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Citation: Lee, S. W. S., & Schwarz N. (in press). Clean-moral effects and clean-slate effects:
Physical cleansing as an embodied procedure of psychological separation. In R. Duschinksy, S.
Schnall, & D. Weiss (Eds.), Purity and danger now: New perspectives. London: Routledge.
Clean-Moral Effects and Clean-Slate Effects:
Physical Cleansing as an Embodied Procedure of Psychological Separation
Spike W. S. Lee
University of Toronto
Norbert Schwarz
University of Southern California
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Handwashing is one of the easiest and most effective opportunities to enjoy substantial
health benefits. Meta-analytic evidence associates handwashing with reduction in risks of
diarrhea diseases by 42-47%, severe intestinal infections by 48%, and shigellosis by 59%;
extrapolation analyses suggest that handwashing could avert 0.5-1.4 million potential diarrhea
deaths (Curtis & Cairncross, 2014). In a randomized controlled trial of 906 households in
Karachi, Pakistan, households that were (vs. were not) given handwashing promotion and plain
soap showed substantial reductions in childhood incidences of pneumonia (by 50%) and acute
lower-respiratory infections (e.g., diarrhea by 53%). Antibacterial soap worked similarly well
(Luby et al., 2005) on these two clinical syndromes that bring about the most childhood deaths
around the world, especially in poor communities in developing countries. Similar effects of
handwashing promotion on respiratory-tract infections and respiratory illness have been found
among children and adults in developed countries including Canada, Australia, and the U.S.
(Carabin et al., 1999; Master, Hess Longe, & Dickson, 1997; Niffenegger, 1997; Roberts et al.,
2000; Ryan, Christian, & Wohlrabe, 2001). The health impact of handwashing is significant
enough that October 15 is designated as the annual Global Handwashing Day, when people all
over the world are educated about the practices and benefits of effective handwashing.
Thanks to the cheap mass production and global reach of soaps and detergents since the
20th century, their physical properties have been meticulously documented (American Cleaning
Institute, 2015). Cleanliness has become a fabric of modern life, a part of our daily routine, an
easy mechanism for the avoidance of contamination, pollution, and diseases to enhance our
chances of survival (Feder, 2015). But cleanliness comes with more than just physical properties
and biological benefits—it has rich symbolic meanings, in both primitive and modern cultures,
religious communities and secular societies, an insight given by Mary Douglas (1966) in her
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classic collection of anthropological observations half a century ago. Experimental research in
the last decade has vastly expanded upon this theme to generate causal evidence that cleanliness
provides mental and behavioral benefits across many domains of contemporary life. These
psychological aspects and consequences of cleanliness are the focus of our chapter.
At first glance, the association of cleanliness with abstract symbolic meanings seems like
a matter of faith. The proverb goes, “Cleanliness is next to godliness.” Across the world’s major
religions, ritual purification symbolizes spiritual purification, as in Christians’ baptism, Judaists’
mikvah, Muslims’ and Buddhists’ ablution, Hindus’ bathing in the Ganges River, and Sikhs’
amrit. The religious overtones are so obvious that even non-religious people unconsciously
associate purity with religiosity (Preston & Ritter, 2012).
Yet cleanliness is not limited to religious contexts. As we review the burgeoning body of
psychological research on cleanliness in this chapter, we will first see that cleanliness is linked to
numerous moral experiences, which have received the lion’s share of empirical and theoretical
attention. But the story turns out to be much broader than that. Cleanliness exerts psychological
effects far beyond the realm of morality: A sense of cleanliness appears to wipe the mental slate
clean. It reduces the residual influence of threats to different facets of the self as well as the
residual influence of various positive experiences. Merely cleaning one’s hands with an
antiseptic wipe, for example, is enough to reduce one’s guilt (Zhong & Liljenquist, 2006), doubts
(Lee & Schwarz, 2010a), and the impact of previous streaks of good or bad luck (A. Xu, Zwick,
& Schwarz, 2012). Clean-slate effects appear valence- and domain-general, leading us to
conceptualize physical cleansing as an embodied procedure of psychological separation. This
procedural perspective integrates existing findings, reveals possible deeper mechanisms, and
makes novel predictions about the boundary conditions of clean-slate effects.
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Clean and Moral
Most psychological research on cleanliness has focused on its metaphorical associations with
morality, consistent with the dominant theme of Douglas’s (1966) seminal work. In current
theorizing, the link between cleanliness and morality is often traced to a conceptual metaphor
that embodies abstract thoughts about morality in concrete experiences of cleanliness (Lakoff &
Johnson, 1980; Landau, Meier, & Keefer, 2010; Lee & Schwarz, 2011, 2014). Numerous
expressions – from “clean hands and a pure heart” to “dirty thoughts and filthy behaviors” –
illustrate the close connection in all languages studied. It is assumed to result from the
scaffolding of higher mental processes upon lower sensorimotor processes over developmental
time (Lakoff & Johnson, 1999; Williams, Huang, & Bargh, 2009). It is also compatible with the
principle of neural reuse, which assumes that existing neural mechanisms acquire new functions
over evolutionary time (Anderson, 2010).
Some findings support the assumption that moral experiences implicate an embodied
metaphorical link to cleanliness. For example, when people were induced to convey a lie on
voicemail (using their mouth), they were subsequently attracted to mouthwash, but not hand
sanitizer; conversely, when induced to convey the lie on email (using their hands), they were
attracted to hand sanitizer, but not mouthwash (Lee & Schwarz, 2010b). Moreover, their
evaluation of mouth-cleaning vs. hand-washing products was associated with higher activities in
the respective sensorimotor neural regions (Denke, Rotte, Heinze, & Schaefer, 2014; Schaefer,
Rotte, Heinze, & Denke, 2015). The assumption that the conceptual metaphor is grounded in
sensorimotor modalities further predicts that moral experiences should influence basic
sensorimotor experiences of cleanliness and vice versa (cf. Lee & Schwarz, 2012). Observing
that clean and dirty are often represented in white and black colors, G. Sherman and Clore (2009,
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Study 1) demonstrated that people judged the color of a word more quickly when moral words
were shown in white and immoral words in black than vice versa. The more strongly people
showed the effect on this moral Stroop task, the more desirable they judged shower soap and
toothpaste to be (Study 3). Furthermore, embodied conceptual metaphors are conducive to
multimodal priming (Lee, in press), so moral effects should be evoked by cleanliness experience
in its various modalities. Numerous studies, as we will now review, show that tactile, olfactory,
and visual experiences of cleanliness are capable of changing both moral self-evaluation and
moral judgments and behaviors towards others.
Cleanliness and the Moral Self
Feeling immoral elicits the pursuit of cleanliness. For example, after describing their past
unethical (vs. ethical) behavior, people completed more cleansing-related word fragments and
became more likely to choose an antiseptic wipe over a pencil as a free gift (Zhong &
Liljenquist, 2006, Studies 1 & 3). Subtle procedures such as hand-copying a story, written in the
first-person perspective, of an unethical (vs. ethical) lawyer also increased people’s desires for
cleaning but not non-cleaning products (Study 2). But blatant procedures backfire. For example,
when people were first asked to complete 183 items about their conscientiousness, which
invoked concepts such as how orderly and organized they are, then describing their past
unethical (vs. ethical) behavior did not increase their likelihood of choosing an antiseptic wipe
over a pencil as a free gift (Fayard, Bassi, Bernstein, & Roberts, 2009, Study 1). A possible
reason was that completing many items about being orderly and organized made these meanings
salient and made it more likely that people saw a link between being orderly and being ethical.
As observed in many social cognition studies, awareness of a potential influence elicits mental
corrections that counteract the otherwise observed effect (e.g., Strack, Schwarz, Bless, Kübler, &
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Wänke; 1993; for a review, see Schwarz, 2015).
Physical cleansing confers a sense of morality and boosts moral self-evaluation. For
example, after describing their past unethical behavior, people who had (vs. did not have) an
opportunity to use an antiseptic wipe reported lower feelings of disgust, regret, guilt, shame,
embarrassment, and anger, and became less likely to volunteer their time for an unpaid
experiment, presumably because they felt morally cleansed and were less driven to engage in
compensatory prosocial behavior (Zhong & Liljenquist, Study 4). Quasi-experimental work also
shows that people cheated more after (vs. before) taking a shower (Lobel et al., 2015, Study 1)
and donated less money to charity after (vs. before) bathing for religious purification (Study 2).
Because active moral concerns can interfere with other cognitive tasks, we may further
expect cleansing to reduce these interference effects. Indeed, after describing a past unethical
behavior, people who had (vs. did not have) an antiseptic wipe to use showed weaker
interference effects in a Stroop task (but not more facilitation effects), weaker interference
effects in an object interference task, and faster stop-signal reaction time in a stop-signal task
(Kalanthroff, Aslan, & Dar, 2015). Apparently, cleansing increases cognitive flexibility,
presumably by freeing people’s minds from ruminating about moral failures.
