A series of systems impact the development of individual personality. The microsystem, such as the family, is the innermost system that gives children their first direct, personal, formative experiences (Bronfenbrenner, 1979). Although other systems such as exosystems (e.g., parents’ workplaces) and macrosystems (e.g., cultural contexts), also play a role by influencing the microsystems, studies have mainly focused on microsystem influences. For example, Sulloway, 1996 and Sulloway, 2001 focused on the family microsystem by showing that birth order is associated with personality traits through sibling competition over parental resources. Many new but inconclusive findings have dealt with Sulloway’s theory, which integrated evolutionary perspective into personality psychology (e.g., Beer and Horn, 2000 and Paulhus et al., 1999).
Regarding the birth order effect, Sulloway (1996, pp. 23 and 99) also suggested future research should examine only children as a control group outside the influences of sibling competition. However, in most cultures, only children are rare. Their families are usually unique in that the parents are likely to be more highly educated or to be single parents (Falbo, 1982). Consequently, past research has usually excluded only children (Beer and Horn, 2000, Dixon et al., 2008, Healey and Ellis, 2007, Marini and Kurtz, 2011, Michalski and Shackelford, 2002 and Paulhus et al., 1999) or has categorized them as firstborns (Jefferson, Herbst, & McCrae, 1998, Studies 2 & 3; Sulloway, 1996). In contrast, China has a unique macrosystem in that its national policy has created an unusual default situation in which only children are the norm. Following an ecological systems framework (Bronfenbrenner, 1979) and echoing other researchers (Falbo and Poston, 1993 and Mancillas, 2006), we argue that in China the birth order effect, which is based on the microsystem (i.e., family), may demonstrate different patterns.
In addition, the birth order effect may be found in domains beyond personality such as the relationship between birth order and life satisfaction. For example, research has shown middleborns to be less religious than firstborns (Saroglou & Fiasse, 2003). Thus we examined whether the same effects would hold true in China.
1.1. Personality, life satisfaction, birth order, and China’s one-child policy
In 1979, China instituted its one-child-per-family national policy to counter the negative effects of overpopulation. In 2002, the policy was consolidated as the Population and Family Planning Law. Each province formulates the regulations. For urban families, exceptions are families that have disabled firstborns, that have adopted a child because of previously diagnosed infertility, that have parents who were both onlyborns, that are blended families in which one parent has no biological offspring, and that have parents who were previously permanent residents or citizens of another country or area. In addition to these exceptions, some rural families may have another child, depending on their locations, professions, firstborn gender, and duration after the birth of the firstborn. For those families who do not meet any of the exceptions and choose to have only one child, they are rewarded with benefits such as bonuses and housing privileges. The policy has drastically altered Chinese family structure. Now members of most urban populations under 30 years-old are only children. Both laypersons and experts have expressed concerns about their social development.
Regarding social development, the few existing studies have suggested that only children are comparable to sibling children in most aspects (Falbo, 1982 and Mottus et al., 2008). For instance, Polit and Falbo’s (1987) comprehensive meta-analysis across various age groups, mainly high school students, found the only difference was that only children were more highly motivated to achieve than were sibling children. However, studies in China were inconclusive. Some found no difference in the personality traits important in Chinese traditional culture (e.g., being cooperative) among only, firstborn, and laterborn preschool and school-aged children (e.g., Falbo and Poston, 1993 and Poston and Falbo, 1990) and general personality traits among college students (Edwards et al., 2005). Others found that sibling individuals reported more neuroticism–anxiety and aggression–hostility, but higher psychological well-being than onlyborns (Wang, Du, Liu, Liu, & Wang, 2002). The finding of greater psychological well-being among sibling children is counterintuitive considering that they encounter social and economic penalties. In addition, it is inconsistent with another study, which found that Hong Kong Chinese only adolescents, including migrants from mainland China, had greater psychological well-being (Kwan & Ip, 2009). Thus we feel a need to clarify the issues of personality and life satisfaction among Chinese individuals with different birth orders.
