Exploring people’s thoughts about the causes of ethnic stereotypes

Abstract

Much research has shown that people tend to view genes in rather deterministic ways—often termed genetic essentialism. We explored how people would view the causes of ethnic stereotypes in contexts where human genetic variability was either emphasized or downplayed. In two studies with over 1600 participants we found that people viewed ethnic stereotypes to be more of a function of underlying genetics after they read an article describing how ancestry can be estimated by geographic distributions of gene frequencies than after reading an article describing how relatively homogeneous the human genome was or after reading a control essay. Moreover, people were more likely to attribute ethnic stereotypes to genes when they scored higher on a measure of genetic essentialism or when they had less knowledge about genes. Our understanding of stereotypes is a function of our understanding of genetics.

Full text

RESEARCH ARTICLE
Exploring people’s thoughts about the causes
of ethnic stereotypes
Anita Schmalor, Benjamin Y. Cheung, Steven J. HeineID*
Department of Psychology, University if British Columbia, Vancouver, British Columbia, Canada
*heine@psych.ubc.ca
Abstract
Much research has shown that people tend to view genes in rather deterministic ways—
often termed genetic essentialism. We explored how people would view the causes of ethnic
stereotypes in contexts where human genetic variability was either emphasized or down-
played. In two studies with over 1600 participants we found that people viewed ethnic ste-
reotypes to be more of a function of underlying genetics after they read an article describing
how ancestry can be estimated by geographic distributions of gene frequencies than after
reading an article describing how relatively homogeneous the human genome was or after
reading a control essay. Moreover, people were more likely to attribute ethnic stereotypes to
genes when they scored higher on a measure of genetic essentialism or when they had less
knowledge about genes. Our understanding of stereotypes is a function of our understand-
ing of genetics.
Introduction
Csana
´d Szegedi, then member of the European Parliament, converted to living his life as an
Orthodox Jew at the age of 30. What makes his conversion remarkable is that shortly before
his conversion he was the vice president of the anti-Semitic Jobbik Party in Hungary, and had
published a book full of anti-Semitic sentiment. So why would such a person convert to Juda-
ism? It appears to have been based on something that he learned about his own ancestry. Sze-
gedi reports having been stunned to learn that his maternal grandmother was Jewish, a fact she
had kept secret [1]. That is, Szegedi had learned that he, too, was Jewish by descent. Szegedi’s
dramatic transformation underscores the important role that our understanding of our biolog-
ical roots play in shaping who we think we are. Despite being raised as a Christian, and not
having any Jewish experiences, Szegedi came to identify himself in line with his genetic ances-
try [2].
Szegedi is not alone in viewing his genetic ancestry as the key to his identity. Consumer
genomic companies inform people about the possible geographic origins of their ancestors,
and many people have reacted to their test results by changing how they identify themselves,
such as choosing different ethnic identities when completing a census, joining new communi-
ties, cheering for different national sports teams, and learning new languages [see 3]. These
rather dramatic reactions from the results of a genetic test of somewhat dubious accuracy [for
critical reviews of genetic ancestry testing see 4–6] are telling. They suggest that people
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OPEN ACCESS
Citation: Schmalor A, Cheung BY, Heine SJ (2021)
Exploring people’s thoughts about the causes of
ethnic stereotypes. PLoS ONE 16(1): e0245517.
https://doi.org/10.1371/journal.pone.0245517
Editor: Heming Wang, Brigham and Women’s
Hospital and Harvard Medical School, UNITED
STATES
Received: September 30, 2020
Accepted: January 1, 2021
Published: January 19, 2021
Peer Review History: PLOS recognizes the
benefits of transparency in the peer review
process; therefore, we enable the publication of
all of the content of peer review and author
responses alongside final, published articles. The
editorial history of this article is available here:
https://doi.org/10.1371/journal.pone.0245517
Copyright: ©2021 Schmalor et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: The data files,
codebooks, and analysis scripts underlying this
study are available on the OSF (https://osf.io/
rdqw3/).

understand genes to be relevant to their ethnic identities, and it raises the question of whether
they believe genes to be relevant to the ethnic identities of others, more generally.
People do tend to be interested in the ethnic identity of others [e.g., 7,8], especially those
who score higher on measures of prejudice [9], and they may identify tendencies that they
believe covary with different ethnic groups [e.g., 10]. For example, a visitor to France may well
notice the sophistication and taste of French cuisine, or a visitor to Japan may be struck by the
orderliness of public behavior. But what do people believe is the cause of these ethnic differ-
ences? Do they think that they are largely the result of people’s cultural experiences, or do they
think of them as the result of innate, genetic factors? Moreover, how does learning about popu-
lation variation in genetics affect people’s views about the underlying causes of ethnic differ-
ences? In this paper, we explore how people’s theories about the bases of ethnic differences are
affected by encounters with scientific descriptions of population variation in gene frequencies.