Vicarious Experience of Morality and Cleanliness
Vicarious experience of a behavior is weaker in intensity than direct enactment of the
behavior (Barsalou, 2008). Hence, vicarious manipulations of morality, like copying a story
about someone else’s immoral behavior, are likely to come with less reliable cleanliness effects
than recalling one’s own immoral behavior (e.g., Earp, Everett, Madva, & Hamlin, 2014).
Similarly, vicarious manipulations of cleansing are likely to exert weaker moral effects.
For example, after describing an incident of doing something bad to someone, people
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who experienced vicarious cleansing by watching a 2-min video of someone else typing numbers
on a keyboard and wiping the fingers, palm, and back of both hands (vs. of someone else typing
numbers on a keyboard only) were less likely to complete and return some questionnaires 3
weeks later, but the effects were weaker than if people actually typed the numbers themselves
and wiped their own fingers, palm, and back of both hands (H. Xu, Bègue, & Bushman, 2014).
The observed linear effect of self vs. other vs. no wiping on the number of questionnaires
completed and returned was mediated by participants’ state guilt, suggesting that direct cleansing
had stronger effects than vicarious cleansing on both immediate guilty feelings and subsequent
guilt-driven behavior weeks later.
Cleanliness and the Moral Self in Social Comparison
Moral self-evaluation is subject to social comparison (Festinger, 1954). For example, in
an experiment allegedly about food preferences (Cramwinckel, van Dijk, Scheepers, & van den
Bos, 2013, Study 1), people tasted a meat sausage and then encountered another “participant”
(actually a confederate) who refused to taste the sausage for moral (vs. non-moral) reasons.
People disliked the moral refuser more and showed physiological changes that indicated a
motivational state of threat, presumably because social comparison with the moral refuser
threatened one’s own moral standing. But if people had an opportunity to clean their hands, they
liked the moral refuser more, considered the moral refuser less agentic, and evaluated themselves
more positively, especially if they had a strong moral identity (Study 2).
When people think about their own moral failures, they become particularly sensitive to
others’ moral failures, which provide an opportunity for self-serving social comparisons (“Look,
others are worse than me, so I’m not too bad”). Accordingly, people condemn others who have
moral failures as dirtier and more evil and, by contrast, see themselves as cleaner and more
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moral. For example, people who read about a target person being guilty of theft and punished
(vs. guilty but not punished, or vs. not guilty) reported feeling physically cleaner themselves, but
only if they had been asked to recall their own unethical experience beforehand, not if they had
been asked to recall a very boring experience (Rothschild, Landau, Keefer, & Sullivan, 2015,
Study 1). Recalling their own unethical (vs. a very boring) experience also increased people’s
tendency to judge a hit-and-run driver (described in an article with his photo shown) as evil
(Study 3) and as physically dirty, mediated by higher levels of their own current feelings of guilt
(Study 2).
A Clean, Moral Self in Different Areas of Life
Cleanliness is linked to moral concerns in many important areas of life, such as law and
violence, business, and sex.
In court proceedings, evidence that is obtained through illegal means is often considered
legally “dirty”. Indeed, lawyers and law students who were induced (vs. not induced) to use
inadmissible evidence (produced from a police officer’s racially motivated search) were more
likely to choose a small bottle of Purell hand disinfectant over a highlighter pen as a free gift
(Bilz, 2012, Study 3), paralleling findings in other domains of moral transgression. Similarly,
people who read criminal (vs. neutral) vignettes completed more cleansing- and disgust-related
word fragments and were more likely to choose an antiseptic wipe or soap over a pen holder as a
free gift (Jones & Fitness, 2008, Study 1). After playing a video game involving violence against
humans (vs. objects), people were more likely to choose cleaning products, an effect that was
mediated by greater moral distress and that emerged only among inexperienced players, not
among experienced ones (Gollwitzer & Melzer, 2012). This suggests that repeated exposure to
violence may mute people’s moral distress and associated desires for cleanliness.
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In the business world, networking is valued, but when motivated by dubious goals, it can
feel dirty and elicit the pursuit of cleanliness (Casciaro, Gino, & Kouchaki, 2014). For example,
recalling an experience of instrumental (vs. spontaneous) networking increased people’s
tendency to complete cleansing-related word fragments; this effect was stronger for recall of
professional (vs. personal) networking (Study 1). Even reading a story and imagining being the
main character who engaged in professional instrumental (vs. personal spontaneous) networking
could increase people’s desires for cleaning over non-cleaning products, mediated by their
stronger feelings of dirtiness, inauthenticity, and discomfort; it also increased their negative but
not positive affect (Study 2). Actually sending a message for professional networking via
LinkedIn (vs. personal networking via Facebook) increased people’s desires for cleaning but not
non-cleaning products, although only among people who were assigned a low-power (vs. highpower) role (Study 4).
Power may moderate cleanliness effects because being in a low-power role may elicit
conformist intentions and inauthentic behaviors, which leave people with a sense of impurity.
For example, people who recalled experiences of being inauthentic (vs. authentic) to themselves
reported lower moral self-regard and stronger feelings of impurity (Gino, Kouchaki, & Galinsky,
2015, Study 1), completed more cleansing-related word fragments, and judged cleaning products
and behaviors but not non-cleaning products and behaviors as more desirable (Study 2),
regardless of whether their recalled inauthentic (vs. authentic) experience involved lying (vs.
telling the truth) to others or not. People who described an experience of being inauthentic to
themselves (vs. failing an activity, or vs. their activities from the previous day) were also more
likely to volunteer time to the experimenter, mediated by stronger feelings of impurity (Study 3).
These effects appear to be driven by a link between inauthenticity and impurity rather than by
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cognitive dissonance, as writing a counterattitudinal (vs. proattitudinal) essay increased people’s
desires for cleaning but not non-cleaning products, regardless of whether they wrote the
counterattitudinal essay with a high or low sense of choice (Study 4). If the effect were driven by
cognitive dissonance, the sense of choice should have mattered; it did not. Finally, using a
cleansing product (hand sanitizer; vs. examining a pen) decreased people’s likelihood and
amount of donation if they had recalled an experience of being inauthentic to themselves, but not
if they had recalled an experience of being authentic to themselves (Study 5).
Sexual behavior is of particular interest to the clean-moral link because sex is more
inherently physical than other moral concerns, such as fairness, and it has been at the center of an
ongoing debate about the theoretical structure of morality (cf. Giner-Sorolla & Sabo, this
volume; see also the debate among Frimer, Gray, Haidt, and Pizarro at SPSP 2016). Empirically,
men who listened to an audio recording to vividly imagine non-consensually (vs. consensually)
kissing a young woman at a party later showed higher levels of self-reported dirtiness (Rachman,
Radomsky, Elliott, & Zysk 2012, Studies 1-4), actual washing behaviors (Studies 2 & 3), urges
to wash (Studies 3 & 4), as well as increases in anxiety, shame, anger, guilt, and sadness (Study
4).
Conversely, being the victim of sexual innuendo triggers dirty feelings. Women who
received objectifying (vs. non-objectifying) positive comments from a male confederate reported
greater sinful feelings and stronger desires for cleaning but not non-cleaning products, both
effects being mediated by increased feelings of dirtiness (Chen, Teng, & Zhang, 2013, Study 1).
Women who recalled a social interaction with a man who objectified them (vs. responded
appropriately) reported greater sinful feelings, mediated by an increased sense of contamination
(Study 2), but this effect occurred only among women high on perceived personal responsibility
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for being objectified, not among women low on it (Study 3).
Summary
Seeing oneself as immoral prompts one’s pursuit of cleanliness, which by metaphorical
association boosts one’s moral self-evaluation. Both morality and cleanliness can be manipulated
vicariously (as opposed to directly) to produce similar but weaker effects. One way to
manipulate how moral people feel about themselves and others is by social comparison. Mutual
influences between the moral self and physical cleanliness are observed in many important areas
of life, such as law and violence, business networking, and sexual morality.
Cleanliness and Moral Judgment and Behavior Towards Others
One’s sense of cleanliness also shapes moral judgments and behaviors towards others.
