Cultural Differences in Human Reasoning: Some Philosophical Reflections on Theories and Implications

1. Introduction

Is human nature culturally universal? This question has been posed to the followers of Social Darwinism, which posits Westerners as the fittest in the world. The assumption of human universality has criticized this false theory, which was once used to explain the hegemony of Westerners and to justify colonialism by Western countries. This assumption has been carried forward by the philosophical stance that the human mind is inherently rational and consistent across cultures. In addition, the concept of universality was taken up by twentieth-century psychology [1]. However, it does not always support Social Darwinism when it comes to cultural differences. Rather, some proponents of the universality assumption may have been misled by the idea that all peoples are like Westerners. Criticisms of the universality assumption are summarized by Henrich, Heine, and Norenzayan [2]. They claim that the majority of psychological data comes from WEIRD (Western, educated, industrialized, rich, and democratic) populations. Consequently, it is invalid to make general statements about the human mind based solely on this data, given the evidence for cultural variations in cognition, fairness judgments, cooperation, and other aspects.

Recent cross-cultural research is beginning to move away from the idea of universality and toward a perspective that sees the human mind as shaped by the interaction of culture and individual experience. Cultural differences in human behavior and thinking have been recognized, and it has been suggested that many psychological tasks can be interpreted differently depending on the culture in which an individual is born and raised. Underlying cultural psychology are the ideas of Vygotskians, who emphasized the non-evolutionary nature and mechanism of the development of higher mental functioning. This framework emphasizes the transmission of cultural elements like values, beliefs, customs, and skills from one generation to the next. Every culture has a structure of shared views and values in terms of customs, pragmatics, morals, educational systems and so on. In this sense, culture and the human mind are inseparable. Shweder [3] claimed that no individual mind can be isolated from its culture. He argued that the concept of independence stemmed from the European view of humanity during the enlightenment: The belief was that because humans possess intelligence and rationality, their minds are considered separate from cultural influences.

Evolutionary psychology is occasionally viewed as conflicting with cultural psychology because it tends to focus on human universals and innate traits. Nevertheless, some psychologists who study culture have incorporated evolutionary psychology perspectives [4]. Evolutionary psychology offers a framework for examining how humans adapt within a cultural context and how they develop cultures to address adaptive challenges. The process of adaptation might be consistent across different cultures. As a result, the issue of which aspects of human nature are universal and how universally they apply becomes significant for cultural psychologists as well [5].

According to the interactive view, cultural systems, each of which has a structure of shared views and values regarding customs, pragmatics, morals, educational system, and so on, are created and invented so that people can solve adaptive problems, but once they are established, people have to be adaptive to the given systems. Their minds must be shaped for such adaptation. For example, a moral system may be designed so that people can cooperate well; therefore, this system requires them to obey the moral rules. Furthermore, some argue that a new cultural system may have triggered human genetic evolution [6]. A cultural system may thus be able to shape human biology.

A socio-ecological approach to cultural differences has made it possible to explain the uneven development of the world, including the hegemony of Westerners, without assuming that some people (mostly Westerners) are genetically more intelligent than others. This approach examines how minds and behavior are shaped by their natural and social environments, and how natural and social environments are in turn partly shaped by minds and behavior [7]. For example, Diamond [8] identified specific geographical and ecological factors to account for current cultural differences and aimed to explain why Eurasian civilizations have endured and dominated others without attributing this to any supposed intellectual, moral, or genetic superiority of Eurasian peoples. In short, explanations of cultural differences need not involve ideas associated with Social Darwinism and do not require us to abandon the assumption of universality.

This chapter addresses the issue of cultural differences in thinking and reasoning between Westerners and Easterners. First, we present some pinioning studies on cultural differences in thinking [9] and discuss what kinds of cultural differences can really be confirmed. Next, we examine two types of explanations for cultural differences: one based on different social patterns and self-concepts across cultures, and the other based on different cultural and philosophical traditions. Third, I present an explanation of cultural differences in thinking in the light of the socio-ecological approach [10]. Finally, we show how the explanation can be developed into a socio-ecological theory in line with the adaptation approach.

