BRIEF REPORT

The metaphor police: A case study of the role of metaphorin explanation

Paul H. Thibodeau1& Latoya Crow1

& Stephen J. Flusberg2

Published online: 7 December 2016# Psychonomic Society, Inc. 2016

Abstract While many scholars have pointed to the role ofmetaphor in explanation, relatively little experimental re-search has examined whether and how metaphors are usedand understood in everyday explanatory discourse. Across 3experiments, we investigated the nature and function of met-aphor in explanation by drawing on a real-world examplewhere the terms guardian andwarriorwere used to metaphor-ically explain the role of police officers. We found, first, thatthe associations participants brought to mind for these con-cepts differed depending on whether they had previously an-swered questions about law enforcement (e.g., associations forwarrior emphasized aggression and violence rather thanstrength and bravery when participants had previously an-swered questions about policing). Second, people were almostevenly split in their judgment of which metaphor was moreappropriate to explain the role of law enforcement; this pref-erence was highly predictive of beliefs related to policing andthe criminal justice system. Third, and most important, usingthese metaphors to explain the job of policing causally

influenced attitudes toward law enforcement in a metaphor-congruent manner (i.e., exposure to the guardian metaphor ledto more positive attitudes), a finding that could not beaccounted for by basic lexical priming. These studies comple-ment existing work that has identified metaphor as a mecha-nism for representing abstract concepts, but also highlight thecommunicative and explanatory, rather than representational,functions of metaphor by showing that metaphors can encap-sulate and convey an array of structured attitudes and beliefs.

Keywords Metaphor . Explanation . Analogy . Persuasion .

Reasoning . Concepts

Explanations without metaphor would be difficult if notimpossible, for in order to describe the unknown, wemust resort to concepts that we know and understand,and that is the essence of a metaphor—an unusual jux-taposition of the familiar and the unfamiliar.Earl R. MacCormac

When you are trying to explain something complex or ab-stract to someone else, it often helps to make a vivid compar-ison to a simpler and more familiar domain. In other words, itoften helps to use a metaphor or analogy. An apt metaphor canquickly establish common ground between communicativepartners, add emotional weight to the discussion, and enablethe listener to use their prior knowledge of a source domain toorganize their understanding and reasoning about the target ofexplanation (Clark, 1996; Thibodeau & Boroditsky, 2011,2013). Take, for example, some explanations of the nature ofexplanation itself: in order to highlight the ubiquity of expla-nation in everyday experience, Wilson and Keil (2000)

Electronic supplementary material The online version of this article(doi:10.3758/s13423-016-1192-5) contains supplementary material,which is available to authorized users.

* Paul H. Thibodeaupaul.thibodeau@oberlin.edu

Latoya Crowlatoya.crow@oberlin.edu

Stephen J. Flusbergstephen.flusberg@purchase.edu

1 Department of Psychology, Oberlin College, 120 W. Lorain St.,Oberlin, OH 44074, USA

2 Department of Psychology, Purchase College, SUNY, 735 AndersonHill Rd., Purchase, NY 10577, USA

Psychon Bull Rev (2017) 24:1375–1386DOI 10.3758/s13423-016-1192-5

remarked, BExplanation is a river that flows through humanlife^ (p. 87). And in a chapter that appeared in the same editedvolume, Alison Gopnik (2000) famously explained the phe-nomenology (and evolutionary origins) of explanation byanalogy to an orgasm.

Yet despite the recent explosion of research in psychologyand the cognitive sciences into the nature of explanation, al-most none of this work has directly examined the role ofmetaphor in this process. Similarly, though there has been agreat deal of theoretical, linguistic, and experimental researchinto the nature and functions of metaphor in language andthought, scant attention has been paid to how metaphors areused and understood in the context of everyday explanatorydiscourse. Rather, most of the focus has been on the cognitivemechanisms underlying metaphor processing (e.g., Gentner,Bowdle, Wolff, & Boronat, 2001; Glucksberg & Keysar,1990; Kao, Bergen, & Goodman, 2014), the representationalrole metaphors play in abstract thinking (e.g., Boroditsky,2000; Gibbs, 1994; Lakoff & Johnson, 1980; Lakoff &Núñez, 2000; Thibodeau & Boroditsky, 2011, 2013), andthe persuasive power of metaphors in communication (e.g.,Ottati, Rhoads, & Graesser, 1999; Sopory & Dillard, 2002).

Taken together, however, this work points to the potentialpower of metaphor as an explanatory device, since metaphors(and analogies) allow us to represent, understand, and reasonabout novel domains by subsuming them under familiar sche-matic knowledge structures (Gentner et al., 2001; Gentner &Gentner, 1982; Glucksberg & Keysar, 1990; Lakoff &Johnson, 1980; Thibodeau & Boroditsky, 2011). This processdovetails with subsumption or unificationist accounts of thestructure and function of explanations developed by philoso-phers of science, which suggest that successful explanationssituate the target of explanation under broad, unifying patternsor theories, guiding the learner to generalize and make predic-tions based on these more abstract schemata (Lombrozo,2011; Woodward, 2014). Experimental research on the roleof self-explanation in category learning provides empiricalsupport for this approach to thinking about the nature of ex-planation: People prompted to explain (as opposed to de-scribe) their decisions during learning are more likely to makeinferences about the general rules governing category mem-bership (Williams & Lombrozo, 2010).We suggest metaphorsfunction as useful and efficient explanatory devices preciselybecause they situate the target of explanation in relation to abroad, structured body of knowledge already stored in long-term memory (i.e., knowledge of the metaphor vehicle),which is then available to drive generalizations, predictions,and inference about the target domain.

One real-world example of metaphor in explanation comesfrom a recent report prepared by President Obama’s (Ramsey& Robinson, 2015) task force on 21st century policing: BLawenforcement culture should embrace a guardian—rather thana warrior—mindset to build trust and legitimacy both within

agencies and with the public^ (emphasis added; Ramsey &Robinson, 2015, p. 1). The task force chose to communicatetheir central message by contrasting two metaphors for polic-ing: the term warrior highlights the similarity between policeofficers and soldiers, who fight not just for their cause but alsofor their lives—an unfortunate reality of policing that is oftenpointed out in recruitment and training materials, as in BYoucould die today, tomorrow, or next Friday^ (Garcia, 2014,para. 3). The term guardian, on the other hand, emphasizesthat protecting and serving the community is the core missionof police. We used this real-world example as test bed forinvestigating foundational questions about the nature andfunction of metaphor in explanation:

1. How is knowledge about a metaphorical source domain(guardian or warrior) activated in the context of a meta-phorical explanation (about policing)?

