#21 - Global Reference, Must Be True, Author's Perspective

[emilyjmyer]

Hi,

I had a question on the main point of question 21. It seemed to me that answer choices A and D and then B and C were pretty much the same answer choice. They both covered the same two points of the passage. In my prephrase, I did not think the part about classifying the chemicals as a family was important so I got rid of those. I did think that A and D seemed like contenders, but they did not discuss how the chemical theory worked, which seemed like an important part of the passage. On top of that, these answers seemed identical to me so I did not see how D could be right and then A could be wrong. I chose E and now I am seeing how it is a bit too specific. But, I am still not sure how D is right while A is wrong.

Thank you!

[ltowns1]

So I got (A) on this one too. I believe it’s wrong because we don’t know that electrical signals don’t play a role at all, whereas we know that electrical impulses are transmitted chemically. If you go back to the beginning of the 1st paragraph, the author says brain scientists believed that the workings of the brain were EXCLUSIVELY guided by electrical signals. The passage proves that this claim isn’t correct, but it doesn’t exclude the idea that there might still be a role for electrical signals

[Adam Tyson]

Correct, ltowns1! That's a good explanation for why answer A is incorrect. I hope that addresses Emily's question!

To reiterate, the passage is not about the brain being guided by chemical rather than electrical signals, but about how electrical signals are transmitted between neurons. The signals are still electrical, but the theory being discussed and supported is that these electrical signals may be carried chemically rather than just leaping electrically across the space between. So it's not that they are not electrical, as answer A says, but about how they are transmitted, as answer D describes. A subtle but crucial difference!