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DRAFT 8/10/05. Comments welcome.
Detecting Trustworthiness: Does Beauty Confound Intuition?
Catherine C. Eckel Department of Economics (0316) Virginia Polytec nic Institute and State University hBlacksburg, VA 24061 540-231-7707 [email protected]
Rick K. Wilson Department of Political Science Rice Universit [email protected]
Abstract We report results of a laboratory experiment that examines the impact of attractiveness on trust and reciprocity in a trust game. Subjects in the experiment interact with a counterpart in a lab at another location, and each observe the others’ photograph while making their decisions. The photographs are rated by a separate set of subjects drawn from the relevant population. We find that attractive people trust less than unattractive people. However, subjects expect greater trust from attractive people, and their expectations are disappointed, leading to lower amounts returned to attractive first movers. Thus we provide some evidence of a beauty penalty in this game that operates through the distorting effect of beauty on the expectations of the players. Thanks go to Sezi Anac, Narine Badasyan, Johanna Dunnaway Adam Ferguson, Selhan Garip, Phil Grossman, Scott Simkins, Jill Stipanov, and Bing Yaun for help in conducting the experiments. Support for this research comes from grants by the National Science Foundation (SES 98-19943) and the Russell Sage Foundation. Neither Foundation is responsible for the content or findings reported here.
Beauty is truth, truth beauty,—that is all Ye know on earth, and all ye need to know.
--John Keats (1795-1821), Ode on a Grecian Urn. Remember that the most beautiful things in the world are the most useless; peacocks and lilies, for example.
–John Ruskin Throughout the animal world, attractiveness certifies biological quality.
--Randy Thornhill University of New Mexico ecologist If you wanna be happy for the rest of your life Never make a pretty woman your wife So for my personal point of view Get an ugly girl to marry you
--Jimmy Soul, “If you wanna be happy.”
I. Introduction.
Labor markets reward beauty. As documented by Hamermesh and Biddle (1994),
relatively attractive people – both men and women – earn a “beauty premium” that is a
significant portion of earnings. The question naturally arises: Is beauty productive – that is, are
the returns to beauty associated with increased productivity?
Beauty can be productive in at least two ways. If customers prefer to deal with attractive
salespersons, for example, then hiring attractive workers can enhance sales. In addition, beauty
may signal higher quality. Evolutionary biologists argue that beauty is associated with
symmetry, which is an indication of quality in an organism (Buss, 1997). Symmetry is positively
associated with IQ and health (e.g., Thornhill and Gangestad, 1993; Thornhill, 1998). In a
related argument, social psychologists contend that the higher quality of attractive people is
developed rather than endowed. They provide evidence that attractive people are treated better,
and so develop superior attributes (Langlois, et al., 2000). If attractive workers are of higher
average quality for whatever reason, they are likely to be more productive.
Considerable evidence points to an association between beauty and perceptions of
positive attributes. Beauty confers an “aura” of quality (McNeil, p. 280) which affects
expectations about attractive people: observers associate beauty with goodness. Many studies
show that people attribute superior ability in a variety of tasks, as well as positive attributes
1
including kindness, strength and power to the attractive (see Webster and Driskell, 1983; Jackson
et al., 1995; Langlois, 2000). In addition, beauty interferes with subjective judgment. There is
strong evidence that beautiful people receive higher evaluations for their work. This result is
robust over a broad range of environments, from the evaluation of children’s essays in
elementary school to the evaluation of applications for managerial positions (McNeil, p. 280;
Langlois, et al., 2000.)
Are these superior evaluations warranted? Is beauty related to objective measures of
ability (such as intelligence) or performance (such as success or advancement)? Kanazawa and
Kovar (2004) develop the earlier observation of Buss (1985), that assortative mating should
produce a positive correlation between beauty and ability. They argue that beauty and
intelligence must become positively related over time, since intelligent men achieve higher status
and marry beautiful women. In a meta analysis of 68 studies, however, Jackson, et al. (1995)
find a strong relationship between beauty and expectations about intelligence, but virtually none
between beauty and measured intelligence as indicated by test scores or grades.
On the other hand, if symmetry is an indication of organism quality, then beauty and
ability should both be related to symmetry and so to each other. In a study where facial
photographs of several hundred subjects of all ages were judged by a sample of university
students, Zebrowitz et al. (2002) provides evidence of a small positive correlation between
attractiveness and intelligence, but this association is not nearly as strong as the correlation
between beauty and perceived intelligence. People’s perceptions get the direction right, but
exaggerate underlying differences. In this and a subsequent study (Zebrowitz and Rhodes,
2004), she shows that people are able to infer information about intelligence from the faces of
people in the lower half of the attractiveness distribution, but not in the upper half. Beauty
masks intuition, and interferes with the rater’s ability to make inferences about intelligence.
Attractiveness also is associated with superior performance and professional success.
Attractive people are more likely to receive an offer of employment and to advance within an
organization (Stone et al. 1992). It is no surprise that beauty is prized for actors and actresses in
the film industry or for high profile models (though for the latter, see the cautionary points by
Bower, 2001; Bower and Landreth, 2001). But a beauty premium also is observed in the broader
labor market. As Hamermesh and Biddle (1994) point out, good looks generate a premium and
bad looks a penalty in the labor market. The difference in earnings between above and below-
2
average attractiveness is robust across occupations, but is larger for men (14.4-16.8 percent) than
for women (9.2-11.7 percent). Likewise Biddle and Hamermesh (1998) show that attractive
attorneys earn more than their unattractive counterparts because they are better able to attract and
retain clients. Beauty carries a premium for male and female attorneys; however, while beauty
enhances the likelihood that a man will make partner early, it reduces the likelihood for women.
Outside the workplace, Sigelman et al. (1986) and Budesheim and DePaola (1994) find
that attractiveness has an impact on vote choice among political candidates, although Riggle et
al. (1992) note that this effect can be diminished or eliminated with additional information.