2. Does preference for a given metaphorical source domain(police officers are more like guardians than warriors orvice versa) predict particular attitudes toward the targetdomain?

3. Are explanatory metaphors effective? That is, does usinga specific metaphorical source domain during explanationaffect listener conceptions of the target domain in ametaphor-congruent manner? If so, what cognitive pro-cesses are involved?

Overview of studies

We present the results of three studies that explored the rela-tionship between metaphors for and conceptions of policing.The goal of Study 1 was to investigate what the termsguardian and warrior mean in order to identify how theymight influence peoples’ conceptions of policing when usedas explanatory metaphors, as well examine whether prefer-ence for one of the metaphors is predictive of attitudes towardlaw enforcement.

In Study 2 we asked whether the metaphors used in theservice of explanation are persuasive. A growing body ofevidence suggests that metaphorical framing can impact howpeople think and reason about complex social issues (e.g.,Dweck, 2006; Hauser & Schwarz, 2014; Landau, Sullivan,& Greenberg, 2009; Sopory & Dillard, 2002; Thibodeau &Boroditsky, 2011, 2013). For example, describing a crimeproblem as a beast that is ravaging a city leads people tosuggest more aggressive crime-fighting solutions comparedto when the same problem is described as a virus(Thibodeau & Boroditsky, 2011, 2013). We hypothesized thata similar effect would be observed when metaphors were usedin the service of framing an explanation; in other words, weexpected that reading a statement explaining how police

1376 Psychon Bull Rev (2017) 24:1375–1386

officers are guardians of the community would lead people toa more positive view of role of law enforcement than reading astatement explaining how police officers are warriors of thecommunity.

In Study 3, we tested whether the power of an explanatorymetaphor is simply the result of lexical priming (cf. McGlone,2011). Do people report more positive views of police whenexposed to a guardian metaphor because activation from theword guardian spreads to positively valenced lexical associ-ates like protection? Do people report more negative views ofpolice when exposed to a warrior metaphor because activa-tion in this case spreads to more negatively valenced lexicalassociates like war? Or, does the explanatory power of thewords come from their explicit use as metaphors to describepolicing? In this study, participants were asked to report theirattitudes toward law enforcement either after listing a syno-nym to a target word (guardian or warrior) or after reading ametaphorical description of police (as guardians or warriors).We expected that presenting the word guardian or warrior inisolation, disconnected from a discussion of policing, wouldnot influence attitudes about police (Thibodeau & Boroditsky,2011).

This pattern of results would suggest that metaphors areuseful in explanation at least in part because of the schematicknowledge structures that they bring to bear on the topic ofdiscussion (Sopory & Dillard, 2002; Thibodeau &Boroditsky, 2011), and not simply because of the emotionalvalence they convey. That is, we argue that metaphors help toorganize complex information about the target domain(policing) in terms of a more general and less complex sourcedomain (guardian or warrior), which is subsequently availableto guide reasoning. Quantifying the conceptual structure ofthese domains and testing for such an influence representsan important challenge for researchers interested in how met-aphors shape thought (e.g., Keysar & Bly, 1995). We presentone approach to this issue based on finer grained analyses ofour key dependent measure after discussing the primary find-ings of the three studies. Data for all three studies are availableon the Open Science Framework (osf.io/6twj8).

Study 1: Guardians and warriors

Participants in Study 1 completed four tasks: they (1) listedwords and concepts they associated with guardian andwarrior, (2) answered targeted questions gauging their atti-tudes toward policing, (3) identified which metaphor—guardian or warrior—they considered more appropriate todescribe the current state of policing in the United States,and (4) explained why they chose the metaphor they did. Wemanipulated the order of the association-listing task so thatsome participants would generate associates to Bguardian^

and Bwarrior^ in a neutral context and others would generateassociates to the terms in a policing context.

One salient dimension that appears to differentiateguardian and warriormetaphors for policing is the emotionalvalence that the metaphor vehicles convey. Explaining thatpolice officers are guardians of the community seems to casta much more positive light on policing. However, in a neutralcontext, both terms have been found to express a similarlypositive valence (Mguardian = 6.50, SD = 1.99; Mwarrior =5.50, SD = 2.21), t(38) = 1.50, p = .14, according to a recentnorming study of a large set of English words (Warriner,Kuperman, & Brysbaert, 2013). Thus, the negative valencethat thewarriormetaphor conveys in a policing context seemsto emerge from an interplay between the topic of discussion(policing) and source domain (warrior).

To test this possibility, we quantified the positive and neg-ative valence of the associations that participants generated inresponse to guardian and warrior in a neutral and policingcontext using the Linguistic Inquiry andWord Count software(LIWC; Pennebaker, Chung, Ireland, Gonzales, & Booth,2010). We expected the word guardian to elicit positive asso-ciations in both contexts, but warrior to elicit more negativeresponses in a policing context because a warrior concept isless consistent with an idealized model of policing—highlighting the combative, rather than protective, role of po-lice (Stoughton, 2015).

At a theoretical level, this finding would supportinteractionist models of metaphor processing (e.g., Black,1979), which suggest that metaphoric vehicles like warriorare more than lexical primes and often convey different mean-ings in different contexts (Thibodeau & Durgin, 2011). Whena professional baseball player or college professor is describedas a warrior, the phrase may highlight perseverance andstrength in the face of adversity. However, when a policeofficer is described as a warrior, the comparison seems toemphasize qualities that are less desirable—drawing out amore negative (aggressive, violent, rash) sense of the word.

Consistent with the valence that guardian andwarrior con-vey in a policing context, we expected to find a relationshipbetween the metaphor that participants felt best captures thecurrent state of policing and their attitudes toward law en-forcement. That is, we expected participants who identifiedpolice officers as guardians to express a more positive attitudetoward law enforcement and the criminal justice system com-pared to participants who identified police officers aswarriors.

Method

Participants

Participants in all three studies were recruited and paidthrough Amazon’s Mechanical Turk. We required that

Psychon Bull Rev (2017) 24:1375–1386 1377

participants live in the U.S. and have an approval rating great-er than 90 % on prior Turk tasks. At the end of the survey,participants were given a completion code; participants whofailed to submit a correct completion code were excluded fromanalysis. Sample sizes were set to be consistent with (or larg-er) than recent work on linguistic framing (e.g., Dweck, 2006;Hauser & Schwarz, 2014; Landau et al., 2009; Thibodeau &Boroditsky, 2011, 2013). Demographic information for allthree samples is shown in Table 1.