There are two broad ways to manipulate “the sense of cleanliness.” One is to manipulate actual
cleansing (e.g., washing hands with soap, wiping hands with an antiseptic wipe), which is what
researchers did in all of the studies reviewed above that examined cleanliness as an independent
variable. Another way is to manipulate clean cues (e.g., clean scents, clean room). Both kinds of
manipulation work by conferring a sense of cleanliness, but their exact effects depend on what
the sense of cleanliness bears on and what precedes it (Lee & Schwarz, 2011). Such contextsensitivity is consistent with the malleable nature of inferences from other phenomenal
experience (Schwarz, 2012) and affords a variety of judgmental and behavioral effects. If people
are induced to feel immoral about their past transgressions, then a sense of cleanliness reduces
their morally dirty feelings and they are less motivated to engage in compensatory prosocial
behaviors and they feel more licensed to engage in self-interested behaviors (see the “Cleanliness
and the Moral Self” section above). If people are induced to feel disgusted about the acts of
someone else, then a sense of cleanliness reduces residual disgust and thus reduces its
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intensification effect on people’s judgment towards others’ immoral behaviors. If no particular
event precedes a manipulation of clean cues or actual cleansing, the sense of cleanliness may
bear either on the self or on others. If it bears on others, it renders others’ immoral behaviors less
dirty and less bad. If it bears on the self, one sees the self as cleaner and more moral and others
as dirtier by comparison.
Cleanliness Can Reduce Disgust and Its Effect on Moral Judgment
Moral judgment is harsher when people experience disgust, even if the disgust was
incidentally induced by watching an unrelated video clip (e.g., Schnall, Haidt, Clore, & Jordan,
2008). This impact of disgust is attenuated when people washed their hands prior to judgment
(Schnall, Benton, & Harvey, 2008, Study 2). Similarly, using (vs. examining) an antiseptic wipe
weakened the association between self-reported germ aversion and unfavorable attitudes towards
outgroups (J. Y. Huang, Sedlovskaya, Ackerman, & Bargh, 2011, Study 3).
Cleanliness Bearing on Others Can Soften Moral Judgment of Them
People who unscrambled sentences containing cleanliness-related (vs. neutral) words
judged moral transgressions as a little less wrong, despite no change in their negative or positive
emotions (Schnall, Benton, & Harvey, 2008, Study 1). For this kind of manipulation to be
effective though, it has to elicit relatively low processing effort (J. L. Huang, 2014), or else it
may not work (Johnson, Cheung, & Donnellan, 2014), consistent with the finding that once
primed cues are overly salient, they lose their influence on judgments (Strack et al., 1993;
Schwarz, 2015).
Extending beyond the conceptual activation of a sense of cleanliness through words,
actual cleansing can reduce physiological changes as well as moral judgment. In a recent
experiment (Kaspar, Krapp, & König, 2015), people saw a number of moral and immoral images
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and judged how moral or immoral each was, while their eye movements were being tracked.
Halfway through the task, there was a break. If people were prompted to wash their hands (vs.
simply waited), afterwards they judged immoral images as less immoral and moral images as
less moral, and showed corresponding changes in pupil size.
Cleanliness Bearing on the Self Can Promote Moral Behavior Towards Others
Incidental cleanliness cues can elicit moral behavior. For example, when people played a
trust game in the recipient role, they were more cooperative and returned more money to the
sender if they were in a room sprayed (vs. not sprayed) with citrus-scented Windex (Liljenquist,
Zhong, & Galinsky, 2010, Study 1). The same manipulation also increased intention to volunteer
for Habitat for Humanity and fund donation, despite little change in positive or negative affect
(Study 2).
The flip side of the beneficial effect of cleanliness cues is that dirtiness cues can reduce
moral behavior. For example, vendors at a local farmers’ market who received a dirty (vs. clean)
banknote from a “customer” (who was in fact a confederate) gave a smaller amount of
vegetables to the customer on a second purchase (Yang, Zhou, Mead, Vohs, & Baumeister, 2013,
Study 1). After people counted dirty (vs. clean) bills, they returned less money in a one-shot trust
game (Study 2) and demanded less money for performing unfair or harmful behaviors (but not
for performing behaviors that would violate ingroup/loyalty, authority/respect, or purity/sanctity;
Study 3). They also reciprocated less in rounds of prisoner’s dilemma games where they
expected the partner to be a cooperator (but not in rounds where they expected the partner to be a
defector; Study 4), and were less likely to reject small unfair offers in ultimatum games (but not
unfair large offers or fair offers; Study 5).
These behavioral effects of cleanliness and dirtiness cues are mediated by changes in
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moral attitudes. Counting ordinary bills after reading a news article about how dirty the country’s
paper currency was (vs. a recent weather report) decreased people’s offers in rounds of dictator
games with allegedly different receivers, mediated by less positive ratings of exchange-related
words (Study 6) or by increased agreement with greed-related sayings (Study 7). Conversely,
counting ordinary bills after reading a news article about how clean the country’s paper currency
was (vs. a recent weather report) increased people’s positive ratings of exchange-related words
(Study 6) and increased their offers in rounds of dictator games with allegedly different
receivers, mediated by decreased agreement with greed-related sayings and increased agreement
with fairness-related ones (Study 7).
Cleanliness Bearing on the Self Can Intensify Moral Judgment of Others
People who were (vs. were not) asked to clean their hands with an antiseptic wipe judged
various social issues as more immoral (Zhong, Strejcek, & Sivanathan, 2010, Study 1). Merely
imagining cleansing can have similar effects. People who read a passage written in the firstperson perspective that prompted detailed visualization of being clean (vs. dirty, or vs. not
reading anything) judged social issues as more immoral (Study 2), mediated by higher ranking of
themselves over fellow students on moral character (but not on other dimensions; Study 3).
Compared with my own clean and moral self, the social issues out there feel dirty and immoral.
In addition to actual or imagined cleansing, subtle cues of cleanliness also change moral
judgments and political attitudes. For example, simply being asked to “step over to the handsanitizer dispenser (vs. the wall) to complete the questionnaire” increased people’s self-reported
conservative political attitudes in moral, social, and fiscal domains (Helzer & Pizarro, 2011,
Study 1). This observation is consistent with the more general finding that conservatives put
more value on purity and are more disgust-sensitive (Graham, Haidt, & Nosek, 2009; Haidt,
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2012; Inbar, Pizarro, & Bloom, 2009). Similarly, people who completed a computer
questionnaire next to a sign about cleanliness and after using an antiseptic wipe (vs. without the
sign and without receiving any wipe) judged sexual purity violations to be more wrong, mediated
by more conservative political attitudes (Study 2).
Summary
A sense of cleanliness, elicited by either subtle cues or actual cleansing, changes moral
judgments and behaviors towards others. Depending on what it means and what it bears on, it
can weaken compensatory prosociality and promote self-interested behaviors; or it can reduce
disgust and soften moral judgments towards others; or it can render the self clean and moral,
elicit identity-consistent moral behaviors, and make others’ immoral behaviors seem even more
dirty and immoral. A full understanding of the moderating variables remains wanting.
Modality-Specific Grounding of Morality in Cleanliness
All of the findings reviewed so far are consistent with two possible accounts. (1)
Cleanliness is linguistically and semantically associated with morality. (2) Cleanliness is the
embodied grounding of morality. Unlike the linguistic-semantic view, the embodied view
assumes that mental representations of morality are grounded in sensorimotor modalities
implicated in cleanliness. As such, it uniquely predicts modality-specific links between morality
and cleanliness. These links emerge when a modality is temporarily or chronically salient.
Temporarily Salient Modality
Cleanliness effects are strongest on the specific modality made temporarily salient by a
transgression. For example, people who had typed a lie on email (manual modality) evaluated
hand sanitizer more favorably than mouthwash, whereas people who had told a lie on voicemail
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(oral modality) evaluated mouthwash more favorably than hand sanitizer (Lee & Schwarz,
2010b; see Schaefer et al., 2015 for a replication). People who listened to a recording or rewrote
a story that prompted them to vividly imagine having to borrow and use a cell phone from a gay
(vs. heterosexual) man—which made the manual and oral modalities salient—completed more
cleansing-related word fragments (Golec et al., 2014, Study 1), indicating that the task brought
cleanliness concerns to mind. Acting on these concerns, they were more likely to choose a
disinfecting wipe over a pencil as a free gift (Study 2) and evaluated disinfectant hand wash and
mouthwash as more desirable, but not other body-cleaning, household-cleaning or non-cleaning
products as more desirable (Study 3).
Neural evidence further supports the role of temporarily salient modality in cleanliness
effects. For example, favorable evaluation of mouth-cleaning products after lying was associated
with neural activities in sensorimotor regions (Denke et al., 2014). Favorable evaluation of
mouthwash products after lying in a voice mail and favorable evaluation of hand-wash products
after lying in a written note were associated with the somatotopically organized neural activities
(Schaefer et al., 2015).