Psychological essentialism
Why did Szegedi convert to Judaism when he learned about his Jewish ancestry? Or, more
generally, why do people often view genes as holding the key to their identity [3,11]? A consid-
eration of psychological essentialism may shed light on these questions. Psychological essen-
tialism describes a set of intuitions that people have which leads them to think of the natural
world to emerge as it does as the result of an underlying hidden essence [e.g., 12]. People have
a variety of intuitions about essences: They are thought to be the ultimate cause for a specific
outcome [e.g., 13], they are believed to be stable over time [e.g., 14], they are considered to be
immutable, even if superficial characteristics are altered [15,16], they are seen to be the bases
of categories, underlying both different species of animals and different human groups [17],
and they are believed to be primarily relevant for natural kinds, and not artifacts [15]. These
intuitions guide the way that people make sense of the natural world.
Genetic essentialism
An influential account of psychological essentialism proposes that people struggle to form con-
crete mental representations of what essences actually are, and they come to rely on essence
placeholders upon which they project their intuitions about essences [18]. While people have
relied upon various essence placeholders over time, such as viewing the four humors of Hip-
pocrates to be the key to health and personality, an especially suitable essence placeholder is
people’s understandings of genes. Genes are often understood as ultimate causes, immutable,
natural, and they carve up the social world into homogeneous and discrete categories, a ten-
dency termed “genetic essentialism” [19]. Hence, when people come to learn that genes are
involved in a particular trait, they come to view that trait in more essentialist ways [for a review
see 20]. For example, when people read about the existence of “obesity genes” they come to
view their weight as more beyond their control [21], or when people are informed that a vio-
lent criminal possesses a “warrior gene” they view him as less responsible for his crimes [22].
While there are indeed genetic causes that can operate in highly deterministic ways that
resemble these essentialist tendencies, such as fully penetrant monogenic conditions (e.g.,
Huntington’s disease), the so-called “fourth law of behavioral genetics” states that “a typical
human behavioral trait is associated with very many genetic variants, each of which accounts
for a very small percentage of the behavioral variability” [23, p. 305]. For example, to account
for the genetic variability of both human height and IQ, two highly heritable traits, would each
require hundreds of thousands of common genetic variants [24,25]. Moreover, the expression
of these many genes is guided by environmental experiences and is further moderated by vari-
ous epigenetic markers across a developmental trajectory [see 4, for a review]. In sum, the
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Funding: SJH 435-2019-0480 Social Sciences and
Humanities Research Council https://www.sshrc-
crsh.gc.ca.
Competing interests: No competing interests exist.

typical ways that genotypes influence phenotypes are vastly more complex than our simple
essentialist intuitions would suggest.
Genetic essentialism and perceptions of ethnicity
How might people’s genetic essentialist biases affect how they understand ethnicity? While the
field of cultural psychology has documented the many ways that people’s cultural experiences
shape their ways of thinking [e.g., 26,27], it is not uncommon for people to assume that some
distinctions between different ethnic groups are grounded in an underlying biological essence
[28,29]. An essentialist view of ethnic identity suggests that people’s views of ethnicity may be
influenced by information that calls attention to any underlying genetic differences between
populations. If one reflects on the fact that people living on one continent are more likely to
possess some genetic variants than people living on another continent, this may highlight how
people living on those two continents belong to discrete categories, and have fundamental dif-
ferences [14,17]. Indeed, there is much research to suggest that people’s understandings of
ethnic identities are influenced by discussions regarding genes.
One study presented German students with either an essay that described how geographic
ancestry could be revealed by genomic analyses or a control essay on an unrelated topic [30].
Participants were later asked questions about their views on expanding the European Union,
and on their feelings towards people from various Western European and Eastern European
countries. Those participants who read the essay about genes and ancestry showed a more
marked ingroup preference for Western Europeans over Eastern Europeans compared with
those who read the control essay. It seems that a consideration of the genetic foundation of
ancestry led people to have more preferences for those who shared their own ancestry. Simi-
larly, people who read arguments that the human population’s genome varied significantly
tended to evaluate ingroup and outgroup faces in a more dichotomous way compared with
those who read that there was little genetic variation across the human species [31; also see 32].
In addition, a study of American Jewish participants compared people who read essays arguing
that Jews and Arabs were either highly genetically similar or that they were genetically distinct.