Materials and design

There were two between-subjects conditions in the first study.One third of participants (n = 89) were asked to list associa-tions with the two target concepts (warrior and guardian) inisolation (a neutral context). These participants were notasked about their attitudes toward law enforcement. The othertwo thirds of participants (n = 192) were presented with thesame free association task, but only after responding totargeted questions about their views on policing (a policingcontext).

Free association All participants were asked two free-response questions: BWhat are some qualities of a warrior?^and BWhat are some qualities of a guardian?^ The order ofthese two questions was counterbalanced across participants.We used the LIWC (Pennebaker et al., 2010) to count thenumber of words generated by participants and to quantifythe responses along two target dimensions: the degree towhich the responses expressed Bpositive^ and Bnegative^ va-lence. Words that indicate positive emotion is being expressedinclude care, kind, helpful, and strong (and cognates). Wordsthat indicate negative emotion is being expressed include ag-gressive, fight, violent, andwar (and cognates). The LIWC hasbeen shown to reveal patterns of results that converge withother methodologies (e.g., human coding of qualitative data;Pennebaker & Chung, 2005) and is a tool that can facilitatemore consistent and objective measurement and analysis ofqualitative data.

One potential limitation of the LIWC is that it reflects boththe writer and what is being written about. Terms like Bcare^

are counted as indicating a positive valence, regardless ofwhether they are used in a phrase like BI care^ or in a phraselike Bguardian’s care.^ However, a careful inspection of par-ticipants’ responses to the prompts revealed that their descrip-tions focused on the prompts (i.e., we found no cases of aparticipant writing BI care,^ BI think,^ or BI feel^). Thus, weinterpret the data generated by the LIWC as reflecting concep-tions of the target concepts—guardian and warrior—ratherthan the participants themselves.

Attitudes toward policing An eight-item survey was devel-oped to gauge participants’ attitudes toward policing. Three ofthe questions were asked on a 7-point scale: BPolice officershave a __ job^ (from very easy to very difficult), BPolice offi-cers are __ at maintaining law and order^ (from veryineffective to very effective), and BHow would you describethe criminal justice system in the U.S.?^ (from very far fromthe ideal to very near to the ideal). The other five questionswere two-alternative multiple choice, asking about whetherparticipants thought police treated citizens equally (yes/no),whether they thought the police were more fair or unfair, morehonest or deceitful, more selfish or selfless, and whether par-ticipants felt safe or unsafe around police officers.

Because the eight questions were highly related—bothconceptually and empirically (α = .79, .75, and .76 inStudies 1, 2, and 3, respectively)—they were combined intoa single measure of attitudes toward policing for the primaryanalyses (items are analyzed separately in the Breaking DownAttitudes Toward Policing section). We used principal com-ponents analysis to combine the responses to the eight ques-tions, using Varimax rotation (Mardia, Kent, & Bibby, 1980).Principal components analysis is a statistical procedure forrevealing the internal structure of a dataset with interrelatedmeasures in a way that best explains the common variance ofthe data (Dunteman, 1989). An inspection of the Scree and theKaiser criterion (i.e., only one eigenvalue was greater than 1)confirmed that responses to the eight survey items were bestexplained by a single source of variance (more than 45 % ofthe variance in the responses was captured by the first factor;see Table 2 for factor loadings).1 The units of this dimensionare centered and normalized; we have shifted them up by twounits so that all of the reported means are positive.

Metaphor preference Participants who were asked abouttheir attitudes toward policing were also asked (a) BWhichmetaphor (guardian or warrior) do you think better describespolicing in the U.S. today?^ and (b) BWhich metaphor do youthink better describes the ideal model of policing in the U.S.?^After making these judgments, participants were asked to

Table 1 Demographic information by sample for Studies 1–3

Study 1 Study 2 Study 3

Sampled 300 350 800

Analyzed 281 319 787

Female 55 % 62 % 59 %

Mean age 36.5 (13.2) 38.5 (13.4) 35.2 (11.4)

Race: White 78 % 87 % 78 %

Democrats; Republicans 42 %; 23 % 36 %; 23 % 39 %, 23 %

Conservativeness 42.5 (28.1) 44.0 (27.9) 43.9 (26.5)

1 It is worth noting that other reliable and valid psychological scales have alsocombined binary and Likert-scale responses into singular measures (e.g., theoriginal 32 item Disgust Scale; see Haidt, McCauley, & Rozin, 1994).

1378 Psychon Bull Rev (2017) 24:1375–1386

explain the reasoning behind their answer to question (a). Twonaïve coders categorized these responses as more Bpositive^or Bnegative^ (Cohen’s κ = .86; disagreements were resolvedin discussion).

We also analyzed participants’ explanations with theLIWC. On the LIWC-based analysis, we were interested inwhether participants extended the language of the metaphorthey chose.We created two new dictionaries to do this: one forguardian and one for warrior. The guardian dictionarycontained the 10 words (and cognates) that were most fre-quently generated by participants in response to Bguardian^in a neutral context (e.g., care, protect, love)—excludingwords that were also among the 10 most frequently generatedin response to Bwarrior^ (e.g., strong). The warrior dictionarycontained the 10 words (and cognates) that were most fre-quently, and uniquely, provided in response to Bwarrior^ in aneutral context (e.g., brave, fearless, tough; see supplement forLIWC dictionaries). The words Bguardian^ and Bwarrior^were not included in either dictionary.

Background questions At the end of the study, all partici-pants were asked about their gender, age, political ideology(on a continuous scale from 0, very liberal, to 100, veryconservative), political affiliation (categorically as Democrat,Republican, or Independent), and racial identity (see Table 1and supplement).

Results

Free association: What do people associate with guardiansand warriors within and outside of a policing context?

Our first goal was to gauge what the words guardian andwarrior mean—both in a neutral and policing context—byusing the LIWC to quantify the valence of participants’ asso-ciations with the terms (see Table 3). A two-way mixedANOVAwith predictors for term (guardian orwarrior; within

subjects) and context (neutral or policing; between subjects)revealed no differences in the number of words that partici-pants used to respond to the prompts, Fs < .6, ps > .4, sug-gesting that the quantity of associations that people had withthe two concepts was similar and independent of the context inwhich they were probed.

