1.1. Social class and prosociality
Social class (SC) has a multifaceted structure consisting of both objective characteristics1, such as material wealth and access to resources, and subjective perception2 of one's position within the social hierarchy3. Since 2010, individuals with high SC have been reported to be selfish, to be self-centered, and to have low prosociality4,5. The most famous study was a series of experiments by Piff et al.5, who reported that individuals with high SC - measured in terms of subjective measures and objective measures such as income and education - were less likely to engage in a variety of prosocial behaviors. The study showed that individuals with high SC did not give points that would later be exchanged for money to anonymous partners in the dictator game, did not prefer to donate to charity, did not give points to assigned strangers in the trust game, and did not help experimental partners in need more than individuals with low SC.
Furthermore, the results showed that people with high SC were not only less likely to engage in prosocial behavior but also more likely to engage in a variety of unethical selfish behaviors6,7. As a representative study, a series of experiments by Piff et al.7 revealed that people with high SC, as measured mainly by subjective indicators and objective indicators such as owning vehicles, were more likely to break the law while driving, steal valuable goods from others, lie in negotiations, commit fraud to increase the likelihood of winning prizes, and take unethical actions in the workplace (increase sales by, for example, making personal long-distance calls at work or overcharging customers) than people with low SC. Other studies showed that people with a high SC, in contrast to those with a low SC, had a lower characteristic score for compassion8; inaccurate emotional reasoning related to others9; more behaviors that indicate a lack of attention to others, such as playing with one’s hands and doodling when interacting with strangers10; and a tendency to engage in humor to control others11.
However, the results from Piff et al.5,7, a representative study showing low prosociality in people with high SC, have often not been supported by subsequent replication studies. Korndörfer et al.12 found that people with a high SC (measured by subjective indicators and objective indicators such as income and education) were more charitable, helpful, and likely to volunteer than those with a low SC and were more cooperative in trust games in a large and representative international sample. To test whether the findings reported by Piff et al.5,7 could be reproduced, preregistered exact replication studies were performed by Stamos et al.13 and Balakrishnan et al.14. However, the relationship between SC and prosocial action and unethical action was not reproduced; rather, the individuals with high SC carried out prosocial action more often, and unethical action was not carried out. In addition, many studies15–18 have shown results that conflict with those of Piff et al.5,7, and in recent years, the finding that people with high SC are more social than those with low SC appears to have become dominant. Thus, the findings of representative studies showing low prosociality in people with high SC5,7 have been rejected, raising questions about the reliability of the findings on the association between SC and other indicators associated with prosociality (e.g., dominant humor and compassion).
In the current study, we focused on the relationship between SC and humor and introduced a new hypothesis by theorizing their association from a different perspective from those considered in previous studies. The objective was then to test the hypotheses by examining the relationship between humor and people's SC as assessed by objective (i.e., income and educational attainment) and subjective (i.e., perceived social status) indicators.
Martin et al.19 conceptualized humor as a multidimensional structure with both adaptive and maladaptive components. The theory distinguishes between two adaptive types of humor (affiliative and self-enhancing humor) and two maladaptive types (aggressive and self-defeating humor). Those with high affiliative humor are more likely to be other-oriented and to tell jokes to entertain others and develop interpersonal relationships, while those with high self-enhancing humor are more likely to maintain a humorous view of life even in adversity. People with high aggressive humor tend to use sarcasm and teasing frequently to dominate others, and people with high self-defeating humor tend to use humor directed at themselves excessively to gain approval from others. Martin et al.19 developed an instrument, the Humor Styles Questionnaire (HSQ), to distinguish and assess these four types of humor, and the HSQ is the most widely used instrument in research on individual differences in humor20.
