Shaping the modern world with a stone-age brain: Brexit and the moral foundations theory.

Decision making is not always a reasoned process. It is often subject to reflexive heuristics. The Moral Foundations Theory is a popular theoretical framework that characterises political decisions by adherence to an evolutionary criterion. Based on recurrent ancestral pressures, this model anticipates our species’ tribal history has resulted in a set of intuitive ethics: Care/ Harm, Fairness/ Cheating, Loyalty/ Betrayal, Authority/ Subversion, and Sanctity/ Degradation. Focusing on the winning side, this paper analyses official communications, polling data and media coverage to explore how the Leave campaigners intentionally or unintentionally appealed to the public’s moral intuitions. In doing so, it aims to show why evolutionary psychology potentially offers a useful layer of analysis with which to understand contemporary politics.

in the most recent election), leaving was not a mainstream stance until relatively recently. Public satisfaction with continued membership had generally been stable since the late 1980s, save for a period in 1999 when the Euro had just become the union's shared currency (a policy which a sceptical Britain was one of two countries to optout of). Mortimore (2016) shows that even when polling reflected immigration as the "most important issue facing the country", in the 1990s and early 2000s, few seemed to bind it to the EU, with leaving or renegotiating terms being a lesser priority.
It is possible Leave sentiments were not mainstream political beliefs until recently because people did not believe it could happen. Although former Prime Minister David Cameron won a majority when promising a referendum (something it is generally thought he did to resolve tensions in his party vs. satisfy public demand, Shipman, 2016), this did not necessarily change efficacy among Leave backers. Referendum day polling showed 70% of people had anticipated a victory for Remain, including a majority (54%) of those who wanted to leave (Lord Ashcroft, 2016). These misconceptions could have been informed by a strong majority of pollsters and bookies incorrectly predicting the outcome, albeit by a narrow margin. The surprise result meant that the bulk of the UK political class had to ask how a policy position that had seemed such a political orthodoxy was overturned. Or, as television network ITV's political editor Robert Peston (2017) memorably put it, "WTF?" Like the victory of Donald Trump in America, commentators and researchers have tended to explore Brexit as part of a wave of populist nationalism in the Western World (Gusterson, 2017). This wider movement is thought to be derived from a cultural backlash against progressive values in countries that have traditionally supported economic globalisation. Some have argued that negative perceptions of the speed and breadth of EU expansionism motivated the surge in UK nationalism (Arnorsson & Zoega, 2016). Others have framed the vote as a reaction against austerity by people feeling the brunt of it (Mckenzie, 2017). In other words, they tend to regard Brexit as a logical culmination of socio-political cirsumstances. Framing the vote in such a way allows us to infer that had circumstances been different Remain could have won via counterfactuals (Sirois & Iyer, 2018). This makes intuitive sense since nothing occurs in a political vacuum. But the ultimate level psychological explanations theorised to influence human decision making, have been comparatively understudied.
Two recurrent findings in political psychology research, across populations, are that the general public simultaneously lacks core knowledge about actors and institutions and have strong opinions on the issues (Petersen, 2015).
Ergo, it is likely that a reflexive vs. rational criterion is responsible for their reasoning (Brader, 2005;McDermott, 2004). In the absence of adequate information, one way to explain this tension is exploring decision making in terms of adaptive heuristics, i.e. rapidly executed mental shortcuts and rules for decision-making that anticipate a narrow relationship between the available information to an individual and their judgment (Petersen, 2015).
Evolution is a prolonged process, meaning it can take thousands of generations to fashion complex cognitive faculties. In contrast, the modern world, with its social parameters, including plebiscites and intricate socioeconomic choices, arose comparatively recently in our species' history. It is therefore unlikely the heuristics with which we solve its problems could be especially attuned to present environmental challenges (Cosmides & Tooby, 1994). This idea has led authors to theorise an innate, moral compass that influences how we make sense of issues today.
Thus a functionalist approach is useful for examining democratic decisions like Brexit, to evaluate why some arguments were more compelling to voters than others.

The Moral Foundations Theory
The Moral Foundations Theory (MFT), developed by Haidt and Graham (2007), is a popular model of intuitive ethics. It is a nativist concept that posits people have a hardwired, ethical sense with which they judge real and imagined behaviour by themselves or others, i.e. an innate preparedness to approve or disapprove of certain outcomes and events. They argue that these intuitions operate outside conscious awareness, reflecting an inbuilt, reflexive reasoning style that emerged as adaptations to survival challenges in ancestral times. The framework anticipates people will view situations as ethical to the extent that they relate to these foundations. In particular, the foundations cited emphasise inter-tribal and intra-tribal conflict scenarios, in which individuals decide between safeguarding their welfare against the interests of their group.
The theory has proven to be an influential model in moral psychology, and other disciplines including personality, decision making and political science (for a review, see Graham et al., 2013). The foundations provide generalised psychological tendencies that predispose individuals towards a set of socio-political beliefs. Following extensive reviews of psychology, anthropology, and philosophy, Haidt and Graham (2007) argue each of us has an intuitive moral code comprising five distinct elements: care/ harm, fairness/ cheating, loyalty/ betrayal, authority/ subversion, and sanctity/ degradation. Haidt (2012) has suggested Liberty/ oppression as a candidate for a sixth foundation, although I am not covering it here because it is not presently considered canonical. However, given the prevalence of the Vote Leave motto "take back control", along with the emphasis on self-governance and cutting red tape, I suspect the Leave campaign communications would more successfully link to it.