Attractiveness also seems to affect outcomes in the judicial system. Castellow et al. (1990) note
an advantage to more attractive plaintiffs and defendants in sexual harassment cases, and Stewart
(1980, 1984) documents an advantage for attractive defendants in conviction and sentencing in
criminal cases. These results are consistent with the notion that attractive people may be
perceived as more trustworthy.
An important element of productivity in a workplace setting is trust: trusting and
trustworthy employees are more productive than others, and enhance the productivity of those
with whom they work. Two possibilities come to mind. First, since attractive people are treated
better than others in many aspects of life, they may perceive the world as a less risky place, and
so be more trusting and trustworthy. In contrast, if attractive people are accustomed to better
treatment, they may not have found trustworthiness to be as important an element of reputation
as others who are less attractive. Their feeling of entitlement may make them less trustworthy.
In this study we examine the relationship between attractiveness and trust and
trustworthiness in a laboratory setting. We also are able to asses the role of expectations in
trusting behavior, and the impact of beauty on expectations of others. Our study uses the
investment game, first examined by Berg, Dickhaut and McCabe (1995), in a setting where
subjects observe the photographs of their counterparts. Interpersonal trust is usually measured
anonymously in laboratory trust game. However, we match subjects with anonymous
counterparts at another site using photographs. This procedure maintains important elements of
anonymity, but allows subjects to observe their counterpart. In previous studies, we have shown
that interpersonal trust is affected by observed information about one’s counterpart. In this study
we evaluate the attractiveness of the players, and show that attractiveness has a significant
impact on the propensity to trust and reciprocate trust.
3
II. Motivation: trust and beauty in the lab.
Trust involves a decision in which an individual puts his payoffs at the discretion of
another. A decision to trust another individual is based on an assessment of that person’s
trustworthiness. In commercial interactions, agents often know something about the
trustworthiness of the counterpart, such as whether the counterpart has acted in a trustworthy
manner in the past and can be expected to continue to be trustworthy. In the business arena, trust
is supported by a number of legal and social institutions from tort law to gossip that monitor the
actions of others and punish transgressions.
Trust as a characteristic of a society is studied in the context of ongoing relationships
among different actors in a pre-existing and very rich environment. In lab experiments much of
the usual social context can be removed. Nevertheless, subjects in most laboratory experiments
on trust are matched with others drawn from the same classes in the same university, and are
close in age and socioeconomic status. These subjects are likely to share expectations of how
others around them will behave.
In our study we examine trust and reciprocity among strangers. Although our subjects
are all drawn from the convenience sample of undergraduate students, each subject is paired over
the internet with someone from a different school in a different state, observing only each others’
photographs. Given the degree of anonymity, expectations cannot be based on experience or
knowledge about the group the particular individual belongs to (i.e., Virginia Tech
undergraduates), but rather must be inferred from their observable characteristics. Several
previous studies have examined the relationship between observable characteristics and trust and
reciprocity in games similar to ours. Croson and Buchan (1999) and Chaudhuri and
Gangadharan (2002) find systematic sex differences in trust and/or reciprocity, though subjects
do not know the sex of their counterparts. In studies where subjects observe photographs of
their counterparts, Scharlemann et al. (2001) and Eckel and Wilson (2003b) find evidence that
smiling invites trust. They also show that there are systematic differences in behavior by sex
pairings in this setting. Fershtman and Gneezy (2001) provide evidence of racial and ethnic
stereotypes using names as labels for subjects; using photographs, Eckel and Wilson (2003a),
Burns (2003), and Buchan, Croson and Solnick (2003) find that observed race and/or gender are
important for initiating and reciprocating trust.
4
In an experimental labor market, Mobius and Rosenblat (2003) decompose the effects of
beauty. They infer that 80 percent of the beauty premium is due to stereotyping effects that
assign positive attributes to better looking subjects, while the remaining 20 percent is due to
greater confidence exhibited by those who are more beautiful. This result is consistent with the
observation from attribution studies that, while there may be some correlation between beauty
and performance, expectations exaggerate the relationship.
Other experiments have explored the effect of attractiveness on behavior in games with
low to modest financial stakes. One of the earliest studies is by Kahn et al. (1971) who used a
repeated prisoner’s dilemma game. Male and female students were paired by sex and level of
attractiveness. Men were found to be motivated by competition and were not influenced by
either the sex or attractiveness of their counterpart. Women, on the other hand, were more
cooperative with male than female partners, except for unattractive women paired with attractive
men, in which case the women behaved competitively. Mulford et al. (1998), also using a PD
game, found that subjects responded systematically to attractiveness. In their design subjects
chose their own partners. Prior to doing so, subjects rated one another, and themselves, for
attractiveness. This study found that subjects tended to choose the most attractive partner, even
though they predicted that they would be left financially worse off as a result. Subject’s
predictions were met, with the most attractive subjects being the least likely to cooperate in the
game. Attractive subjects earned more because others cooperated with them, and they defected.
In an ultimatum game Solnick and Schweitzer (1999) found no difference in the
decisions made by attractive and unattractive people, but they did find a difference in how these
groups were treated by others. Proposers offered more money to attractive responders, although
attractive responders did not have higher minimum acceptable offers. On the other hand, higher
minimum offers were demanded from attractive than unattractive proposers, a result that is
echoed in our own results below.