Chronically Salient Modality
In the above studies, cleanliness effects were strongest on the modality involved in the
transgression. Consistent with these temporary situational influences, cleanliness effects are also
stronger on the specific modality that is chronically salient in a culture. For example, East Asians
emphasize the face as a representation of their public self-image in sociomoral discourse.
Accordingly, face-cleaning was more effective in reducing guilt and regret when ChineseCanadian biculturals were primed with their Chinese background than when primed with their
Canadian background (Lee, Tang, Wan, Mai, & Liu, 2015, Study 1). When Chinese people used
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an antiseptic wipe to clean their face, it freed them from guilt-driven compensatory prosocial
behavior (Study 2), whereas cleaning their hands, or merely examining the wipe, did not. The
effectiveness of facial cleansing as a coping mechanism is further supported by Chinese people’s
specific interest in face-cleaning products and their tendency to engage in face-cleaning (vs.
hands-cleaning) behavior in the wake of their own immorality (Study 3).
Summary
These lines of evidence indicate that the clean-moral association shows the strongest
effects on whichever modality is salient, whether momentarily or chronically. The principle of
modality salience is not predicted a priori by the amodal view that morality is merely
linguistically or semantically associated with cleanliness. It is predicted a priori by the embodied
view that morality is grounded in sensorimotor modalities responsible for cleanliness experience
(see Lee & Schwarz, 2010b, for a discussion).
Individual Differences in Cleanliness and Morality
The embodied grounding of morality in cleanliness predicts that people should make
stronger moral judgment if they are sensitive to disgust (often evoked by dirtiness), to
cleanliness, or to their bodily experience in general. They should also show stronger clean-moral
effects if they have strong faith in their intuitions.
Disgust Sensitivity and Moral Judgment
Mock jurors high on disgust sensitivity exhibited a bias toward convicting criminals
(Jones & Fitness, 2008, Study 2). Disgust-sensitive people also considered it more likely that
suspects in crime vignettes were culpable, attributed more evilness to criminals, recommended
longer sentences for criminals, and perceived higher community crime levels (Study 3). People
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who frequently feel disgusted in daily life showed stronger disapproval of behaviors that violate
the moral foundation of purity and stronger approval of behaviors that uphold purity (whereas
trait anger and trait fear did not have the same predictive effects; Horberg, Oveis, Keltner, &
Cohen, 2009, Study 3).
Regarding the moral foundation of purity, disgust-sensitive people were more likely to
ascribe intentionality to an agent whose behavior had the side effect of causing gay men to kiss
in public (Inbar, Pizarro, Knobe, & Bloom, 2009, Study 1) and showed more unfavorable
automatic associations with gay people (vs. heterosexuals; Study 2). Stronger moral
condemnation of suicide was also predicted by higher disgust sensitivity, as were more intense
disgust responses to obituaries, stronger beliefs that suicide taints the victims’ souls, and greater
concerns about the moral foundation of purity (Rottman et al., 2014).
The predictive effects of disgust sensitivity, however, are not limited to the moral
foundation of purity or to moral violations that involve physical disgust (e.g., sexual immorality,
bloody murder). Higher disgust sensitivity also predicted stronger condemnation of moral
transgressions that go beyond the purity domain and involve no disgust and higher likelihoods of
moralizing violations of social conventions (Chapman & Anderson, 2014).
Sensitivity to Cleanliness or Bodily Experience and Moral Judgment
Excessive cleaning due to fear of contamination is the most common symptom of
obsessive-compulsive disorder (OCD; National Institute of Mental Health, 2016). Accordingly,
people with OCD show particularly strong cleanliness effects: After people described a past
unethical behavior, having (vs. not having) an antiseptic wipe to use decreased their feelings of
disgust, regret, guilt, shame, embarrassment, and anger, and their tendency to volunteer; these
effects were stronger among people with OCD than people without OCD (Reuven, Liberman &
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Dar, 2014).
Cleanliness is a bodily experience, and people higher on private body consciousness
(PBC) are more attentive to their internal bodily experiences (Miller, Murphy, & Buss, 1981).
Accordingly, people high on PBC show particularly strong cleanliness-related effects: People
who sat in a physically disgusting (vs. clean) room (Schnall, Haidt, et al., 2008, Study 2), wrote
about a physically disgusting experience (vs. skipped this task; Study 3), or watched a physically
disgusting (vs. sad, or vs. neutral) film clip (Study 4) judged moral transgressions as more
wrong, regardless of whether the transgressions themselves evoked disgust or not; these effects
were limited to people high on PBC and not observed among people low on PBC.
Faith in Intuition and Moral Judgment
In the eyes of moral rationalists (e.g., Kohlberg, 1969), moral judgment ought to be based
on abstract reasoning, not tethered to irrelevant bodily experiences like being dirty and disgusted
or feeling clean and pure. But as is obvious from the reviewed studies, people are susceptible to
influence from incidental feelings. Does it follow that clean-moral effects are stronger among
people who trust their gut feelings? On the one hand, there is evidence that after people imagined
writing a deceitful (vs. an apologetic) email, their willingness to pay for hand-cleaning products
(but not office supplies or general body care products) increased with their faith in intuition, even
controlling for their positive and negative affect (Ward & King, 2015, Study 1). On the other
hand, even professional philosophers, who supposedly rely less on intuition and gut feeling but
more on reflection and logical thinking, are susceptible to the influence of cleanliness:
Philosophers who completed surveys sprayed with clean scents (vs. odorless water) in a space
sprayed with clean scents (vs. odorless water) judged behaviors that violate the moral foundation
of purity to be less wrong from an observer’s perspective (Tobia, Chapman, & Stitch, 2013).
20
These findings raise more questions than they answer. They highlight the need to
investigate whether and how clean-moral effects interact with fast vs. slow mental processes
(Kahneman, 2011), what affective and cognitive mechanisms underlie them, and when and for
whom they are strongest.
Summary
Compatible with the embodied grounding of morality in cleanliness, moral judgments
and cleanliness effects are stronger for people sensitive to disgust, cleanliness, or bodily
experience. Investigating whether clean-moral effects are driven by feelings-as-information
(Schwarz, 2012) or also by other processes will allow clearer predictions about their personal
and situational moderators.
Specificity vs. Generality of the Link between Cleanliness and Morality
Are clean-moral effects specific to a particular kind of morality? One view holds that
different basic emotions are mapped onto different moral foundations. From this perspective,
disgust is the primary emotional response to violations of the moral foundation that has been
variously referred to as divinity, purity, or sanctity (Rozin, Lowery, Imada, & Haidt, 1999). But
the strength of the original evidence for this claim has undergone serious questioning (see
Chapman & Anderson, 2013, for details). In addition, multiple lines of counterevidence have
emerged, casting doubt on the specific mapping view. For example, facial expressions of disgust
can be evoked by violations of moral codes that are unrelated to divinity/purity/sanctity, like
fairness (Cannon, Schnall, & White, 2011; Chapman, Kim, Susskind, & Anderson, 2009).
Similarly, incidental manipulations of distaste (Eskine, Kacinik, & Prinz, 2011) and disgust
(Cheng, Ottati, & Price, 2013; Schnall, Haidt et al., 2008; Wheatley & Haidt, 2005) influence
moral judgments that are unrelated to divinity/purity/sanctity; and higher disgust sensitivity
21
predicts harsher condemnation of moral transgressions beyond the divinity/purity/sanctity
foundation (Chapman & Anderson, 2014). These findings suggest that moral disgust is more
general than initially thought.
The picture is further complicated by evidence for the pervasive role of anger in morality.
Anger is the predominant emotional response to moral transgressions that involve no physically
disgusting elements or, as some theorists argue, to moral transgressions in general, “irrespective
of the normative content involved” (Royzman, Atanasov, Landy, Parks, & Gepty, 2014, p. 892).
Consistent with this view, anger is evoked by violations of many sacred values, including
divinity/purity/sanctity violations (Tetlock et al., 2000). When people are asked to choose
between prototypically angry or disgusted behaviors in response to divinity/purity/sanctity
violations (e.g., disrespecting the Bible), they choose prototypically angry rather than disgusted
behaviors (Royzman et al., 2014). Indeed, anger results in harsher judgments of both
divinity/purity/sanctity and fairness violations (Cheng et al., 2013). Anger and disgust effects are
sometimes confounded or co-occurring. For example, both anger and disgust influence
judgments of harm (Ugazio, Lamm, & Singer, 2012); both anger and disgust can be evoked by
both harm and divinity/purity/sanctity violations (Cameron, Lindquist, & Gray, 2015). Table 1
provides an organized summary of the relevant findings (for full coverage of their details, see
Giner-Sorolla & Sabo, this volume).
Table 1. Emotional responses to disgusting and immoral stimuli.
