Human Sexual Cycles are Driven by Culture and Match Collective Moods

Abstract

Human reproduction does not happen uniformly throughout the year and what drives human sexual cycles is a long-standing question. The literature is mixed with respect to whether biological or cultural factors best explain these cycles. The biological hypothesis proposes that human reproductive cycles are an adaptation to the seasonal (hemisphere-dependent) cycles, while the cultural hypothesis proposes that conception dates vary mostly due to cultural factors, such as holidays. However, for many countries, common records used to investigate these hypotheses are incomplete or unavailable, biasing existing analysis towards Northern Hemisphere Christian countries. Here we show that interest in sex peaks sharply online during major cultural and religious celebrations, regardless of hemisphere location. This online interest, when shifted by nine months, corresponds to documented human births, even after adjusting for numerous factors such as language and amount of free time due to holidays. We further show that mood, measured independently on Twitter, contains distinct collective emotions associated with those cultural celebrations. Our results provide converging evidence that the cyclic sexual and reproductive behavior of human populations is mostly driven by culture and that this interest in sex is associated with specific emotions, characteristic of major cultural and religious celebrations.

Ambient temperature and sexual activity: Evidence from time use surveys

“…In this paper we examine the first mechanism: the relationship between ambient temperatures and sexual activity. Although previous papers have studied the seasonal variation in sexual activity (Fortenberry et al 1997;Levin, Xu, and Bartkowski 2002;Markey and Markey 2013;Rodgers, Harris, and Vickers 1992;Udry and Morris 1967;Wood et al 2017), our paper is among the first to analyze the effect of ambient temperatures explicitly. To our knowledge, only Wilde, Apouey, and Jung (2017) have analyzed temperature-induced changes in sexual behavior.…”

The individual dynamics of affective expression on social media

“…Note that this approach assumes that affect can be measured from its expression through human communication. While a substantial level of noise can be expected when using these text analysis methods to quantify emotions, the use of large-scale data from social media and other digital resources allows the analysis of individual and collective emotions through temporal and structural patterns [16,19,21,33,34]. We quantify valence and arousal expressed in each status update through unsupervised methods that compute mean scores over stemmed terms in a text [35].…”

“…These results are very similar when using the alternative sentiment analysis method, as reported The memory patterns of our model, while consistent with previous research, could also be explained by collective and cultural synchronization processes that influence emotional expression. For example, seasonal greetings such as "happy New Year" or "merry Christmas" could introduce artifacts in our measurement as manifestations of collective mood [34]. We account for these effects in our analyses, we repeated the model fits including additional inter-individual weekly baselines for valence and arousal.…”

Mining Social Media Data for Biomedical Signals and Health-Related Behavior

“…Although the accuracy of Google trends data alone has been problematic for epidemic flu modeling (21), such data add value in combination with other health data (22). Several studies have also shown that social media analysis is useful for: tracking and predicting disease outbreaks such as influenza (11,23), cholera (24), Zika (25), and HIV (26); playing an important role in pharmacovigilance (3,(27)(28)(29)(30)(31); and measuring public sentiment and other signals associated public health issues such as depression (4,(32)(33)(34), human reproduction (35), vaccination rates (36,37), and mental disorder stigma (13).…”