Hohm, I., O’Shea, B. A., & Schaller, M. (2024).
PNAS, 121(33).
Abstract
Moral values guide consequential attitudes and actions. Here, we report evidence of seasonal variation in Americans’ endorsement of some—but not all—moral values. Studies 1 and 2 examined a decade of data from the United States (total N = 232,975) and produced consistent evidence of a biannual seasonal cycle in values pertaining to loyalty, authority, and purity (“binding” moral values)—with strongest endorsement in spring and autumn and weakest endorsement in summer and winter—but not in values pertaining to care and fairness (“individualizing” moral values). Study 2 also provided some evidence that the summer decrease, but not the winter decrease, in binding moral value endorsement was stronger in regions with greater seasonal extremity. Analyses on an additional year of US data (study 3; n = 24,199) provided further replication and showed that this biannual seasonal cycle cannot be easily dismissed as a sampling artifact. Study 4 provided a partial explanation for the biannual seasonal cycle in Americans’ endorsement of binding moral values by showing that it was predicted by an analogous seasonal cycle in Americans’ experience of anxiety. Study 5 tested the generalizability of the primary findings and found similar seasonal cycles in endorsement of binding moral values in Canada and Australia (but not in the United Kingdom). Collectively, results from these five studies provide evidence that moral values change with the seasons, with intriguing implications for additional outcomes that can be affected by those values (e.g., intergroup prejudices, political attitudes, legal judgments).
Significance
We report evidence that people’s moral values change with the seasons. Analyses of a decade of data (232,975 questionnaire responses from 2011 to 2020) revealed a consistent seasonal cycle in Americans’ endorsement of moral values pertaining to loyalty, authority, and purity (with stronger endorsement in spring and autumn and weaker endorsement in summer and winter). This seasonal cycle was partially explained by an analogous seasonal cycle in Americans’ experience of anxiety. Similar seasonal cycles were observed in data from Canada and Australia (but not the United Kingdom). These findings have implications for attitudes and actions that can be affected by moral values, including intergroup prejudices, political ideologies, and legal judgments.
The article is linked above. It is paywalled.
Here are some thoughts:
Recent research reveals that seasons may influence moral decision-making at a population level. The study found that binding values, which include loyalty, authority, and purity, exhibit biannual patterns, peaking in spring and fall while dipping in winter and summer. In contrast, individualizing values, such as care and fairness, remain relatively stable across seasons. This seasonal pattern was consistent over multiple years in the United States, Canada, and Australia, although it was not observed in the United Kingdom. Additionally, the researchers discovered that population-level anxiety patterns correlate with fluctuations in binding values, with anxiety peaking in spring and fall. These increases in anxiety may be linked to seasonal transitions in school and work, which can contribute to feelings of threat and a desire for group cohesion.
The implications of this research suggest that morality may be less rational and objective than commonly believed. While dramatic moral shifts do not occur at the individual level, collective small shifts in individual moral thinking could influence broader societal trends, such as discrimination, legal systems, and public compliance with government advice. Understanding these subtle influences can provide valuable insights into population-level behavioral trends and help us better anticipate seasonal shifts in social and political dynamics.