However, a three-way ANOVA with predictors for term(guardian or warrior), context (neutral or policing), and va-lence (positive and negative) revealed a significant three-wayinteraction, F(1, 837) = 10.93, p < .001, suggesting that theemotional content of these responses differed—by conceptand by context. As shown in the left panel of Fig. 1, the termselicited similar levels of positive emotion in a neutral context,t(88) = .95, p = .346, but guardian elicited marginally morepositive emotion than warrior in policing context, t(191) =1.79, p = .075, d = .13. As shown in the right panel ofFig. 1, warrior elicited more negative emotion in both a neu-tral, t(88) = 5.49, p < .001, d = .82, and policing context,t(191) = 12.44, p < .001, d = 1.27. This suggests that the termwarrior conveys a more negative valence overall. However,the context manipulation had a much stronger impact on par-ticipants’ responses to warrior than guardian. Participantsresponded somewhat less positively, t(279) = 4.81, p < .001,d = .60, and more negatively, t(279) = 2.40, p = .017, d = .34,to guardian in a policing, compared to a neutral, context; theyresponded much less positively, t(279) = 6.18, p < .001, d =.76, and much more negatively, t(279) = 5.09, p < .001, d =.70, towarrior in a policing, compared to a neutral, context. Inother words, althoughwarrior seems to conveymore negativevalence than guardian overall, using the term to describe po-lice officers seems to draw out an especially negative conno-tation of the word.

These patterns can also be seen in the most common wordsused to describe a guardian and warrior (see Table 4). Theword strong appears frequently in responses to both words inboth contexts. However, considering the full scope of frequentwords suggests that guardian calls to mind an image of

Table 2 Factor loadings computed by principal components analysis

Job difficulty Efficacy Equal Fair Honest Selfless Safe Justice system

Loading .29 .39 .24 .41 .41 .37 .35 .32

Table 3 Means (and SDs) for target dimensions computed by the Linguistic Inquiry andWord Count software by context (neutral or policing) and term(guardian or warrior)

Dimension Neutral (n = 89) Policing (n = 192)

Guardian Warrior Guardian Warrior

Word count 7.79 (10.35) 7.74 (7.74) 8.56 (8.15) 8.47 (8.08)

Positive 38.07 (30.02) 41.10 (33.22) 21.43 (25.44) 18.00 (27.04)

Negative 0.73 (2.75) 9.91 (16.62) 2.30 (5.86) 23.63 (23.07)

Psychon Bull Rev (2017) 24:1375–1386 1379

compassionate protection, whereas warrior makes violencemore salient, especially in a policing context.

Attitudes toward policing

A second way in which we quantified what the metaphorsmean was by asking people to choose whether they thoughtpolice officers were more like guardians or warriors of thecommunity. Overall, 82 % of participants reported thinkingthat police officers should, ideally, strive to be guardians ofthe community, χ2(1, N = 192) = 77.52, p < .001. However,only 60 % of participants reported thinking that the guardianmetaphor more accurately describes the current state of polic-ing in the U.S., χ2(1, N = 192) = 7.52, p = .006. This latterjudgment was highly predictive of participants’ attitudes to-ward policing, t(190) = 6.84, p < .001, d = 1.01. As illustratedin the leftmost bars of Fig. 2, participants who identified po-lice officers as guardians (M = 2.58, SD = 1.51) reported amore positive view of policing than participants who identi-fied police officers as warriors (M = 0.70, SD = 2.29).

How do people explain which metaphor they think is moreaccurate?

Finally, at the end of the first study, participants were asked toexplain why they chose the guardian or warrior metaphor to

describe how they think about policing. Explanations for whypeople chose the guardian metaphor tended to emphasize theprotective or defensive role that police officers play in society,whereas explanations for why people chose the warrior met-aphor tended to focus on the police force’s capacity forviolence.

Using the LIWC to quantify the tone of responses revealeda statistically significant interaction between the metaphorchosen (guardian or warrior) and valence (positive or nega-tive), F(1, 190) = 9.42, p = .002. Participants’ explanationswere similarly positive for why they chose guardian (M =2.40, SD = 5.19) or warrior (M = 1.98, SD = 4.75), t(190) =.56, p = .575, but explanations for choosing warrior (M =7.43, SD = 11.51) were significantly more negative than ex-planations for choosing guardian (M = 3.10, SD = 6.20),t(190) = 3.37, p < .001, d = .50.

A similar pattern emerged when two naïve coders catego-rized participants’ explanations as Bpositive^ or Bnegative.^Of the 60% of participants who chose the guardianmetaphor,96 % described positive qualities of police officers or theirimpact on the community. Of the 40 % of participants whochose the warrior metaphor, only 13 % described positivefeatures of policing, χ2(1) = 130.96, p < .001.

Interestingly, participants often used language that extend-ed the guardian and warrior metaphors in their explanations,further suggesting that the metaphors provided a structure for

Fig. 1 Positive (left) and negative (right) valence associated with the guardian and warrior terms by context (neutral or policing), as quantified by theLinguistic Inquiry and Word Count software. Error bars denote standard errors of the means

Table 4 The five most frequent words used to describe guardian and warrior in a neutral and policing context. The number of times each wordappeared is shown in parentheses

Frequency Rank Neutral context (n = 89) Policing context (n = 192)

Guardian Warrior Guardian Warrior

1 Caring (29) Strong (46) Protect (28) Strong (32)

2 Protect (26) Brave (29) Caring (20) Aggressive (30)

3 Loving (14) Fearless (18) Strong (15) Fight (28)

4 Kind (12) Tough (12) Safe (12) Brave (25)

5 Strong (10) Fight (9) Watchful (9) Violent (18)

1380 Psychon Bull Rev (2017) 24:1375–1386

thinking about police. For example, two explanations forchoosing the warrior metaphor described police officers asBarmed and looking for people to capture^ and Bprone tobattle^; one stated that Bthere is a thin line between chaosand civility.^ To quantify this tendency to extend the meta-phor, we created a guardian dictionary and a warrior dictio-nary in the LIWC: the dictionaries were built from the free-association data—from the 89 participants who listed associ-ations to guardian and warrior in a neutral context; then theywere used to analyze the explanations generated by the other192 participants in Study 1 (i.e., the ones who answered ques-tions about policing). We found that people who thoughtguardian was a better metaphor for policing used moreguardian language (M = 9.75, SD = 13.98) to explain theirchoice than people who thought warrior was a better meta-phor for policing (M = 2.43, SD = 11.63), t(190) = 3.79, p <.001, d = .56. On the other hand, people who thought warriorwas a better metaphor for policing use morewarrior language(M = 3.31, SD = 7.65) to explain their choice than people whothought guardian was a better metaphor for policing (M =0.60, SD = 3.10), t(190) = 3.41, p < .001, d = .50.

Discussion

The results of Study 1 revealed that the associations peoplebrought to mind for the terms guardian and warrior differeddepending on whether or not they had previously answeredquestions about law enforcement: associations for both con-cepts were overwhelmingly positive when probed in a neutralcontext; however, associations with Bwarrior^ were especiallynegative when participants had previously answered questionsabout policing, emphasizing aggression and violence ratherthan strength and bravery.

