring effect.
Specifically, we are interested in how individual differences in
the personality trait of openness-to-experience influences anchoring
effects.
Openness-to-experience. In the last couple of decades the
five-factor model of personality has become the most widely tested and
well-regarded personality trait model. A great deal of research has
supported this model's validity and reliability
(Goldberg, 1981; John, 1990; McCrae & Costa, 1987). While most
research has agreed on the nature of the first four factors, the nature
of the fifth factor has been controversial; a controversy predominately
based upon whether a lexical approach, derived from language frequency
within the lexicon of a particular language (Saucier & Goldberg,
1996), or a questionnaire approach (McCrae & Costa, 1997) should be
used to measure it.
The fifth factor is often labeled openness-to-experience, which
refers to a propensity to adjust beliefs and behaviors when
exposed to new types of information or ideas (John, 1990).
Individuals scoring high on this dimension are more open to new
ideas (McCrae, 1987) and motivated to seek variety and external
experience. Individuals scoring low tend to be less inclined to
consider alternative opinions and are more steadfast in their own
beliefs (John, 1990) making them more likely to rely upon
information that is familiar and conventional (McCrae & Costa,
1997).
A fundamental aspect of the anchoring effect is that individuals
are sensitive to information which they have experienced. This
change in judgment, which is based upon external cues, seems
particularly relevant and related to the openness-to-experience
personality trait. Specifically, as research has shown, the
openness trait reflects individual propensities to "adjust"
one's beliefs (John, 1990) and to consider external information
(McCrae, 1987).
Therefore, based upon the nature of the openness-to-experience trait and
the processes involved in the anchoring effect, we hypothesize that
individual differences in openness-to-experience will influence
susceptibility to anchoring effects. Specifically, we hypothesize that
the judgments of those individuals high in this trait will be more
influenced by previously presented anchors whereas those individuals
low in this trait will be less influenced by the anchor. To test this
hypothesis, we first measured individual levels of the personality
trait of openness-to-experience. We then provided participants with an
anchoring task involving either the Mississippi river (Study 1) or
African nations in the UN (Study 2).
2 Experiment 1
2.1 Method
2.1.1 Participants and design
We distributed questionnaires to a sample of 197 undergraduate students
at Appalachian State University2.
The design of our study included the observed variable of
openness-to-experience and our manipulated variable of anchor (high,
low). Participants' estimates of the length of the
Mississippi river served as our dependent variable.
2.1.2 Procedure and materials
All participants were first informed about the nature of our study.
After consenting to take part in the study, participants were presented
with the ten-item personality inventory, otherwise known as TIPI
(Gosling, Rentfrow, & Swann, 2003). The TIPI contains two separate
items that address each of the Big-Five factors (e.g., extraverted,
self-disciplined, anxious, warm, calm, uncreative). In this scale,
participants are asked to rate the extent that they feel each of the
traits applies to them. All responses to these items were made on a
7-point scale. This measure was utilized because of its accuracy and
brevity in assessing individual differences pertaining to the
Five-Factor Model. Despite having somewhat diminished psychometric
properties due to its truncated length, the TIPI has nonetheless shown
adequate test-retest reliability. Furthermore, research has
demonstrated that the TIPI has convergence validity with widely used
Big-Five measures and convergence between self and observer ratings
(Gosling, Rentfrow, & Swann, 2003).
After completing the TIPI scale, participants were presented with a
traditional anchoring task involving the Mississippi river (Jacowitz &
Kahneman, 1995). In this task, participants were first asked to
estimate whether the length of the Mississippi river is more or less
than 200 or 20,000 miles; this initial activity serves as the
"anchor". Participants were then
asked to estimate the exact length of the Mississippi river. All
participants were then informed about the nature of our study, thanked,
and released from the study.
Table 1: Average Mississippi river length estimate as a function of openness to
experience and anchor.
| Anchor |
| High | Low |
(lr)2-4(lr)5-7
Openness | N | Mean | Std. error | N | Mean | Std. error |
High | 50 | 10,021.26 | 1360.36 | 68 | 698.50 | 82.01 |
Low | 47 | 6,876.02 | 1204.82 | 30 | 1,372.00 | 606.04 |
|
2.2 Results
In order to investigate whether the personality factor of
openness-to-experience influenced participants'
susceptibility to the anchor, we performed a regression analysis with
anchor (high, low) and participants'
openness-to-experience scores serving as our independent variables.
