The social construction of birthdays: There are many fewer modern U.S. births than would be expected on Christmas Day; in addition, modern parents appear to use birth medicalization to avoid undesirable birthdays (Friday the 13th)

Identity Selection and the Social Construction of Birthdays. Brett W. Pelham et al. Front. Psychol., October 26 2021. https://doi.org/10.3389/fpsyg.2021.693776

Abstract: We argue that rather than being a wholly random event, birthdays are sometimes selected by parents. We further argue that such effects have changed over time and are the result of important psychological processes. Long ago, U.S. American parents greatly overclaimed holidays as their children's birthdays. These effects were larger for more important holidays, and they grew smaller as births moved to hospitals and became officially documented. These effects were exaggerated for ethnic groups that deeply valued specific holidays. Parents also overclaimed well-liked calendar days and avoided disliked calendar days as their children's birthdays. However, after birthday selection effects virtually disappeared in the 1950s and 1960s, they reappeared after the emergence of labor induction and planned cesarean birth. For example, there are many fewer modern U.S. births than would be expected on Christmas Day. In addition, modern parents appear to use birth medicalization to avoid undesirable birthdays (Friday the 13th). We argue that basking in reflect glory, ethnic identity processes, and superstitions such as magical thinking all play a role in birthday selection effects. Discussion focuses on the power of social identity in day-to-day judgment and decision-making.

General Discussion

The studies in this report attest to the powerful role intuitive beliefs play in people's preferences for their children's birthdays. They suggest, for example, that basking in reflected glory, superstitious thinking, and the pragmatic goals of health care providers all influence preferences for a real-world outcome, namely a child's date of birth. The finding that birthday selection effects are larger than usual for more important holidays suggests that parents long ago engaged in motivated social cognition or even outright fabrication when recalling their children's dates of birth. This finding, combined with the aversions we have found here and elsewhere for undesirable birthdates, suggests that birthday selection is not simply a matter of memorial accessibility. For example, modern parents clearly avoided giving birth on the 13th of the month. These were actual birthdays rather than remembered birthdays. These findings strongly suggest that parents themselves play at least some role in birthday selection effects. The aversions to certain dates we have observed here and elsewhere suggest that there is much more to birthday selection than simple memorial accessibility.

The naming patterns observed in Study 1 strongly suggest that at least some parents try to help their children bask in the reflected glory of famous people—rather than simply misremembering salient dates as their children's dates of birth. Future research should try to dissect impression management processes and magical thinking processes as separate explanations for the effects document here. Given how robust birthday selection effects are, it would be surprising if a single mechanism were responsible for all cases of birth date selection. Many social preferences are overdetermined.

Limitations of this Research

Many of the studies in this report are open to more than one interpretation. For example, even showing that some parents gave their children names such as “George Washington Johnson” does not guarantee that all parents who chose this birthday for their children were trying to bask in reflected glory. Likewise, most of these studies cannot tell us exactly which parents falsely claimed desirable birthdays and which ones reported birthdays accurately. Further, we assume that more than one psychological mechanism is likely to be at the root of the preferences documented here. Along similar lines, we did not present any evidence that magical thinking played a role in any of these preferences. To address this concern, Pelham and von Hippel (2021) directly asked both parents and college students whether they endorsed “magical” beliefs about birthdays and holidays. These preliminary studies show that people clearly believe that others expect children to possess the traits associated with certain holidays. For example, people report that they believe most Americans think that a child born on Christmas Day will be perceived as “holy” and “generous” —whereas a child born on September 11th will be perceived as “evil” and “Anti-American.” Respondents even concede that they themselves endorse such beliefs—although to a weaker extent than they think such beliefs are endorsed by others. Magical thinking appears to be at least part of the reason for the preferences documented here. But this reinforces the fact that the present studies could not definitively identify the exact mechanisms responsible for the birthday selection effect.