This finding is consistent with the observation that peopleselectively import knowledge of a source domain in the ser-vice of metaphor comprehension. The word jail, for example,brings to mind different associations when you are describingwhere your inebriated friend spent the night than when you are(metaphorically) describing your job (as in, Bmy job is a jail^).This has been taken as evidence that (some)metaphors may beprocessed as category-inclusion statements, where the sourcedomain functions as a prototypical exemplar of a broaderschematic concept that the target domain is then placed into(e.g., a jail is prototypical example of a dreadful confiningspace you cannot leave, much like some people’s jobs; seeGlucksberg & Keysar, 1990). In other words, the specificassociations and relational structure that are transferred froma given source domain (e.g., warrior) depend on the topic ofdiscussion (Black, 1979). The meanings of metaphoric vehi-cles, like the meanings of words and phrases in general, arenot static but can change dramatically as a function of thecontext in which they are used (Thibodeau & Durgin, 2011).

Another key finding of Study 1 that builds on this insightwas that participants were almost evenly split in their judgmentof which metaphor—guardian or warrior—was more appropri-ate to explain the role of law enforcement, and this preferencewas highly predictive of participants’ attitudes toward policing.People who think of police officers as guardians of the com-munity reported a more positive view of policing. Interestingly,when people explained why they chose a specific metaphor,they often extended their preferred metaphor in the service oftheir explanation. These results support the view that metaphorsplay a key role in how people represent and reason about com-plex domains, and highlight the utility of metaphor as an ex-planatory device that helps people make sense of and commu-nicate about complicated subjects.

One important issue that Study 1 did not address is whetheror not explanatory metaphors actually affect how listenersunderstand and think about the target of explanation. In pro-moting the role of police as the guardians (and not warriors) ofthe community, one important goal of the Obama task forcehas been to persuade the public that how we think about lawenforcement needs to change. Therefore, in Study 2 we testedwhether explaining the role of police officers using these met-aphors would influence participant attitudes toward policing.

Study 2: Testing explanatory metaphors

Method

Participants

Data from 350 participants were collected for Study 2, also fromMechanical Turk, using the same inclusion criteria as Study 1,which left data from 319 participants for analysis (see Table 1).

Fig. 2 Attitudes toward policing as a function of metaphor preference inStudy 1 (the correlational study), and either as a function of whichmetaphor was used to explain the role of polices officers in Studies 2and 3 or the lexical prime that participants saw in Study 3. Higherscores indicate more positive attitudes. Error bars represent standarderrors of the means

Psychon Bull Rev (2017) 24:1375–1386 1381

Materials and design

There were two between-subjects conditions in Study 2,which varied in how they (metaphorically) explained the roleof police officers. One read, BPolice officers are the guardiansofmodern communities—strongmen and women who serve avital role in society, often placing themselves in harm’s way inorder to protect their fellow citizens,^ while the other ex-plained, BPolice officers are the warriors of modern commu-nities—strong men and women who serve a vital role in soci-ety, often placing themselves in harm’s way in order to fightfor their fellow citizens^ (italics added). Of note, in addition toa difference in the metaphor used to describe police officers,the guardian condition highlighted that police officers striveto Bprotect^ citizens, while the warrior condition emphasizedthat police officers Bfight for^ their fellow citizens. Thesewere the most common verbs associated with two terms andwere included in Study 2 to stress different ways of concep-tualizing law enforcement. To ensure that differences betweenconditions were the result of the explanatory metaphors, andnot these verbs, however, we used more consistent phrasing inStudy 3.

After participants read the description of police officers,they responded to the same eight questions about their atti-tudes toward policing and the same demographic and back-ground questions as in Study 1.

Results

As illustrated in Fig. 2, participants who read that police offi-cers are guardians of the community (M = 2.36, SD = 1.71)reported a more positive attitude toward policing than partic-ipants who read that police officers are warriors of the com-munity (M = 2.08, SD = 1.86), t(317) = 2.16, p = .032, d = .24.

Discussion

The results of Study 2 revealed that explanatory metaphorscausally impacted people’s attitudes towards law enforcement.Participants who were exposed to the guardian metaphorexpressed more positive views of the police than participantsexposed to the warrior metaphor. A follow-up study—de-scribed in detail in the online Supplementary Material—alsofound that exposure to the guardian metaphor made peoplemore likely think that the demographic characteristics of apolice force should match the demographic characteristics ofthe communities they serve, and less likely support the viewthat police should have access to military-grade weaponry.These findings suggest that metaphors may be especially use-ful when the speaker’s goal is to influence the listener’s atti-tudes toward the target of explanation.

There are two potential limitations of Study 2 that are ad-dressed in Study 3. First, as noted above, the two conditions in

Study 2 differed not only in how they metaphorically ex-plained the role of police officers in the community but alsowith respect to the verbs used to describe police officers (asseeking to Bprotect^ vs. Bfight for^ the community). Thus, it ispossible that the difference in conditions resulted from a dif-ference in these verbs rather than the explanatory metaphors.

Second, it may be the case that the words guardian andwarrior do not need to be used as metaphors to influencepeople’s conception of policing. Just as these words seem totake on a different meaning in a policing context, the meaningof police may differ depending on whether people have re-cently been exposed to the word guardian or warrior, regard-less of whether the term is used to metaphorically explain therole of police officers in the community. For example, it maysimply be that exposure to the term warrior primes morenegative thoughts and feelings, which results in more negativeattitudes toward law enforcement across the board. Thoughwe think it is likely that metaphor framing effects result in partfrom the low-level spread of activation from the metaphorvehicle (see Flusberg, Thibodeau, Sternberg, & Glick, 2010;Thibodeau, 2016), we expected explanatory metaphors to bemost influential when used explicitly to frame the topic ofdiscussion. We tested this possibility in Study 3.

Study 3: Lexical priming

Method

Participants

Data from 800 participants were collected for Study 3, alsofrom Mechanical Turk, using the same inclusion criteria asStudies 1 and 2, which left data from 787 participants foranalysis.

Materials and design

In Study 3, half of the participants were presented with ametaphorical description of police before being asked abouttheir attitudes toward policing. The descriptions were similarto those of Study 2, but, importantly, only differed in themetaphoric frame. The explanation comparing police officersto guardians read, BPolice officers are the guardians of mod-ern communities. They are strong men and women who servea vital role in society.^ The explanation comparing policeofficers to warriors read, BPolice officers are the warriors ofmodern communities. They are strong men and women whoserve a vital role in society^ (emphasis added).