2. Cultural differences in human thinking

It has been suggested that those who do not receive a Western-style education are less likely to engage in logical reasoning [11]. Although the observed fact that tribal people in Africa are less likely to use deductive rules has not been attributed to a disability in logical ability, some people have accepted this fact as reflecting the glory of Western-style education. However, Medin and Atran [12] compared the performance of ornithologists, American university students and Maya people in reasoning about bird categories and found that the Maya data showed a similar pattern to that of the ornithologists. This does not mean that the differences between ornithologists and American university students are due to professional training in biology, but rather to how people conceptualize living species. Their findings, gathered from standard populations in industrialized societies, are often not generalizable to humanity as a whole.

Similarly, the style of reasoning in which people do not favor logical rules cannot be attributed to deficiencies in Western-style education. Norenzayan, Smith, Kim, and Nisbett [13] found that when choosing which of two groups a target object resembled, Americans typically concentrated on one specific property for categorization, whereas Koreans did not. Americans favored linear reasoning (referred to as “formal” and/or “rule-based” in the original paper), which involved focusing on a single characteristic. In contrast, Koreans preferred similarity-based, nonlinear reasoning (described as “intuitive” in the paper), where they viewed items within a group as sharing a family resemblance.

Instead of the term “Easterners’ intuitive thinking,”, many researchers accept the term “Easterners’ dialectical thinking,” which means that people consider several characteristics or rules based on family resemblance as a key for categorization. In other words, they look at rules dialectically. Similarly, instead of the term Westerners’ rule-based thinking, many researchers accept the term Westerners’ linear thinking. The term “rule” can be understood as a conditional statement like if p then q, so “rule-based” suggests that people use this formal logic for reasoning. However, since Westerners’ thinking patterns do not always align with strict logical reasoning, we use the term “linear thinking” in this chapter instead.

Peng and Nisbett [9] claimed that the thinking of Easterners is dialectical. They found that the thinking style of Chinese people was more dialectical than that of Americans. Compared with Americans, Chinese were less bothered by and more accepting of contradictory proverbs such as “Too modest is half proud,” suggesting a higher tolerance for contradiction and a preference for dialectical thinking. In addition, Peng and Nisbett found that Chinese participants expressed more moderate agreement with two contradictory statements when presented together than when each statement was presented separately. This pattern was not found in the American data. These findings suggest that the Chinese are more likely to take the middle ground when faced with conflicting opinions.

The contrast between Westerners’ linear thinking and Easterners’ dialectical thinking may be related to differences in the tendency to consider more or fewer rules, factors, and properties in thinking and reasoning [14]. It is proposed that Easterners make more situational attributions, whereas Westerners make more dispositional attributions [15, 16]. In Easterners’ dialectical reasoning, the tendency to consider two contradictory possibilities was observed in a cross-cultural study of hindsight bias. Hindsight bias is the tendency, after an event has occurred, to see it as predictable. Yama, Manktelow, Mercier, Van der Henst, Do, Kawasaki, and Adachi [17] confirmed in a study with Japanese, Korean, British, and French participants that hindsight bias was stronger in Easterners than in Westerners [18]. Easterners were more inclined to engage in dialectical thinking when faced with both a plausible and an unexpected outcome in a vignette, while Westerners’ judgments were less affected by the unexpected outcome.

The distinction between the linear thinking of Westerners and the dialectical thinking of Easterners has been interpreted in different ways. Some who still believe in the superiority of Westerners see it as evidence that Easterners are irrational and illogical thinkers. Others believe that dialectical thinking reflects the wisdom of Easterners, which can serve as a way to break through the impasses of contemporary civilization. In general, dialectical thinking focuses on how an individual perceives conflicting concepts to develop a comprehensive point of view. Hegelian dialecticism is the best-known of these forms of thought. Hegel proposed that dialecticism involves deriving a synthesis from a thesis and its antithesis. Consequently, dialecticism aims to achieve a higher-level resolution of conflicting viewpoints. While dialectical thinking embraces contradiction and may appear illogical, it is also viewed as a more advanced form of reasoning that transcends the binary nature of propositional logic.

