Catie Burnell
Mr. Ippolito
Core Biology Honors
March 31, 2017
The article “A Change in Diet May Have Helped Our Brains Get So Big” by BBC’s Melissa Hogenboom gives fascinating insight into the human body’s most complex organism: the brain. Anthropologists have long believed that the reason behind humans’ large brain size is living in social groups - a belief known as the social brain hypothesis - but new findings have disputed this reasoning. “...The social brain theory does not tell the whole story.
Rather, brain size is more accurately predicted by primates' diet, according to their new study published in the journal Nature Ecology and Evolution” (Hogenboom 2017). This change in thinking comes from a team at New York University lead by anthropologist Alex DeCasien. This team of experts compared the skulls of 140 species of primates, such as lemurs, aye-ayes, and chimpanzees. Researchers studied these skulls to gain information about the species’ brain sizes and supplemented their findings with information about each species’ social patterns, such as social structure and group size, in order to test the social brain hypothesis. Their data, however, excluded species such as orangutans that live in solitary conditions despite their large brain sizes.
The results of the NYU study were surprising: ultimately, the research team found that, contrary to the social brain hypothesis, diet plays a major role in brain size. However, DeCasien’s research team had suspected that this would be the case. “It has long been known that fruit-eating primates (frugivores) tend to have bigger brains than leaf-eating primates (folivores), says Higham” (Hogenboom 2017). Not only are fruits more difficult for the body to digest than leaves, but frugivores often must travel further in order to find fruit than folivores must travel in search for leaves. However, the NYU research team still acknowledges that the social brain hypothesis still does play a factor in brain size, albeit smaller than previously believed. Frugivores, because they must travel larger distances in order to obtain food, congregate in larger social groups along their searches for food. Additionally, varying group sizes play a role in competition for food. James Higham, an anthropologist at NYU’s primatology department and a researcher on DeCasien’s team, says that "If there's another group in that fruit tree, what determines which group ends up holding the fruit is usually just about group size.” The larger group will ultimately win the food simply because there are more of them.
However, these findings have faced criticism, notably from Oxford University’s Robin Dunbar. Dunbar argues that the size of the neocortex - the part of the brain that plays a large role in spatial reasoning, cognition, and language - plays a much more important role than brain size in a primate species. "There is an important distinction between neocortex volume and brain volume… The original social brain analyses showed that social group size does not correlate especially well (if at all) with total brain size, but only with neocortex size… That would be difficult to reconcile with their claim,” says Dunbar. Nevertheless, Dunbar agrees with most anthropologists that social group size is the main deciding factor of a primate’s brain size.
Hogenboom, Melissa. "A Change in Diet May Have Helped Our Brains Get so Big." BBC News. BBC, 27 Mar. 2017. Web. 29 Mar. 2017.
This week, I read my classmate Catie Burnell’s current event on an article published in the BBC. The article, “A Change in Diet May Have Helped Our Brains Get So Big” talks about new findings and discusses the correlation between diet and brain size. The first thing that caught my eye was the original hypothesis of social interactions determining brain size. However, a study comparing 140 species denied this. I also found it interesting that organisms who ate fruits had bigger brains, because they were harder to digest. Finally, I found it compelling that it did not totally disprove the social interaction hypothesis, but expanded upon the claims of previous researchers.
ReplyDeleteOverall, the review by Catie was wonderfully written, and conveyed the point in a seamlessly. She added just enough quotes and background information to really let the reader understand. It was very hard to find a certain instance where she did something that could've affected my learning, but I did think that she could have explained the difference between fruit and leaves correlates to brain size, not just how they digest differently. I also think that she could've included when and how the social interaction theory was hypothesised, to see if the the process or tests used were outdated.
Personally this article sparked my interest because I never really focused or read on major topics like this. Going forward, I will definitely look into more evolution related topics. Reading this definitely prepared me for learning on evolution, and how humans got to be so different from other species.
Hogenboom, Melissa. "A Change in Diet May Have Helped Our Brains Get so Big." BBC News. BBC, 27 Mar. 2017. Web. 29 Mar. 2017. .
Hogenboom, Melissa. "A Change in Diet May Have Helped Our Brains Get so Big." BBC News.
ReplyDeleteBBC, 27 Mar. 2017. Web. 29 Mar. 2017.
My classmate, Catie Burnell, wrote an excellent review of the article “A Change in Diet May Have Helped Our Brains Get so Big.” As the title implies, the article was about a group of anthropologists at NYU that suggested that the diet our ancestors may have played a significant role in the development of our brains. There were many things that Catie did well in reviewing the article. For one, her review was very well written. There were no noticeable grammatical issues in the review. This made it much easier to understand and process the information that Catie was trying to communicate. Catie also did a good job explaining key terms and making the information understandable for those who are reading about this subject for the first time. Finally, Catie incorporated sections from the article into her review. This gives the reader a sense of what the article was like to read, and backs up Catie’s statements about the article.
One thing that Catie could have done to further improve her review was to include a section that discusses how the article was written, and what impact it had on the reader. Though she somewhat covered this by including quotes in her writing, it would have been nice to see such a section. Another would have improved the review would have been a couple of sentences that summarize the significance of the findings, or lack thereof. This would have helped the reader to have a greater appreciation for the findings summarized in the article.
One thing that struck me about Catie’s review is the fact that we have a lot left to learn about our past. Our understanding of the world is still evolving today, as new information is discovered. Though we have come very far with scientific discovery, there is still much left to learn. It is exciting to think of what we have yet to learn about our planet. Even though we have been around for a long time, we still have a ways to go before we understand how we evolved into what we are today.
Marina Alfano
ReplyDeleteMr.Ippolito
4/16/17
Current Event #8
Hogenboom, Melissa. "A Change in Diet May Have Helped Our Brains Get so Big." BBC News. BBC, 27 Mar. 2017. Web. 29 Mar. 2017.
http://www.bbc.com/earth/story/20170327-why-our-brains-grew-so-big
My classmate Catie Burnell wrote a well written review on an article titled “A Change in Diet May Have Helped Our Brains Get so Big” published on BBC. The article discusses new findings suggest that it is the diets of our ancestors that played an important role in the development of our brains. It is clear that Catie spent time reading over her review and making sure it had no grammatical errors which made it easy to understand what she was saying. Catie uses quotes from the article to assist her in explaining the studies that were conducted at NYU. I like how she provided details about the study, saying how many animals were involved and how the researchers were able to test their hypothesis. One more thing that was well done in Catie's review was that she also discussed the results of the experiments and then applied them to the hypothesis of the scientists at NYU. This was helpful because it makes it easier for the reader to understand how the results of the study prove their theory of how brain size is affected by diet.
Although Catie touched on the results of the experiment, I think she could have added a few concluding sentences that summarized the findings and how they prove or disprove the theory. This would have made it completely clear to the reader as to what the findings really mean in case they didn’t understand when she briefly touched on it. Also, to further the reader's understanding of how diet affects the brain, Catie could have talked about how fruits and vegetables impact the brain differently instead of only discussing how they digest differently.
Overall, Catie did an excellent job reviewing this article and she articulated her words very well. This article review caught my eye because I am interested in how our bodies evolved and I never knew that the type of food that our ancestors ate is why our brains are the size they are now. I think it's interesting that we are just finding these types of things and we are constantly discovering more things that change the way we think about our own species. I will definitely look into this topic because I found it very interesting and I would like to learn more about it.