Those who read about the genetic similarities between Jews and Arabs indicated more support
for peacemaking efforts in the Middle East than those who had read about the genetic differ-
ences between these groups [33]. The common finding across these studies is that discussions
about genetic differences between populations is associated with tendencies to think of those
populations as fundamentally distinct. Converging findings have also been observed by com-
paring people who read essays arguing that race is a biological construct in contrast to those
who read a social account of race; those who are led to focus on a biological basis of race show
more evidence of prejudice [34], and less of a tendency to think of Asian-Americans as Ameri-
cans [35,36]. These studies highlight how ethnic differences are viewed as more pronounced
when biological factors are considered [also see 37].
While the extant literature has found that genetic information can affect the ways people
think about different ethnicities, we explore whether thinking about genetic differences
between different populations leads people to think of any differences between these popula-
tions as being more likely the result of genes. Because genes are often perceived as carving up
the social world into homogenous and discrete categories [19], different populations may be
seen as fundamentally different which might increase the psychological distance people feel
towards them.
Specifically, how might people think about ethnic stereotypes when genes are brought into
the discussion? People can readily describe different ethnic stereotypes, but it is unclear why
people believe those stereotypes exist. Are they the product of people’s different cultural
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experiences, or are they grounded in the different genes that people possess? Because people’s
genetic essentialist biases make them think of social categories as more homogeneous and dis-
crete [19], it would seem that a consideration of genes would make ethnic stereotypes appear
to be more likely to have a genetic basis. For example, one study found that informing people
that DNA tests can measure one’s racial ancestry led people to have a more reified view of race
[38]. To explore this question, we investigated across two studies how people attributed the
cause of different ethnic stereotypes when they were presented with accurate scientific argu-
ments highlighting either the homogeneity or the heterogeneity of gene frequencies from
around the world.
Study 1
In Study 1, we aimed to test whether participants who are led to believe that there is much
genetic variation across different human groups would attribute various stereotypes about dif-
ferent ethnic groups more to genetic causes (and less to environmental causes) compared to
people who are led to believe that different human groups show little genetic variation. We
also included a control condition in which people learned about neither of these perspectives
to test which of the two experimental conditions is closer to people’s default thoughts about
human genetic variation. We also explored whether participants who score higher on an indi-
vidual difference measure of genetic essentialist tendencies would attribute various stereotypes
about ethnic groups more to genetic and less to environmental causes. Last, because social
dominance orientation is associated with more prejudicial attitudes towards outgroups [39],
we also explored how this variable would relate to people’s understandings about the causes of
ethnic stereotypes.
Method
Participants. Using G�Power [40], we calculated the minimum sample size needed to
detect a significant effect with 0.80 power, assuming a small-to-medium effect size between
three groups (d= 0.30). This yielded a recommended sample size of 336. We collected data
from 425 Americans through MTurk in case some participants do not pass comprehension
checks (discussed later; Mage = 33.55, SD = 10.75; 52% male, 47% female, 1% other; 67% Cau-
casian, 6% Black/African American, 6% Hispanic, 5% Asian, 4% mixed, 3% other). Participants
provided informed written consent and the studies received ethical approval from the Univer-
sity of British Columbia Behavioral Research Ethics Board. All participants were over 18.
Measures. Manipulation. Participants were randomly assigned to read one of three arti-
cles, each of which was scientifically accurate. Those assigned to the Genetic Differences condi-
tion read an article that argued that people’s geographic ancestry could be estimated through
their genes. Those assigned to the Genetic Similarities condition read that the human genome
is unusually homogenous, much less variable than that of chimpanzees, and that we all share
common ancestors. In contrast, those in the Control condition read an article that described
ways to improve home decoration (see SOM for articles). Following the article, participants
were then asked 5 multiple choice questions about the content of the article as comprehension
checks.
Perceived accuracy of the ethnic stereotypes and attribution to environmental and genetic
causes. Participants saw a list of 10 stereotypes about different ethnic groups (e.g., “Japanese
have longer lifespans than people from most other countries,” “The Dutch are, on average, tal-
ler than people from most other countries;” see S1 Table in S1 File SOM for complete list). We
generated this list of stereotypes from internet searches, discussions with various individuals,
and by reading a list of racial stereotypes [41]. After reading each stereotype, participants were
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asked to indicate on a scale from 0% to 100% to what extent each stereotype could be attrib-
uted to genetic causes (M= 40.73%, SD = 18.29%). Likewise, they were then asked on the
same scale the extent to which each stereotype could be attributed to environmental causes
(M= 65.67%, SD = 17.64%). Then participants had to indicate how accurate they found the
stereotype to be on a 7-point scale from “completely inaccurate” to “completely accurate”
(M= 4.15, SD = 0.91).