Stimuli
Distaste stimuli (e.g., bitterness)
Physically disgusting stimuli (e.g., feces)
Moral violations of divinity/purity/sanctity
that involve or imply physically disgusting
stimuli (e.g., incest)
Response
Disgust output
Disgust output
Disgust output, but it may have nothing to do with
the acts’ immoral nature (Rozin, Haidt, &
McCauley, 2008)
22
Moral violations of divinity/purity/sanctity Disgust output can occur, but (1) whether it results
that do not involve or imply any physically from the same appraisals as to physically disgusting
disgusting stimuli (e.g., idolatry)
stimuli is unclear and (2) whether disgust is the
predominant emotion is unclear because there is
evidence for disgust (Chapman & Anderson, 2013)
or anger (Royzman et al., 2014) as the predominant
emotion
Moral violations of fairness that do not
Disgust output can occur, but the same caveats as
involve or imply any physically disgusting above apply
stimuli (e.g., biased resource allocation)
Moral violations of care, loyalty, and
Disgust output can occur, but anger seems to be the
authority that do not involve or imply any predominant emotional response
physically disgusting stimuli (e.g.,
intentional harm, betrayal, disrespect)
In short, there appears to be a multiplicity of relations between emotions and moral
foundations. Why is it so? One possible reason is that the supposedly singular foundation of
divinity/purity/sanctity, as is perhaps noticeable from its unwieldy plurality, is anything but
singular. Theorists have pointed out that measures of this foundation are fraught with confounds
and need to be, for lack of a better verb, “purified” such that they tease apart its multiple facets
and measure them more precisely (Pizarro, 2016; see also the debate among Frimer, Gray, Haidt,
and Pizarro at SPSP 2016). Pending such finer-grained measures, maybe we will see a specific
mapping between a particular emotion and a particular facet of divinity/purity/sanctity.
Another possible reason is that all moral foundations share a common, deeper cognitive
template that tracks an agent’s intentional harm on a patient (Gray, Young, & Waytz, 2012).
From this perspective, what appear to be different moral foundations are really different
manifestations of the same underlying process. This dovetails a constructionist view on the fluid,
context-sensitive links between emotion and morality (Cameron et al., 2015), hence the apparent
multiplicity in their relations.
The debate continues. But whether one sees disgust as specifically tied to one moral
23
foundation or as generally related to multiple moral foundations, both sides of the debate have
focused on the role of disgust, cleanliness, and purity within the realm of morality. Is cleanliness
only related to moral issues?
Beyond Morality: Defense Against Threats
An emerging stream of research shows that beyond its metaphorical associations with
morality, a sense of cleanliness reduces the residual influence of recent negative and positive
experiences, even if they have nothing to do with morality. We first review cleanliness effects on
threatening experiences, then on positive experiences, and finally propose an integrative
mechanism.
A Threat to the Rational Self
After people make a free choice between similarly attractive options, they often
experience postdecisional dissonance (“Did I make the right decision?”), which is a threat to
their rational self. It motivates people to justify their choice by developing a stronger preference
for the chosen over the rejected option (Brehm, 1956; Festinger, 1957). This classic “spreading
of alternatives” effect disappears once people wash or wipe their hands clean. After choosing
between two similarly attractive music albums, people tended to rank the chosen album as better
than the rejected album, but this tendency was eliminated once they had used (vs. examined) a
bottle of hand soap (Lee & Schwarz, 2010b, Study 1). Likewise, after choosing between two
fruit jams, people tended to expect the chosen jam to taste better than the rejected jam, but this
tendency was eliminated once they had used (vs. examined) an antiseptic wipe (Study 2).
An extended replication (Marotta & Bohner, 2013) showed that the ability to wipe off
cognitive dissonance was independent of people’s trait preference for consistency. It also showed
24
that using substances that lack a cleansing quality (a sticky chocolate rub) did not attenuate
dissonance. Finally, cleaning one’s hands was insufficient to reduce dissonance among people
high on brooding tendencies, intolerance of uncertainty, and generalized anxiety, but it reliably
eliminated dissonance among people low on these attributes (De Los Reyes et al., 2012).
A Threat to the Competent or Secure Self
Failures often lead people to feel less optimistic about their future performance and to put
in compensatory effort. Wiping off one’s failure is counterproductive under these conditions.
People who washed (vs. did not wash) their hands after failing a first anagram task showed more
optimistic expectations about their future performance on a second anagram task—but their
actual performance deteriorated, presumably through reduced effort (Kaspar, 2012).
Various cleansing effects—on the competent self, the rational self, and the moral self—
converge to suggest that a sense of cleanliness may be effective for reducing residual distress
from threats to any facet of the self (Millet, van der Wal, Grinstein, & Lee, 2016). Consistent
with this possibility, after watching a tension-inducing video clip of a physically threatening
scene, people who watched another video clip involving hand-washing (vs. circle-drawing, or vs.
egg-peeling) reported less tension (Study 1). Compatible effects emerged in the context of an
economic threat. People who watched a video about ongoing recession and described the process
of job search in times of high unemployment (vs. watched a video about oceanic nature and
described the process of doing laundry) evaluated cleaning but not non-cleaning products more
favorably (Study 2). The effect vanished once people affirmed values core to the self, consistent
with the hypothesis that a sense of cleanliness serves to protect the self from threats, unless it is
already protected (e.g., by self-affirmation).
Summary
25
A sense of cleanliness helps people cope with distress from threats to different facets of
the self. Following this reasoning, preliminary evidence shows that cleanliness effects are weaker
after self-affirmation. Whether cleanliness serves similar protective functions as self-affirmation
(D. Sherman & Cohen, 2006) in the face of all self-threats remains to be explored.
Beyond Morality: Clean-Slate Effects
All of the studies reviewed so far examined cleanliness effects on threatening
experiences, dovetailing Douglas’s (1966) interest in the symbolic meanings of cleanliness and
purity in contexts of danger and order maintenance. Yet there is evidence for cleanliness effects
on positive, non-threatening experiences as well. Cleansing appears to wipe the mental slate
clean. It exerts valence-general effects on diverse domains such as luck, endowment, and goals.
Luck
Not surprisingly, people are more willing to take risks when they think it is their lucky
rather than unlucky day. For example, Canadian business students who had to recall a good
financial decision took more risk on a subsequent financial decision task than people who had to
recall a bad financial decision. However, cleaning their hands with an antiseptic wipe (vs. merely
examining it) attenuated the influence of both kinds of recall. After wiping, those who had
thought about a good decision took less risk, whereas those who had thought about a bad
decision took more risk (Xu, Zwick, & Schwarz, 2012, Study 1).
In a related study, Hong Kong students played a gambling task in which they had good or
bad luck. Subsequently, they were offered the opportunity to play an additional round with their
own money. Those who had experienced a winning streak invested more of their money than
those who had experienced a losing streak. However, washing their hands eliminated the
26
influence of their previous good or bad luck such that winners and losers no longer differed in
how much money they bet (Study 2). Similarly, people who had good luck in four rounds of a
color-guessing game were less likely to want to play the game again after washing their hands
(Moscatiello & Nagel, 2014, Studies 1 & 2). In contrast, those who had bad luck were more
likely to play the game again after washing (Study 2). Across these studies, participants acted as
if good or bad luck left a physical trace that could be wiped off, limiting the impact of one’s luck
on future outcomes.
Endowment
When people sell a product, they ask for more money than they would be willing to
spend to acquire the product (Kahneman, Knetsch, & Thaler, 1991). This so-called endowment
effect appears to be eliminated through physical cleansing. People who washed their hands (vs.
evaluated a liquid soap) were more likely to exchange a previously endowed chocolate bar for a
different one (Florack et al., 2014, Study 2). Similarly, people who washed their hands (vs. had
their height measured) were more likely to exchange a previously endowed drink for a different
one (Study 1), reported better mood, and evaluated both drinks as more positive (but not negative
or acceptable; Study 3).
Goals
Cleansing has also been found to change basic goal priming effects. After unscrambling
sentences containing words related to the goal of academic achievement, people who used (vs.
examined) an antiseptic wipe completed fewer word fragments about the primed goal (academic
achievement) but more word fragments about a conflicting goal (socializing), whereas their
completions pertaining to an unrelated goal (kindness) remained unaffected (Dong & Lee, 2016,
Study 1). This pattern suggests that cleansing can reduce the accessibility of the goal that is
27
active at the time of cleansing.
Because accessible goals guide behavior, cleansing’s effect on accessibility can also
influence active goal pursuit. After unscrambling sentences containing words related to the goal
of being healthy, people who used (vs. examined) an antiseptic wipe were less likely to choose a
healthy granola bar over an unhealthy chocolate bar (Study 2). But if people unscrambled
sentences containing neutral words (i.e., words not priming a health goal), using (vs. examining)
an antiseptic wipe did not influence their snack choices.