The MFT model thus defines culture in terms of the narratives and constructs they establish around each foundation, with variations explaining why temporally or geographically distinct populations hold divergent opinions on similar issues. Graham et al. (2011) showed that, after controlling for demographic factors, world region was a strong predictor of concerns on an MFT inventory. In particular, participants from Western cultures reliably expressed lower concern for loyalty and sanctity than participants from Eastern cultures. This finding is consistent with typical regional divisions in individualism vs. collectivism.
The most culturally persistent attitudes are still subject to individual differences, with significantly more variation within than between cultures. Haidt and Joseph (2004) argue socialisation accounts for the values people place on each foundation, and how they are applied to make or judge decisions. The plurality of ideological views and moral standards within and between cultures, therefore, reside in experiential differences. Haidt (2012) suggests if evolution provides the first draft of a book, then childhood (and indeed, adulthood) revises it. Accordingly, the types of environment people are exposed to influence the ethical criterion they adopt when making decisions.
As shall be later discussed, when I summarise the role of the loyalty foundation, the UK is no exception. The union comprises four different countries (in reverse order of population; England, Scotland, Wales and Northern Ireland) with pointedly different cultures and political profiles. These nuances can be lost when it is addressed as a single unit (for a discussion on the fallacy of treating the UK as a single unit of analysis, see Henderson et al., 2017).
Except for England, all have localised assemblies with control over devolved areas, although these powers may be abrogated or constrained by the sovereign UK parliament. only recorded Scottish support for Remain falling below 60% once. Likewise, Northern Irish participants overwhelmingly supported Remain, with up to 80% favouring continued membership. On polling day, both Scotland and Northern Ireland voted by a majority to stay (62% and 55% respectively). Hence shared sovereignty cannot necessarily predict mutual values and customs.
The MFT has been utilised to explore individual differences in attitudes towards a range of socio-political issues typified by left vs. right wing polarisation. Among other examples, the literature finds foundation profiles predict people's opinions on how to combat climate change (Jansson & Dorrepaal, 2015), the best means of addressing poverty (Low & Wui, 2016), attitudes towards sexual offences (Harper & Harris, 2017), the extent people blame victims (Niemi & Young, 2016), beliefs about stem-cell research (Clifford & Jerit, 2013) and how willing participants are to make charitable donations (Winterich et al., 2012). In the UK, the left/right consistent foundation are also reflected by the communications of the Labour and Conservative partites respectively (Smith & Baroni, 2017).
Both between and within cultures, MFT has also been used to explore differences in voting behaviour and attitudes between people on the political left and right. In a practical example, responses to an MFT questionnaire had strong predictive validity for forecasting how people voted in the 2012 American election (Franks & Scherr, 2015).
Data collected online and in the field suggests people on the political left are more likely to emphasise the principles of care for the vulnerable and fairness than conservatives. In contrast, the more people identify as conservative, the more likely they are to regard in-group loyalty, respect for authority and sanctity as guiding their reasoning (Graham et al., 2009;Graham et al., 2011;Nilsson & Erlandsson, 2015). This division is neither binary nor absolute, though it is roughly reflected in the UK. Before the 2017 election, more voters for the centre-left Labour party vs.
centre-right Conservative party cited funding socialised, free at the point of use, healthcare as the top issue (42% vs. 11%). Scores were reversed for leaving the EU (39% vs. 11%) ("Kantar Public," 2017). Graham, Nosek, and Haidt (2012) studied moral stereotypes by ideological orientation and found that people on the left struggled more than conservatives to understand their counterparts' motivations. Both groups exaggerated the ideological extremity of their opponents, though left-wingers were significantly worse at taking on their opponents' perspective. The authors argue this happens because both groups respond to the care and fairness foundations, albeit left-wingers more. However, conservatives rely more on the other three foundations, effectively giving rightwing parties more moral taste buds to which they can appeal. Hence Graham and colleagues think people on the left misinterpret the moral motivations of conservatives. Haidt (2012) expands on this point, theorising the left's characteristic scepticism towards patriotism, traditional institutions and sanctity put their parties at a disadvantage politically. Swales (2016) suggests the left-right split was a less important predictor of voting behaviour than the extent to which people endorsed authoritarianism vs. libertarianism. In that respect, they say Brexit campaigners should not be pigeonholed as conservative. Nonetheless, the UK's biggest polling company, YouGov, identified that people who voted for right-wing parties in the 2015 election were significantly more likely to have voted for Brexit (Moore, 2016a). Fittingly, the political orientation of right vs. left-wing newspapers and other media outlets predicted their support for Leave vs. Remain (Moore & Ramsay, 2017). The Lexit campaign (i.e. a niche left-wing movement to leave the EU) was also markedly different in content from the mainstream Leave campaigns and, in comparison, went neglected (Guinan & Hanna, 2017;Worth, 2017). It, therefore, seems fair to argue that while the Brexit vote cannot necessarily be politically differentiated, there was a greater tendency for people on the right to support leaving the EU.

The Present Paper
This paper applies the MFT to the decision to leave the EU taken by British voters. In writing this commentary, I am not implying this framework represents the key reason voters British chose to leave the EU, or even necessarily a significant one. Rather, I am hoping to add a relatively ignored layer of analysis to a political decision far too complex to be reduced to a unicausal explanation.
