A new study from Indiana University finds regular spikes in an area's birth rate can be attributed to cultural practices. For example, there is a birth spike in the U.S. every September and October, about nine months after Christmas.
IU researchers worked with an institute in Portugal to look at online searches and social media to better understand people's moods and behaviors.
They also looked at data in Israel, for example, and found different birth peaks nine months after major Jewish and Muslim holiday celebrations.
Luis Rocha, a professor at the IU School of Informatics, co-led the study.
"The mood that is present in these holidays is one where people are happy, generally happy," says Luis Rocha, a professor at the IU School of Informatics and co-leader of the study. "There's less anxiety, so they tend to be calm as a whole."
Rocha says the research can be useful for public health officials.
"This is useful to target safe sex campaigns," he says. "For instance, you wouldn't think to do it around Christmas time to do them. And also expanding on these techniques toward other health problems."
Rocha says holidays like Thanksgiving and Easter did not have the same results as other holidays like Christmas and Ramadan.