Andreoni and Petrie (2003) focused on a 5-person, repeated play, public goods game in
which subjects viewed the photographs of others in their group. An independent group of
evaluators rated the photographs for attractiveness and other characteristics. Like Hamermesh
and Biddle (1994) and Mulford, et al, they found some evidence of an initial reward to beauty
premium, with higher contributions occurring initially in groups with a larger proportion of
relatively attractive participants. However, unlike Mulford et al. (1998) they did not find
5
attractive people to be more self-interested: attractive people contributed to the public good at the
same rate as less attractive people. When individual contribution information was provided, this
information had a strong impact on contributions, and the presence of attractive subjects in a
group resulted in decreased overall contributions to the public good. They conclude:
“In general, our results show that premiums to beauty and gender are information conditional. Indeed, when group members are kept in the dark about the performance of each group member, people tend to reward beauty and women. However, when group members know what others are contributing, the beauty premium disappears….” (p. 20)
Our study investigates the impact of beauty on trust and reciprocity in a two-person
sequential game. The structure of the trust game allows us to examine expectations of trust and
reciprocity and how subjects react to surprise and disappointment by others. We match subjects
over the internet to play a trust game, then measure attractiveness levels after the fact. This
allows us to make a more careful comparison between the attractiveness and other observable
characteristics of the players without calling the subjets’ attention to any particular
characteristics.
III. Research Design.
Subjects in our experiment participated in a series of tasks, including trust games, risk-
assessment instruments, and surveys. All tasks were computer mediated. Before beginning the
experiment we photographed each subject with two neutral and two smiling expressions. Once
seated at their computers, the subjects chose one from the four photos that they wanted their
counterparts to observe. Subjects did not know what decisions they would be making before
choosing the photo, only that their counterparts would see it. The same photo was used
throughout the experiment. For the trust game component of the experiment, each subject was
randomly paired with other individuals at a different laboratory, whose photos they observed.
One site was the Lab for the Study of Human Thought and Action at Virginia Tech in
Blacksburg, Virginia; the other was the Behavioral Research Lab at Rice University in Houston,
TX. Use of two sites allows us to show subjects each others’ photographs without compromising
anonymity.
The first task was a 40-question survey designed to measure attitudes toward risk, the
widely used Zuckerman Sensation-Seeking Scale (SSS), form V (Zuckerman (1994)). Subjects
earned 10 experimental laboratory dollars for completing the survey (the exchange rate was 2 lab
6
dollars for each US dollar). This earned payment was used as the endowment for the second
task, the trust game.
Subjects completed a series of trust games similar to the one first conducted by Berg, et
al. (BDM hereafter). In each game, the first mover was given the opportunity to send any part of
the $10 earned from the risk surveys (in whole dollars) to a counterpart whose photo they
observed. The sent amount was tripled. The second mover then decided how much to return (if
any) to the sender. Subjects were randomly assigned to the role of first mover or second mover,
and they kept that role throughout the experiment. A given subject participated in as many as 10
trust games, each with a different counterpart.1 A subject played with a given counterpart only
once. As explained to the subjects, in fact only one of the pictured counterparts was playing the
game at the same time at the other site, and this is the choice subjects were paid for. The other
photographed participants had completed the experiment previously.
First movers were given no feedback from decision to decision, and only learned the
amount returned to them for the paid decision.2 Thus they never received feedback on the
“robots” players with whom they were matched. In our data set, we use only the decision-
maker’s decision of what to send; second-mover data for the robots is not included in the data
set. Second movers were shown the actual offer of their real counterpart, and for the other
decisions saw the offer that had been made by those counterparts in the photos when they played
the game. Second movers also were paid for only one decision, the one with the real-time
counterpart. The amount sent to second movers by the “robot” first-movers was the amount that
player had sent to a real player when they actually played the game. Thus for second movers, the
amount sent by the robot players is included in the data set because the second movers observed
those amounts. All of this was explained to the subjects.
This feature of the trust-game component accomplishes two goals. First it gives us a
within-subjects design, so that we can gauge whether and how a given subject reacts to
differences in their counterparts. Second, this approach allows us to boost the number of
1 In the first session subjects participated in six trust games; in the second session subjects participated in eight trust games; in the remaining sessions subjects participated in ten trust games. At first we were concerned with how much time it would take to run the additional trust games. A pilot test indicated it might take a considerable amount of time. However, once we began running the experiment it was clear that subjects could quickly complete ten games. 2 Anderhub et al. (2002)use a repeated trust game. They find that population dynamics take effect, with subjects learning about the behavior of others and adjusting their strategies accordingly. In our experiment there is no feedback for the first mover, so no opportunity for dynamics to emerge.
7
observations for different racial and ethnic minorities by increasing the number of times a racial
or ethnic minority appears as a “robot” counterpart, compensating in part for the small number of
minority subjects in our sample.
The “real” counterpart was not revealed until the end of the trust game. Before they were
informed, the subjects were asked to guess which player was their real counterpart and told that
if they guessed correctly they would earn $1.00. First movers only managed this 11.5 percent of
the time and second movers did so 12.4 percent of the time, which is no better than random
guessing. The two on-line players were always paired in the very first period, although the
subjects did not know this. This allows us to compare the first period play, with a real player,
and subsequent plays with “robot” players.
Data also were collected on subjects’ expectations of each others’ decisions at each stage
of the trust game. The first mover was asked to predict the second mover’s choice. Likewise,
before being informed of whether any money was sent, the second mover was asked to predict
what the first mover would do. Elicitation of expectations was incentivized: subjects received an
extra dollar for guessing their counterpart’s action.
To summarize, the trust-game component of our experiment differs from what has
become the standard BDM setup in several ways. First, subjects played a series of trust games
instead of only one. Second, our experiment is computerized, while theirs is hand-run. Third,
subjects observed one another’s photographs when making their decisions, while in BDM care
was taken to keep the groups separated to ensure anonymity. After subjects were told who was
their on-line counterpart and how much they had earned, they then were asked to write out a
short description of what sort of situation the trust experiment reminded them of. This was an
attempt to find out if subjects framed the experience in the same way we, the experimenters, did.
In the third component of the experiment subjects completed another task designed to
elicit risk preferences, a computerized version of the procedure used in Holt and Laury (2002).
In the final component subjects responded to questions that collected demographic information
as well as survey measures of trust and altruism. Subjects were paid, one at a time and in
private, and given a debriefing statement.
