It is commonly recognized that it is good to smile—Louis Armstrong sang that when you smile the world smiles with you, and various trainers and guidebooks advise smiling because it improves interpersonal communication. These lay beliefs are supported by numerous studies demonstrating that smiling individuals are perceived as happier (Otta et al. 1994), more attractive, communal, competent (Hess et al. 2002; Matsumoto and Kudoh 1993), likable (Palmer and Simmons 1995), approachable, and friendly, and that a smile from another promises a safe and satisfying interaction (Miles 2009).

Cultures may shape different scripts for social behavior and as a consequence, different logics of nonverbal behavior and its social perception (Matsumoto 2006; Leung and Cohen 2011). In the past few decades, increasingly more psychological research has been carried out in non-WEIRD (Western, Educated, Industrialized, Rich, and Democratic; Henrich et al. 2010) societies indicating difficulties to replicate results from psychological experiments across cultures (Smith et al. 2013). Although psychologists broadly recognize the interrelationship between culture and behavior, and the sub-discipline called cross-cultural psychology is flourishing, interactions between culture and social perception of nonverbal behavior still remain understudied. One example of this lack of cross-cultural study is the assessment of cultural variation of traits attributed to smiling individuals that goes beyond East–West cultural comparisons (Hess et al. 2000). Rychlowska and collaborators (2015) were among the first to address this pointing to the importance of heterogeneity versus homogeneity of cultures in predicting the endorsement of smiling.

Although numerous studies confirm that positive perceptions of smiling individuals seem to be universal, anecdotal evidence suggests that in some cultures the opposite may be true. For example, a well-known Russian proverb says ‘Улыбкa, бeз пpичины - пpизнaк дypaчины’ (smiling with no reason is a sign of stupidity). The Norwegian government humorously explains nuances of Norwegian culture by indicating that when a stranger on the street smiles at Norwegians, they may assume that the stranger is insane (EURES 2010). British authors of a popular guidebook about Poland warn tourists that smiling at strangers is perceived by Poles as a sign of stupidity (Bedford et al. 2008). Even Darwin (1872/1998) wrote about “the large class of idiots who are … constantly smiling” (p. 199).

Previous studies have tested this counterintuitive phenomenon in different countries (Krys et al. 2014, 2015). However, these studies included only a small number of cultures (seven) compared to the much broader cross-cultural experiment reported here, which was conducted in 44 cultures. Cross-cultural comparisons involving that many different cultures allow for multilevel and country-level analyses, and are necessary to reliably identify cultural factors that are related to the differential social perception of the most often encountered facial expression, viz., the smile.

Meanings Attributed to Smiles

Smiles are highly diverse in their types and in their possible meanings. They are used to communicate a range of different psychological signals, including positive emotions, social intentions, or a person’s social status (Matsumoto and Willingham 2009). Past research has offered a number of distinctions among smiles. The utility of one of the most popular distinctions, viz. Duchenne versus non-Duchenne smiles (Duchenne 1862), has been recently questioned because there is evidence that the use of the Duchenne marker of a ‘true’ smile is not universal, but rather limited to certain cultures (Abe et al. 2002; Thibault et al. 2012). In their simulation of smiles model, Niedenthal et nl. (2010) focus on the perception of smiles and suggest that the distinction between Duchenne and non-Duchenne smiles may be largely superseded by a distinction based on the functions of smiles, which may be derived from (and mapped onto) identifiable brain systems that represent different meanings of smiling.

Niedenthal et al. (2010) describe three types of smiles that have important and discrete functions, namely, enjoyment, affiliative, and dominance smiles. Humans (and some other primates) smile spontaneously during experiences of pleasure or success (Ekman 2009) and this expression is called the enjoyment smile. Affiliative smiles are those that signal positive social intentions and are essential for the creation and maintenance of social bonds; personal enjoyment does not have to accompany affiliative smiles. The third group of smiles—dominance smiles—reflect social status or control, and may include scheming smiles, critical smiles, and proud smiles which have different physical attributes than affiliative and enjoyment smiles (Niedenthal et al. 2010). Chang and Vermeulen (2010) claim that affiliative and enjoyment smiles cannot be discriminated from each other on the basis of physical markers—their meaning may be derived only from contextual information. Rychlowska and collaborators (2015) delivered evidence that the above distinctions may be cross-culturally identified, and documented that heterogeneity and homogeneity of cultures (i.e., the extent to which a country’s present-day population descended from migration from numerous vs. few source countries over a long period of time) may predict the endorsement of affiliative and dominance smiles, respectively.