Participants' estimates of the length of the
Mississippi river acted as the dependent variable. This analysis
revealed a significant interaction (F (1, 191) = 7.72, p
.007) indicating a greater anchoring effect for greater
levels of openness-to-experience (see Table 1). In the high anchor
condition, participants level of openness had a significant effect on
their estimates (F (1, 95) = 4.9, p .03) such
that, higher levels of openness were associated with higher estimates.
In the low anchor condition we again found significant results for
openness and participants estimates (F (1, 96) = 11.25, p
.002), indicating that higher levels of openness were associated with
lower estimates.
We also wanted to examine whether any of the other Big-Five personality
traits may have an influence on susceptibility to anchoring cues. In
order to investigate this, we performed a regression analysis with each
of the remaining four trait scores and anchor as independent variables
and participants' estimates of the length of the
Mississippi river as the dependent variable. These analyses revealed
no significant interaction effects for any of the remaining Big-Five
traits: extraversion (F (1, 191) = 1.97, p
.16), agreeableness (F (1, 191) = 1.0, p .3),
conscientiousness (F (1, 191) = .4, p .5) and
emotional stability (F (1, 191) = .85, p .36).
3 Experiment 2
Study 2 was designed to test for a conceptual replication of our
findings involving the openness trait and its influence on anchoring
effects. In Study 1 we used the traditional Mississippi river
anchoring task, however, in Study 2 we wanted to examine our hypothesis
using a different scenario. Therefore, in this experiment we used an
anchoring task involving the percentage of African nations in the
United Nations.
3.1 Participants and design
We distributed questionnaires to 200 undergraduate psychology students
at Appalachian State University3. Similar to Study 1, the design of our experiment
included the independent variables of participants'
level of openness-to-experience and anchor (high, low).
Participants' estimates of the percentage of African
nations in the United Nations served as our dependent variable.
3.1.1 Procedure and materials
After consenting to take part in our study, participants were first
presented with the TIPI Big-Five personality scale. After completing
the scale, participants were presented with our anchoring task (Tversky
& Kahneman, 1974). In this task, we first asked participants whether
the percentage of African nations that are members of the United
Nations is more or less than 85 (high anchor condition) or 25 (low
anchor condition). We then asked participants to estimate the exact
percentage of African nations.
Table 2: Average African nation percentage estimate as a function of openness to
experience and anchor.
| Anchor |
| High | Low |
(lr)2-4(lr)5-7
Openness | N | Mean | Std. error | N | Mean | Std. error |
High | 69 | 43.46 | 3.07 | 66 | 33.70 | 2.53 |
Low | 31 | 25.29 | 3.50 | 34 | 37.27 | 4.49 |
|
3.2 Results
As was the case in Study 1, we wanted to examine whether high and
low openness-to-experience participants differed in their
susceptibility to anchors. To do so, we performed a regression
analysis with participants' openness scores and anchor as our
independent variables and participants' estimates of percentage
of African nations in the UN as our dependent variable.
Similar to Study 1, we found a significant interaction between
openness scores and anchor (F (1, 195) = 4.95, p
.03) again, indicating greater anchoring effects for
greater levels of openness (see Table 2). Further analysis
revealed that, in the high anchor condition, participants level
of openness was significantly related to their estimates (F (1,
97) = 9.77, p .003) with greater openness
scores associated with greater estimates. In the low anchor
condition however, no significant relationship was found between
openness and participants estimates (F (1, 98) = .03, p
.8).
As was the case in Study 1, we also wanted to examine whether any of
the remaining Big-Five personality traits may be influencing
susceptibility to anchoring cues. Therefore, we again performed
separate regression analyses with the remaining Big-Five personality
traits and anchor cue acting as independent variables and estimates of
the percentage of African nations in the UN as the dependent variable.
These analyses revealed no significant interaction effects for any
other Big-Five personality traits: extraversion (F (1, 195) = .01,
p .9), agreeableness (F (1, 195) = .14,
p .7), conscientiousness (F (1, 195) = .34,
p .56) and emotional stability (F (1, 195) =
.27, p .11).
4 Discussion
In this paper we set out to test whether the fifth factor of
openness-to-experience, as depicted by McCrae & Costa (1997; 1999),
may influence individual sensitivity to anchor cues and in turn,
individual judgments. Across two separate tasks involving estimates
about the length of the Mississippi river (Study 1) and membership of
African nations in the UN (Study 2) we examined the hypothesis that
individuals high in the personality trait of openness-to-experience
would be more influenced by a previously presented anchor relative to
individuals low in this trait. We found partial support for this
hypothesis. Our findings demonstrated that high openness-to-experience
participants were more influenced by high and low anchoring cues for
the Mississippi river estimation task but only for high anchors in the
African nations task.