Genetic essentialism. Participants indicated to what extent they viewed genes as the essence
of traits and behavior on the 24-item Genetic Essentialism Tendencies Scale [42] on a 5-point
scale from “strongly disagree” to “strongly agree” (M= 2.71, SD = 0.60).
Social Dominance Orientation (SDO). Participants indicated on a 16-item scale to what
extent they viewed some groups as inferior to others on a 7-point scale from “strongly dis-
agree” to “strongly agree” [M= 2.23, SD = 1.18; 39].
Results and discussion
We first explored whether participants had completed the 5 comprehension checks correctly.
Anyone who got more than 2 incorrect was excluded from analyses, which resulted in the
exclusion of 7 participants. On average, participants answered 4.77 of the 5 questions correctly,
indicating good comprehension. We further included two questions about their opinion on
different aspects of the article which were intended to distract them from the true purpose of
the manipulation and were not analyzed. Moreover, because it is meaningless to consider what
the causes are of stereotypes if one does not believe the stereotype to be accurate, we only ana-
lyzed the data for stereotypes that a participant indicated they believed was accurate (i.e., the
participant had to rate the accuracy of that particular stereotype at or above the midpoint of
the scale). On average, participants perceived 69.59% (SD = 25.32) of the stereotypes to be
accurate. For 3 participants (0. 72%), none of the stereotypes reached the minimum accuracy
score, and so they were not included in the analyses (see S1 Table in S1 File SOM for mean
accuracy, mean genetic, and mean environmental attributions by stereotype). Note that there
was no significant difference in believing the stereotypes to be accurate between conditions, F
(2, 414) = 1.50, p= .224, η
2
= .007. To compare the extent to which stereotypes are attributed
to genetic and environmental causes between the three conditions, we conducted two ANO-
VAs and used Holm’s corrections for multiple comparisons. The difference between condi-
tions in attributing ethnic stereotypes to genetic causes was significant, F(2, 411) = 5.13, p=
.006, η
2
= .02. As hypothesized, participants in the Genetic Differences condition attributed
the ethnic stereotypes more to genetic causes (M= 47.58%, SD = 20.13%) than did participants
in the Genetic Similarities condition (M= 40.73%, SD = 18.89%), p= .014, d= 0.35. Partici-
pants in the Control condition also attributed ethnic stereotypes more to genetic causes
(M= 47.51%, SD = 19.87%) than did participants in the Genetic Similarities condition, p=
.014, d= 0.35. There were no significant differences between the Control and Genetic Differ-
ences condition, p= .976, d= 0.003 (Fig 1).
The difference between conditions in attributing ethnic stereotypes to environmental
causes was also significant, F(2, 411) = 4.53, p= .011, η
2
= .02. Participants in the Genetic
Differences condition attributed the ethnic stereotypes marginally less to environmental
causes (M= 67.46%, SD = 17.49%) than participants in the Genetic Similarities condition
(M= 71.72%, SD = 14.85%), p= .091, d= 0.26. Participants in the Control condition attributed
ethnic stereotypes less to environmental causes (M= 65.38%, SD = 18.96%) than did partici-
pants in the Genetic Similarities condition, p= .009, d= 0.37. There were no significant differ-
ences between the Control and Genetic Differences condition, p= .306, d= 0.11. The null
effects between the Control and Genetic Differences condition suggests that the default
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position of people in the Control condition was to assume that different populations are some-
what genetically distinct.
We correlated people’s attributions for the ethnic stereotypes with their scores on the
genetic essentialism tendencies measure and the social dominance orientation measure. The
higher participants scored on genetic essentialist tendencies, the more they attributed the eth-
nic stereotypes to genetic causes, r= .41, p<.001, and the less they attributed them to environ-
mental causes, r= -.16, p= .002. Likewise, the higher participants scored on social dominance
orientation, the more they attributed the ethnic stereotypes to genetic causes, r= .20, p<.001.
On the other hand, there was no significant correlation between social dominance orientation
and attributions to environmental causes, r= -.004, p= .379 (see Table 1: for these analyses, all
participants were included in these analyses, even if they rated the accuracy of a stereotype to
be below the midpoint of the scale).
In sum, the results provide initial support for our hypothesis. People who were led to reflect
on the homogeneity of the human genome were less likely to think of ethnic differences as the
product of underlying genetics. Participants in the control condition were similar to those in
the Genetic Differences condition, suggesting that this may be consistent with people’s default
Fig 1. Mean attribution of stereotypes to genes by condition. Error bars are 95% confidence intervals.
https://doi.org/10.1371/journal.pone.0245517.g001
Table 1. Correlations between perceived accuracy of stereotypes, attribution of stereotypes to genes, environment, genetic essentialism, and social dominance
orientation.