As explained below, in a separate protocol, photographs of subjects in the trust game
were evaluated by an independent set of subjects drawn from the same population that they faced
in the trust game. These evaluations included assessments of the attractiveness of the
8
photographed subject as well as measures of affective state, trustworthiness, cooperativeness,
etc.
Procedure. A total of 206 subjects, half from Virginia Tech, 42.2 percent from Rice University
and 7.8 percent from North Carolina A & T, participated in 8 experimental sessions. Subjects
were recruited from introductory classes in Principles of Economics at Virginia Tech and NCAT
and from dining halls at Rice University. They were told to report at a specific time to an off-
campus laboratory at their respective locations. The number of subjects in a session ranged from
10 to 32. Subjects were 55.8 percent male and just under 94 percent of subjects were between
the age of 18 and 22. Care was taken to recruit an ethnically-diverse subject pool.3 The ethnic
composition of the subjects was 62.6 percent Caucasian, 15.0 percent African-American, 12.6
percent Asian-American, 5.3 percent Hispanic and the remaining 4.4 percent self-identified
foreign nationals (most were from India or the Middle East.)
When subjects arrived at the lab they were asked to sign a consent form and given a card
assigning them to a specific computer. Subjects posed for four pictures, then were seated at
computers and told that they could browse the internet before the experiment began. Because
subjects arrived at different times and because we had to coordinate activity at two sites, we
allowed subjects to browse, rather than converse with one another once in the lab. Once both
sites had an equal number of subjects, then everyone was asked to stop browsing and open a
window on the machine pointing to the experiment. Brief oral instructions were read to subjects
before beginning, then subjects went through self-paced, computerized instructions. In a post-
experiment questionnaire a little over 90 percent very strongly or strongly agreed that the
instructions were clear. Once subjects began the experiment, no talking was allowed. Subjects
were asked to raise their hands if they had a question or problem, and the experimenter would
answer their questions privately.
In previous two-site experiments, we found that subjects doubted whether they were
paired with real counterparts: their decisions shifted from trusting the image they viewed to
trusting the experimenter. In order to get around this problem, a subject was randomly selected
at each site and asked to think up a 4-5 letter “secret word.” That word was communicated to the
other site, written on a large sheet of paper, and a digital photograph was taken of the word and
3 One session was conducted between Virginia Tech and North Carolina A&T. The latter was chosen because it is an Historically Black University with a heavy emphasis on engineering. This provided a useful match with subjects from Virginia Tech.
9
subjects in the background (their backs were turned to the camera). The pictures from both
locations were uploaded to the server and then displayed. Subjects could then view their own
secret word displayed at the other site as well as observing the other site’s secret word displayed
and photographed at their own site. This was a tedious, but effective way to build beliefs that the
counterparts were real (see the discussion by Eckel and Wilson (2003a)). At the end of the
experiment subjects were asked whether they though they were participating with a real
counterpart and 93 percent indicating that they thought they were.
Figure 1. Sample First-Mover Decision Screen.
Figure 2. Sample Second-Mover Decision Screen.
10
IV. Photo evaluations
The second phase of the experiment involved an independent sample of subjects
evaluating the photograph displayed in the trust game. These subjects had not participated in a
trust experiment, were only asked to evaluate a set of images and were paid for their evaluations.
In this experiment subjects were asked to rate a series of photos. Subjects were recruited over
the internet and from large classrooms at all of the sites. Each subject was asked to rate between
15 and 24 photos on 15 word-pairs and was paid between $.25 and $.50 per photo. Photos and
their order were randomly assigned to each subject. Subjects evaluated photos from their paired
University: i.e. subjects at Rice and NCAT viewed photos from Virginia Tech, etc. A total of
296 subjects participated: 56.4% were male. Subjects spent an average of 80.2 seconds per
photo (with a standard deviation of 64.5 seconds). Because subjects only evaluated photos of
people from a different University, because photos were randomly assigned and because turnout
at each site varied, the number of raters per photo ranged from 9 to 42, with an interquartile
range between 18 and 27. There were 230 photos rated with a total of 5216 evaluations.
Figure 3: A Sample Screen and Subset of the Word Pairs Used in the Evaluation
Experiment
Each image was evaluated using 15 opposite word pairs. A sample of the word-pair
items and the screen used by subjects is shown in Figure 3, which reproduces a decision form.
11
The left/right order of the word pairs was randomly fixed prior to the experiment. The order of
presentation of the word pairs was randomized across each photograph for each subject,
providing control over response-set bias in the word pairs.
Our interest for this paper is with the attractiveness rating, and as a consequence we do
discuss results for the other word pairs. Raters were presented with the opposite word-pair
unattractive-attractive and asked to rate the photo. The words were anchors on a six-point scale,
with the word fitting the person in the photograph either “Very Well,” “Well” or “Somewhat
Well.” All word pairs were scaled such that a low value reflects a negative evaluation.
We find, similar toAndreoni and Petrie (2003), that women give significantly higher
ratings of attractiveness on average than men. To deal with this problem, we mean-center the
attractiveness rating such that:4
Attractivenessi = ( )jij xx − where . ⎩⎨⎧
==
evaluatorjth photoith
ji
Regardless of whether the original values or the mean-centered values are used, subjects were in
substantial agreement concerning their evaluations. Using Cronbach’s alpha as a measure of
consistency we get values of .80 and .83 for the original values and the mean-centered values,
respectively.5 These evaluations were then averaged across all evaluators and a composite score
was then generated. Figure 4 gives the distribution of the composite score broken out by male
and female photos. As is clear, from the figure, differences remain between the two sexes.
Following Andreoni and Petrie (2003), the upper and lower quartiles for the composite score
were used to identify attractive and less attractive individuals.
4 This procedure removes heterogeneity in individual evaluators. Unadjusted evaluations do vary systematically by gender and ethnicity. This analysis is available on request. 5 Because there were different numbers of evaluators for each photo, a bootstrap method was used to calculate the values of Cronbach’s alpha. Sample evaluations of 9 subjects were used for each photo. A total of 50 runs were used to compute the average scores.