As it was the victor, I am focusing exclusively on how campaigners advocating leaving the EU intentionally or unintentionally appealed to each of the five foundations to reflect on their effectiveness. This is not to suggest the Remain side did not similarly attempt to appeal to voters' moral foundations, given their arguments were often focused on the same themes. To the extent that the MFT can be applied to voting behaviour in the referendum, Remain sides were perhaps not able to do so in a way that engaged voters as effectively. Thus their failure presents an interesting opportunity for an analogous follow-up.
Evidence of the success of Leave campaigns is demonstrated by how polling transformed between the declaration of the vote and election day. As per other pollsters an initial sample by YouGov, working with The Times newspaper, collected in the immediate aftermath of the referendum's announcement, saw Leave losing at 38% ("YouGov/ Times survey," n.d.-a). In early March the same pollster had found support for Leave drop to 35% ("YouGov survey results," n.d.-a). And while they still wrongly predicted a Remain victory, their final polls were reliably higher, showing Brexit at 48% ("YouGov survey results," n.d.-b) and 49% ("YouGov/ Times survey," n.d. -b) ii . Admittedly this pattern is ambiguous, as gains for one side may be in part due to the ineffectiveness of the other. Although losses for Remain are compatible with the interpretation Leave were better able to provoke fundamental concerns to sell their vision to the voters.
In the following section, I explain each foundation and summarise how the Leave movement engaged with them, citing campaign events and survey data. In doing so, I aim to show today's biggest political issue could have been, at least partially, owed to a stone age mind. I concentrate on the official campaign, entitled Vote Leave, but also mention key figures from secondary groups. By suggesting they were able to generate responses from instinctive, reflexive decision-making systems I do not mean to imply they lacked substance or acted in an underhanded manner (not that these explanations are mutually exclusive). Inciting topics framed as relating to care, fairness, loyalty, authority and sanctity may be advantageous, but offering approaches that resonate is essential.
No issue in the UK better exemplifies this value than healthcare. The organization, funding and delivery of the National Health Service have been among the most important issues facing the country for decades ("Important issues facing Britain," 2014). Famously, former Chancellor of the Exchequer Nigel Lawson called the health service the closest thing the English have to a religion. Polling data overwhelmingly supports its continued existence, and keeping it free at the point of use ("What does the public think", 2017). The public even voted it the foremost symbol of what is great about Britain, placing in higher esteem than the monarchy (Jolley, 2013). It is therefore unsurprising the Vote Leave campaign director Dominic Cummings (2017) suggested the promise of greater funding/ resources for public health services was vital to a Brexit victory. By representing the then current arrangement as constraining the quality of care availble to needy people, they were able to take advantage of the regard with which people hold the health service. It was potentially helpful for broadening the appeal of the campaign to a left-wing audience, traditionally more focused on health funding.
To create an ethical imperative to vote leave, the campaigns portrayed a zero-sum calculation suggesting government could directly increase the National Health Service budget at the expense of the European Union one. Most memorably, the Vote Leave battle bus pledged a misleading figure of 350 iii million pounds a week to health that would otherwise be spent on EU membership. Although the sum was widely contested throughout the campaign, Ipsos Mori estimated just under half of the people who had heard the claim (47%) thought it was true Britain gave this amount to the EU vs. 39% who thought it was not (as cited in Stone, 2016). Without an understanding of the rebate, or the economic benefits of single market membership, many Leave voters could have seen their cause as supplying a greater standard of care to those that need it.
Vote Leave cited benefits to the National Health Service, including additional funding, as the primary reason to support Brexit on their website and leaflets ("Why vote Leave," n.d.). Throughout the campaign, their use of the NHS logo became so ubiquitous that the Department of Health threatened litigation over its unauthorised use to maintain the impression of neutrality (Gallagher, 2016). In a particularly extreme example of weaponising care, Leave supporting tabloid The Daily Express paraphrased a senior health consultant saying a remain vote risked the end of the service (Maddox, 2016). Vote Leave also shared a letter from fifty health professionals claiming Brexit would allow billions of pounds to go directly into improving services (Mossialos et al., 2016). This message was potentially persuasive to voters viewing the EU in terms of its cost vs. benefits. Campaign frontman, and then Conservative cabinet member, Boris Johnson further cited the care foundation when he suggested Brexit would reduce waiting times at accident and emergency departments, better helping those in need (Sparrow, 2016).
It was not just in terms of the budget Leave campaigns characterised the EU as working against the National Health Service and its patients. Labour MP Gisela Stuart declared that health tourism from European Union migrants cost the UK billions (Hope, 2016). This figure was widely shared by Vote Leave, who claimed the UK pays an average £723m a year more to EU countries for the medical treatment of UK nationals than it gets back for EU nationals who use the UK services ("UK gives £5.8 billion," n.d.). Most controversially, the prominent Leavecampaigner and right-wing politician Nigel Farage said immigrants with HIV, although not specifically from the EU, placed a financial strain on the UK (Mason, 2015a).
The effectiveness of framing the EU as depriving British natives of care, by straining existing resources with costs and immigration, could be rooted in a selective benevolence towards one's in-group. Social identity theory anticipates preferential attitudes and behaviour towards the group a person identifies with (for a review, see Brown, 2000).
Among other findings, priming in-group membership, even with an arbitrary marker, has been sufficient to prompt Journal of Social and Political Psychology 2019, Vol. 7(2), 863-889 https://doi.org/10.5964/jspp.v7i2.1032 significant differences in empathy (Cikara, Bruneau, & Saxe, 2011) and the distribution of resources (Tajfel, Billig, Bundy, & Flament, 1971). Since group identity may be reinforced systematically by influential figures or institutions, such as politicians and press, controlled lab experiments with only brief exposure to prompts may show us only the tip of the iceberg.
