The human eye makes tiny, rapid, almost constant motions called microsaccades. Investigators have long been unsure what function, if any,...
GMAT Reading Comprehension : (RC) Questions
Source: Mock
...
...
Post a Query
The human eye makes tiny, rapid, almost constant motions called microsaccades. Investigators have long been unsure what function, if any, microsaccades serve. Some have even gone so far as to suggest that microsaccades could impair vision by blurring it. But it is likely that microsaccades enable perception of stationary objects.
Visual systems have evolved to most readily detect moving objects, because motion may indicate that a predator is approaching or prey is escaping. So visual neurons respond to motion with electrochemical impulses. Unchanging objects less often pose a threat, so visual neurons do not respond as strongly to a static scene. Some animals, such as frogs, are completely unable to see stationary objects, but can easily see objects in motion. The reason humans see stationary objects better than do frogs may be that human eyes create their own motion, prompting visual neurons to keep firing.
In an experiment supporting this hypothesis, researchers asked subjects to stare fixedly at a dot in the center of a computer screen while reporting changes in their perception of another, peripheral dot. While staring at the central dot, they reported the peripheral dot fading from view. Their microsaccades became sparser and slower just before the peripheral dot seemed to vanish, then returned to normal immediately before it reappeared.
Ques. 1/3
The main purpose of the passage is to
Solution
1. Passage Analysis:
Progressive Passage Analysis
| Text from Passage | Analysis |
|---|---|
| The human eye makes tiny, rapid, almost constant motions called microsaccades. | What it says: Our eyes are constantly making small, fast movements What it does: Introduces the main topic - a specific eye movement Source/Type: Scientific fact Connection to Previous Sentences: N/A - This is the opening sentence Visualization: Imagine your eye making about 1-3 tiny jerking movements every second, so small you don't notice them Reading Strategy Insight: Clean, simple introduction - the author is being helpful by defining the term immediately What We Know So Far: Eyes make tiny movements called microsaccades What We Don't Know Yet: Why this matters, what purpose they serve |
| Investigators have long been unsure what function, if any, microsaccades serve. | What it says: Scientists don't know if these eye movements do anything useful What it does: Sets up the central mystery/question the passage will explore Source/Type: Report of scientific uncertainty Connection to Previous Sentences: This builds on sentence 1 by revealing the puzzle about microsaccades. We know WHAT they are, but not WHY they exist Visualization: Picture researchers for many years scratching their heads, saying "We see these movements, but we have no idea what they're for" Reading Strategy Insight: This is classic RC structure - introduce concept, then reveal the question about it |
| Some have even gone so far as to suggest that microsaccades could impair vision by blurring it. | What it says: Some scientists think these movements might actually hurt our vision What it does: Presents one theory - that microsaccades are harmful Source/Type: Some researchers' hypothesis Connection to Previous Sentences: This elaborates on the uncertainty from sentence 2. Not only do scientists not know the purpose, some think microsaccades might be BAD Visualization: Think of a camera shaking slightly while taking a photo - the result would be blurry. Some scientists think microsaccades do this to our vision Reading Strategy Insight: The phrase "even gone so far" suggests this is an extreme view - setting up for contrast |
| But it is likely that microsaccades enable perception of stationary objects. | What it says: The author thinks microsaccades probably help us see things that aren't moving What it does: Presents the author's opposing theory - microsaccades are helpful, not harmful Source/Type: Author's opinion/hypothesis Connection to Previous Sentences: This directly contrasts with sentence 3. Instead of hurting vision, the author believes they help us see stationary objects Visualization: Imagine looking at a parked car - microsaccades might be what allows you to keep seeing it clearly Reading Strategy Insight: Key transition! The "But" signals the author's position against the previous theory. This is likely the main argument. |
| Visual systems have evolved to most readily detect moving objects, because motion may indicate that a predator is approaching or prey is escaping. | What it says: Our vision is naturally designed to spot moving things because they could be dangerous animals or food What it does: Provides evolutionary background to explain why motion detection is important Source/Type: Scientific explanation based on evolution Connection to Previous Sentences: This begins building support for the author's theory from sentence 4. To understand why microsaccades help with stationary objects, we first need to understand how vision normally works Visualization: Picture early humans whose survival depended on quickly spotting a charging lion (predator) or a running deer (prey) Reading Strategy Insight: The author is building the foundation for their argument step by step |
| So visual neurons respond to motion with electrochemical impulses. | What it says: Brain cells that handle vision get activated when they detect movement What it does: States the biological mechanism behind motion detection Source/Type: Scientific fact about brain function Connection to Previous Sentences: This restates sentence 5 in more technical terms. The evolutionary reason (predator/prey detection) leads to this biological reality (neurons firing) Visualization: Think of motion-detecting brain cells like motion sensors on security lights - they "turn on" (send electrical signals) when they detect movement Reading Strategy Insight: Feel relieved here - this is just a restatement of the previous idea in scientific terms, not new complexity |
| Unchanging objects less often pose a threat, so visual neurons do not respond as strongly to a static scene. | What it says: Non-moving objects are usually safe, so our brain cells don't react much to them What it does: Explains the visual system's weakness - poor detection of stationary objects Source/Type: Scientific explanation Connection to Previous Sentences: This is the logical flip side of sentences 5-6. If neurons fire strongly for moving objects (dangerous), they fire weakly for still objects (safe) Visualization: Those same motion-sensor security lights stay dim when nothing moves. Similarly, brain cells stay "dim" (inactive) when looking at a stationary tree or rock Reading Strategy Insight: This is setting up the problem that microsaccades solve! The author is building toward the connection. |