12
Figure 4. Distribution of attractiveness scores using a mean-centered adjustment.
0.2
.4.6
kden
sity
cen
t_at
tract
-2 -1 0Mean-centered attractiveness ra
Male Photos
Consistent with findings from the stranger attribution
evaluators attribute particular characteristics to more attracti
models in which the evaluation of the other opposite word-p
regressed against variables controlling for the sex and race o
the photograph and the attractiveness rating. Table 1 indicat
scaled) were either positively or negatively correlated with a
derived from regressions in which the evaluation of the indiv
variable, and the sex, race or ethnicity of the photograph, the
attractiveness rating were on the right-hand side of the equat
attractiveness were significant at p=.01 or better. It is not su
friendly and happy are all positively associated with the attra
analyses by Eagly et al. (1991); Jackson et al. (1995) or Lan
trustworthy and trusting are positively correlated with attrac
guarantee that such individuals are always seen in a positive
negatively related to cooperativeness, honesty and generosit
attractive subjects in bargaining games that depend on both c
13
Female Photos
1 2ting
literature in social psychology,
ve subjects. We estimated statistical
air items by each subject was then
f the evaluator, the sex and race of
es which words (all positively
ttractiveness. Correlations are
idual word pair was the dependent
evaluator and the photo
ion. All coefficients for
rprising that terms like intelligent,
ctiveness rating (see the meta-
glois et al., 2000). Note that both
tiveness. Yet attractiveness does not
light. In particular attractiveness is
y. These items may work against
ooperation and generosity.
Table 1: Attributes positively and negatively correlated with attractiveness rating.
Positive Correlations Negative Correlations
Motivated Cooperative
Trustworthy Honest
Trusting Generous
Hardworking Calm
Intelligent
Respectful
Friendly
Happy
Accepting
Dependable
V. Analysis of the Trust Game
Because of the nature of our experiment, the data set has an unusual structure. First
movers observe a set of M second movers, only one of which they are actually matched with.
They only observe the amount returned for their real counterpart. Second movers see a set of M
first movers, only one of which they are actually matched with. In addition, some subjects were
over sampled in the analysis to increase data on minority counterparts. Thus the number of
observations that are responses to any particular photo vary in the data set. For first movers, the
data includes only the decisions made by the actual first movers in response to the photos of real
and robot counterparts. For second movers, the data include decisions made by second movers
in response to amounts sent by real and robot first movers. These amounts sent – both real and
robot – are also included in the data set as they were observed by the second movers.
Descriptive statistics for the overall levels of trust are shown in table 2. Overall, subjects
sent an average of $4.91 (compared with the $5.16 sent by subjects in BDM). While subjects
send slightly more to their on-line counterpart than to robot players the difference is not
significant (t=.267, p=.79, df=954). In the aggregate, trust pays. Subjects returned $6.43 on
average, while for BDM an average of $4.66 was returned. Although slightly more is returned to
robots than to an on-line counterpart, the difference is not statistically significant (t=.581, p=.56,
14
df=900). For the remainder of the analysis we pool the data in the following way: first mover
data includes offers made by each (real) first mover to real and to robot counterparts; second
mover data includes amounts returned by (real) second movers to real and robot counterparts.
The relatively high standard deviations indicate considerable heterogeneity in what individuals
send and return.
TABLE 2: Average Amount Sent by First Movers and Average Amount Returned by Second
Movers (SD in parentheses)
Manipulation
Overall Average
Average for “Real”
Counterpart
Average for a “Robot”
Counterpart Average Amount Sent to Counterpart
$4.91 (3.23) n=954
$4.99 (3.06) n=103
$4.90 (3.25) n=851
Average Amount Returned
$6.43 (5.90) n=902
$6.10 (5.17) n=98
$6.47 (5.98) n=804
Percentage Returned
33.24% (22.56) n=902
38.73% (22.95) n=98
32.56% (22.21) n=804
Figure 5 below is a scatter plot of amounts sent and returned for all second-mover
decisions. Each circle indicates what was sent by the first mover as seen by the second mover,
and what was returned. In part because amounts only could be sent and returned in whole
dollars, many of these points coincide. They have been perturbed by a small value in order to
give a sense of the distribution. The solid line on the figure represents equal amounts sent and
returned. Circles above the solid line meant that trust was more than reciprocated. This figure
suggests that there is a positive relationship between the amount sent and the amount returned.
There also appears to be a relationship between the percent returned and the offer amount: the
more the first-mover sends, the higher fraction of the payoff is returned to her. It is also clear
that there is substantial heterogeneity across decisions. For any given amount offered, there are
many different responses, from zero to the full tripled amount.
15
Figure 5. Amount Returned by Second Movers.
02
46
810
1214
1618
2022
2426
2830
Am
ount
Ret
urne
d (in
Dol
lars
)
0 1 2 3 4 5 6 7 8 9 10Amount Sent (in Dollars)
We find heterogeneity across subjects, and also for a given subject across decisions. One
feature of this design is that it allows us to examine the behavior of individuals across many
decisions. We find that 25 of 103 first movers (24.3 percent) never change their strategy during
the course of the experiment. They always do exactly the same thing. Almost half always sent
their full endowment (12 of 25), two subjects never sent anything, and five always sent half of
their endowment. The remaining 75.7 percent of first movers all exhibit some variation in what
they choose to send.
There also considerable heterogeneity among the second movers. Only 7 of the 103
reciprocators showed obvious rules in their strategy for returning (5 always returned nothing, 1
returned exactly what was sent and 1 returned everything). These data indicate that subjects are
conditioning their decisions on something they observe about their counterparts.