This process can also be aided by propagating negative impressions of the out-group, such as them being freeloaders, prompting fearful or hostile responses via outgroup derogation (van Prooijen, Krouwel, Boiten, & Eendebak, 2015). The Leave side's focus on unrestricted immigration as a threat to public prosperity and identity (Moore & Ramsay, 2017) could have characterised them as an outgroup that voters were less sympathetic to.
And potentially one for whom they resented either providing healthcare or compromising the quality of their own.
As previously mentioned, people on the political left tend to prioritise health funding as a policy area, so this may have been a means of expanding the Brexit voting base. But with the vehicle for doing so taking the form of binding health provision to an out-group, defined by national identity, they may have been deterred by a strategy that appealed more to right-wing voters (Graham et al., 2009). However, I have insufficient data to be conclusive either way. I will return to these points when I detail how Leavers made political capital out of national identity and primed/ exploited anti-immigrant tensions when addressing Loyalty/ Betrayal.
Vote Leave's strategy of focusing on a cherished British institution that, a) could benefit from the additional funding the EU took instead, and b) was undermined by the EU's open borders policy, evidently had traction. Come referendum day polling data found more people believed leaving would improve health provision than the amount who thought it would have no effect or a detrimental one ("Do you think," n.d.-a). Leave campaigns had convinced them that the level of care people receive could only be maintained or increased by voting leave. The sentiment was most common amongst older voters, who are disproportionately conservative in the UK and were more likely to support Brexit (Ashcroft, 2016). Remain campaigners used the care foundation to counter this narrative, warning the National Health Service was unsustainable without the economic growth leaving the world's biggest trading block would undermine. The cautious approach was evidently less compelling.

Foundation 2: Fairness/ Cheating
This foundation is related to the evolutionary process of reciprocal altruism, i.e. when individuals make sacrifices in the expectation of similar treatment in the future. Graham et al. (2013) claim fairness relates to instinctual concerns about unfair treatment, inequality and abstract injustices. These evolved responses may be crucial to survival since social animals encounter frequent opportunities to take part in non-zero-sum exchanges and relationships (Trivers, 1971). Given humans are not the strongest species and do not have the best natural defences, they likely became the dominant species because of evolved aptitudes which motivate alliance formation and cooperation. Haidt and Graham (2007) argue all cultures have developed virtues related to the promotion of social ideals relating to fairness and justice. From their perspective, emotions such as anger, guilt and gratitude carry out the function of pushing people towards forming mutually beneficial coalitions and working for the good of others.
Though moral anxieties informed by the other foundations may override them, e.g. the common sanctity argument against gay marriage. Hence, egalitarian societies are considered a rarity with their creation dependent on members' ability to suppress other predispositions. An understanding of fairness is necessary for societies to generate consensual ideas of justice, rights, and autonomy. However, this does not mean individuals think about it in the same way. Haidt (2012) explains that people on the political left and right characterise the foundation differently. More left-wing individuals tend to think of fairness in terms of equal opportunities and outcomes, whereas conservatives typically conceptualise it as reflecting a correlation between rewards and contribution i.e. proportionality. The Leave campaigns targeted both of these approaches in their literature and talking points on the run-up to the Brexit referendum.
Most noticeably, they depicted the EU itself as a fundamentally unfair entity, intent on transferring power from local populations to "unelected bureaucrats" or "metropolitan elites": terms used to refer to Members of the European Parliament and lobbyists (Bell, 2017;Calhoun, 2016). The extent of the EU's democratic deficit is open to dispute, although this interpretation chimed with the public in a way the Remain rebuttal could not after they partially accepted the premise (Oliver, 2016). The fairness-relevant principle that people in the UK should make decisions about the UK was the single biggest reason for Conservative and Labour voters alike to support leaving the EU (Ashcroft, 2016). Perceptions of a fundamental injustice may explain the power behind the relentlessly used slogan "take back control", i.e. the implication that people in Britain are not in charge of their democracy. Farrell (2016) expects that unfairness is particularly authoritative if those with power are represented not as public servants, but a corrupt, self-perpetuating cabal of "elites".
Comparable rhetoric extended beyond MEPs, to the Remain side as a whole. "Of course the elites want to remain.
They will always have power. The losers are the hundreds of millions of Europeans whose only power is their vote... That power is being taken away" wrote Boris Johnson (2016b) in a column for The Telegraph. His then right-hand man, and fellow Conservative cabinet member, Michael Gove, also evoked fairness when he compared the Remain camp, who "have done very well, thank you, out of the EU", and have "vested financial interests" with the Brexiters who want to ensure "the working people of this country, at last, get a fair deal" because the majority of people "are suffering from EU membership" (Sky News, 2016). The public shared this conception, with polling from YouGov showing they felt big businesses, banks and the political class were the main beneficiaries of EU membership (Moore, 2016b). In contrast, people in work/ looking for work, and vulnerable groups, including pensioners and those on a low income, were seen as losing out from it (again, foundations are not necessarily disconnected, since this idea is congruent with the care foundation).
The unfairness of an apparent democratic deficit was made worse by public impressions of an economic deficit.
Data presented by Ipsos Mori ("The perils of perception," 2016) revealed most of the public knew the UK contributed more financially to the EU than it received directly. But they harboured misconceptions about other countries' net contributions, with almost a quarter of the sample erroneously believing Britain to be the top payer. iv A very high proportion of Leave voters (85%) also thought the UK did not receive a financial benefit through shared trade or investment, seeing the union mostly as being an expenditure.