Finally, active goals suppress competing goals. If cleansing reduces the accessibility of
an active goal, it may wipe the slate clean for subsequent goals to exert stronger influence.
Indeed, in addition to diminishing effects of goals primed beforehand, cleansing amplifies effects
of goals primed afterwards. If people unscrambled sentences containing words related to one
goal (e.g., health) before a cleansing manipulation and also unscrambled sentences containing
words related to another goal (e.g., saving) after the cleansing manipulation, then using (vs.
examining) an antiseptic wipe decreased people’s judged importance of the previously primed
goal and increased their judged importance of the subsequently primed goal, whatever the goal
contents were (Study 3). This contrastive pattern completely vanished once another manipulation
had psychologically separated a primed goal from the present self (Study 4). By the logic of
moderation of process (Spencer, Zannna, & Fong, 2005), these findings suggest that cleansing is
functionally similar to a procedure of psychological separation.
Summary
Cleansing reduces the influence of recent prior experience, be it negative (e.g., guilt from
immoral behavior, dissonance from free choice, pessimism from academic failure, tension from
physical threat, risk aversion from bad luck) or positive (e.g., moral behavior, good luck, product
28
endowment, primed goals). Cleansing seems to amplify the influence of subsequent experience
(e.g., a new goal) as well. Just how broad are clean-slate effects? They appear valence- and
content-general. We have yet to find domains where cleansing does not exert any influence. To
identify the boundary of clean-slate effects, we need to understand the underlying mechanism.
Physical Cleansing as an Embodied Procedure of Psychological Separation
Because cleanliness effects extend far beyond the moral realm, the embodied metaphor of
moral cleanliness (Lakoff & Johnson, 1999; Landau, Meier, & Keefer, 2010; Williams, Huang,
& Bargh, 2009) cannot be the only mechanism at work. After all, it can only predict clean-moral
effects, but not the full range of clean-slate effects.
We propose that physical cleansing functions as an embodied procedure of psychological
separation (Dong & Lee, 2016). By separating physical traces from a physical target object (e.g.,
detaching dirt from hands), physical cleansing serves as the embodied grounding for the
separation of psychological traces from a psychological target object (e.g., dissociating goals
from the self). As a procedure, separation is content-neutral and applicable across domains,
hence the valence- and domain-general nature of clean-slate effects. Psychological separation, by
marking what belongs to a category and what does not, may even be such a basic component of
cognitive processing that it serves as a deeper basis of the supposedly “basic metaphor” (Schnall,
2014) of moral cleanliness.
What sorts of psychological separation may be conferred by a sense of cleanliness?
Psychological research in several areas can shed some light on different processes that may
underlie cleansing and that predict different boundary conditions of clean-slate effects. For
example, does cleansing work by affectively neutralizing prior experiences? This speculation is
compatible with the observation that washing behaviors appear to trigger termination signals in
29
the security motivational system (Szechtman & Woody, 2004). It is also compatible with studies
in which cleansing reduces the impact of affective (emotional or motivational) experiences, such
as guilt, dissonance, failure, luck, or goal pursuit. If true, this account predicts that cleansing
effects should be limited to affective experiences and should not extend to non-affective domains
(e.g., declarative memory).
Another possibility is that cleansing exerts its influence by distancing one’s prior
experience from one’s present self. Based on research showing that self-distancing enhances
reappraisals of affective experiences (Kross, Ayduk, & Mischel, 2005) and that greater
psychological distance leads to more abstract construal (Trope & Liberman, 2003, 2010), we
expect that if cleansing works through a distancing process, it should enhance not just
reappraisals of affective experiences, but also abstract construals of both affective and nonaffective experiences. Digging deeper, if cleansing does promote distancing, how does it do so?
By functioning as a temporal marker that separates the past from the present (for research on
temporal markers, see Dai, Milkman, & Riis, 2015; Zauberman, Levav, Diehl, & Bhargave,
2009)? If so, clean-slate effects should be mediated by temporal distancing and one may expect
that cleansing reduces the accessibility, clarity, vividness, and concreteness of mental
representations of past events. One may also expect that cleansing changes the construal of past
events such that they seem less spatially near, less socially related, and less causally linked to the
present self.
Or does physical cleansing work by imposing a category boundary that excludes a prior
experience from the construal of the present reality such that people use the former as a standard
for evaluating the latter (Schwarz & Bless, 1992)? If so, clean-slate effects would be mediated by
a comparative process of subjective construal, which should influence not just the accessibility,
30
but also the relevance and use of information.
These deeper mechanisms, their relative contributions, and the boundary conditions they
predict await empirical testing. Teasing them apart will reveal the underpinnings of cleansing as
an embodied procedure of psychological separation. It may provide insights into why cleanliness
and purification are linked to taboo and dangerous things from which we want to separate
ourselves as Douglas (1966) observed in her pioneering work. It may also shed light on medical
practitioners’ common failure to wash their hands (Pittet et al., 2004), thereby pointing to more
effective psychological approaches to nudging this behavioral problem (Griffing, 2012) and
reducing health risks in society.
References
American Cleaning Institute. (2015). Soaps & detergent. Retrieved October 1, 2015, from
http://www.cleaninginstitute.org/clean_living/soaps__detergent_history.aspx
Anderson, M. L. (2010). Neural reuse: A fundamental organizational principle of the brain.
Behavioral and Brain Sciences, 33, 245–266.
Barsalou, L. W. (2008). Grounded cognition. Annual Review of Psychology, 59, 617–645.
Bilz, K. (2012). Dirty hands or deterrence? An experimental examination of the exclusionary
rule. Journal of Empirical Legal Studies, 9, 149–171.
Brehm, J. W. (1956). Postdecision changes in the desirability of alternatives. Journal of
Abnormal and Social Psychology, 52, 384–389.
Cameron, C. D., Lindquist, K. A., & Gray, K. (2015). A constructionist review of morality and
emotions: No evidence for specific links between moral content and discrete emotions.
Personality and Social Psychology Review, 19, 371-394.
31
Carabin, H., Gyorkos, T. W., Soto, J. C., Joseph, L., Payment, P., & Collet, J.-P. (1999).
Effectiveness of a training program in reducing infections in toddlers attending day care
centers. Epidemiology, 10, 219–227.
Casciaro, T., Gino, F., & Kouchaki, M. (2014). The contaminating effects of building
instrumental ties: How networking can make us feel dirty. Administrative Science
Quarterly, 59, 705–735.
Chapman, H. A., & Anderson, A. K. (2013). Things rank and gross in nature: A review and
synthesis of moral disgust. Psychological Bulletin, 139, 300–327.
Chapman, H. A., & Anderson, A. K. (2014). Trait physical disgust is related to moral judgments
outside of the purity domain. Emotion, 14, 341–348.
Chapman, H. A., Kim, D. A., Susskind, J. M., & Anderson, A. K. (2009). In bad taste: Evidence
for the oral origins of moral disgust. Science, 323, 1222–1226.
Cheng, J. S., Ottati, V. C., & Price, E. D. (2013). The arousal model of moral condemnation.
Journal of Experimental Social Psychology, 49, 1012–1018.
Chen, Z., Teng, F., & Zhang, H. (2013). Sinful flesh: Sexual objectification threatens women’s
moral self. Journal of Experimental Social Psychology, 49, 1042–1048.
Cramwinckel, F. M., van Dijk, E., Scheepers, D., & van den Bos, K. (2013). The threat of moral
refusers for one’s self-concept and the protective function of physical cleansing. Journal
of Experimental Social Psychology, 49, 1049–1058.
Curtis, V., & Cairncross, S. (2003). Effect of washing hands with soap on diarrhoea risk in the
community: a systematic review. The Lancet Infectious Diseases, 3, 275–281.
32
Dai, H., Milkman, K. L., & Riis, J. (2015). Put your imperfections behind you: Temporal
landmarks spur goal initiation when they signal new beginnings. Psychological Science,
26, 1927–1936.
De Los Reyes, A., Aldao, A., Kundey, S. M. A., Lee, B. G., & Molina, S. (2012). Compromised
decision making and the effects of manipulating physical states on human judgments.
Journal of Clinical Psychology, 68, 1–7.
Denke, C., Rotte, M., Heinze, H.-J., & Schaefer, M. (2014). Lying and the subsequent desire for
toothpaste: Activity in the somatosensory cortex predicts embodiment of the moral-purity
metaphor. Cerebral Cortex, 26, 477–484.
Dong, P., & Lee, S. W. S. (2016). Wipe off and write on: Physical cleansing changes goal
priming effects. Manuscript in Preparation.
Douglas, M. (1966). Purity and danger: An analysis of the concepts of pollution and taboo.