Spencer-Rodgers, Williams, and Peng [19] suggested that Easterners’ dialectical thinking is neither merely flawed nor illogical nor a form of advanced reasoning, but what they refer to as “naïve dialecticism.” The naive dialecticism of Easterners consists of folk beliefs and is a lay theory that people have acquired through their rich cultural practices. Peng and Nisbett [9] had proposed three principles of naive dialecticism:

1. The principle of contradiction

   Due to the interrelated nature of things and the constantly changing world, paradoxes and contradictions frequently emerge. It is possible for two opposing statements to both be true and apparent opposites may merely be illusions.

2. The principle of change

   The universe is continuously in motion and evolving, so concepts that represent it must also be adaptable. What seems stable is often an indication that change is imminent.

3. The principle of holism

   Nothing exists independently; everything is interconnected.

Paletz, Bogue, Miron-Spektor, and Spencer-Rodgers [20] identified two key differences between Hegelian dialecticism and the naive dialecticism found in Eastern cultures. The first difference concerns the nature of cognitive styles: naive dialecticism is a practical, culturally shaped set of beliefs, whereas Hegelian dialecticism is a philosophical theory with various forms used for different purposes. The second difference pertains to how contradiction is handled. Hegelian dialecticism focuses on creating a synthesized solution to contradictions, while naive dialecticism emphasizes the acceptance and tolerance of contradictions without necessarily seeking to resolve them. In this regard, East Asian philosophy does not aim to resolve contradictions.

The naive dialecticism of Easterners is reflected in their self-concept. Spencer-Rodgers, Boucher, Mori, Wang, and Peng [21] developed a questionnaire, the Dialectical Self Scale (DSS), consisting of 32 items. Their participants were asked if they often agreed with both, when they heard two sides of an argument, for instance. It was designed to measure the individual’s level of naive dialecticism and thus the individual’s ontological worldview, which is either contradictory or consistent. Their finding that DSS scores were higher among Easterners than Westerners supports the claim that Easterners tend to have a more dialectical self-concept compared to Westerners and perceive the world as inherently full of contradictions. This claim is consistent with the finding that Chinese gave more contradictory responses in their self-evaluations than Americans [22]. Chinese respondents’ self-evaluations were both positive and negative, whereas American respondents’ self-evaluations were not.

3. Do Easterners really think dialectically?

Do the cultural differences reported in scientific journals describe what they really are? This doubt arises because psychological differences are sometimes overestimated due to publication bias. Cross-cultural studies that find cultural differences are more likely to be published in scientific journals, while those that do not find cultural differences are less likely to be accepted for publication. As a result, the cultural differences reported by scientific journals are overestimated.

While Peng and Nisbett [9] demonstrated that Easterners are more inclined to adopt a middle way, their finding about Chinese dialectical judgment was only observed when contradictory statements were presented simultaneously. Some studies report that Easterners do not take the middle way when faced with contradictory statements. Mercier, Zhang, Qu, Lu, and Van der Henst [23] replicated Peng and Nisbett’s study with French and Chinese participants but found that neither group adopted a middle way when presented with contradictory statements. Additionally, Mercier, Yama, Kawasaki, Adachi, and Van der Henst [24] discovered that neither French nor Japanese participants chose a middle way when given advice that conflicted with their own views. In other words, both French and Japanese participants maintained their original opinions. Is this because the cognitive style of the French is different from that of other Westerners? We can conclude that this cultural difference is not robust [25].

Furthermore, Friedman, Chen, and Vaid [26] did not replicate Peng and Nisbett’s [9] findings using contradictory proverbs. Their study was designed to confirm Peng and Nisbett’s claim, but both Chinese and Americans preferred dialectical proverbs better to non-dialectical ones and decided dialectical proverbs to be wiser. Their study was designed to control for the effect of poeticism, which possibly covaried with preference judgments. They concluded that the cultural differences identified by Peng and Nisbett were influenced by the poetic quality of the proverbs. Specifically, the Chinese perceived dialectical proverbs as more poetic than non-dialectical ones and thus preferred them. This means that the results found by Peng and Nisbett do not support the idea that Easterners think more dialectically than Westerners.