I will look at the role of immigration in detail during the next section. However, it is worth pointing out Vote Leave explicitly used the foundation of fairness to attack the EU's immigration system. On their website and advertising, the official campaign claimed the system of open borders was both "immoral" and "unfair" since it prevented the UK from autonomously controlling who entered ("The EU immigration system," n.d.). They also explicitly framed the set-up as one that allowed EU citizens to exploit the UK benefits system, offsetting the value of a living wage, i.e. another zero-sum claim. Allowing Britain to control its borders was, therefore, the second reason to vote Brexit on the Vote Leave website and adverts ("Why vote Leave," n.d. Leave voters seemed to either agree with this message already or thought it was convincing. Goodwin and Milazzo (2017) found evidence that increases in the rate of immigration, and resentments over the country's lack of control, were key predictors of the vote for Brexit even after accounting for other popular theories of Eurosceptic voting.
This finding is in line with the previous correlation between low perceived power and anxiety/ hostility towards outgroups (Azzam, Beaulieu, & Bugental, 2007). Perhaps the relationship is exacerbated when people think the EU is unaccountable and undemocratic.
Leave campaigns also addressed fairness from a proportionality perspective. They contended that as well as putting a strain on the National Health Service and welfare systems, the EU immigration policy was fundamentally "unfair". The uncharacteristically pro-immigration argument stipulated the two-tier system, required by EU demands for freedom of movement, inhibited job creators from entering the country because "criminals" may be entering instead ("The EU immigration system," n.d.). Nigel Farage agreed, shortly before the referendum, optimistically saying "more black people" would qualify to enter the UK under a meritocratic points-based system (Dathan, 2016). Likewise, Boris Johnson and Michael Gove complained that the existing system was unfair because it discriminated "on the ground of nationality" rather than skills (Cockburn, 2016). Thus those more deserving of the right to enter would be able to do so without the immigration policy priotiritising EU citizens.

Foundation 3: Loyalty/ Betrayal
In The Descent of Man, Charles Darwin (1871)  As briefly summarised in the Care section, there is evidence of social cognitions selectively responding to others boasting salient categorical in-group traits over out-group counterparts. The identity of in-groups is relatively fluid since data support biases whether common features are intrinsic or arbitrary (Golby et al., 2001;Ruckmann et al., 2015), extending to political affiliation (Rand et al., 2009 Smith 871 ploiting another in-group member (e.g. a British person) is exploiting the whole in-group (e.g. British people).
Sometimes the concept is considered in terms of self-sacrifice for the greater cause, but in the political arena, it is more likely to manifest in patriotism and in-group favouritism (Haidt, 2012). By priming different group memberships between individuals, and focusing on collective differences, campaigners may be able to stimulate these responses.
After the referendum, Michael Gove claimed: "Britain has the most liberal attitude towards migration of any European country" (Hall, 2018). However, concerns about the cultural and economic impact of uncontrolled mass immigration were among the key reasons people voted Brexit (Clarke, Goodwin, & Whiteley, 2017;Goodwin & Milazzo, 2017;Hobolt, 2016). It was also the topic Leave campaigns focused on most heavily as the election approached, including the cost of open borders and its impact on native culture (Swales, 2016 average. Four in every ten people from the same group also overestimated the proportion of child benefits going to children living in other parts of Europe (0.3%) by a factor of at least 40. Swales (2016) found that concerns about immigration resonated with a group of voters he characterised as Economically Deprived Anti-Immigration. In contrast to the group labelled Middle-Class Liberals, who predominantly backed Remain, this group very strongly voted Leave. These patterns could be a function of the worries, most prevalent among lower classes, that immigrants provide an economic threat which impacts upon both wages and welfare vii (Dustmann & Preston, 2007;Manstead, 2018;Mayda, 2006). As mentioned in the fairness section, this issue was one of the ways the Leave campaign invoked the fairness foundation ("The EU immigration system," n.d.). It was a focal point for Eurosceptic media and figures both before (Graham, 2014) and on the run-up to the referendum (Moore & Ramsay, 2017;Portes, 2016). The use of dehumanising language about out-groups has been similarly recurrent in the UK press and blogger debates about immigration (Musolff, 2015). The most common instances include metaphors of immigrants as parasites, leeches, or bloodsuckers, anchoring their alleged threat to public money.
viii Psychologically, social class as a predictive factor could be explained, in part, by the relationship between power and anxiety or hostility towards outgroups mentioned earlier. Typically, people identifying as part of a lower social class are disproportionately likely to report higher feelings of powerlessness (Dubois, Rucker, & Galinsky, 2015), that may have pushed many of them towards voting Leave. Working class populations are also more likely to see themselves lacking personal control and autonomy over their lives (Manstead, 2018). This trend may be one reason the Leave campaign's message of taking back control, which I will cover in the next section, was such a powerful one to working-class communities (Mckenzie, 2018). This framework has also been used to explain, among other things, the rise of Donald Trump, who similarly promised to look out for "ignored" working class communities (Inglehart & Norris, 2016 The extent to which anti-immigration narratives prevail may also depend on the extent to which the political context condones an essentialist form of nationalism (Hooghe, Marks, & Wilson, 2002). Hence Henderson et al. (2017) pointed out that treating the UK as a single unit of analysis in polling is an oversight that can downplay the diverse characteristics of its constituent members. As mentioned before, the comparatively large influence of England in the referendum (accounting for 84% of the total British population) offset substantial Remain majorities in Scotland and Northern Ireland. This division highlights the fallacy of treating attitudes in the UK as being consistent across borders. One reason for such divergence may be nationalism is expressed between countries. The differences could have influenced how attuned each was with the Leave campaign's protectionist messaging.