London: Routledge.
Earp, B. D., Everett, J. A. C., Madva, E. N., & Hamlin, J. K. (2014). Out, damned spot: Can the
“Macbeth effect” be replicated? Basic and Applied Social Psychology, 36, 91–98.
Eskine, K. J., Kacinik, N. A., & Prinz, J. J. (2011). A bad taste in the mouth: Gustatory disgust
influences moral judgment. Psychological Science, 22, 295–299.
Fayard, J. V., Bassi, A. K., Bernstein, D. M., & Roberts, B. W. (2009). Is cleanliness next to
godliness? Dispelling old wives’ tales: Failure to replicate Zhong and Liljenquist (2006).
Journal of Articles in Support of the Null Hypothesis, 6, 21–29.
Feder, Y. (2015). Contamination appraisals, pollution beliefs, and the role of cultural inheritance
in shaping disease avoidance behavior. Cognitive Science.
Festinger, L. (1954). A theory of social comparison processes. Human Relations, 7, 117–140.
33
Festinger, L. (1957). A theory of cognitive dissonance. Stanford, CA: Stanford University Press.
Florack, A., Kleber, J., Busch, R., & Stöhr, D. (2014). Detaching the ties of ownership: the
effects of hand washing on the exchange of endowed products. Journal of Consumer
Psychology, 24, 284–289.
Frimer, J., Gray, K., Haidt, J., & Pizarro, D. (2016). Purity and harm in the American culture
war: A debate on the structure of morality. Presented at the Annual convention of the
Society for Personality and Social Psychology, San Diego, CA.
Giner-Sorolla, R., & Sabo, J. S. (in press). Disgust in the moral realm: Do all roads lead to
character? In R. Duschinksy, S. Schnall, & D. Weiss (Eds.), Purity and danger now: New
perspectives. London: Routledge.
Gino, F., Kouchaki, M., & Galinsky, A. D. (2015). The moral virtue of authenticity: How
inauthenticity produces feelings of immorality and impurity. Psychological Science, 26,
983–996.
Golec de Zavala, A., Waldzus, S., & Cypryanska, M. (2014). Prejudice towards gay men and a
need for physical cleansing. Journal of Experimental Social Psychology, 54, 1–10.
Gollwitzer, M., & Melzer, A. (2012). Macbeth and the joystick: Evidence for moral cleansing
after playing a violent video game. Journal of Experimental Social Psychology, 48,
1356–1360.
Graham, J., Haidt, J., & Nosek, B. A. (2009). Liberals and conservatives rely on different sets of
moral foundations. Journal of Personality and Social Psychology, 96, 1029–1046.
Gray, K., Waytz, A., & Young, L. (2012). The moral dyad: A fundamental template unifying
moral judgment. Psychological Inquiry, 23, 206–215.
34
Griffing, G. T. (2012). Why don’t doctors wash their hands? Journal of the American Medical
Directors Association, 13, 662.
Haidt, J. (2012). The righteous mind. New York: Free Press.
Helzer, E. G., & Pizarro, D. A. (2011). Dirty liberals! Reminders of physical cleanliness
influence moral and political attitudes. Psychological Science, 22, 517–522.
Horberg, E. J., Oveis, C., Keltner, D., & Cohen, A. B. (2009). Disgust and the moralization of
purity. Journal of Personality and Social Psychology, 97, 963–976.
Huang, J. L. (2014). Does cleanliness influence moral judgments? Response effort moderates the
effect of cleanliness priming on moral judgments. Frontiers in Psychology, 5, 1276
Huang, J. Y., Sedlovskaya, A., Ackerman, J. M., & Bargh, J. A. (2011). Immunizing against
prejudice: Effects of disease protection on attitudes toward out-groups. Psychological
Science, 22, 1550–1556.
Inbar, Y., Pizarro, D. A., & Bloom, P. (2009). Conservatives are more easily disgusted than
liberals. Cognition and Emotion, 23, 714–725.
Inbar, Y., Pizarro, D. A., Knobe, J., & Bloom, P. (2009). Disgust sensitivity predicts intuitive
disapproval of gays. Emotion, 9, 435–439.
Johnson, D. J., Cheung, F., & Donnellan, M. B. (2014). Does cleanliness influence moral
judgments? A direct replication of Schnall, Benton, and Harvey (2008). Social
Psychology, 45, 209–215.
Jones, A., & Fitness, J. (2008). Moral hypervigilance: The influence of disgust sensitivity in the
moral domain. Emotion, 8, 613–627.
Kahneman, D. (2011). Thinking, fast and slow (1st ed). New York: Farrar, Straus and Giroux.
35
Kahneman, D., Knetsch, J. L., & Thaler, R. H. (1991). Anomalies: The endowment effect, loss
aversion, and status quo bias. Journal of Economic Perspectives, 5, 193-206.
Kalanthroff, E., Aslan, C., & Dar, R. (2015). Washing away your sins will set your mind free:
physical cleansing modulates the effect of threatened morality on executive control.
Cognition and Emotion, 1–8.
Kaspar, K. (2012). Washing one’s hands after failure enhances optimism but hampers future
performance. Social Psychological and Personality Science, 4, 69–73.
Kaspar, K., Krapp, V., & König, P. (2015). Hand washing induces a clean slate effect in moral
judgments: A pupillometry and eye-tracking study. Scientific Reports, 5, 10471.
Kohlberg, L. (1969). Stage and sequence: The cognitive-developmental approach to
socialization. In D. A. Goslin (Ed.), Handbook of socialization theory and research (pp.
347–480). Chicago: McNally.
Kross, E., Ayduk, O., & Mischel, W. (2005). When asking “why” does not hurt: Distinguishing
rumination from reflective processing of negative emotions. Psychological Science, 16,
709–715.
Lakoff, G., & Johnson, M. (1980). Metaphors we live by. Chicago, IL: The University of
Chicago Press.
Lakoff, G., & Johnson, M. (1999). Philosophy in the flesh: The embodied mind and its challenge
to Western thought. New York: Basic Books.
Landau, M. J., Meier, B. P., & Keefer, L. A. (2010). A metaphor-enriched social cognition.
Psychological Bulletin, 136, 1045–1067.
Lee, S. W. S. (in press). Multimodal priming of abstract constructs. Current Opinion in
Psychology.
36
Lee, S. W. S., & Schwarz, N. (2010a). Washing away postdecisional dissonance. Science, 328,
709.
Lee, S. W. S., & Schwarz, N. (2010b). Dirty hands and dirty mouths: Embodiment of the moralpurity metaphor is specific to the motor modality involved in moral transgression.
Psychological Science, 21, 1423–1425.
Lee, S. W. S., & Schwarz, N. (2011). Wiping the slate clean: Psychological consequences of
physical cleansing. Current Directions in Psychological Science, 20, 307–311.
Lee, S. W. S., & Schwarz, N. (2012). Bidirectionality, mediation, and moderation of
metaphorical effects: The embodiment of social suspicion and fishy smells. Journal of
Personality and Social Psychology, 103, 737–749.
Lee, S. W. S., & Schwarz, N. (2014). Metaphor in judgment and decision making. In M. Landau,
M. D. Robinson, & B. P. Meier (Eds.), The power of metaphor: Examining its influence
on social life (pp. 85–108). Washington: American Psychological Association.
Lee, S. W. S., Tang, H., Wan, J., Mai, X., & Liu, C. (2015). A cultural look at moral purity:
wiping the face clean. Frontiers in Psychology, 6, 577
Liljenquist, K., Zhong, C.-B., & Galinsky, A. D. (2010). The smell of virtue: Clean scents
promote reciprocity and charity. Psychological Science, 21, 381–383.
Lobel, T. E., Cohen, A., Kalay Shahin, L., Malov, S., Golan, Y., & Busnach, S. (2015). Being
clean and acting dirty: The paradoxical effect of self-cleansing. Ethics and Behavior, 25,
307–313.
Luby, S. P., Agboatwalla, M., Feikin, D. R., Painter, J., Billhimer, W., Altaf, A., & Hoekstra, R.
M. (2005). Effect of handwashing on child health: a randomised controlled trial. The
Lancet, 366, 225–233.
37
Marotta, M., & Bohner, G. (2013). Dissonanz abwaschen, Dissonanz reinreiben: Symbolische
Abschwächung vs. Verstärkung von Dissonanz nach Entscheidungen. Presented at the
Tagung der Fachgruppe Sozialpsychologie, Hagen, Germany.
Master, D., Hess Longe, S. H., & Dickson, H. (1997). Scheduled hand washing in an elementary
school population. Family Medicine, 29, 336–339.
Miller, L. C., Murphy, R., & Buss, A. H. (1981). Consciousness of body: Private and public.