Limitations. Several limitations are present within the
current studies. First, the measure we selected to assess
openness-to-experience was chosen because of its conciseness and
brevity; however, its short length comes at the expense of reliability,
a psychometric limitation that is indigenousness to all short
instruments. Furthermore, the TIPI scale, again due to its length, is
able to offer only a broad assessment of the Big-Five personality
constructs. The Big-Five dimensions are principally broad constructs
that can be broken down into several related but discrete components.
For example, it has been argued that openness-to-experience consists of
several narrower facet-level constructs, such as creativity and
intelligence. As noted by its authors, the TIPI is unable to provide
scores for these facet-level constructs, which are often better
predictors of specific criteria (Gosling, Rentfrow, & Swann, 2003).
Though the TIPI scale offered a sensible option for the present
studies, future research investigating how personality traits mediate
susceptibility to anchoring cues may benefit from investing in
multi-item measures of the Big-Five to avoid these limitations.
Another potential problem surfaces around the fact that we found our
strongest evidence within the high anchor condition. Because our
findings were largely driven by the high anchoring condition in Study
2, it is possible that our results could be an artifact of high
openness individuals making higher estimates in general. More
specifically, it could be the case that high openness participants have
a general tendency to estimate higher numbers relative to low openness
individuals, especially in Study 2. In order to examine this
possibility, we provided a separate set of participants with either the
Mississippi length estimation task or the African nations task without
the presence of an anchor. If it is the case that greater levels of
openness lead to greater number estimations then we would expect
correlations indicative of this relationship. Our results did not
reveal a significant correlation between openness scores and
participants' estimates for either the Mississippi river task
(r (33) = .2 p .24) or the African
nations task (r (33) = .02 p .87).
Thus, these results provide evidence that our earlier findings were not
just due to a relationship between openness and estimation tendency.
Rather, the nonexistence of such a correlation supports our contention
that higher levels of openness lead individuals to become relatively
more influenced by anchoring cues.
Future research. The fact that we found differences for
openness and low anchors in one study and not the other raises
some interesting questions for future research. For example, It
could be the case that we experienced a "floor
effect"4, in that, anchor-free estimates for the African
nations study may be closer to low anchor estimates relative to
the Mississippi river study. Although speculative, this could be
why high openness participants did not appear to be as affected
by the low anchor in the African nations study. In order to
attempt to provide a post-hoc observation of this possibility, we
collapsed across our openness variable and only observed mean
estimates for the high and low anchor conditions for both our
studies as well as our anchor-free study. Observation of this
data across studies reveals that the anchor free estimates of the
Mississippi river length (M = 4681.50) fell roughly between the
average estimates in the high anchor (M = 8497.28) and low anchor
(M = 904.66) conditions. The African nations anchor-free study
yielded a mean (M = 35.15) that appears descriptively closer to
the low anchor mean (M = 34.91) than the high anchor mean (M =
37.77). While this is only a post-hoc observation, it does
provide an interesting possibility for future research.
These findings also pose interesting questions about how individual
differences in openness-to-experience may influence judgments for other
heuristics and biases as well. This should be especially true for
decision tasks where reliance on external information is involved. One
example of when external cues influence judgments is the framing effect
(Kahneman & Tversky, 1979). Previous research has found a
relationship between openness and risk preference, such that, high
openness individuals demonstrated relatively more risk-seeking in their
choices for typical framing tasks (Lauriola & Levin, 2001; Levin,
Gaeth, Schneider, & Lauriola, 2002). Future research may want to
explore whether this effect is due to reliance on external information
(e.g., the frame) or whether it represents a general tendency among
high openness individuals.
Another interesting question that emerges is whether individuals low in
openness-to-experience may be influenced by other factors when making
judgments. Specifically, just as high openness-to-experience
individuals were more influenced by external anchoring cues, might it
be the case that low openness individuals are more influenced by
internally generated information? While we did not explore this
question in our current set of studies it certainly raises questions
for future research.
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Footnotes:
1Address: Todd McElroy, Department of
Psychology, College of Arts and Sciences, P.O. Box 32109, 265
College St., Boone NC. 28608. Email:
mcelroygt@appstate.edu
2 Two participants were
excluded from our analysis because their
"estimates" were extremely high
and were more than 3 standard deviations from the mean. Statistically
significant results were still obtained when these participants were
included in our analysis, however, we did not feel that it was
representative of our findings. One participant was not included in
our analysis because they did not complete the questionnaire.
3 One participant in our study
failed to provide an estimate and was not included in our analysis of
the data.
4 Special thanks to the reviewers for pointing
this out.
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