The other half of participants were asked to list a synonymto either guardian or warrior on one screen, and then werepresented with a nonmetaphorical description of police on thefollowing screen (BPolice officers are strong men and women

1382 Psychon Bull Rev (2017) 24:1375–1386

who serve a vital role in society^) before being asked abouttheir attitudes toward law enforcement. The most commonsynonyms given for guardian were protector (38 %), parent(23 %), and caretaker (12 %). The most common synonymsgiven for warrior were fighter (55 %), soldier (29 %), andhero (4 %).

Finally, participants were asked the same background anddemographic questions as in Studies 1 and 2.

Results

The goal of Study 3 was to test whether the effects found inStudy 2 were the result of the explanatory metaphor or simplythe result of lexical priming. A between-subjects ANOVAwith predictors for term (guardian or warrior) and task (ex-planatory metaphor or synonym) on participants’ attitudes to-ward policing revealed a statistically significant interactionbetween the two factors, F(1, 783) = 6.922, p = .009.Neither main effect was statistically significant, ps > .1.Planned pairwise comparisons revealed that participants re-ported more positive attitudes toward policing after readingthat police officers were guardians (M = 2.33, SD = 1.71) thanwarriors (M = 1.75, SD = 1.87), t(387) = 3.16, p = .002, d =.32; in contrast, there was no difference between the two con-ditions in which participants listed a synonym—for guardian(M = 1.87, SD = 2.06) or warrior (M = 2.01, SD = 1.97),t(396) = .70, p = .486.

In addition, participants reported more favorable views ofpolicing when guardianwas used as an explanatory metaphorthan a lexical prime, t(382) = 2.36, p = .019, d = .24. Therewas no difference in attitudes toward policing as a function ofhow warrior was used, t(401) = 1.36, p = .175, d = .14. Theseeffects are illustrated in the two rightmost pairs of bars inFig. 2.

Discussion

The results of Study 3 replicated and extended the results ofStudy 2. Participants who read that police officers areguardians of the community reported more positive attitudestoward policing than participants who read that police officersarewarriors of the community. On the other hand, participantswho listed a synonym for guardian did not report more posi-tive attitudes toward policing compared to participants wholisted a synonym for warrior. This suggests that explanatorymetaphors are most influential when used explicitly to framethe topic of discussion, and that lexical priming cannot fullyaccount for these effects.

So far, we have focused on the emotional valence of theterms guardian and warrior because one way in which ex-planatory metaphors seem to influence how people think is bycasting the topic of discussion in a more positive or negativelight. We do not think this is the only way in which

explanatory metaphors influence thought, however—al-though it may be easiest to quantify. For one thing, the resultsof Study 1 demonstrate that the term warrior calls to mindmore negatively valenced associations than guardian, even ina neutral context. If the only mechanism at work in thesestudies were the activation of negative affect, we would haveexpected the lexical priming manipulation in Study 3 to resultin a similar shift in attitudes toward law enforcement as themetaphorical framing manipulation. As illustrated in Fig. 2,this was certainly not the case.

In addition to conveying emotional resonance, therefore,we suggest explanatory metaphors work in part by helpingto situate the target of explanation under a broader (and morefamiliar) schematic domain (e.g., guardians), which the lis-tener can then use in the service of reasoning. In other words,metaphors facilitate the subsumptive or unifying function ofexplanation (Lombrozo, 2011; Williams & Lombrozo, 2010;Woodward, 2014) by providing a candidate schema or pattern(e.g., police officers have the properties of and behave likeguardians) for thinking about the target of explanation (e.g.,Flusberg et al., 2010; Gentner et al., 2001; Glucksberg &Keysar, 1990; Sopory & Dillard, 2002).

Notably, this account makes specific predictions about howparticipants in Studies 2 and 3 should be affected by the ex-planatory metaphors. Namely, the metaphors should have alarger effect on survey items that directly tap into the actualentailments of the guardian and warrior metaphors and asmaller effect on items that do not. Next, we use the resultsof Study 1 to identify specific ways in which an explanationthat metaphorically describes polices officers as guardians orwarriors should affect peoples’ conception of law enforce-ment. Then we test whether the explanatory metaphors usedin Studies 2 and 3 actually resulted in patterns of respondingthat reflected these more nuanced predictions.

Breaking down attitudes toward policing

Method

In our analysis of Studies 1–3, we treated responses to eighttarget questions about participants’ attitudes toward policingas a unified measure. Here we analyze responses to differenttypes of questions separately. Recall that three of the questionswere rated on 7-point scales: asking participants to judge howdifficult it is to be a police officer (difficulty), how effectivelythe police have enforced the law (efficacy), and how fairly thecriminal justice system treats citizens (justice system).Participants were also asked five binary questions: whetheror not they think the police treat people equally, fairly, hon-estly, selflessly, and whether they feel safe around police offi-cers. For the present analysis, we combined responses to these

Psychon Bull Rev (2017) 24:1375–1386 1383

binary questions (α = .79, .73, and .75 in Studies 1, 2, and 3,respectively) into a fourth scalar measure (police officers).

First, we examined how well participants’ endorsement ofthe guardian or warrior metaphors for policing in Study 1predicted the four outcome measures. Then we tested howstrongly the explanatory metaphors influenced these measuresin Studies 2 and 3. For brevity, we have pooled the data fromStudies 2 and 3 (excluding the condition in which participantslisted a synonym for guardian or warrior in Study 3); therewas no overall difference in participants’ attitudes toward po-licing by Study (2 or 3) or interaction between metaphor con-dition (guardian vs. warrior) and Study, ps > .4.

Results

As shown in Table 5, the results of the correlational study(Study 1) suggest that that the two metaphors for policingdescribe some aspects of policing more aptly than others,F(3, 570) = 14.29, p < .001. Specifically, participants whoendorsed the guardian metaphor over the warrior metaphorreported a muchmore favorable view of police officers, t(190)= 6.86, p < .001, d = 1.01, and the criminal justice system,t(190) = 6.42, p < .001, d = .94. Although the guardian met-aphor was also associated with thinking that it was somewhatmore difficult to be a police officer, t(190) = 1.97, p = .051, d =.29, and thinking police officers were more effective at main-taining law and order, t(190) = 4.46, p < .001, d = .66, partic-ipants’ choice of metaphor was less predictive of theseassessments.

Table 5 shows that the influence of the explanatory meta-phors (in Studies 2 and 3) mirrored this pattern—with a stron-ger influence on participants’ responses to some questions anda weaker influence on responses to others, F(3, 2118) = 3.56,p = .014. Specifically, the framing manipulation had a morepronounced influence on participants’ views of police officers,t(706) = 3.74, p < .001, d = .28, and the criminal justicesystem, t(706) = 3.73, p < .001, d = .28, and a lesser influenceon judgments of how difficult it was to be a police officer,t(706) = 1.41, p = .159, d = .11, and how effectively the policehavemaintained law and order, t(706) = 2.27, p = .023, d = .17(see Fig. 3 for a comparison of effect sizes).

