Evolution of the female brain: From biology to behaviour

Female and male brains evolved differently to help ensure survival of the species. In ancient times, each sex had a very defined role: Cavemen hunted; cave women nurtured the family. Specific brain areas perhaps sharpened to enable each sex to carry out their jobs. Interest and research on sex differences in the brain especially increased over the past two decades. It emerged that while there are more similarities than differences in the brain structure, function and brain chemicals (neurochemicals) between healthy women and men, there are important differences that distinguish the female from the male brain. Women and men think, feel, perceive and behave differently; socialization alone does not account for all of it.

Women have more brain circuits for communication, reading emotions , social nuances, nurturing skills and a greater ability to use both sides of the brain simultaneously, although the number of brain cells in women and men is the same. Women are, on an average, better at expressing emotions and remembering details of emotional events (hippocampus—the hub of emotion and memory is larger in a woman’s brain).

Women are better at reading faces and recognizing emotional overtones in others (face coding is bilateral in the female brain). This may also account for some well known feminine intuitive abilities.

The outstanding verbal agility of women is undebatable! A significant proportion of the female verbal advantage can be attributed to a larger area of the female brain devoted to language. Yale University researchers showed the brain of women processes verbal language simultaneously on both sides unlike in men.

Women’s brain is better able to multi-focus, hence multi-task , a talent that has helped them juggle a home, career and social responsibilities . Some researchers attribute this to a differently shaped corpus callosum—the area connecting the two sides of the brain—and to a greater ability to use both simultaneously.

Women and men are differently sensitive to stress, conflict and the perception of pain; distinct sex-specific differences in neurochemicals such as dopamine, serotonin and gamma-aminobutyric acid contribute towards this difference.

How do all these differences take shape in the brain cells? Although 99% of the genetic coding is exactly the same among men and women, the one per cent difference impacts every cell in the body. Sex-linked genes and sex hormones have a powerful influence on the developing embryo and generate anatomical differences, and differences in the functional organization within brain hemispheres. A 2007 study by the National Institute of Health, USA on brain development during childhood and adolescence demonstrated consistent sex differences in the speed with which the brain matures.

Recognition of gender-specific ways of thinking, feeling and behaving and awareness about sex differences in brain structure, function and chemistry can benefit relationships and perhaps help women and men understand each other better. Men deserve due credit for a significant shift in attitude towards women over the years! Let’s celebrate our cerebral gender differences and continue to believe in ourselves, identify our strengths and apply them wisely in all areas of our lives.

(The writer is associate director, psychiatry research & consultant psychiatrist, Jaslok Hospital & Research Center, Mumba