Perceived Accuracy of
Stereotypes
Attribution of stereotypes
to genetic causes
Attribution of stereotypes to
environmental causes
Genetic Essentialism
Tendencies
Social Dominance
Orientation
Perceived Accuracy of
Stereotypes
0.36(<.001) 0.27(<.001) 0.29(<.001) 0.23(<.001)
Attribution of stereotypes to
genetic causes
0.36(<.001) -0.28(<.001) 0.41(<.001) 0.20(<.001)
Attribution of stereotypes to
environmental causes
0.27(<.001) -0.28(<.001) -0.16(.002) -0.04(.379)
Genetic Essentialism
Tendencies
0.29(<.001) 0.41(<.001) -0.16(.002) 0.29(<.001)
Social Dominance Orientation 0.23(<.001) 0.20(<.001) -0.04(.379) 0.29(<.001)
Computed correlation used pearson-method with listwise-deletion.
https://doi.org/10.1371/journal.pone.0245517.t001
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theories about genetic variation. We also found that participants who believe in genetic essen-
tialism attributed the ethnic stereotypes more to genetic and less to environmental causes,
suggesting that people’s understanding of the role of genes is associated with how they think
about ethnic stereotypes.
Study 2
In Study 2, we aimed to replicate our key finding that people who are led to believe that there
is much genetic variation across the human species attribute stereotypes about ethnic groups
more to genetic causes. The study was identical to Study 1, except we expanded the list to
include 20 ethnic stereotypes. We also included an additional measure of genetic essentialist
tendencies, and we explored the role of knowledge about genes, and the effect that the manipu-
lation may have on feelings towards the different ethnic groups.
Method
Participants. Since Study 1 results suggest a small but significant effect of the independent
variable, we adjusted our sampling accordingly. Using G�Power [40], we calculated the mini-
mum sample size needed to detect a significant effect with 0.80 power, assuming a small effect
size between three groups (d= 0.20). This yielded a recommended sample size of 969. We
collected data from 1238 Americans through MTurk in case some participants did not pass
comprehension checks (Mage = 34.53, SD = 11.16; 54% female, 45% male, 1% other; 69% Cau-
casian, 12% mixed, 8% Asian, 7% Black/African American, 2% Native American, 2% other).
Participants provided informed written consent and the studies received ethical approval from
the University of British Columbia Behavioral Research Ethics Board. All participants were
over 18.
Measures. Manipulation. Participants were randomly assigned to read one of the same
three articles as in Study 1. We again followed this with 5 comprehension check items.
Perceived accuracy of the ethnic stereotypes and attribution to environmental and genetic
causes. Participants saw a list of 20 stereotypes about different ethnic groups (e.g., “On average,
French people have a more refined palate than people from most other countries, and they pre-
fer the taste of high quality cuisine.”; see S2 Table in S1 File in the SOM for complete list). The
stereotypes touched upon a broad array of traits, and many of them were distinctly negative.
Participants were asked directly after reading each stereotype how offensive they found it on a
7-point scale from “not offensive at all” to “completely offensive” (M= 2.98, SD = 1.21). We
reasoned that if participants were given the chance to express their discomfort with these ste-
reotypes, they might be more willing to consider the accuracy of them. Participants then
were asked to indicate how accurate they found the stereotype to be on a 7-point scale from
“completely inaccurate” to “completely accurate” (M= 3.60, SD = 0.92). Following this, partici-
pants were asked to indicate on a scale from 0% (“not at all) to 100% (“entirely”) to what extent
each stereotype (assuming it was true) can be attributed to genetic (M= 34.82%, SD = 19.04%)
and to environmental causes (M= 69.01%, SD = 17.51%). Since we were not interested in how
offensive participants found the stereotypes we did not analyze this question further.
Genetic essentialism. We assessed genetic essentialist beliefs in two ways. As in Study 1, par-
ticipants responded to the Genetic Essentialist Tendencies Scale [M= 2.71, SD = 0.58; 42]. Par-
ticipants also completed the Belief in Genetic Determinism Scale [30] on a 7-point scale from
“strongly disagree” to “strongly agree” (M= 4.10, SD = 0.88; Note that we only have 16 items
for the Belief in Genetic Determinism rather than 18 due to a copying and pasting error in the
survey).
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Social Dominance Orientation (SDO). Participants indicated to what extent they viewed
some groups as inferior to others on a 16-item scale from “strongly disagree” to “strongly
agree” [M= 2.43, SD = 1.22; 39].
