You're not my type: Do conservatives have a bias for seeing long-term mates?

Abstract

When choosing a mate, humans favour genetic traits (attractiveness, high sex drive) for short-term relationships and parental traits (warmth, high status) for long-term relationships. These preferences serve to maximise fitness of future offspring. But this model neglects the role of social norms in shaping evolved mating strategies. For example, in conservative cultures, individuals are likely to face costs such as punishment for short-term mating. Here we show that conservatives over-perceive some mates' suitability as long-term partners. Study 1 found that conservatives were less likely to use a short-term strategy that was distinctive from their long-term strategy. Study 2 showed that conservatives over-perceived hypothetical mates as long-term investing partners, despite their lack of commitment-compatible traits. Conservatism was measured at the regional- (India, USA, UK) and individual-level. Our results demonstrate how social norms may bias behaviour. We anticipate our findings to be a starting point for more sophisticated models, drawing on developments from evolutionary and social psychology.

Introduction

What traits do humans seek in a sexual partner? Should we expect a similar answer from a British college student and a middle-aged individual from Sudan? For decades, evolutionary and social psychologists have been interested in the traits that men and women desire in a sexual or romantic partner. Because human evolution has been shaped as much by social interactions as immunological diseases, a cultural view of psychology should play a central role in an evolutionary account of mating behaviour. Here we investigate the role of cultural norms in shaping evolved mating strategies. Specifically, we ask: (a) whether individuals from conservative backgrounds moderate their preferences by avoiding short-term mating even when, potentially, the benefits to offspring outweigh the costs, and (b) what mechanisms support this bias.

According to evolutionary psychologists, successive generations of early humans faced recurrent problems when choosing a suitable partner. Specifically, ancestral men and women would trade-off between mates offering genetic and parental quality (Pillsworth and Haselton, 2006, Gangestad and Simpson, 2000). As such, humans have developed two distinctive mating strategies. For short-term relationships, individuals favour genetic traits that signal fertility, such as physical attractiveness and high sex drive (Li and Kenrick, 2006, Pillsworth and Haselton, 2006, Regan et al., 2000). For long-term relationships, however, individuals prioritise material traits, such as emotional warmth, wealth, and high social status (Gangestad and Simpson, 2000, Li et al., 2002, Regan et al., 2000).

The trade-off between genetic and parental quality is shaped further by ecological factors, such as historical levels of disease and resource scarcity, which influence fitness outcomes for offspring. For example, when rates of infectious disease are high, it would be prudent to favour mates with symmetrical faces, as symmetry is highly correlated with immunological functioning (Trivers et al., 1999, Thornhill, 1997). Additionally, when women's economic independence is low, they should favour men with wealth and high status (Stanik and Ellsworth, 2010, Lu et al., 2015). Cross-cultural research has also shown that people from countries with a low average birth rate, high infant mortality, higher parasite stress, or shorter life expectancy are less likely to engage in uncommitted sexual behaviour (Schmitt, 2002, Schaller and Murray, 2008, Thornhill et al., 2010, Muggleton and Fincher, 2017).

Although there has been substantial focus on how environmental factors shape mate preference, previous research has typically focussed on an individual's motivation to maximise the fitness of offspring. Yet most individuals will take into account factors that are indirectly related to their own fitness, such as the attitudes of their parents, society, and other potential mates. Furthermore, sex with multiple or unfamiliar partners can result in the transmission of many pathogens, including sexually transmitted infections, making uncommitted sex particularly risky when disease prevalence is high. As such, there could be opportunities where individuals should avoid uncommitted sex with mates with a high good genes value because the potential benefits to offspring may be outweighed by social costs, such as punishment for promiscuous behaviour, which can reduce an individual's residual reproductive value.

Given that social cues influence mate choice, how are social norms surrounding sexuality maintained? One possibility is that individuals from conservative groups conform because they fear punishment. Yet harsh punishment is an inefficient mechanism for maintaining norms because it increases the risk of rebellion and a social backlash (Baumeister and Twenge, 2002, Brehm, 1966, LaFree et al., 2009). This, by definition, would undermine social cohesion. Alternatively, a more adaptive approach would be for individuals to internalise the norms of the group, by means of a bias. It could be, for example, a cognitive, learning, or cultural bias, but we are agnostic about the form this bias should take.

At first glance, biases can be viewed as violations of rational choice, and thus an evolutionary maladaptation. Economic utility theory, philosophical reasoning, and conventional wisdom dictate that humans who are rational in their decision-making should outperform those who demonstrate bias. However, in some social situations biases can result in improved decision-making. Just as a smoke detector is attuned to prioritise safety (i.e., minimise false-negatives, even if this maximises the number of false-positives) over accuracy (minimise error rate overall), evolution has selected for psychological responses that maximise human survival (Nesse, 2005, Schaller and Park, 2011). In this view, biases, instead of design flaws, are design features (Haselton, Nettle, & Murray, 2015).