Gardner (2017)  possible between the two countries that make up a partitioned Ireland.
As per Kumar (2000), Henderson et al. (2017) suggested that this political differentiation comes from the presence of nationally entrusted parliaments. The relatively recent devolution of controls over some policy fields to minority governments in the UK has shifted the balance of power (Paddison & Rae, 2017 In the next section, I will consider the concept of sovereignty more broadly as I discuss the role of authority/ subversion.

Foundation 4: Authority/ Subversion
This foundation is closely connected to the loyalty foundation since both relate to preserving the integrity of the in-group. As such, it is similarly more emphasised by people identifying as more strongly conservative (Graham et al., 2009). Authority specifically relates to the in-group's organization. It is active when people grant legitimacy to institutions such as courts or, as is relevant for this article, parliaments (Graham et al., 2013). We share dominance hierarchies with our ancestors, with many primates living in such arrangements. Those best able to forge beneficial relationships have an advantage over those that are not able to respond to status appropriately. Hence, Haidt (2012) and colleagues reason that our long history of hierarchical social interactions shaped an authority foundation. Politically, this foundation underlies virtues of leadership and followership, including deference to legitimate authority and a respect for local traditions.
Sovereignty was a major campaign issue for the Leave side; it was mentioned frequently in their adverts and press coverage alike (Moore & Ramsay, 2017). Most pertinently, this includes the previously mentioned slogan "Take Back Control" i.e. reasserting national sovereignty through Parliament. The subtext was that a dictatorial, and unelected out-group had neutered the in-group (Pabst, 2016). The Leave side built the claim that ever closer union, and centralisation, would make the EU less answerable than national governments, eroding the connection between voters and political decision making. The Vote Leave website exemplifies this, with one of the main incentives to vote Brexit being that afterwards people who can be elected and subsequently removed will create laws ("Why vote Leave?," n.d.). They also claim that the European Court has the power to overrule national government on "everything", including tax legislation to immigration. Perhaps sensing the issue's toxicity, symbolic sovereignty featured heavily in then Prime Minister David Cameron's unsuccessful negotiations to change the UK's position in the EU.
Before and during the campaign, a disagreement ensued to the proportion of British laws made overseas. In a debate organized by the UK national phone-in and talk radio station Leading Britain's Conversation, centrist Remain figure Nick Clegg claimed it was as little as 7% while Nigel Farage said it was around 75% (LBC, 2014). Writing for The Sun, Boris Johnson (2016a) claimed it was 60%, as per the Eurosceptic lobby group Business for Britain.
Regardless of the nature of these laws, since most relate to technical regulations that would not normally be part of public discourse, it is potentially an emotionally significant argument; especially, as previously suggested, among English nationalists feeling they already had less autonomy than people in other parts of the UK (Henderson et al., 2017). The statistic exemplifies the fairness foundation mentioned previously, and palpably subverts the authority foundation by conveying a lack of accountability. Its arresting nature may partially explain why polling showed Farage won the debate (57% to 36%), despite representing a far smaller party than Clegg and pro-EU messages typically polling higher at the time of broadcast (Kellner, 2014, March 27).
The Leave campaigns also induced the traditional aspect of the authority foundation by sharing a favourable view of Britain's past that internationalism forfeited. A loss of socio-political control is arguably focal to other populace movements, including Trump's promise to return jobs to America and put it first for trading relationships. Bachmann and Sidaway (2016)  Smith 875 have also been crucial to the Brexit campaign. Until relatively recently the UK controlled over a quarter of the world, with the gradual end of its empire still falling within living memory of some voters. The authors argue the subsequent rise of a shared European identity, owed in part to the development of a collaborative union controlled in Brussels, has become associated with a lack of control. Risse (2003) foresaw this tension, thinking visible signs of collective European identity like the Euro would increase a feeling of displacement from the continent due to a preoccupation with retaining Englishness. Thus the Euro as an identity marker was hard to align with a British dominant identity discourse. He reminds readers of the Winston Churchill nation-state attitude to Britain as being with but not of Europe.
Weale (2016)  Reflecting on prior accomplishments, and sharing stories to remind people of the achievements of the "imagined community" they feel an affinity towards, is an effective way to induce a national identity. Anderson (2006) points out that most members of communities bigger than traditional villages will never be able to interact with one another, so communion is established via shared historiography, narratives and culture. The British Empire's once far reach feeds into the idea of long-distance nationalism: that areas outside of one's state boundaries can be a part of their nationhood by association. In sum, the slow erosion of British territories, the aforementioned gradual succession of the UK into its constituent elements and the prospect of centralised European control all undermine the integrity of English, and to a lesser extent British, identity. The Brexit referendum offered a symbolic and literal means to defy this process. Consequently, a big part of changing the future may be an imagined past.

Foundation 5: Sanctity/ Degradation
The final canonical foundation refers to feelings of disgust, degradation and moral corruption. The combination of our ancestors' omnivorous food habits and relatively large groups could have put them at risk of bacteria spreading (Haidt & Graham, 2007). Thus reflexive disgust responses are thought to have evolved as mental tools to circumvent the threat of pathogens and parasites, i.e. a useful disease-avoidance mechanism (Oaten, Stevenson, & Case, 2009). In the moral domain, it is thought to manifest in a conservative caution towards deviant or taboo behaviour and transgressions. Perceived ethical offences elicit comparable physiological activity to close contact with a person who is contagiously ill, implying principled judgements of others reflect its outer limits (Rozin, Lowery, & Ebert, 1994). Haidt and colleagues characterise the foundation as underlying notions of an often religious purity that prevents the virus-like spread of impure values or behaviour. It serves the social function of marking the group's cultural boundaries, e.g. theist or secular societies.