Genetics knowledge. Participants responded to 9 questions about different aspects of genes
—some were created by us, while others were adapted from [43]. We added up the number of
correct responses (M= 6.28, SD = 1.46).
Attitudes towards different ethnic groups. We asked participants how they felt towards the
different ethnic groups about which they saw the stereotypes on a feeling thermometer from
“very cold or unfavorable feeling” (0 degrees) to “very warm or favorable feeling” (100 degrees)
(M= 70.09, SD = 16.89).
Results and discussion
First, we analyzed how participants did on the 5 comprehension check items. On average par-
ticipants scored 4.75 out of 5, indicating good comprehension. As in Study 1, we excluded any-
one who got more than 2 incorrect, which resulted in the exclusion of 15 participants. As in
Study 1, we only analyzed participants’ attributions to genetic and environmental causes if
they viewed the stereotype as accurate (i.e., they had to score at or above the midpoint on the
scale). On average, participants perceived 54.02% (SD = 24.35) of the stereotypes to be accu-
rate. For 15 participants (1.23%), none of the stereotypes reached the minimum accuracy
score, and so they were not included in the analyses (see S2 Table in S1 File SOM for mean
accuracy, mean genetic, and mean environmental attributions by stereotype). Note that, as in
Study 1, there was no significant difference in believing the stereotypes to be accurate between
conditions, F(2, 1173) = 1.63, p= .196, η
2
= .003.
To compare the extent to which stereotypes are attributed to genetic and environmental
causes between the three conditions, we conducted two ANOVAs and used Holm’s correc-
tions for multiple comparisons. The difference between conditions in attributing ethnic stereo-
types to genetic causes was significant, F(2, 1157) = 7.07, p<.001, η
2
= .01. Replicating Study
1, participants in the Genetic Differences condition attributed the ethnic stereotypes more to
genetic causes (M= 43.47%, SD = 19.68%) than participants in the Genetic Similarities condi-
tion (M= 38.63%, SD = 21.00%), p= .002, d= 0.24. Unlike in Study 1, participants in the Con-
trol condition attributed ethnic stereotypes less to genetic causes (M= 38.93%, SD = 20.80%)
than did participants in the Genetic Differences condition, p= .005, d= 0.22. There were no
significant differences between the Control and Genetic Similarities conditions, p= .841,
d= 0.01 (Fig 2). The similarities between the Control and Genetic Similarities condition sug-
gests that people’s default perspective in the Control condition was to be thinking along the
lines that different populations are quite genetically similar.
The difference between conditions in attributing ethnic stereotypes to environmental
causes was marginally significant, F(2, 1157) = 2.82, p= .060, η
2
= .005. As in Study 1, partici-
pants in the Genetic Differences condition attributed the ethnic stereotypes marginally less to
environmental causes (M= 69.98%, SD = 16.71%) than participants in the Genetic Similarities
condition (M= 72.56%, SD = 17.86%), p= .084, d= 0.15. Participants in the Control condition
did not differ in their tendencies to attribute ethnic stereotypes to environmental causes
(M= 72.19%, SD = 15.26%) either from those in the Genetic Similarities condition, p= .768,
d= 0.02, or from those in the Genetic Differences condition, p= .137, d= 0.14.
Analyzing the correlations among the measures revealed that the higher participants scored
on genetic essentialist tendencies, the more they attributed the ethnic stereotypes to genetic
causes both when using the Genetic Essentialist Tendencies scale, r= .41, p<.001, and when
using the Beliefs in Genetic Determinism scale, r= .47, p<.001 (see Table 2; for these analyses,
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all participants are included, regardless of whether they viewed the stereotypes as accurate).
Likewise, genetic essentialist tendencies were also negatively correlated with attributions to
environmental causes, r= -.18, p<.001 and r= -.14, p<.001, for Genetic Essentialist Tenden-
cies and Beliefs in Genetic Determinism, respectively. In addition, the higher participants
Fig 2. Mean attribution of stereotypes to genes by condition. Error bars are 95% confidence intervals.
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Table 2. Correlations between perceived accuracy of stereotypes, offensiveness of stereotypes, attribution of stereotypes to genes, attribution of stereotypes to envi-
ronment, genetic essentialism tendencies, belief in genetic determinism, social dominance orientation, knowledge,and feelings towards ethnic groups.