The relationship between these patterns of results—from asituation in which participants explicitly compared the meta-phors and chose one deliberately to express how they thoughtabout policing (Study 1) and a situation in which the meta-phors were used to explain the role of police officers in thecommunity (Studies 2 and 3)—suggests that these explanato-ry metaphors capture and convey more than an emotionaltone. Instead, these metaphor vehicles seem to instantiate dif-ferent schematic knowledge structures for thinking about po-licing and the criminal justice system (Boroditsky, 2000;Gibbs, 1994; Lakoff & Johnson, 1980; Thibodeau &Boroditsky, 2011).

General discussion

Across three studies, we investigated the role metaphors playin the process of explanation using a real-world case study ofpolice metaphors. Study 1 revealed that participants who con-sidered police to be guardians expressed more positive atti-tudes toward law enforcement and felt the justice system was

Table 5 Mean judgments (and SDs) of four subcomponents ofparticipants’ attitudes toward policing as a function of which metaphorparticipants chose to describe police officers (Study 1) or which metaphor

was used to explain the role of police officers in the community (Studies 2and 3)

Study 1: Correlational Studies 2 and 3: Explanatory

Guardian (n = 115) Warrior (n = 77) Guardian (n = 348) Warrior (n = 360)

Difficulty 6.36 (1.00) 6.05 (1.12) 6.64 (0.83) 6.33 (1.00)

Efficacy 5.50 (0.86) 4.75 (1.47) 5.36 (1.19) 5.16 (1.23)

Justice system 2.99 (0.84) 2.19 (0.84) 2.84 (0.98) 2.57 (0.96)

Police officer 3.75 (1.30) 2.23 (1.76) 3.47 (1.36) 3.07 (1.47)

Fig. 3 Comparison of effect sizes (Cohen’s d) from Study 1 on fouroutcome measures (as a function of which metaphor participantsthought more accurately described the police) to effect sizes elicitedfrom the explanatory metaphor in Studies 2 and 3 (pooled data)

1384 Psychon Bull Rev (2017) 24:1375–1386

more fair and effective than those who considered police to bewarriors. What’s more, in explaining why they chose the met-aphor they did, participants often extended the metaphor itselfin the service of their explanation. This suggests that theywereusing the metaphor to organize and structure their reasoningabout the domain of law enforcement. Consistent with previ-ous work on metaphor comprehension, Study 1 also revealedthat associations with Bwarriors^ and Bguardians^ differeddepending on whether they were probed in a neutral or polic-ing context. This highlights the fact that schematic knowledgeof the source domain is dynamically brought to bear on thetarget domain (Black, 1979; Glucksberg & Keysar, 1990;Lakoff & Johnson, 1980). A given metaphor vehicle will nothave the same effect on reasoning in all contexts (e.g.,warriormetaphors are not always negatively valenced).

The results of Study 2 demonstrated that metaphors can beeffective explanatory devices: using the guardian versuswarrior metaphor to explain the job of policing causally in-fluenced peoples’ conceptions of policing, giving rise to morepositive attitudes overall. This is consistent with previouswork showing that metaphor framing can influence how peo-ple represent and reason about complex social issues (Sopory&Dillard, 2002; Thibodeau&Boroditsky, 2011, 2013). Study3 revealed that this was not merely a result of lexical priming:The metaphor had to appear in the context of the explanationitself in order to exert a causal influence on participants’ atti-tudes. Additional analyses examining specific aspects of par-ticipants’ attitudes toward policing and the criminal justicesystem further support the view that these metaphors instanti-ate different conceptual entailments.

Taken together, these findings help illuminate why meta-phors are useful tools in the process of explanation.Metaphorsallow us to represent a complex, abstract, or novel domain interms of a familiar and often simpler conceptual schema thatwe already understand. Thus, when we explain somethingusing an appropriate metaphor, we can enrich listener under-standing by encouraging them to use the knowledge they al-ready have of the source domain to structure their thinkingabout the target of the explanation (Clark, 1996). This fits witha subsumption or unificationist account of the nature of expla-nation (Lombrozo, 2011; Williams & Lombrozo, 2010;Woodward, 2014) and helps explain why metaphors and anal-ogies play such an important role in both science educationand scientific practice (Aubusson, Harrison, & Ritchie, 2005;Brown 2003; Gentner & Gentner, 1982; Gentner & Jeziorski,1993).

Finally, these studies highlight an often-underappreciatedpragmatic feature of how explanations function in everydaycommunicative practice:When people explain things to some-one else, they are not always just interested in increasing lis-tener understanding as such; rather, they want the listener tothink about the target of explanation in the same way they do.In other words, explanation often includes an element of

persuasion. As our findings reveal, it is possible to think aboutthe police using either a guardian or warrior metaphor, andthe population we sampled was roughly split on this issue.And yet, as the authors of the Obama task force report werehoping, using one of these metaphors in particular during thecourse of explanation had an effect on how our participantscame to conceptualize the nature and role of law enforcement.We suggest that this pragmatic dimension of explanation, andthe role metaphor in this process (and in the process of expla-nation more generally) remains an important area for futureresearch.

In sum, the present studies help to illuminate both how andwhy metaphors are useful tools the service of explanation.They can efficiently encapsulate and communicate an arrayof structured attitudes and beliefs, and can guide people tothink about a target domain in new ways. Recent violentclashes between law enforcement and civilians have generateda national conversation about the role of police officers in ourcommunities, and the present research suggests that we needto pay careful attention to the metaphors we use to support ourexplanations (much as the Obama Task Force has attempted todo already).

References

Aubusson, P. J., Harrison, A. G., & Ritchie, S. M. (2005).Metaphor andanalogy in science education (Vol. 30). New York, NY: SpringerScience & Business Media.

Black, M. (1979). More about metaphor. In A. Ortony (Ed.), Metaphorand thought (pp. 19–43). Cambridge, UK: Cambridge UniversityPress.

Boroditsky, L. (2000). Metaphoric structuring: Understanding timethrough spatial metaphors. Cognition, 75, 1–28.

Brown, T. L. (2003). Making truth: Metaphor in science. Chicago:University of Illinois Press.

Clark, H. H. (1996). Using language. Cambridge, UK: CambridgeUniversity Press.

Dunteman, G. H. (1989). Principal components analysis. Newbury Park,CA: SAGE Publications.

Dweck, C. (2006). Mindset: The new psychology of success. New York:Random House.