A small majority of the UK population still identify as religious (Field, 2018), with the biggest single group being Christian. Faith also has a role in how prime ministers create and communicate policies (Crines & Theakston, 2015), with Theresa May citing her Christian belief as helping her through Brexit. However, religion is not an overt theme in modern political communications, particularly amongst parties on the left (Spencer, 2017). Former Labour head of communications Alastair Campbell examplied this when he declared "We don't do God". The pattern prevails despite most of Britain's seven prime ministers in the past four decades being practising Christians.
The Leave campaign did not frame itself as a religious movement. Yet its inverse of degradation was alluded to frequently via the out-grouping of Muslims as a recurrent theme. For instance, a content analysis of contemporary media found negative impressions of Turkey, a Muslim majority country, dominated the pre-referendum immigration debate. Despite not being part of the EU, it received more negative mentions than any member state on the runup, from predominantly right-wing outlets (Moore & Ramsay, 2017). This is in line with literature elsewhere showing the abstract threat to western values, by Muslims, is a recurrent characteristic of anti-immigrant sentiments within Europe (Azrout, van Spanje, & de Vreese, 2013;Schiffer & Wagner, 2011).
Earlier in the year, the United Kingdom Independence Party released a broadcast warning voters about the possibility of Turkey being a member state by 2020 should they back Remain (Exposure VC, 2016 Smith 877 The Vote Leave site and literature further implied the threat of Islamist extremism and Islamic culture by reminding people that Turkey "borders Syria and Iraq" ("Why vote Leave?," n.d.). As well as priming the terrorist organization the Islamic State of Iraq and the Levant (ISIL), who were active in these regions, this innuendo relates to the refugee crisis ongoing on the European continent. A related talking point was the idea that Angela Merkel's decision, taken in 2015, to allow refugees on mass into Germany could result in them gaining freedom of movement. The website extends this possibility to UK citizens fighting for ISIL abroad, theorising that the lack of systematic checks on anyone with an EU passport would allow them an unperturbed passage from Greece to the English Channel.
x In support of the Schengen zone leaving the UK vulnerable, Vote Leave member, and Conservative MP, Owen Paterson claimed after five years many refugees could get citizenship and be able to move freely (Khomami, 2016). The prevalence of this argument may be why one voter said he backed Leave to stop Muslims coming to the UK (York, 2016).
Towards the end of the campaign, Nigel Farage unveiled a now notorious poster playing on this fear, reading "Breaking Point" over the image of refugees (Stewart & Mason, 2016). It proved contentious among the public, the press and other politicians alike ("Do you think," n.d.-b; Durrheim et al., 2018), perhaps because of the perceived vulnerability of the group implicated. Nonetheless, this othering may be related to why Islamophobia, and a belief in Islamic conspiracy theories, has been linked to individual intentions to vote Leave (Swami et al., 2018). The Remain campaign responses to Turkish membership were negative, though to protect their strategic alliance, Ker-Lindsay (2018) suggests they did not wholly reject it. He also claims that, for these reasons, the Turkish ascension question was instrumental to the Leave campaign victory and may have even swung the election.
The possibility of a predominantly Muslim country having the highest representation in the Union ought to resonate more with strongly right-wing voters than other groups. They mutually place a greater emphasis on sanctity than their left-wing counterparts and care more about conserving aspects of their culture against an out-group (Graham et al., 2009;Haidt, 2012). In response to high profile attacks by ISIL, these concerns have birthed a common anti-Muslim programme between right-wing European parties. Hafez (2014) claims that Islamophobia is a particularly useful tool for populist parties establishing right-wing unity within Europe, and broadening their vote. In several European cities, across different countries, the radical right has been mobilised by narratives surrounding Islam as being fundamentally incompatible with western values (Bangstad, 2018;Ebner, 2017).
The message has been persuasive resulting in, among other examples, the rise of Front National in France and the FPÖ in Austria. The United Kingdom Independence Party also conjured these ideas, warning against liberal attitudes towards fundamentalist Islam. At one point this narrative became so ingrained in their messaging that the far-right British National Party said they were taking their territory by adopting a stance against the "Islamic colonisation" of Britain (Ford & Goodwin, 2014, p. 83). It also seems to have informed this part of the campaign, evoking nationalist identity politics to encourage a protectionist attitude towards an intergroup threat facilitated by EU expansion (Swami et al., 2018).

General Discussion and Conclusion
The British public's decision to leave the EU and its unwieldy aftermath are among the country's most dramatic political events since the end of the second world war. Here, I suggest the success of the Leave side may be due, in part, to the campaign arousing ancient decision-making mechanisms (Graham et  However, I do argue that the salience afforded to these topics may be adaptive. In making this case, I have discussed the Leave campaign broadly. To validate these claims, and better explore the role of reflexive heuristics in the Brexit referendum, content analyses of their literature would be more authoritative. This approach has methodological precedent in MFT research (Clifford & Jerit, 2013), and may offer a better understanding of how reflexive heuristics underlie UK public attitudes towards the EU. Alternatively, researchers may wish to prime participants' moral foundations in the lab to directly test the effect of relevant communications on voting behaviour. These designs could be of interest to political scientists looking to understand the vote, or people in political communication roles looking to "sell" ideas to the public in an accessible way. They could also explore the emotional component of the MFT, namely how foundation-relevant prompts (such as statistics or posters) make people feel as well as think. This approach could be beneficial, given Haidt (2012) and colleagues have claimed the affective value afforded to related stimulus underline our political decision making.