Table 4 presents the amount sent and the percentage returned by the characteristics of the
first mover. For example, the first row of the table shows the average amount that male first
movers trust to all counterparts, and the trustworthiness or percent returned on average to male
first movers by second-mover decision makers. Each line indicates trust by and reciprocity
16
toward persons with the relevant characteristic. The table includes data sorted by the sex of the
first mover, the race/ethnicity of the first-mover, and the evaluators’ ratings of whether the
subject was smiling in the photo. Although men who were first movers sent slightly more than
women, the difference is not statistically significant (t=-1.277, p=.20, df=952). The amount sent
differs by race and ethnicity. Caucasians are likely to send more than African-Americans,
Hispanics and Asians. However, only the difference between Asians and Whites statistically
significant in pairwise comparisons. (This is different from results reported by Eckel and Wilson
(2003) for a slightly different game in which African American and Hispanic subjects are trusted
less than white subjects.)
Table 4. Average Amount Sent and Percentage Returned by characteristics of the first mover. (Standard deviation, Frequency in parentheses)
First mover Amount Sent
by first-mover Percent Returned
to first mover Male 5.03
(3.19, n=516) 34.97
(21.16, n=482) Female 4.76
(3.28, n=438) 31.23
(23.52, n=420) Caucasian 5.26
(3.35, n=572) 31.87
(22.86, n=488) African-American 4.28
(3.07, n=166) 38.53
(20.09, n=143) Asian 4.25
(2.74, n=134) 29.07
(23.32, n=162) Hispanic 4.47
(3.03, n=36) 37.33
(16.68, n=44) Other 5.02
(3.16, n=46) 39.31
(20.93, n=65) Smiling 4.96
(3.27, n=584) 33.38
(23.02, n=591) Not Smiling 4.84
(3.18, n=370) 32.93
(21.08, n=311)
In a previous published study, we found evidence that smiling invites trust (Scharleman
et al., 2002). Subjects in the face-evaluation phase were asked to judge whether the person in the
photograph was smiling. A score ranging from 0 to 1.00 was derived from the judgments of
subjects and a value of .75 was used as a cut-off between those smiling and those not. Given
17
these data this meant that 65 percent of the second movers were perceived as smiling. We find
no difference in the amount sent by smiling and nonsmiling first movers
The second column shows the percent of the tripled sent amount that was returned to first
movers who were male, female, etc. More was returned to male than female first movers
(t=2.51, p=.01, df=900). The race/ethnicity of the first-mover is related to what was returned to
them. We also observe significant variations in the percent returned, with less returned to whites
and Asians than to other ethnic groups. For example, the paired difference between blacks and
whites is significant (t=3.14, p=.002, df=629); the difference between the amounts returned to
Asians and whites is not significant (t=-1.34, p=.18, df=648). Using the same measure as above,
smiles have no effect on the percentage returned (t=-.29, p=.77, df=900).
Table 5: Amount Sent and Percentage Returned by the Characteristics of Second Mover (Standard Deviations, Frequencies in parentheses)
Second-Mover Characteristics
Sent to the second mover
Percent Returned by the second mover
Male 4.77 (3.20, n=555)
31.74 (21.86, n=504)
Female 5.10 (3.27, n=438)
35.11 (22.85, n=398)
Caucasian 4.95 (3.22, n=485)
32.76 (23.85, n=585)
African-American 4.86 (3.46, n=162)
33.45 (16.07, n=124)
Asian 5.02 (3.21, n=180)
35.39 (22.24, n=107)
Hispanic 4.58 (3.01, n=71)
29.90 (19.43, n=52)
Foreign 4.75 (3.11, n=56)
38.73 (19.07, n=34)
Smiling 4.93 (3.22, n=618)
32.94 (22.91, n=627)
Not Smiling 4.86 (3.26, n=336)
33.89 (21.06, n=275)
Table 5 contains the amount sent and percent returned broken down by the characteristics
of the second mover. We see that more is sent to second movers that are women, although that
difference is not statistically significant (t=-1.523, p=.13, df=952). We also observe little
variation by the race or ethnicity of the counterpart: the difference between black and white
18
counterparts is not significant (t=-.311, p=.75, df=645), nor is the difference between white and
Asian counterparts (t=.27, p=.78, df=663). Slightly more is sent to smiling than nonsmiling
counterparts though the difference is not statistically significant ((t=.308, p=.76, df=952).
Turning to the second-movers, women return a significantly higher percentage than men
(t=-2.256, p=.024, df=900). Referring back to Table 4, we see that women are sent more than
men. This pair of results is consistent with women being more trustworthy, and perceived as
such by their counterparts. There are no significant differences across race and ethnicity; while
Asians return the most and Hispanics the least, the difference between those groups is not
significant (t = -1.51, p=.13, df=157).
Table 6 contains average amounts sent by sex pairing. Men send more on average than
women do. While both men and women send more to female second movers, the difference is
only statistically significant in pairwise t-test for M1F2 compared with F1M2: that is, men send
more to women than women send to men. More is returned on average by both men and women
to male than to female counterparts (t = 2.4458, p=.015).
Table 6: Amounts sent and returned by sex pairing
(standard errors and number of observations in parentheses)
Sex Pairing Amount Sent Percent Returned Male 1 with Male 2 4.95
(3.22, n=251) 33.40
(20.18, n=255) Male 1 with Female 2 5.25
(3.11, n=177) 35.85
(21.63, n=176) Female 1 with Male 2 4.45
(3.08, n=234) 29.90
(24.60, n=185) Female 1 with Female 2 4.97
(3.45, n=152) 29.88
(23.58, n=141)
Is There a Beauty Premium?
The simplest measure of a beauty premium is the difference in overall earnings by
attractive and unattractive subjects. If we compare the earnings in the trust game for the most
attractive and least attractive trusters and trustees we find no evidence for a beauty premium.