The present research focuses on the attributions given to affiliative and enjoyment smiles presented in still photographs in order to uncover the cultural variation of meanings attributed to the most commonly expressed smiles. Limiting the scope of the current research in this way avoids the problems related to differences in cultural scripts that may influence the attributions to dominance smiles. We examined perceptions of honesty and intelligence attributed to smiling individuals because these traits reflect the big two of social perception (Abele and Wojciszke 2013; Bakan 1966). Among academic psychologists, there seems to be a consensus about two fundamental dimensions of social judgments, though these basic dimensions are named differently and have slightly different meanings. For example, Abele and Wojciszke (2014) call them agency and communion, whereas Fiske et al. (2006) use the labels warmth and competence. These dimensions reflect the logic of evolutionary pressure and help us determine whether ‘others’ are friend or foe (communion/warmth/honesty) and whether ‘others’ have the ability to enact their friendly or hostile intentions (agency/competence/intelligence).

Cultural Predictors of Smile Perception

Descriptive accounts of general cultural differences have been available for a long time, but empirical assessments of cross-cultural variability have only emerged relatively recently (Hofstede 2001; House et al. 2004; Leung and Bond 2004). In our research we tested two predictions related to cultural variation. First, we tested the relation between cultural uncertainty avoidance (UA; House et al. 2004) and the social perception of smiling versus non-smiling individuals with regards to intelligence. Societies that rank high on UA socialize their members to alleviate the unpredictability of future events, whereas in societies that rank low on UA, the future is judged to be relatively unpredictable and there are fewer societal guidelines on how to behave (House et al. 2004). As argued elsewhere (Krys et al. 2014), in cultures low on UA, social conditions are regarded as uncertain, so expressing certainty through smiling (Hareli and Hess 2010) can be perceived as inconsistent behavior and people who exhibit inconsistency may be evaluated as unintelligent (Weisbuch et al. 2010).

The second hypothesis tests whether ‘corruption corrupts smiling’. We predicted that the more corrupt a society is, the less trust should be granted to a smile. On the one hand, a smile is the most common signal of positive intentions. In fact, a smile conveys a message that even a newborn baby understands and infants start smiling as early as 3 months old (Wörmann et al. 2014). The smile is perhaps the most commonly observed affiliative signal (Méhu and Dunbar 2008). A smile facilitates the establishment and maintenance of social bonds, and helps to coordinate social interactions (Fridlund 2002). All the above suggest that smiling evolved as a universal signal of honesty and functions as a social glue (Centorrino et al. 2015). On the other hand, this social glue may be counterfeited without difficulty because smiling is a signal that can be easily produced (Méhu 2011). In particular circumstances, some smiles may be expressed to benefit the signaller and may be deceptive (Ekman and Friesen 1982).

Therefore, we predicted that the ease of producing a smile may in some conditions lead to lower trust in this signal and one of the pre-conditions of scepticism about a smile’s honesty is excessive corruption in society. In highly corrupt societies, individuals are exposed to relatively frequent unfair or untruthful behaviors and, thus, scepticism about the positive intentions underlying a smile may be well-grounded and justified. Hence, in our second hypothesis we offer the novel prediction that the higher the corruption index of a country, the more smiling individuals will be perceived as dishonest. In other words, we empirically tested whether ‘corruption corrupts’ the evolutionary social glue of the smile.

Past research has shown that social judgements of smiling and non-smiling individuals may also be affected by gender-related expectations (Hess et al. 2009). Gender stereotypes and beliefs about emotional expressiveness can lead to different standards when men and women evaluate the nonverbal behavior of other men and women (Krumhuber et al. 2007). Women tend to smile more than men (LaFrance et al. 2003; Hall 1984) and there is a greater expectation for them to do so (Brody and Hall 2008). Therefore, the gender of the assessor and poser were included as control variables in all analyses. The contributions of these control variables will be reported, though a detailed discussion of this contribution is beyond the scope of the current paper.