Recently, Tsukawaki and Imura21 pointed out a problem with the self-defeating humor scale, a subscale of the HSQ. This scale measures individual differences in the use of self-directed humor (SDH), but it focuses only on its inappropriate dimension. However, Tsukawaki and Imura21 argued that famous theorists of the past22,23 and contemporary researchers24,25 have emphasized the adaptive aspect of SDH. Adaptive SDH relates to humor to distance oneself from the problems one is facing and to downplay stressful events. This type of SDH can address fears and anxieties arising from problems in a positive way by allowing the individual to laugh at the problems faced. Along these lines, Tsukawaki and Imura21 developed the Dual Self-Defeating Humor Scale (DSDHS), the first instrument to assess individual differences in SDH use from two dimensions, positive and negative. Initial validation of the DSDHS has provided promising evidence of reliability and validity21,26.
1.3. SC and humor
Navarro-Carrillo et al.11 examined the association between humor and SC assessed by subjective indicators and objective indicators such as income and educational attainment. In their study, they hypothesized that SC is negatively correlated with affiliative humor and positively associated with aggressive humor based on theories that emphasize the self-centered and selfish tendencies of people with high SC27,28. The results on SC and aggressive humor support this hypothesis and show that people with high SC engage in selfish and controlling humor. However, given the relatively small sample size of this study (N = 156 for Study 1 and N = 201 for Study 2) and the recent rejection of representative studies5,7 revealing low prosociality in those with high SC, the reliability of this hypothesis and result is questionable. Furthermore, research findings that individuals with high SC are less aggressive29,30 also call into question this hypothesis and the results. Therefore, we propose a new hypothesis regarding the association between SC and humor from a health behavior perspective.
Health behavior comprises the behavior patterns, actions and habits that relate to health maintenance, health restoration and health improvement31. There are many actions that can be classified as impacting health, such as smoking, diet, exercise, and alcohol use. The relationship between SC and health behaviors is an active research topic, and researchers have generally agreed that people with high SC are more engaged in healthy behaviors (e.g., physical activity, healthy diet) and less engaged in unhealthy behaviors (e.g., smoking, early sexual activity)32–38. The HSQ and DSDHS, which are instruments for assessing an individual's humor, were developed to focus on the type of humor that is thought to be most associated with an individual's well-being19,21. Subsequently, the HSQ was widely used in hundreds of studies to examine its association with health indicators; a meta-analysis by Schneider et al.39 summarized the relationship between the HSQ and health and found that, in general, affiliative humor and self-enhancing humor are adaptive and aggressive humor and self-defeating humor are maladaptive, supporting the initial findings40. The DSDHS is an instrument that was only recently developed, but to date, it has shown promising results, with deleterious SDH being detrimental to psychological health and benign SDH being beneficial21,26. Therefore, humor, as assessed by the two scales, can be considered a health behavior because of its well-established link to health. Again, given that people with high SC engage in healthier behaviors and less unhealthy behaviors, we argue that high levels of SC are positively correlated with adaptive humor and negatively correlated with maladaptive humor.
1.4. Present study
The current study proposes and tests a new hypothesis about the relationship between SC and humor: previous research on SC and humor11 was limited to using only some subscales of the HSQ (affiliative and aggressive humor) to assess individual humor. We considered four types of humor as measured by the HSQ and two types of humor as assessed by the DSDHS to broadly capture the multidimensional structure of humor. Of the four types of humor assessed by the HSQ, adaptive humor (affiliative and self-enhancing) is positively associated with psychological and physical health, while maladaptive humor (aggressive and self-defeating) is associated with the opposite pattern19. Therefore, we proposed the following hypotheses about the relationship between SC and HSQ:
There is a positive association between SC and adaptive humor (affiliative and self-enhancing) as measured by the HSQ.
There is a negative association between SC and maladaptive humor (aggressive and self-defeating) as measured by the HSQ.
Next, among the two types of SDH assessed by the DSDHS, benign SDH has been shown to be positively associated with psychological health, while deleterious SDH has been shown to be negatively associated with psychological health21,26. From this, we formed the following hypotheses between SC and DSDHS:
There is a positive association between SC and benign SDH.
There is a negative association between SC and deleterious SDH.
In Study 1, we tested our hypotheses by measuring individual SC by an objective measure, household income. In Study 2, which was conducted to extend Study 1, SC was measured in a multidimensional way from the objective measures of household income and educational attainment and the subjective measure of one's perceived social status to test the hypotheses.