Similar logic could apply to individuals' perception of long-term mates. Consider this: social groups differ in the extent to which they are conservative. Conservative social norms dictate that individuals should be chaste; violation of these norms can result in malicious gossip, reputation damage, or honour killings (Ghanim, 2015, Hartung, 2012, Mayeda and Vijaykumar, 2016, Flood, 2013). A potentially adaptive bias could be an internalisation of social norms surrounding chastity, which results in an over-perception of a mate's suitability as potential long-term partners. In conservative groups, for example, the cost of a false positive (e.g., over-perceiving the risks of promiscuity) could lead to a missed opportunity to mate with a high quality mate. However, the cost of a false negative (e.g., failing to detect the risks of promiscuity) could result in social ostracism. Thus, in conservative contexts, individuals may demonstrate a bias that promotes social conformity to long-term mating. However, in liberal groups, where the costs of short-term mating are lower, individuals can benefit from engaging in distinctive mating strategies, by favouring short-term mating with good genes mates, but long-term mating with good parent or good provider mates.

We propose a theoretical model where personal and societal levels of conservatism predict the likelihood of a long-term mate bias. In all societies, humans can benefit from engaging in short-term mating. Benefits include increased offspring fitness, opportunities for mate poaching, mate value feedback, and immediate access to resources (Greiling and Buss, 2000, Meston and Buss, 2009, Smuts, 1992). However, the costs of engaging in short-term mating are moderated by social norms in a given ecology. If the social group is tolerant of short-term mating, the potential payoff of mating with good genes mates is relatively high. However, if the social group is conservative, the potential payoff of short-term mating is diminished.

Observational data support the claim that conservatism promotes a long-term mating bias. Individuals from conservative regions enter into marriage at a younger age (Schmitt, 2005) and are less likely to terminate these long-term bonds (Vandello & Cohen, 1999). Societal conservatism negatively predicts willingness to engage in short-term mating (Schmitt, 2005, Muggleton and Fincher, 2017, Thornhill et al., 2009), which could lead to costly punishment. The present report, however, seeks to test empirically whether individuals from conservative groups over-perceive prototypically short-term mates as potential long-term mates.

To test this proposition, we selected two relatively liberal regions (UK and USA) and one conservative region (India). The three regions also differ in mean number of sexual partners (UK: 9.8; USA: 10.7; India: 3.0) and one-night stands (UK: 52%; USA: 50%; India: 13%). Indians are also more likely to encourage young people to abstain from intercourse until they are married (49%, vs. UK: 6%; USA: 14%) (Durex Sexuality Study, 2005). As such, we might expect that Indian mating strategies are influenced by more conservative social norms and a higher likelihood of punishment. We also measured conservatism at the individual level to account for within-region variation amongst individuals.

We propose that conservatives have a bias for seeing long-term mates. Although prior research has demonstrated that conservatives possess distinctive short- and long-term mate preferences, displaying a short-term strategy may prove costly in conservative groups. As such, an adaptive response could be a bias that promotes long-term mate preferences, even under ecological conditions where - in some societies - a short-term mating strategy is adaptive. From this, four predictions emerge.

In Study 1, we predict that liberals will demonstrate stronger, more distinctive preferences for short- and long-term mates, relative to conservatives (Prediction 1). Central to this proposition is the prediction that conservatives avoid a distinctive short-term strategy as a mechanism to maintain traditional social norms. In conservative cultures, short-term mating could threaten traditional values, which poses a greater societal risk to conservative than liberal cultures (Roos et al., 2015). To test this assumption directly, we investigated whether an individual's motivation to conserve traditional values promotes convergent short- and long-term strategies. We predicted that adherence to traditional norms should negatively predict the distinctiveness between short- and long-term preferences (Prediction 2).

The proposed theory assumes that similar short- and long-term mate preferences are indicative of a long-term mating bias among individuals from conservative groups. In Study 2, we investigated whether conservatism-liberalism predicts the extent to which individuals over-perceive a mate's suitability as a potential long-term partner. Compared with liberals, conservatives should be less willing to engage in short-term mating with the archetypal one-night stand. That is, when selecting their ideal relationship with a ‘sexy cad’ (Durante, Griskevicius, Simpson, Cantú, & Li, 2012), conservatives should favour longer commitments than liberals (Prediction 3). However, ratings of the archetypal spouse should be unaffected by conservatism; that is, all participants should perceive this mate as an ideal spouse (Prediction 4).

The purpose of our report was to investigate whether conservatives are less prone to demonstrate distinctive short- and long-term sexual strategies, relative to liberals. In Study 1, we examined whether participants from the USA and UK (liberal regions) demonstrated more distinctive short- and long-term preferences than Indian participants (conservative region). We also investigated whether this was associated with a drive to maintain traditional values. Study 2 directly investigated whether conservatives over-perceived a mate's suitability as potential long-term partner.