The cross-cultural study by Zhang, Galbraith, Yama, Wang, and Manktelow [27] was designed to investigate whether cultural differences in cognitive style could be found. They used the DSS questionnaire and counter-attitudinal pairs. They reported that the mean DSS scores for Japanese and Chinese participants were higher compared to those of British participants. This result mirrored the findings of Spencer-Rodgers et al. [21, 22], which indicated that Easterners generally had higher mean scores than Westerners. However, when participants were presented with pairs of opposing opinions and asked to rate their agreement with each opinion, the Japanese and Chinese did not exhibit a greater tendency toward dialectical responses compared to the British. In other words, Easterners were no more likely than Westerners to agree or disagree with both sides of an argument. In summary, while Easterners often believe they agree with both sides when presented with opposing views, this does not necessarily translate into making dialectical choices. On the other hand, our recent cross-cultural study [28] found that Japanese were more dialectical thinkers than the British and French when confronted with opposing religious beliefs such as Hell and paradise are real” and “Hell and paradise are superstitions.” The result is inconsistent with Zhang et al. [27], but suggests that Eastern religious traditions may influence Japanese religious dialectical thinking. we will discuss this further in the next section.

In summary, my tentative conclusions are as follows. First, it is very doubtful that Easterners are more likely than Westerners to take the middle way when confronted with opposing opinions. Rather, Easterners’ dialectical thinking is naive, and thus different from Hegelian dialecticism, and may not include taking the middle way to infer a higher-level resolution. Therefore, the data of Mercier et al. [23, 24] do not provide a counter-example to the naive dialectic of Easterners. Second, it is doubtful that Easterners are more likely than Westerners to agree with contradictory statements, but for religious contradictions, and that Easterners are more likely than Westerners to prefer proverbs with contradictions. Third, however, the results on the DSS consistently support Easterners’ naive dialecticism, so there are certainly cultural differences in individual ontological worldviews. In contrast to Westerners, Easterners are more likely to perceive the world as inherently contradictory and, as a result, often view their thoughts as encompassing both positive and negative elements within their cultural practices.

4. How shall we explain cultural differences in thinking?

Three types of explanations have been proposed for cultural differences in thinking styles, as shown in Table 1. The first is based on the distinction between the individualist culture of Westerners and the collectivist culture of Easterners. It has been argued that Westerners have developed a more individualist culture, while Easterners have developed a more collectivist culture. According to Triandis [29], individualism is characterized by a social pattern where individuals are loosely connected and view themselves as independent from groups such as family, colleagues, tribes, or nations. They are driven mainly by their preferences, needs, and rights, and by the agreements they form with others. They prioritize their personal goals over those of others and focus on rational evaluations of the benefits and drawbacks of interactions with others. In contrast, collectivism is described as a social pattern where individuals are closely connected and see themselves as part of one or more groups. They are primarily motivated by the norms and responsibilities of these groups, are willing to place the goals of the groups above their own personal objectives, and emphasize their connection to other members of these groups.

There are two ways of explaining the link between cultural patterns and thinking styles. The first emphasizes the direct influence of culture on thinking style. Focusing on contradiction, Peng and Nisbett [9] propose that resolving contradictions by finding a middle way is adaptive within a collectivist cultural tradition and has influenced the implicit ontology and epistemology of Easterners. They argue that dialectical thinking serves as a cognitive tool for managing social conflict, which is beneficial in collectivist cultures that value group harmony. In contrast, dichotomous judgments, which aim to avoid contradictions, are less adaptive in such cultures. However, as mentioned earlier, it remains uncertain whether Easterners are indeed more inclined to adopt a middle way compared to Westerners. Therefore, this route of explanation may not be necessary.

The second route is to see thinking styles as an aspect of the distinction between analytic and holistic cognition. The goal of this approach is not specifically to account for the cultural differences between linear thinking by Westerners and dialectical thinking by Easterners, but to propose an account for the distinction between analytic cognition by Westerners and holistic cognition by Easterners. This distinction has been discussed in terms of the contrast between Westerners’ analytic cognition and Easterners’ holistic cognition [30]. Linear thinking is a form of analytic cognition, whereas dialectical thinking is a form of holistic cognition. Analytic cognition involves separating an object from its context, concentrating on the object’s attributes to categorize it, and using category-based rules to explain and predict its behavior. On the other hand, holistic cognition focuses on the overall context or field, considers the relationships between the focal object and its surroundings, and prefers to explain and predict events based on these relationships. In cultures where individuals are required to prioritize group goals, such as maintaining group harmony, people must consider not only the object itself but also its contextual information to uphold harmony within their groups. Dialectical thinking is a form of holistic cognition because people have to consider many situational elements and factors to make a dialectical decision.