Perceived
Accuracy of
Stereotypes
Offensiveness
of stereotypes
Attribution of
stereotypes to
genetic causes
Attribution of
stereotypes to
environmental
causes
Genetic
Essentialism
Tendencies
Belief in
Genetic
Determinism
Social
Dominance
Orientation
Genetic
Knowledge
Feelings
towards the
different
ethnic
groups
Perceived
Accuracy of
Stereotypes
-0.19(<.001) 0.47(<.001) 0.05(.555) 0.36(<.001) 0.30(<.001) 0.29(<.001) -0.12(<
.001)
-0.12(<
.001)
Offensiveness of
stereotypes
-0.19(<.001) -0.12(<.001) 0.07(.098) -0.05(.468) -0.16(<.001) -0.20(<.001) 0.02(>.999) 0.05(.584)
Attribution of
stereotypes to
genetic causes
0.47(<.001) -0.12(<.001) -0.29(<.001) 0.41(<.001) 0.47(<.001) 0.25(<.001) -0.29(<
.001)
-0.10(.008)
Attribution of
stereotypes to
environmental
causes
0.05(.555) 0.07(.098) -0.29(<.001) -0.18(<.001) -0.14(<.001) -0.15(<.001) 0.24(<
.001)
0.02(>.999)
Genetic
Essentialism
Tendencies
0.36(<.001) -0.05(.468) 0.41(<.001) -0.18(<.001) 0.57(<.001) 0.25(<.001) -0.23(<
.001)
-0.08(.037)
Belief in Genetic
Determinism
0.30(<.001) -0.16(<.001) 0.47(<.001) -0.14(<.001) 0.57(<.001) 0.15(<.001) -0.19(<
.001)
-0.04(.940)
Social Dominance
Orientation
0.29(<.001) -0.20(<.001) 0.25(<.001) -0.15(<.001) 0.25(<.001) 0.15(<.001) -0.12(<
.001)
-0.29(<
.001)
Genetic
Knowledge
-0.12(<.001) 0.02(>.999) -0.29(<.001) 0.24(<.001) -0.23(<.001) -0.19(<.001) -0.12(<.001) 0.01(>.999)
Feelings towards
the different
ethnic groups
-0.12(<.001) 0.05(.584) -0.10(.008) 0.02(>.999) -0.08(.037) -0.04(.940) -0.29(<.001) 0.01
(>.999)
Computed correlation used pearson-method with listwise-deletion.
https://doi.org/10.1371/journal.pone.0245517.t002
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scored on social dominance orientation, the more they attributed the ethnic stereotypes to
genetic causes, r= .25, p<.001, and the less they did to environmental causes, r= -.15, p<
.001. Interestingly, knowledge about genes was associated with less of a tendency to attribute
stereotypes to genetic causes, r= -.29, p<.001, and a greater tendency to attribute them to
environmental causes, r= .24, p<.001.
The data files, codebooks, and analysis scripts for both studies are available at https://osf.io/
rdqw3/.
Finally, we wanted to explore whether participants in the genetic differences condition
would show less positive attitudes towards people from the ethnic groups listed in the stereo-
types. However, the overall ANOVA was not significant, F(2, 1147) = 0.59, p= .557, η
2
=
.001, and there were no significant differences between participants in the Genetic Differ-
ences condition (M= 69.48%, SD = 17.37%), the Genetic Similarity condition (M= 70.76%,
SD = 15.93%), or the Control condition (M= 70.08%, SD = 17.40%; all ps>.05).
The results largely replicated those from Study 1. People who reflected on the common
genes that humanity shared, were less likely to interpret ethnic stereotypes in terms of underly-
ing genetics compared to participants who reflected on genetic variation across the globe. One
key difference between Studies 1 and 2 was that in Study 1 the results of the Control condition
were more similar to those in the Genetic Differences condition, whereas in Study 2 those in
the Control condition more closely resembled those in the Genetic Similarities condition. It is
unclear why the Control condition varied across studies; perhaps because the stereotypes in
Study 2 contained a larger number of negative stereotypes it is possible that people viewed
more negative stereotypes to be more likely the product of environmental as opposed to
genetic influences. In both studies, people’s estimates for the environmental contribution to
ethnic stereotypes was largely unaffected by our manipulations.
Study 2 also replicated our findings that people who score higher on measures of genetic
essentialism are more likely to attribute stereotypes to genetic causes, and are less likely to attri-
bute them to environmental causes. Similarly, across both studies people higher in social domi-
nance orientation also attributed stereotypes more to genetic and less to environmental causes
(although the correlation with environmental causes was not significant in Study 1). Further-
more, we found that people who had more knowledge about genes were less likely to attribute
ethnic stereotypes to genetic causes, and were more likely to view them as the product of envi-
ronmental causes. Finally, participants who perceived the stereotypes as more accurate, who
attributed them more to genetic causes, who were higher on genetic essentialism (although this
was only significant for one of the two measures), and who scored higher on social dominance
orientation, had less positive feelings towards the different ethnic groups.
