Birth Season and Brain Development

Twenty years ago when I was considering going for a graduate degree in neuroscience this was one of the studies that I wanted to perform if I eventually became a research scientist. It occurred to me as an undergraduate that some of the tenets of astrology might be derived from observations based on birth seasons. I live in Minnesota, where the seasonal variations are quite severe, and it only made sense that the month in which a child was born would influence how they experienced their first year of life, and potentially set them on a cycle of activities that could influence their personality development. For example, a baby born at the beginning of winter would spend his or her first several months indoors, while a baby born at the beginning of summer would have access to outdoor exposure right away. Now a neuroscience researcher has performed such a study, and identified a specific brain characteristic that seems to correlate with birth seasons.

The season we’re born in can have far-reaching consequences. For instance, Spring babies are more likely than others to develop schizophrenia later in life, whereas Summer babies tend to grow up to be more sensation seeking. There are many more of these so-called season of birth effects. Scientists aren’t sure, but they think such patterns could be due (among other things) to mothers’ and infants’ exposure to viruses over the Winter period, or to the amount of daylight they’re exposed to, either or both of which could influence genetic expression during early development. Now Spiro Pantazatos, a neuroscientist at Columbia University Medical Center, has studied links between season of birth and brain structure in healthy adults. He thinks the association between season of birth and psychiatric and behavioural outcomes later in life could be mediated by genetic factors that affect the growth of the brain.

Pantazatos has analysed MRI brain scans taken from 550 healthy men and women at hospitals in London, England. In one analysis he looked to see if there were any particular areas of the brain that differed between people according to the season they were born in. He defined the seasons as follows: Winter (Dec 23 to March 19); Spring (March 22 to June 19); Summer (June 22 to September 21); and Fall (September 24 to December 20). For the men only, he found that those born in the Fall and Winter tended to have more grey matter in a region known as the left superior temporal sulcus (STG), as compared with men born in Spring and Summer. Looking month by month, men born at the end of December tended to have the most grey matter in this region; men born at the end of June tended to have the least.

This particular correlation between season and brain structure only seems to hold for men, but with the way that protosciences work that could be enough to suggest a relationship between birth season and particular traits. The sifting process of information gathering in such disciplines is based on holding onto information that seems to valid and discarding relationships that fail to hold up over time. It is far more vulnerable to error and cognitive bias than formal scientific inquiry, but the observations thus accumulated can suggest potential areas for more rigorous inquiry. It's too bad that anything dubbed "paranormal" has gotten so little attention in academic circles, but some of that is starting to turn around with studies like this one and others relating brain activity to altered states of consciousness such as those employed in both meditation and magical operations.