Both routes are from a group level (individualism/collectivism) to an individual-level cognitive style. However, as with the second route, Varnum, Grossman, Kitayama, and Nisbett [31] suggested an individual-level explanation linking Westerners’ independent self-concept to analytical cognition, and Easterners’ interdependent self-concept to holistic cognition. According to this perspective, the self-acts as a bridge between culture and cognitive style. In collectivist cultures, Easterners exhibit a greater inclination toward sociability and interdependence compared to Westerners.

The second explanation is based on philosophical traditions. Spencer-Rodgers and colleagues [19, 21, 22] emphasize the influence of philosophical traditions on ways of thinking and ontology: Western (ancient Greek) philosophy and Eastern (ancient Chinese) philosophy. This explanation may coincide with that based on the individualist culture of Westerners and the collectivist culture of Easterners [30], in the sense that Western philosophical traditions have nurtured an individualist culture, while Eastern philosophical traditions have developed a collectivist culture. However, this perspective differs from the individualism/collectivism explanation for two reasons. First, Spencer-Rodgers contends that the difference between linear and dialectical thinking is not the same as the difference in attention between analytical and holistic. Instead, she recognizes that this distinction is related to those manifested in causal inference [16] and the perception of change [32]. In short, the style of thinking that Spencer-Rodgers was concerned with is different from the style of attention. Second, Spencer-Rodgers proposes that this distinction is not closely linked to the individualism/collectivism distinction. This is supported by findings from Spencer-Rodgers et al. [22], which showed that Latinos in the United States, who come from collectivist cultures, did not exhibit contradictory self-views [33]. Therefore, the individualism/collectivism framework does not adequately explain the cultural difference between Western linear thinking and Eastern dialectical thinking.

Spencer-Rodgers et al. [19] assert that linear thinking originated from ancient Greek philosophy, such as Aristotle’s logic, while dialectical thinking emerged from ancient Chinese philosophical traditions, including Taoism, Confucianism, and Buddhism. This dialectical approach is closely linked to the Eastern perspective of a mutable world, influenced by broader beliefs about contradiction and change. Easterners’ naive dialectic and folk beliefs are rooted in the Taoist concept of yin (negative aspects) and yang (positive aspects), which illustrates how opposing forces are interconnected and interdependent in reality. This concept reflects the Chinese ontology that the world is in a constant state of change, oscillating between yin and yang, and is inherently full of contradictions.

This tradition is evident in their reluctance to make hasty final judgments. For example, the well-known story of Sāi Weng’s lost horse, featured in the Huáinánzǐ—a classic Chinese text that integrates Taoism and Confucianism—illustrates this. The story tells of an old man named Sāi who raised horses and faced fluctuating fortunes without making definitive judgments about whether each event was good or bad. This narrative gave rise to a proverb about the reversal of fortune, where bad luck can turn into good and vice versa. Similarly, many classic Japanese tales and essays reflect the folk belief in constant change, emphasizing the absence of permanence and the concept of impermanence. The term ‘impermanence’ embodies the Buddhist idea that all conditioned existence is transient and perpetually in flux, often interpreted as a reminder of the mutable nature of individual life. For instance, Japanese classical literature, the Tale of the Heike, provides examples of this concept. The story tells impermanence of prosperity. The Tale of the Heike depicts the story of the Heike clan which rose to the top of power in the twelfth century but fell within a short time.

Furthermore, this explanation is strongly supported by our findings that the Japanese were more dialectical thinkers than the British and French when confronted with opposing religious beliefs [28]. It is plausible that the dialectical religious beliefs of Easterners have been influenced by the tradition of Taoism and Buddhism, and thus the world view of naive dialecticism has been formed among Easterners.