Flusberg, S. J., Thibodeau, P. H., Sternberg, D. A., & Glick, J. J. (2010).A connectionist approach to embodied conceptual metaphor.Frontiers in Psychology, 1(197), 1–11.

Garcia, U. J. (2014, March 22). Experts say strongly worded police cur-riculum is risky with cadets. Santa Fe NewMexican.Retrieved fromhttp://www.santafenewmexican.com/news/local_news/experts-say-strongly-worded-police-curriculum-is-risky-with-cadets/article_6fcb7d45-436c-5e48-aa06-2fc6fdcc35a1.html

Gentner, D., Bowdle, B., Wolff, P., & Boronat, C. (2001). Metaphor islike analogy. In D. Gentner, K. J. Holyoak, & B. N. Kokinov (Eds.),The analogical mind: Perspectives from cognitive science (pp. 199–253). Cambridge, MA: MIT Press.

Gentner, D., &Gentner, D. R. (1982). Flowing waters or teeming crowds:Mental models of electricity. In D. Gentner & A. L. Stevens (Eds.),Mental models. Hillsdale, NJ: Erlbaum.

Psychon Bull Rev (2017) 24:1375–1386 1385

Gentner, D., & Jeziorski, M. (1993). The shift from metaphor to analogyin western science. In A. Ortony (Ed.), Metaphor and thought (2nded.). Cambridge, UK: Cambridge University Press.

Gibbs, R. W. (1994). The poetics of mind: Figurative thought, language,and understanding. Cambridge, UK: Cambridge University Press.

Glucksberg, S., & Keysar, B. (1990). Understanding metaphorical com-parisons: Beyond similarity. Psychological Review, 97(1), 3–18.

Gopnik, A. (2000). Explanation as orgasm and the drive for causal un-derstanding: The evolution, function and phenomenology of thetheory-formation system. In F. Keil & R. Wilson (Eds.), Cognitionand explanation (pp. 299–323). Cambridge, MA: MIT Press.

Haidt, J., McCauley, C., & Rozin, P. (1994). Individual differences insensitivity to disgust: A scale sampling seven domains of disgustelicitors. Personality and Individual Differences, 16(5), 701–713.

Hauser, D. J., & Schwarz, N. (2014). The war on prevention bellicosecancer metaphors hurt (some) prevention intentions. Personalityand Social Psychology Bulletin, 41, 66–77.

Kao, J. T., Bergen, L., & Goodman, N. D. (2014). Formalizing the prag-matics of metaphor understanding. Proceedings of the 36th annualMeeting of the Cognitive Science Society. Retrieved fromhttps://mindmodeling.org/cogsci2014/papers/132/

Keysar, B., & Bly, B. (1995). Intuitions of the transparency of idioms:Can one keep a secret by spilling the beans? Journal of Memory andLanguage, 34, 89–109.

Lakoff, G., & Johnson, M. (1980). Metaphors we live by. Chicago, IL:University of Chicago Press.

Lakoff, G., & Núñez, R. E. (2000).Where mathematics comes from: Howthe embodied mind brings mathematics into being. New York, NY:Basic books.

Landau, M. J., Sullivan, D., & Greenberg, J. (2009). Evidence that self-relevant motives and metaphoric framing interact to influence polit-ical and social attitudes. Psychological Science, 20, 1421–1427.

Lombrozo, T. (2011). The instrumental value of explanations. PhilosophyCompass, 6(8), 539–551.

Mardia, K. V., Kent, J. T., & Bibby, J. M. (1980). Multivariate analysis.New York, NY: Academic Press.

McGlone, M. S. (2011). Hyperbole, homunculi, and hindsight bias: Analternative evaluation of conceptual metaphor theory. DiscourseProcesses, 48(8), 563–574.

Ottati, V., Rhoads, S., & Graesser, A. C. (1999). The effect of metaphoron processing style in a persuasion task: A motivational resonance

model. Journal of Personality and Social Psychology, 77(4), 688–697.

Pennebaker, J. W., & Chung, C. K. (2005). Tracking the social dynamicsof responses to terrorism: Language, behavior, and the Internet. In S.Wessely & V. N. Krasnov (Eds.), Psychological responses to thenew terrorism: A NATO-Russia dialogue . Amsterdam,The Netherlands: ISO Press.

Pennebaker, J.W., Chung, C. K., Ireland,M., Gonzales, A., & Booth, R. J.(2010). The LIWC2007 application. Available at: http://www.liwc.net/LIWC2007LanguageManual.pdf

Ramsey, C., & Robinson, L. (2015). Final report. The President’s taskforce on 21st century policing. Retrieved Oct 28, 2016 https://cops.usdoj.gov/pdf/taskforce/taskforce_finalreport.pdf

Sopory, P., & Dillard, J. P. (2002). The persuasive effects of metaphor: Ameta-analysis. Human Communication Research, 28(3), 382–419.

Stoughton, S. (2015). Law enforcement’s Bwarrior^ problem. HarvardL a w R e v i e w F o r u m , 1 2 8 ( 6 ) . R e t r i e v e d f r o mhttp://harvardlawreview.org/2015/04/law-enforcements-warrior-problem/

Thibodeau, P. H. (2016). Extended metaphors are the home runs of per-suasion: Don’t fumble the phrase.Metaphor and Symbol, 31(2), 53–72.

Thibodeau, P. H., & Boroditsky, L. (2011). Metaphors we think with: Therole of metaphor in reasoning. PLoS ONE, 6(2), e16782.

Thibodeau, P. H., & Boroditsky, L. (2013). Natural language metaphorscovertly influence reasoning. PLoS ONE, 8(1), e52961.

Thibodeau, P. H., & Durgin, F. H. (2011). Metaphor aptness and conven-tionality: A processing fluency account. Metaphor and Symbol,26(3), 206–226.

Warriner, A. B., Kuperman, V., & Brysbaert, M. (2013). Norms of va-lence, arousal, and dominance for 13,915 English lemmas. BehaviorResearch Methods, 45(4), 1191–1207.

Williams, J. J., & Lombrozo, T. (2010). The role of explanation in dis-covery and generalization: Evidence from category learning.Cognitive Science, 34(5), 776–806.

Wilson, R. A., & Keil, F. (2000). The shadows and shallows of explana-tion. In F. Keil & R. Wilson (Eds.), Cognition and explanation (pp.87–114). Cambridge, MA: MIT Press.

Woodward, J (2014, Winter). Scientific explanation. In E. N. Zalta (Ed.),The Stanford encyclopedia of philosophy. Retrieved fromhttp://plato.stanford.edu/archives/win2014/entries/scientific-explanation/

1386 Psychon Bull Rev (2017) 24:1375–1386