General discussion
These results further the notion that people’s understanding about genes can have broad
implications for how they understand other aspects of their lives [4,19]. Across two studies we
found that people were more likely to view genes as underlying ethnic differences under the
following conditions: a) when people had recently read an article describing how people’s
ancestry can be assessed by examining their genomes (in contrast to those who read an article
describing the homogeneity of the human genome, and in contrast to those in a control group
in Study 2); b) when people tend to have more deterministic and essentialist views of genes
in general; and c) when people have relatively less general knowledge about genes. People’s
thoughts about genetics thus contribute to the ways they understand ethnic stereotypes. More-
over, the content in our Genetics Differences article was similar in kind to that conveyed by
the advertisements of genetic ancestry companies, suggesting that the existence of this service
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Genetic attributions for ethnic stereotypes
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may be contributing to a more genetically based view of ethnic stereotypes. Such findings are
important because other research has found that considering a biological basis of ethnic iden-
tity is often associated with a number of negative consequences [30,35,36], although we note
that we did not find that our manipulations were associated with any differences in the warmth
of attitudes towards other ethnic groups.
Previous work has found that encounters with genetic information can affect the ways that
people think about ethnicity. For example, reading about genetic ancestry led Germans to have
an ingroup preference for Western Europeans over Eastern Europeans [30], reading about var-
iability in the human genome led participants to evaluate ingroup and outgroup faces in a
more dichotomous way [31], and reading about genetic similarities between Jews and Arabs
led American Jewish participants to support peacemaking efforts in the Middle East less [33].
While our study didn’t find any difference in attitudes towards the different ethnic groups, it
points to a possible reason for the findings from previous research: When people think about
the genetic differences between different populations, they come to think of any differences
between those populations as being caused more by genes. Because genes tend to be seen as
ultimate causes, immutable, natural and as carving the social world up into homogeneous and
discrete categories [19], different populations come to be seen as fundamentally different.
It is encouraging that genetics knowledge was associated with a tendency to view ethnic
stereotypes to have less of a genetic foundation and more of an environmental one [also see
44]. This suggests that educating people about genetics may be an avenue for reducing people’s
more harmful stereotypes about other groups [45,46].
Limitations
This research relied upon presenting people with a list of ethnic stereotypes and asking them
to consider the genetic and environmental causes to these. It is possible that there are demand
characteristics in this method that resulted in people estimating a larger proportion of genetic
influences than they would have spontaneously considered on their own. However, demand
characteristics could not explain why people with different attitudes, knowledge, and those
who read the Genetics Differences article would perceive a larger genetic foundation to these
ethnic stereotypes.
Furthermore, the two experimental manipulations focused solely on the role of genes in the
similarity/difference among different populations. While this design allowed us to distinguish
the effects of perceiving different populations as genetically similar or different on people’s
attributions of stereotypes to genetic causes, it cannot speak to the role of perceived cultural
similarities/differences between populations. It is possible that emphasizing cultural differ-
ences or similarities would also influence people’s judgments of the causes of ethnic
stereotypes.
In addition, while we tried to make the essays convincing and based on accurate scientific
explanations, the two manipulations are not precise polar opposites of each other. For example,
the genetic similarity condition describes explicitly that there is relatively little genetic variation
among human populations while the genetic difference condition describes how ancestry can
be traced based on genetic maps of the world that show how people from different parts of the
world are genetically distinct. Hence, direct comparisons of the potency of the two experimental
essays are complicated by the different kinds of information that each essay contains.
While we have demonstrated here that genetic essentialist beliefs are correlated with the
ways that people conceive of population differences, we have not provided any evidence regard-
ing where these beliefs come from. There are likely some cognitive and motivational precursors
of genetic essentialist beliefs, and this remains an important question for future research.
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These studies were conducted with American MTurk workers and it’s not clear how well
the results would generalize to samples from other cultural backgrounds, or with varying
knowledge about genetics. Research conducted with other samples would be informative.
Supporting information
S1 File.
(DOCX)
Author Contributions
Conceptualization: Steven J. Heine.
Data curation: Anita Schmalor, Benjamin Y. Cheung.
Formal analysis: Anita Schmalor, Benjamin Y. Cheung.
Funding acquisition: Steven J. Heine.
Resources: Steven J. Heine.
Supervision: Steven J. Heine.
Writing – original draft: Anita Schmalor.
Writing – review & editing: Benjamin Y. Cheung, Steven J. Heine.
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