The third explanation is based on context and communication [10]. Hall [34] proposed the distinction between the high-context culture of Westerners and the low-context culture of Easterners. Context consists of implicit beliefs, such as common sense, that are shared by people and can be used for communication. In high-context cultures, people can understand messages from others without needing detailed descriptions because they share implicit information that aids interpretation. These shared understandings are further supported by established relationships within the group. In contrast, individuals in low-context cultures require explicit verbal communication since they do not rely as heavily on shared implicit knowledge. Consequently, they depend on communication that is direct and explicit. According to Hall, Western cultures are generally low-context, while Eastern cultures are high-context. Thus, the distinction between high-context and low-context cultures can be viewed as a facet of the broader individualism/collectivism distinction [29]. However, this contextual distinction is based on differences in communication practices and language use rather than on data about human relationships. Additionally, the low-/high-context dimension does not always align perfectly with the individualism/collectivism distinction.

Hall [34] did not provide an explanation for the cultural differences between Westerners’ linear thinking and Easterners’ dialectical thinking, but his idea has been extended by Yama and Zakaria [10] to explain the differences in thinking. It is uncertain whether Easterners are actually more likely than Westerners to draw a middle conclusion regarding contradictory opinions, but they may have a stronger tendency than Westerners to hold a view that the world is contradictory. According to their explanation, the norm that contradictions can be resolved through context is likely to be formed in a high-context culture, from which people do not hesitate to see the world as full of contradictions.

The key point is that a low-context situation typically arises when people engage in intercultural communication and interaction [35, 36]. In this regard, Gudykunst [37] suggested that implicit common sense (context) cannot be relied upon in intercultural communication. Individuals are uncertain about how much-shared knowledge exists between them and their interlocutors from different communities. Consequently, explicit, intentional, and careful communication is necessary to achieve mutual understanding in the absence of shared context. Building on the differences in communication between humans and other primates, Tomasello [38] proposed that the evolutionary roots of human communication lie in gestures rather than vocalizations. Early humans relied more on nonverbal communication tools, such as gestures, and could not effectively interpret others’ messages without contextual cues. When common contexts are absent, this form of communication becomes ineffective. The very early human communication is thought to have been in a high-context culture. Thus, with the evolution of language, humans were able to create a low-context culture in which they could engage in explicit communication. Humans have sought clearer and more general rules that can be applied in situations where there is no shared context. General rules are especially necessary when interacting with different cultural groups. Therefore, the tendency to focus on a single property [13] is an adaptive strategy in this situation. This tendency helps people address inconsistencies resulting from changes, which can become more frequent in cross-cultural interactions. Consequently, individuals adapt their ontological views to align with naive dialecticism. This adjustment likely causes Westerners to perceive the world as less fluid compared to Easterners, since viewing the world as changeable complicates the development of a few general rules or principles. Conversely, those in high-context cultures, who share implicit beliefs, can communicate effectively without explicit expressions. Because they have fewer interactions with other cultural groups, they do not require explicit rules or a universal rule for cross-cultural communication. They are more attuned to the inconsistencies arising from various factors and more accepting of these inconsistencies due to their cultural practices, unlike those in low-context cultures. This sensitivity to change and acceptance of contradictions may explain Easterners’ perception of the world as full of contradictions and their preference for dialectical thinking. Additionally, when faced with apparent contradictions, Easterners tend to resolve them more easily using implicit contextual beliefs within their high-context culture.

5. Socio-ecological explanations for cultural diversity

Although we do not reject the explanation based on philosophical traditions [19, 21, 22], what is lacking is an explanation of how these traditions were formed in history. That is, we should know how such philosophical traditions have been formed, accepted, and transmitted by socio-ecological and geographical factors. However, it is beyond the scope of this chapter to fully discuss socio-ecological explanations for each of these traditions, Taoism, Confucianism, Buddhism, and ancient Greek philosophy.

Some socio-ecological explanations have been proposed for the difference between individualist and collectivist cultures, as shown in Table 1. Note that the distinction between individualist and collectivist culture can be linked to a social-ecological approach. For example, Talhelm, Zhang, Oishi, Shimin, Duan, Lan, and Kitayama [39] found that individuals from the southern rice-growing regions of China are more holistic in their thinking and interdependent compared to those from the northern wheat-growing areas, who exhibit less holistic cognition and interdependence. They suggest that the history of rice cultivation fosters greater interdependence in cultures than wheat farming does and that these agricultural traditions continue to influence people in contemporary society. In short, their explanation is based on livelihoods constrained by socio-ecological factors.

