IMAT 2018 Q6 [Conclusion | Brain Size]

Sperm whales have the largest brains on the planet, although both humans and dolphins have larger brains relative to their body size. But why should relative brain size be important? If one thinks of a brain as a computer, there is no obvious reason why it must be sized in proportion to the body it lives in. Why for example should a whale need an especially large brain, when a hummingbird – which has complex tasks to perform – manages with a tiny one?

Which one of the following is a conclusion that is supported by the above passage?

A. Brain size and the ability to perform complex tasks are not necessarily related.

B. Hummingbirds and whales have equally complex tasks to perform, despite huge difference in brain size.

C. Dolphins are more intelligent than whales.

D. There is no important difference between a brain and a computer.

E. Whales need larger brains than either dolphins or humans because of their enormous size.

Summary of Steps to Solve Drawing Conclusion Type Questions:

  • Read the Question (Every question)
  • Go through the text and underline evidence
  • Read the answer and eliminate the outliers
    • (easiest to eliminate contradictory conclusions)
  • Using the underlined evidence and examples, prove each conclusion. Ask yourself “is this another piece of evidence? Or is this proved and strengthened by what’s in the text?”
  • Remember to ignore bias and disregard answers that may be true in the real world, but are not supported in the text.

This is a tricky question as it poses many questions throughout. It seems that the author is trying to teach the reader by having questions that drive the argument. This stimulates the reader to come up with their own answer based on what is given. The importance here is on the brain-to-body ratio, and this is actually an argument that has been presented in previous IMAT papers. Brain size to body ratio is what matters, and this is what the author is trying to show us, take the last sentence for example: “Why for example should a whale need an especially large brain, when a hummingbird – which has complex tasks to perform – manages with a tiny one?”. The author is trying to show us that even though a hummingbird has a small brain, it is relative to its body size. Clearly, a blue whale has a larger brain, but it is also a much larger animal, so it’s relative to body size. Now that we have figured out the argument, let’s break down the answer choices.

A. Brain size and the ability to perform complex tasks are not necessarily related.

This is what the author is trying to get across and they use various pieces of evidence. The author uses an analogy comparing a computer to the brain. The author wants to show us that a computer can be small and powerful just like the brain, so the size of the brain does not correspond with its ability to perform complex tasks. Then the author uses a hummingbird as an example, which has a small brain but also important tasks to complete. Therefore A is the correct answer.

B. Hummingbirds and whales have equally complex tasks to perform, despite huge difference in brain size.

This is something similar to what was said in the last sentence. The author says that the hummingbird still has complex tasks to perform but can still manage with a smaller brain. This is used as proof to show that the size of the brain does not matter because a small brain (like in the hummingbird) can be still powerful. Therefore B is not a conclusion but rather evidence.

C. Dolphins are more intelligent than whales.

This is a statement that is trying to confuse you. Dolphins are known to be smart animals in real life, but the text is not supporting the claim that they are above the intelligence level of whales. The first sentence says that humans and dolphins have a larger brain-to-body ratio than whales, but we are not told if this is linked to intelligence here. We know that there is a relationship between the brain and body but we cannot make this conclusion off what is given in the text, nor would it be the most important thing we can draw from the text. Therefore C is incorrect.

D. There is no important difference between a brain and a computer.

The author is using computers as an analogy to the brain because the relative size of either does not matter, it is what the computer has or where the brain is found. Therefore D is incorrect.

E. Whales need larger brains than either dolphins or humans because of their enormous size.

This is not stated in the text nor is it important. The author has used the analogy of computers to show that it is not necessarily the size of the brain which is important. The author is saying that computers can be small and powerful but they can also be big and weak, it depends on circumstance. Therefore E is incorrect.