Future research might also assess whether birthday selection in our older data is grounded in (a) motivated memory biases (ranging from self-deception to “judgment calls” that happen when children are born in very close proximity to midnight), or (b) consciously calculated fabrications. Illusory beliefs that portray us and those we love in a favorable light appear to be both more satisfying and more convincing to others when we truly believe them ourselves (Murray et al., 1996; Von Hippel and Trivers, 2011). But it is surely reasonable to assume that some of these parents consciously claimed a desirable birthday for their children. And if some of these parents lied about their children's birth dates, one must ask why they did so. Our findings suggest that at least some of these parents may have felt their children would benefit from basking in the reflected glory of a famous person or event. It is less clear that an obvious fabrication of a child's birth date could allow parents themselves to conclude that their child was especially holy. Magical thinking probably works best among people who personally buy into the relevant association. However, as Von Hippel and Trivers (2011) have argued, the line between self- and other deception is much fuzzier than most people assume. People who are able to convince themselves that a fabrication is true may well have an easier than average time convincing others.

Do our results reflect “cherry picking”? When researchers are able to study entire populations rather than convenience samples, and when they are able to examine every possible operationalization of a variable (as one can do with U.S. holidays but not with variables such as “self-esteem” or “cognitive dissonance”), concerns about “cherry picking” and “researcher degrees of freedom” are largely ruled out. Of course, one can always open the conceptual net—by examining the cross-cultural generality of an effect, for example. This is exactly what some members of this research team are currently doing. Whatever one's perspective, the findings reported here pave the way for critics who might wish to disconfirm our hypotheses. For example, the Social Security Death records examined here are freely available at ancestry.com. Thus, it would be possible to see how robust any one of these holiday biases is across the 50 U.S. states—or to see if these biases vary with cultural variables such as collectivism (see Vandello and Cohen, 1999). Our initial analyses suggest that cultural variables do matter. Both the pro-Christmas bias of yesteryear and the preference for July 4th birthdays were stronger than average in more collectivistic U.S. states. The Christmas Day preference was also much stronger than average in more religious U.S. states. As a final example, researchers could manipulate well-studied self-concept motives in the lab (e.g., using self-affirmation vs. self-concept threat manipulations) to examine the effects of such manipulations on the birthday preferences examined here.

One surprising aspect of our findings in Study 4 is that birthday number effects (e.g., the 11th vs. the 12th of the month) were so large in the 1890–1910 window that they introduced some noise into the assessment of some of the 10 specific holidays we examined in Study 1. In principle, one could ipsatize (i.e., proportionalize) the 31 days of the month during a given historical period to reduce noise when creating effect sizes for the holidays in the same exact window. Of course, these ipsatized scores would need to be calculated separately for different temporal windows, making this task a bit more complex than it would be otherwise. Having said all this, our supplemental analyses (e.g., those comparing claimed birthdays on the 25th of December vs. the 25th of other months) do make it very clear that holiday effects are not merely calendar day effects—or day of the week effects—in disguise. It is also possible that different psychological mechanisms underly the subtle preferences for certain calendar days and the preferences for specific holidays. It is not clear, for example, whether any parents would ever expect their children to bask in the glow of the likable number 14.

Of course, arguments such as these rest on the assumption that a person's birthday can be a part of a person's identity. Is this true? Research suggests so. Most people strongly like their birthday numbers (Kitayama and Karasawa, 1997). Further, many researchers have incorporated liking for one's birthday numbers into measures of implicit self-esteem (DeHart et al., 2006). In principle, any letter, number, or symbol that is associated with a person can become a part of a person's identity. Former professional athletes Reggie Jackson and Wayne Gretsky even incorporated their uniform numbers into their signatures (Armstrong, 1986). Of course, fans of famous athletes often advertise their psychological connection to such athletes—and to the teams for which the athletes play—by wearing copies of the jerseys of famous athletes. Symbols and events that are connected to us and to the groups to which we belong truly become a part of us. Finally, even if most people were not highly invested in their birthdays, those who believe that their birthday is special—because it doubles as a widely adored holiday—might be expected to identify more strongly than average with their birthdates.

These findings attest to the power and pervasiveness of both identity and magical thinking. We have long known that human beings care deeply about their identities (James, 1890; Cooley, 1902; Mead, 1934), including the ethnic, religious, and cultural groups to which they belong. The present findings suggest that parents are keenly aware of the subtle ways in which people can derive a sense of value or worth by merely sharing a birthday with a person who is deeply valued or respected by most others. Likewise, taken together, these studies strongly suggest that magical thinking is alive and well in the distortion and creation of children's dates of birth. For well over a century, U.S. parents have apparently gone to great lengths to create happy birthdays for their children.