Table 7 presents the mean earnings for subjects by their position in the game. The table takes
subjects who are in the lower and upper quartiles of attractiveness based on the overall
19
distribution of the composite measure of attractiveness described above. Using this measure,
attractive first-movers earn slightly less than unattractive first-movers. Attractive second
movers earn 15.8 percent less than unattractive second movers, but this is insignificantly
different from zero.
Table 7. Earnings by real players in lower and upper quartile of attractiveness rating (standard deviation in parentheses).
Earnings First mover
Unattractive(Lower Quartile)
$11.27 (4.18)
Attractive(Upper Quartile)
$11.11 (4.34)
t-test t=.15, df=66, p=.44 Second mover
Unattractive(Lower Quartile)
$9.00 (7.88)
Attractive(Upper Quartile)
$7.58 (5.72)
t-test t=-.80, df=61, p=.21
To better understand the components of the earnings difference, Table 8 compares the
amount sent, conditional on the attractiveness of the first and second movers. Relatively
attractive people are less trusting than relatively unattractive people. Both attractive and
unattractive first-movers send more to attractive than to less attractive second-movers. There is
an overall beauty premium of 11.6 percent in the amount sent. Despite the fact that they receive
less, unattractive second movers send back a higher percentage. Both attractive and unattractive
second-movers send back a higher percentage to unattractive than attractive first movers, perhaps
because of the greater trust exhibited by the unattractive first movers. This discrimination is
especially evident for attractive second movers.
Examining only the upper and lower quartiles of the counterpart may be masking more
complicated relationships. After all, what is returned to the subject is sensitive to what was sent
in the first place. Moreover, the relative rather than the absolute attractiveness of subjects may
be an important factor. In addition, interactions by gender and race/ethnicity may affect trust and
reciprocity. The next section presents multivariate analysis.
20
Table 8. Average amounts sent to and percentage returned by players, contingent on the attractiveness ratings of the decision makers and counterparts
(standard deviation in parentheses).
Unattractive Decision Maker
Attractive Decision Maker
Amount Sent to counterpart who is: Unattractive
(Lower Quartile)$5.29 (3.06)
$3.79 (2.71)
Attractive(Upper Quartile)
$6.12 (3.19)
$4.46 (3.07)
t-test t=1.33, df=100, p=.09 t=1.22, df=112, p=.11Percent Returned to counterpart who is:
Unattractive(Lower Quartile)
35.03 (21.20)
40.11 (19.94)
Attractive(Upper Quartile)
28.62 (22.20)
30.91 (19.21)
t-test t=.89, df=98, p=.19 t=2.24, df=95, p=.01 Multivariate Models. Table 9 contains an analysis of the first-mover’s decision of how much to
send to the second mover. The dependent variable in this regression is the amount in lab dollars
that the first-mover sent to the second-mover. Because each first-mover made between 6 and 10
decisions, we estimate a random-effects model. In addition, decisions were censored: subjects
could not send more than 10 or less than 0. To account for this we use Tobit regression.
The model in Table 9 includes control variables for sex, race/ethnicity, self-reported
trustworthiness, and expected return, as well as attractiveness measures. Other regressions (not
reported) tested for differences in behavior by sex-pairing, and we could not reject the null
hypothesis that subjects were not conditioning on the sex of their counterpart. The
trustworthiness survey scale is calculated from seven questions included on the final
questionnaire, which had a 6-point range (1-6), which ask the subject about their own degree of
trustworthiness. These questions were taken from a survey instrument reported in Wrightsman
(1991). The scores on this survey scale averaged 3.47 and ranged from 1.71 (low
trustworthiness) to 5.29 (high trustworthiness). The truster’s expectations for what would be
returned are included; recall that first-movers are asked after deciding what to send the amount
they expect to be returned, and are paid for correct forecasts. On average trusters expected $8.88
to be returned. Two attractiveness variables are included. First, we include the attractiveness
rating of the first mover to test for the effect of absolute levels of beauty. The second variable is
21
the difference between the rated attractiveness of the first mover minus the rated attractiveness of
the second mover. This variable picks up any additional variation in the amount sent that is due
to relative attractiveness.
Table 9: Determinants of the Amount Sent by First Movers Dependent variable = amount sent in lab dollars.
(Standard error in parentheses)
Model 1: Attractiveness difference ( 1st – 2nd mover)
-0.277 (0.084) p=0.001
Female to Male 0.273 (0.201) p=0.173
Female to Female 0.240 (0.229) p=0.293
Male to Female 0.215 (0.189) p=0.254
Black 1 -1.403 (0.201) p<0.001
Asian 1 0.044 (0.218) p=.839
Hispanic 1 -1.181 (0.385) p=0.002
Black 2 (photo rating) 0.477 (0.192) p=0.013
Asian 2 (photo rating) 0.222 (0.214) p=0.300
Hispanic 2 (photo rating) 0.128 (0.225) p=0.571
Trustworthiness 1 (self-report survey)
0.703 (0.131) p<0.001
Expected amount returned 0.176 (0.013) p<0.001
Constant 1.755 (0.512) p=0.001
Log Likelihood -1597.7 Uncensored 641 Left-censored 86 Right censored 170
The coefficients on the control variables are consistent with what others have found. We
find a strong positive coefficient on the trustworthiness variable, a result similar to that found by
Glaeser et al. (2000), who noted that an individual’s own sense of trustworthiness affects trusting
22
behavior. Other researchers have shown that the sex of the counterpart is significantly related to
trust and reciprocity. For example Croson and Buchan (1999) and Chaudhuri and Gangadharan
(2002) find systematic sex differences in behavior. Scharlemann et al. (2001) find differences
specifically due to different male/female pairings. Our data do not replicate these results: we
find no significant difference in sex pairing once the attractiveness difference is included.
Likewise, Fershtman and Gneezy (2001), Eckel and Wilson (2003a) and Burns (2003) all find
racial and ethnic effects across subject pairings. These features, like the sex of the counterpart,
can be observed in the photos. Since evaluators sometimes made errors in judging the race or
ethnicity of their counterpart, we classified the second-mover photos by the modal response of
the evaluators. We think this most closely approximates how the average subject viewed the
photograph. Conditional on the control variables, we see a statistically significant, negative
effect of the difference in attractiveness. People who are more attractive than their counterparts
tend to send less.
