Your birthday may be to blame for certain personality traits. (Photo by Henglein and Streets/Cultura/Getty Images)
Even if you don’t buy into astrology, recent research suggests that the time of year you were born does actually play a big role in who you become. Specifically, your season of birth may be linked to your moods later on in life, according to a new study presented at the European College of CNP Congress in Berlin.
The scientists’ interest was sparked by a body of research suggesting a link between birth season and something more stable than mood: personality. In a British study, for example, young and middle-aged adults born from October to March tended to seek new, intense experiences more than those born in the other half of the year. Another study, published in Neuroscience Letters, suggests that people born in the winter may be less agreeable.
And the effects of your arrival date aren’t just psychological — there’s also evidence that your birth season can affect everything from your bedtime (spring- and summer-born folks go to bed later) to your risk of developing cancer. According to a 2014 International Journal of Cancer study, a spring or summer birthday is associated with a significantly higher risk of non-Hodgkin’s lymphoma in childhood and young adulthood. And an Italian study found that women born in March may begin menopause earlier, while those born in October experience the change later.
So can your season of birth affect daily fluctuations in mood? To answer this, the Hungarian researchers evaluated the temperaments of more than 400 people then matched their moods with their birth months. Here are the most significant trends:
- People born in the summer are more likely to experience rapid, frequent swings between feeling sad and cheerful, compared to folks born in the winter.
- Individuals with spring or summer birthdays tend to be excessively positive. In a previous study in the Journal of Affective Disorders, the same researchers observed this quality in people born between April and June.
- Winter babies grow up to be more irritable adults than people born in any other season.
- People born in the fall are less prone to bouts of the blues than people who arrived in the winter. In the Journal of Affective Disorders study, October emerged as the birth month least associated with depression, although this finding wasn’t statistically significant.
If your inner skeptic isn’t convinced, consider this: Your birth season reflects differences in several environmental influences during gestation and after birth — nutrients available, your mother’s level of physical activity, outdoor temperature, types of pathogens, light exposure; all of these factors play a role in nervous-system development, study author Xenia Gonda, a psychologist at Semmelweis University in Budapest, Hungary, told Yahoo Health in an email.
There’s also evidence that the time of year you were born affects levels of various neurotransmitters, like dopamine and serotonin, which play a clear role in mood, she added.
A simpler explanation: Certain times of year may be more conducive to babymaking. “Season influences how likely parents are to procreate,” said Gonda. People with seasonal affective disorder, for example, may be less likely to get busy during the colder months, when they’re feeling down. The result? “Kids inheriting a risk for this illness are less likely to be born during autumn,” she said. “So there may be both environmental and genetic reasons.”