Journal of Personality and Social Psychology, 41, 397–406.
Millet, K., van der Wal, A., Grinstein, A., & Lee, S. W. S. (2016). Threat and cleanliness.
Manuscript in Preparation.
Moscatiello, T., & Nagel, E. (2014, May). The effects of cleansing on risk taking. Poster
presented at the Celebration, Gettysburg, PA. Retrieved from
http://cupola.gettysburg.edu/cgi/viewcontent.cgi?article=1592&context=celebration
National Institute of Mental Health. (n.d.). Obsessive-compulsive disorder. Retrieved March 7,
2016, from http://www.nimh.nih.gov/health/topics/obsessive-compulsive-disorderocd/index.shtml
Niffenegger, J. P. (1997). Proper handwashing promotes wellness in child care. Journal of
Pediatric Health Care, 11, 26–31.
Pittet, D. (2004). Hand hygiene among physicians: Performance, beliefs, and perceptions. Annals
of Internal Medicine, 141, 1.
Pizarro, D. (2016). Disgust and the domain of moral purity. Paper presented at the Annual
convention of the Society for Personality and Social Psychology, San Diego, CA.
Preston, J. L., & Ritter, R. S. (2012). Cleanliness and godliness: Mutual association between two
kinds of personal purity. Journal of Experimental Social Psychology, 48, 1365–1368.
38
Rachman, S., Radomsky, A. S., Elliott, C. M., & Zysk, E. (2012). Mental contamination: The
perpetrator effect. Journal of Behavior Therapy and Experimental Psychiatry, 43, 587–
593.
Reuven, O., Liberman, N., & Dar, R. (2014). The effect of physical cleaning on threatened
morality in individuals with obsessive-compulsive disorder. Clinical Psychological
Science, 2, 224–229.
Roberts, L., Smith, W., Jorm, L., Patel, M., Douglas, R. M., & McGilchrist, C. (2000). Effect of
infection control measures on the frequency of upper respiratory infection in child care: A
randomized, controlled trial. Pediatrics, 105, 738–742.
Rothschild, Z. K., Landau, M. J., Keefer, L. A., & Sullivan, D. (2015). Another’s punishment
cleanses the self: Evidence for a moral cleansing function of punishing transgressors.
Motivation and Emotion, 39, 722–741.
Rottman, J., Kelemen, D., & Young, L. (2014). Tainting the soul: Purity concerns predict moral
judgments of suicide. Cognition, 130, 217–226.
Royzman, E., Atanasov, P., Landy, J. F., Parks, A., & Gepty, A. (2014). CAD or MAD? Anger
(not disgust) as the predominant response to pathogen-free violations of the divinity code.
Emotion, 14, 892–907.
Rozin, P., Haidt, J., & McCauley, C. R. (2008). Disgust. In M. Lewis, J. M. Haviland-Jones, &
L. F. Barrett (Eds.), Handbook of emotions (3rd ed., pp. 757–776). New York: Guilford.
Rozin, P., Lowery, L., Imada, S., & Haidt, J. (1999). The CAD triad hypothesis: A mapping
between three moral emotions (contempt, anger, disgust) and three moral codes
(community, autonomy, divinity). Journal of Personality and Social Psychology, 76,
574–586.
39
Ryan, M. A., Christian, R. S., & Wohlrabe, J. (2001). Handwashing and respiratory illness
among young adults in military training. American Journal of Preventive Medicine, 21,
79–83.
Schaefer, M., Rotte, M., Heinze, H.-J., & Denke, C. (2015). Dirty deeds and dirty bodies:
Embodiment of the Macbeth effect is mapped topographically onto the somatosensory
cortex. Scientific Reports, 5, 18051.
Schnall, S. (2014). Are there basic metaphors? In M. Landau, M. D. Robinson, & B. P. Meier
(Eds.), The power of metaphor: Examining its influence on social life (pp. 225–247).
Washington: American Psychological Association.
Schnall, S., Benton, J., & Harvey, S. (2008). With a clean conscience: Cleanliness reduces the
severity of moral judgments. Psychological Science, 19, 1219–1222.
Schnall, S., Haidt, J., Clore, G. L., & Jordan, A. H. (2008). Disgust as embodied moral judgment.
Personality and Social Psychology Bulletin, 34, 1096–1109.
Schwarz, N. (2012). Feelings-as-information theory. In P. A. M. Van Lange, A. W. Kruglanski,
& E. T. Higgins (Eds.), Handbook of theories of social psychology (pp. 289–308).
Thousand Oaks, CA: Sage.
Schwarz, N. (2015). Metacognition. In M. Mikulincer & P. R. Shaver (Eds.), APA Handbook of
Personality and Social Psychology: Attitudes and Social Cognition (pp. 203–229).
Washington, DC: American Psychological Association.
Schwarz, N., & Bless, H. (1992). Constructing reality and its alternatives: An inclusion/exclusion
model of assimilation and contrast effects in social judgment. In L. L. Martin & A. Tesser
(Eds.), The construction of social judgments (pp. 217–245). Hillsdale, NJ: Erlbaum.
40
Sherman, D. K., & Cohen, G. L. (2006). The psychology of self‐defense: Self‐affirmation theory.
In M. P. Zanna (Ed.), Advances in experimental social psychology (Vol. 38, pp. 183–
242). San Diego, CA: Elsevier.
Sherman, G. D., & Clore, G. L. (2009). The color of sin: White and black are perceptual symbols
of moral purity and pollution. Psychological Science, 20(8), 1019–1025.
Spencer, S. J., Zanna, M. P., & Fong, G. T. (2005). Establishing a causal chain: Why
experiments are often more effective than mediational analyses in examining
psychological processes. Journal of Personality and Social Psychology, 89, 845–851.
Strack, F., Schwarz, N., Bless, H., Kübler, A., & Wänke, M. (1993). Awareness of the influence
as a determinant of assimilation versus contrast. European Journal of Social Psychology,
23, 53-62.
Szechtman, H., & Woody, E. (2004). Obsessive-compulsive disorder as a disturbance of security
motivation. Psychological Review, 111, 111–127.
Tetlock, P. E., Kristel, O. V., Elson, S. B., Green, M. C., & Lerner, J. S. (2000). The psychology
of the unthinkable: Taboo trade-offs, forbidden base rates, and heretical counterfactuals.
Journal of Personality and Social Psychology, 78, 853–870.
Tobia, K., Chapman, G., & Stich, S. (2013). Cleanliness is next to morality, even for
philosophers. Journal of Consciousness Studies, 20, 194–204.
Trope, Y., & Liberman, N. (2003). Temporal construal. Psychological Review, 110, 403–421.
Trope, Y., & Liberman, N. (2010). Construal-level theory of psychological distance.
Psychological Review, 117, 440–463.
Ugazio, G., Lamm, C., & Singer, T. (2012). The role of emotions for moral judgments depends
on the type of emotion and moral scenario. Emotion, 12, 579–590.
41
Ward, S. J., & King, L. A. (2015). Individual differences in intuitive processing moderate
responses to moral transgressions. Personality and Individual Differences, 87, 230–235.
Wheatley, T., & Haidt, J. (2005). Hypnotic disgust makes moral judgments more severe.
Psychological Science, 16, 780–784.
Williams, L. E., Huang, J. Y., & Bargh, J. A. (2009). The scaffolded mind: Higher mental
processes are grounded in early experience of the physical world. European Journal of
Social Psychology, 39, 1257–1267.
Xu, A. J., Zwick, R., & Schwarz, N. (2012). Washing away your (good or bad) luck: Physical
cleansing affects risk-taking behavior. Journal of Experimental Psychology: General,
141, 26–30.
Xu, H., Bègue, L., & Bushman, B. J. (2014). Washing the guilt away: Effects of personal versus
vicarious cleansing on guilty feelings and prosocial behavior. Frontiers in Human
Neuroscience, 8, 97.
Yang, Q., Wu, X., Zhou, X., Mead, N. L., Vohs, K. D., & Baumeister, R. F. (2013). Diverging
dffects of clean versus dirty money on attitudes, values, and interpersonal behavior.
Journal of Personality and Social Psychology, 104, 473-489.
Zauberman, G., Levav, J., Diehl, K., & Bhargave, R. (2009). 1995 feels so close yet so far: The
effect of event markers on subjective feelings of elapsed time. Psychological Science, 21,
133–139.
Zhong, C.-B., & Liljenquist, K. (2006). Washing away your sins: Threatened morality and
physical cleansing. Science, 313, 1451–1452.
Zhong, C.-B., Strejcek, B., & Sivanathan, N. (2010). A clean self can render harsh moral
judgment. Journal of Experimental Social Psychology, 46, 859–862.