The equation in Table 10 focuses on what is reciprocated. Because the amount of money
that subjects have to deal with varies with how much is sent, the dependent variable is calculated
as the percentage of the amount that was passed (and tripled) and returned to the truster. This
allows comparisons across all subjects. Once again a random effects model is used to estimate
the coefficients. The distribution of percent return is also censored at zero and 100%, so Tobit us
used.
The equation includes control variables for the sex and race/ethnicity of the first and
second movers. As before, variables for the race/ethnicity of the first mover were based on the
evaluations of the photos. Because these subjects received some information about their
counterpart’s offers in each round of the game, it is possible for subjects to learn something
about the distribution of offers in the population. To account for this, we include a variable for
the period in which they were making the decision. A variable was also included measuring the
difference between what the second mover expected to receive and what was actually sent, a
measure of disappointment. Along the lines of Rabin (1993) this measure captures dashed
expectations. If what was sent was less than what was expected, then the measure is negative,
indicating disappointment. If expectations were exceeded, then the measure is positive. Finally,
a survey measure of altruism, again based on Wrightsman (1991), is included. Like the measure
of trustworthiness, it is constructed from seven questions, it is an additive scale and it has been
23
widely used. Higher values of the variable indicate a greater commitment to altruism. Again we
use the modal response for the race or ethnicity of the photo. Attractiveness is measured as in the
first equation, the difference between the attractiveness ratings of the first mover and the second
mover. Again a positive value reflects the fact that the first mover was rated more attractive than
the second mover.
The results indicate that there are no important main effects for the sex, race or ethnicity
of the second mover. There is a large effect for the measure of altruism: subjects with a greater
commitment to altruism return a larger percentage of what was sent. There is also a period
effect, with a smaller percentage being returned over time. Expectations play an important role
in the decision of how much to return. More is returned to the first mover when his trusting
move is more generous than expected. Those who fail to meet expectations are given less (the
difference between what was sent and what was expected turns negative, thereby decreasing
what is returned).
Conditional on the control variables, the coefficient on the attractiveness variable is
negative and significant. This means that for positive values of the variable (when the first
mover is more attractive) a lower percentage is returned. This result is the opposite of a beauty
premium – a beauty penalty.
24
Table 10: Second mover decision to reciprocate Dependent variable = percent of tripled amount that is returned to the sender.
(Standard error in parentheses)
Model 1: Attractiveness difference ( 1 – 2)
-2.225 (0.783) p=0.005
Female 1 x Male 2 0.413 (1.661) p=0.804
Female 1 x Female 2 -2.145 (2.306) p=0.352
Male 1 x Female 2 -0.352 (2.237) p=0.875
Black 2 -2.969 (5.030) p=0.555
Asian 2 3.565 (5.420) p=.511
Hispanic 2 3.114 (6.853) p=0.649
Black 1 (photo rating) 2.155 (1.710) p=0.207
Asian 1 (photo rating) -1.010 (1.737) p=0.561
Hispanic 1 (rating) 1.465 (2.061) p=0.477
Altruism 2 (self-report survey)
5.720 (2.858) p=0.045
Expected – received amount
0.999 (0.143) p<0.001
Period -0.433 (0.189) p=0.022
Constant 17.593 (9.335) p=0.0059
R2 Within 0.133 Between 0.012 Overall 0.055
Disappointment, the difference between the expected and received amount trusted,
appears to play an important role in determining the decision of the second mover. This variable
is a measure of bias in expectations. A disappointed person sends back less, while a pleasantly
surprised person sends back more as a fraction of the amount sent. To further examine when
people are disappointed, we present a regression analysis of the correlates of disappointment.
25
This regression shows the direction and magnitude of biases in expectations by players by gender
and ethnicity, as well as biases that are induced by the observable characteristics of the first-
mover. These results are shown in table 11.
Table 11: Determinants of disappointment, random effects. Dependent variable is
disappointment: Amount Expected – Amount Received from the first mover.
Model 1: Attractiveness of first mover
-0.940 (.477) p= 0.049
Attractiveness of second mover
0.276 (0.169) p=0.104
Female first mover 0.793 (0.704) p=0.260
Female second mover -0.296 (0.223) p=0.263
Black 2 0.121 (0.321_ p=0.707
Black 1 (rating) 2.170 (0.865) p=.012
Asian 2 -.349 (0.330) p=0.290
Asian 1 (rating) -.386 (.928) p=0.677
Hispanic 2 -0.214 (.456) p=0.638
Hispanic 1 (rating) 2.314 (1.198) p=0.053
Constant -0.373 (0.555) p=0.502
R2 Within 0.007 Between 0.053 Overall 0.114
The significant negative coefficient on the attractiveness of the first mover indicates that
second movers systematically overestimate the generosity of first movers, and are disappointed
by them. However, second movers are systematically surprised in a positive way by black and
Hispanic first movers. Since disappointment leads second movers to return a smaller percentage
of what they were sent, relationship between disappointment and attractiveness may partially
explain why there is no beauty premium in this trust game experiment, as well as why observable
26
minorities are not disadvantaged.
Discussion and Conclusion Beauty has a substantial impact on behavior in two ways. It affects people’s expectations
of others’ behavior, but it also has an independent effect over and above the effect on
expectation. Second-mover subjects expect attractive first movers to be more generous than
others. Since attractive persons are not more generous, this leads to disappointment, which is
then punished in the second stage of the of this game. We also find, similar to the results of
Mulford et al. (1998) and Solnick and Schweitzer (1999), that more is sent to attractive second
movers. We also provide evidence that attractive second movers are not more trustworthy. This
in this context we do not find evidence of a beauty premium.
27
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