We will show that the explanation based on the high/low-context contrast is promising as a socio-ecological theory. As noted above, the basic idea is that a low-context culture typically emerges when people engage in multicultural communication. Context shapes the type of information needed to produce an accurate interpretation of meaning. The absence of any of these three elements - context, information, and meaning - makes it difficult for a high-context culture to work with a low-context culture, and vice versa. It is advantageous for people to develop a low-context culture where relying on context-dependent styles not shared by strangers is minimized, especially when they frequently engage in intercultural communication and interactions [35, 36]. Therefore, a multicultural environment is crucial for fostering a low-context culture, where clear and unambiguous expressions are preferred over those that require extensive contextual information. Further support for this was provided by Rychlowska, Miyamoto, Matsumoto, Hess, Gilboa-Schechtman, Kamble, et al. [40], who found that individuals in countries with high historical (cultural) diversity need to use more explicit facial expressions. Historical heterogeneity refers to how a country’s current population descends from a large number of source countries, which is typically greater in Western nations. They analyzed data from 32 countries, representing both Western and Eastern regions, to examine the explicitness of facial expressions. They reported that explicitness is determined by historical heterogeneity, which is associated with the norm favoring explicit facial expressions. In a historically heterogeneous society, people have less context to interpret others’ facial expressions. Therefore, they need to make explicit facial expressions. Although Rychlowska et al.’s study does not address the distinction between dialectical and linear thinking, the principle that ambiguous expressions are avoided in multicultural settings can be applied to distinctions in thinking styles. Although Rychlowska et al. did not extensively address the low-/high-context distinction, it is evident that shared beliefs (context) are less accessible to individuals in historically heterogeneous—essentially, low-context—cultures. Generally, people in low-context cultures should avoid using ambiguous language and must ensure that their communication is consistent and clear.

So the next step is to identify the factors of multicultural communication. Our ancestors lived in tribal or clan societies where they predominantly used nonverbal communication and developed a high-context culture. However, upon encountering and interacting with different cultural groups, they likely developed a low-context culture. Originally, human culture was highly contextual in a self-sufficient society where there was much less need to interact with other cultural members. We point out two necessary conditions for a low-context culture. The first condition is a multicultural environment, as has been mentioned repeatedly. This notion is possibly consistent with the socio-ecological approach, since many socio-ecological factors form the multicultural environment. For instance, if there is an unbalanced distribution of resources (e.g., edible livestock, natural resources, etc.) among different social groups, if they can move to obtain distant resources (by foot, horseback, boat, etc.), and if different groups are not hostile to each other, then multicultural interactions involving cross-cultural communication will be widespread and likely to form a multicultural environment. It is then adaptive for people to create a low-context culture because they do not share much context. Intercultural interaction also occurs in times of human migration, as most human migration is caused by socio-ecological factors such as climate change, which may cause famine. However, if the groups are hostile to each other, it is unlikely that a low-context culture will develop even in this multicultural environment, and the interaction will result in war. Interaction is likely to be hostile when trade is a zero-sum game rather than a win-win game.

Even when people form a low-context culture, some negative factors prevent such a development and restore a high-context culture. The key factor is that if various cultural groups come together and form a unified monocultural group through interaction, it is highly probable that they will revert to a high-context culture. Thus, a second requirement for maintaining a low-context culture is that people do not merge into a single monoculture. This unification is more likely to occur when one cultural group holds more power and exerts influence over the others. Geographic and ecological factors can also play a role in this process. For instance, if cultural interactions occur in expansive plains with large rivers, it is likely that distinct cultural groups will blend into larger, more homogeneous cultural groups. This explains how the philosophical traditions that have been used to explain cultural differences between the linear thinking of Westerners and the dialectical thinking of Easterners were formed in history. Ancient Greece is a typical place that fulfills both conditions. It consisted of small, loosely connected, not unified city-states among which there was extensive trade and interaction. Although there were some conflicts between the cities, they needed to trade with each other because none of the cities formed a self-sufficient society. For example, the level of food self-sufficiency in Ancient Athens was low; Ancient Athens could not produce enough food for its people. It is not certain whether Ancient Greece had a low-context culture, but we do know that the Greeks created logic, which is a set of rules for resolving contradictions. This is in stark contrast to the case of ancient China, which developed on a vast plain with large rivers that nourished the philosophical tradition of dialectic. Although there were several countries on the North China Plain before the third century B.C., these countries were united into one under these ecological conditions. The Han Chinese, who resided in the plains, emerged as the dominant cultural group in China. Consequently, despite interacting with surrounding ethnic groups, most of these groups were assimilated into Han Chinese culture. In this way, in spite that the Chinese had the opportunity to develop a low-context culture, they maintained a high-context culture. This may explain how the tradition of logic was developed in Ancient Greece and the tradition of Taoism and Buddhism was nurtured in ancient China.

