Puberty and Sex Differences

Every person on the planet goes through puberty, the fluctuation of sex hormones, at a point of their life. Men typically get cracking voices, increased testosterone levels, and acne. Women get periods, increased estrogen levels, and breast development. According to some scientists, these sex hormones are capable of influencing sex differences. Yet, Melissa Hines considers these claims to be false. Instead, she believes that this hormonal fluctuation accidently coincides with increased cognitive ability, and in reality, our environment has a bigger impact on cognitive differences. She also believes letting this perception of cognitive sex differences become more prevalent in society, then this debate will cause “a shortage of women in science” (110). By using Melissa Hines’ essay Sex Differences in Cognition, I believe that changes in hormone levels during adolescence are coincidentally linked to fluctuations in cognitive skills and the the environment we grow up in has a greater influence on the development of these abilities.

Melissa Hines’ essay analyzes the different influences that hormones can trigger. Two areas that she looks in depth at are activational and organizational influences. Organizational influences are changes that occur either prenatally or in adulthood, and they change the organization of the brain and behaviors that are used to describe sex differences (104-105). Activational influences on sex differences cause changes in behavior by activating a certain spot in the brain (105). By understanding these changes, we can see if, for instance, the woman’s cycle can affect woman’s cognitive ability. Hines’ essay shows that available research data does not lead to reproducible and consistent results. The findings of the different studies either cannot be replicated with larger sample sizes, support another factor at play, or imply that there is no significant difference in abilities. In the end, Hines concludes that instead of concentrating on biological influences on women and men, we should be looking further into environmental impacts. She also claims that the reason that cognitive differences cause a “shortage of women” in STEM is due to us focusing so much on sex differences in cognition that it now influences women’s confidence in their own potential (110).

When we first think about women’s cycle, we imagine the emotional woman who is being overtaken by a biological hormonal “attack”. Yet in reality, even though some women could get a bit emotional, most have control of themselves and can function normally when on their period. This monthly fluctuation of hormone level in women is believed to have caused women to vary in cognitive skills. Scientists, like Doreen Kimura, believe that when women release lower levels of estrogen (higher testosterone levels) in their cycle, the male-typical abilities, like spatial ability, increase (107-109). Yet, Newcombe believes that hormone levels are accidentally linked with cognitive skills, causing sex differences to rise (73-74). Hines believes that these studies show that other factors could be influencing the results, such as genetics and environment. According to a study published in 2013 by Developmental Psychology, genetic influence on variance on these skills goes up from 20% in childhood to 80% in adults. The study also examines the amount of influence our environment has on us. Family environment accounts for significant variance during our childhood but drops to zero by adolescence, which means the family experiences we have when we are little can greatly influence us at a younger age versus an older age. In addition, the study states that unshared environments, like school, cause significant differences in skills throughout our lifespan, meaning that the surroundings outside of our home have a major effect on development of skills. Overall, environmental factors and genetics have a greater influence than hormones.

Overall, I found that while Hines made good points in her essay, she did not really delve into detail on what she believes impacts us. In the entire essay, she talks about hormones and it’s not until the conclusion that she offers a different factor that affects cognitive skills. Her belief on environmental impacts resonated with me and provoked me to investigate that matter further. Even though there is evidence that hormones can influence us, genetics and environmental factors can induce greater contrasts between cognitive skills in men and women.

Petrill, S. A., Lipton, P. A., Hewitt, J. K., Plomin, R., Cherny, S. S., Corley, R., & DeFries, J. C. (2013, July 14). Genetic and Environmental Contributions to General Cognitive Ability Through the First 16 Years of Life. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3710702/

Why aren’t more women in math and Science? — Sex Differences in Cognition by Melissa Hines