Experimental paradigms may also allow researchers to better gauge whether or not political sides necessarily consider the five foundations in comparable manners. In the introduction to the MFT, I explained that the fairness foundation is conceptualised differently by people on the political left and the right, but so far less is known about the others. If in-group loyalty is less important to left-wingers, then bringing to mind it in a way relevant to Care may be unsuccessful, e.g. saving health resources by limiting immigration. But were an out-group characterised as on the side of big business, like how Lexiteers depicted the EU (Guinan & Hanna, 2017), priming a left-leaning in-group identity may be effective.
Researchers tend to study the MFT in terms of how political communications can be used to attract voters. What is less clear is the extent that they reflect reductions vs. enhancements in support for causes. When discussing the sanctity foundation, I outlined how the use of Islamophobic rhetoric may have appealed to reflexive fears of social corruption that were more common among strongly conservative voters (Graham et al., 2009;Hafez, 2014).
Although these adverts were condemned by left-wing outlets (e.g. Stewart & Mason, 2016), at present, it is ambiguous whether left-wing voters were actively deterred by it. The Leave communications relating to an Islamic threat may even have aroused left-winger voters' sanctity foundation, albeit in revulsion to a message seen as intolerant or insensitive. If this were the case, then campaign messaging on foundation-relevant points should be considered in terms of trade-offs. Thus some groups of voters can be selectively targeted, with an understanding that the same poster, video or speech could deter another group, due to differences in their moral foundation profiles.
Since the referendum, polling has reflected a scepticism towards the success of Brexit, with negative projections and impact assessments challenging the economic case for leaving. Over two-thirds of voters surveyed believe Brexit is going badly (Smith, 2018). Yet, conceivably given the importance of fairness in political decision making, "the will of the people" has remained an effective rebuttal. This intuitive priority may be why the majority of Leave backers expect their support for enacting the outcome of the vote would be unchanged in the event of an economic downturn ("Left-Foot-Forward/ BMG Poll," 2018). For them, upholding the referendum result is perhaps a moral vs. pragmatic necessity, for which it is worth taking a short-term financial hit. Earlier this year, Nigel Farage created Smith 879 the populist Brexit Party. Within six weeks of launching, they were the single biggest party in the 2019 European Parliament elections despite having no manifesto. Their success points toward a great sense of anger and betrayal among Leave voters that is in line with the fairness foundation.
The proportion of Remainers supporting a second referendum is still considerably lower than the proportion who think leaving the EU is wrong, despite attempts to rebrand it the fairer sounding "People's Vote". John Curtice (2019) outlines data showing that this framing makes it more appealing to voters than asking people if they want "another referendum". However, he cautiously notes the proposal's popularity is largely among Remainers wishing to reverse Brexit. To bridge the gap, the research presented here suggests campaigners hoping to convert Leave voters should not shy from making a positive case for immigration since an evasive approach has been ineffective.
Doing this may involve encompassing multiculturalism into British identity, to offset in-group vs. out-group reflexes.
They could also address the democratic deficit by highlighting political similarities with other EU countries and more forcefully refute the now debunked Turkish ascension timetable. Otherwise, they will be outnumbered five moral foundations to two.
This commentary intends to encourage more researchers to look at Brexit from an evolutionary angle. Decisions are not always made rationally, regardless of where a person falls on the political spectrum. They are, therefore considered to be subject to reflexive cognitive heuristics (Petersen, 2015). Given the rapid, unconscious nature of these decision mechanisms, it is likely they represent evolved heuristics (Haidt, 2012). It is, therefore, useful to explore them from a functionalist perspective to consider how evolutionary priorities may still be relevant to current political realities (McDermott & Hatemi, 2018). Doing so may enable us to make novel hypotheses about the sorts of issues and campaigns the public will respond to and the forms of political communication that may be effective. In other words, to understand the present it can help to look back.

Notes
i) For accessibility, throughout this paper I will be using the terms United Kingdom and Great Britain synonymously. However, I am utilising the definition of the former. This means that both are used to refer to the union comprising England, Scotland, Wales and Northern Ireland.
ii) Across the surveys cited here, the average amount of participants surveys was 3419.
iii) This amount referred to the annual cost of subscription. It omitted the rebate the UK received on its contribution to the budget prior to any transaction taking place. With this deduction included the figure was approximately £280m, making it an exaggerationg of 25% (Ackrill, 2016). iv) Data from the European Commision in the same year showed that the UK were actually the eighth largest net contributor to the EU budget (Wyatt, 2016).
v) Another reason immigration may have been less threatening before the enlargement of the EU was in 1997 the UK and Ireland had opted out of passport-free movement, as stipulated by the Treaty of Amsterdam. This meant internal border controls prevented people from entering without checks, potentially aiding impressions of security and the UK's relative independence in the union. In contrast, the government accepting uncapped immigration could have mutually reduced feelings of control and exclusivity in the in-group.
vi) On average the same sample underestimated the proportion of total immigrants to the UK coming from the European Union as being 25%. The real total is 37%. Taken together, these contrasting findings imply the British public greatly overestimate the extent of EU and non-EU immigration to the UK as a whole.