New research suggests there’s no such thing as a distinctly male or female brain.
An analysis of more than 1,400 MRI scans suggests that biologically unmistakable sex differences don’t extend to the brain. Instead, the brain is home to a mix of masculine and feminine characteristics, the researchers found.
“This is the first study to look at the brain as a whole and ask whether brains are of two types. The answer is no,” said study lead author Daphna Joel, a psychologist and professor at Tel Aviv University in Israel.
“Each person possesses a unique mosaic of characteristics: some more common in females compared to males, some more common in males compared to females, and some common in both,” said Joel.
The question has been debated throughout the ages: Are human brains as gender-specific as chromosomes and sexual organs are in most people? Or are things more complicated?
To gain more insight, Joel and colleagues analyzed MRI brain scans of 1,400 people. They found that the brains of males and females tended not to stand apart in terms of gray matter, white matter and connections inside the brain. (Gray matter refers to brain cells known as neurons; white matter connects neurons to each other.)
The findings revealed that “many more brains” included both traits that are common in females and traits more common in men, Joel said.
Still, Joel said the new study doesn’t address how your actions reflect your gender. “We did not deal at all with the questions where differences in brain and behavior come from – nature or nurture – nor did we attempt to link differences in brain structure to differences in behavior,” she said.
“Our results undermine the entire concept of boy/girl brains. Who has a boy brain? The few boys who are consistently at the male end?” Joel said. “And if these boys have a ‘boy brain’ then what type of brain do the other boys have?”
Dr. Meng-Chuan Lai, an assistant professor of psychiatry at the University of Toronto, agreed. “Over the decades, scientists have already learned that most features of the brain and mind between male and female animals, including humans, are not categorically distinct,” Lai said. It’s akin to body height in humans, she said. “On average, males are taller, but there are many female individuals who are taller than male individuals.”
“This paper strengthens this common scientific view,” said Lai.
December 1, 2015