By Imogen Robinson
Spikes in pregnancies are rooted in society, not biology, with online interest in sex rising at Christmas, a new study has revealed.
The study also showed that this post-holiday ‘baby boom’ occurs regardless of culture, nationality, religion, and even hemisphere.
The evidence was discovered through looking at web searches and Twitter posts that appear to reveal our hidden desires and motivations.
The study is the first ‘planetary-level’ look at human reproduction as it relates to people’s moods and interest in sex online.
Co-leader of the study, Luis M. Rocha of Indiana University, said, “The rise of the web and social media provides the unprecedented power to analyse changes in people’s collective mood and behaviour on a massive scale.”
The study, which appears in the journal
Researchers found that interest in sex peaks during major cultural or religious celebrations, based on greater use of the word “sex” or other sexual terms in web searches.
The peaks broadly corresponded to an increase in births nine months later in countries which had available birth-rate data.
The effect was observed in two different cultures, with the biggest spikes occurring in two major holiday celebrations: Christmas in Christian-majority countries and Eid al-Fitr in Muslim-majority countries.
The use of data from Northern and Southern hemispheres is notable since past analyses tended to focus on smaller geographic areas in the Western and Northern hemispheres.
The case of Eid is significant because the holiday occurs on different days each year, but the resultant effect still shifts accordingly.
Because the seasons are reversed on opposite sides of the globe, and birth rates and online interest in sex did not change based on geography, researchers concluded that the relationship between these effects is not due to biological shifts caused by changes in daylight, temperature, or food availability.
Professor Rocha said: “We didn’t see a reversal in birth rate or online interest in sex trends between the Northern and Southern hemispheres, and it didn’t seem to matter how far people lived from the equator.
“Rather, the study found culture, measured through online mood, to be the primary driver behind cyclic sexual and reproductive behaviour in human populations.”
To further understand the higher interest in sex during holiday periods, researchers also conducted a review of word choices in Twitter posts, a method known as “sentiment analysis”.
This showed that, unsurprisingly, people appear to feel happier, safer, and calmer during the holidays.
When these collective moods appear on other occasions throughout the year, there is the same corresponding increase in online interest in sex.
Interestingly, however, Thanksgiving and Easter did not generate the same mood and online interest in sex.
Professor Rocha said, “We observe that Christmas and Eid-Al-Fitr are characterised by distinct collective moods that correlate with increased fertility.
“Perhaps people feel a greater motivation to grow their families during holidays when the emphasis is on love and gift-giving to children.”
The findings could be used to help public health researchers pinpoint the best dates to launch public awareness campaigns encouraging safe sex in developing countries lacking in reliable birth-rate data.
Professor Rocha added, “The strong correlation between birth rates and the holidays in countries where birth-rate data is available, regardless of hemisphere or dominant religion, suggests that these trends are also likely to hold true in developing nations.
“These types of analyses represent a powerful new data source for social science and public policy researchers.”