As mentioned above, a socio-ecological approach to cultural differences is expected to provide explanations for this uneven development around the world without introducing the idea that some people are genetically more intelligent than others. This means that this approach is one of the recipes for reducing peoples prejudices against those who live in undeveloped areas [41]. In fact, there is little difference in IQ between people [42]. Therefore, the explanations for the uneven development of civilization worldwide, without recourse to the concept of intellectual ability, are consistent with the empirical evidence. Initially, the term “big history” described an academic field that examines history from the universe’s “big bang” to the present day. However, the term is in use in the fields of psychology and anthropology to focus on human evolution and cultural development from the time of the earliest humans to the contemporary world. The migration of Homo sapiens out of Africa some 60,000 years ago begins the great story of how modern cultural diversity developed. This approach has brought outstanding works on explaining cultural diversity and how contemporary civilizations developed [43].

There are still more facts that we do not know than those that we do know about how each culture has been shaped and how cultural diversity has emerged in human history. Psychologists should join research teams of historians, archaeologists, sociologists, and economists to describe the exact process in the grand scheme of history. Cultural diversity is a consequence of the human struggle for survival and prosperity. Diamond [8] sought to account for cultural diversity through ecological and geographic factors, specifically addressing why Eurasian civilizations have endured and expanded while challenging the notion that Eurasian dominance stems from intellectual, moral, or genetic superiority.

However, this approach has been criticized by those who focus on institutions or cultural products [44]. For example, Acemoglu and Robinson [45] argue that political institutions are the strongest factor responsible for the political and economic success or failure of states. Political institutions can be seen as one of the products of culture invented to solve an adaptive problem (adaptation to the ecological environment) in the interactive view of the adaptation approach. However, once an institution is established, it constrains how people think and behave. Thus, it becomes more important for people to adapt to the institution than to the original ecological environment. Similarly, Henrich [46] emphasizes the importance of Western Christianity, which has led to the decline of close kinship, making Westerners more individualistic than other peoples. Western Christianity may be a consequence of peoples adaptation to the ecological environment, but it has become more influential on human thinking and behavior than ecological factors. The acceptance of Buddhism and Taoism by the Japanese may be a result of adaptation. However, the results of our study [28] suggest that Japanese dialectical thinking has been strengthened by Buddhism and Taoism, which have inherent dialectic, in addition to their adaptive purpose.

6. Conclusion

After introducing the distinction between Westerners’ linear thinking and Easterners’ dialectical thinking, we present three explanations for cultural differences: the distinction between Westerners’ individualistic culture and Easterners’ collectivist culture, philosophical tradition (ancient Greek philosophy and ancient Chinese philosophy), and the distinction between Westerners’ low-context culture and Easterners’ high-context culture. The third explanation is promising to be developed into an interactive view of the adaptation approach, which holds great promise for providing socio-ecological explanations for cultural differences and for contributing to the development of the big history approach. The explanation of cultural differences in thinking discussed in this chapter may be one such socio-ecological explanation, and thus one of the big pieces of big history. We should recognize, however, that there are some critics of the socio-ecological approach, which places too much emphasis on ecological and geographical factors in explaining cultural diversity.

Conflict of interest

The author has no competing interests to declare that are relevant to the content of this article.

Funding

This research has been supported by a grant-in-aid from the Japanese Society for the Promotion of Science (No. 21KK0042).