| Some animals, such as frogs, are completely unable to see stationary objects, but can easily see objects in motion. | What it says: Frogs can't see still things at all, but have no trouble seeing moving things What it does: Provides a concrete example of the principle just explained Source/Type: Scientific fact/example Connection to Previous Sentences: This gives us a real-world example of sentence 7. Frogs represent the extreme case where neurons completely ignore stationary objects Visualization: A frog sitting next to a motionless fly sees nothing, but the instant that fly moves, the frog spots it immediately Reading Strategy Insight: Examples make abstract concepts concrete - this helps solidify understanding of the motion detection principle |
| The reason humans see stationary objects better than do frogs may be that human eyes create their own motion, prompting visual neurons to keep firing. | What it says: Humans see still objects better than frogs because our eyes make their own movement (microsaccades), which tricks our brain cells into staying active What it does: Connects microsaccades to the vision problem, explaining how they solve it Source/Type: Author's hypothesis Connection to Previous Sentences: This is the payoff! It connects back to microsaccades (sentence 1) and explains how they solve the stationary object problem (sentences 7-8). The "create their own motion" refers to microsaccades Visualization: While a frog's eye stays perfectly still and can't see a motionless fly, human eyes constantly make tiny movements that make even stationary objects appear to move slightly, keeping our brain cells active Reading Strategy Insight: Major connection moment! This ties together everything we've learned into one clear theory. |
| In an experiment supporting this hypothesis, researchers asked subjects to stare fixedly at a dot in the center of a computer screen while reporting changes in their perception of another, peripheral dot. | What it says: Scientists tested this theory by having people stare at a center dot while watching what happened to their view of a side dot What it does: Introduces experimental evidence for the author's hypothesis Source/Type: Description of research methodology Connection to Previous Sentences: This begins providing proof for the theory stated in sentence 9. The experiment is designed to test whether microsaccades affect perception of stationary objects Visualization: Picture looking at a computer screen: a dot in the center you stare at, and another dot off to the side that you monitor with peripheral vision Reading Strategy Insight: Classic RC pattern - state theory, then provide supporting evidence |
| While staring at the central dot, they reported the peripheral dot fading from view. | What it says: When people stared steadily, the side dot seemed to disappear What it does: Reports the key experimental observation Source/Type: Experimental results Connection to Previous Sentences: This continues describing the experiment from sentence 10. It shows what happens to stationary object perception under controlled conditions Visualization: You're staring hard at the center dot, and gradually the peripheral dot starts to fade away until you can't see it anymore Reading Strategy Insight: This demonstrates the problem with stationary objects that the theory predicts |
| Their microsaccades became sparser and slower just before the peripheral dot seemed to vanish, then returned to normal immediately before it reappeared. | What it says: Right before the side dot disappeared, people's eye movements slowed down and became less frequent. When the movements returned to normal, the dot became visible again What it does: Provides the crucial evidence linking microsaccades to perception of stationary objects Source/Type: Experimental results Connection to Previous Sentences: This completes the experimental evidence for the author's theory from sentence 9. It proves that microsaccades are directly connected to seeing stationary objects - when microsaccades decrease, the stationary dot fades; when they return, the dot reappears Visualization: Timeline: Normal eye movements (dot visible) → Fewer, slower eye movements → Dot fades → Eye movements return to normal → Dot reappears Reading Strategy Insight: Perfect circular proof! This experiment confirms everything: microsaccades help us see stationary objects, and when they diminish, our ability to see stationary objects diminishes too. |
2. Passage Summary:
Author's Purpose:
To explain how microsaccades (tiny eye movements) help humans see stationary objects by providing evidence for a new theory about their function.
Summary of Passage Structure:
The author builds their argument in clear steps:
- First, they introduce microsaccades and explain that scientists have long been puzzled about their purpose, with some thinking they might even hurt vision by making it blurry.
- Next, they present their own theory that microsaccades actually help us see stationary objects, then explain the biological background of why this makes sense.
- Then, they describe how visual systems evolved to detect moving objects for survival, which means our brains respond weakly to stationary objects, using frogs as an example of animals that can't see still objects at all.
- Finally, they explain how human microsaccades solve this problem by creating artificial motion, and they support this theory with experimental evidence showing that when microsaccades slow down, stationary objects fade from view.
Main Point:
Microsaccades serve an important function by helping humans see stationary objects better than animals like frogs because these tiny eye movements create artificial motion that keeps our visual neurons active and firing.
3. Question Analysis:
This question asks us to identify the main purpose of the passage - essentially, what is the author's primary goal in writing this piece? We need to look at the overall structure and the author's central argument rather than getting caught up in specific details or examples.
Connecting to Our Passage Analysis:
From our analysis, we can see that the passage follows a clear argumentative structure:
- The author introduces microsaccades and the scientific uncertainty about their function
- The author presents their own theory that microsaccades help us see stationary objects
- The author builds scientific support for this theory through evolutionary biology and visual neuron function
- The author provides experimental evidence that confirms their hypothesis
The key insight from our analysis is that sentence 4 contains the author's main argument: "But it is likely that microsaccades enable perception of stationary objects." Everything after this sentence serves to support and prove this claim.
Prethinking:
The passage is structured as an argument for a specific theory about microsaccades. The author isn't just describing experiments or comparing theories - they're actively arguing that microsaccades serve a particular function. The main purpose should reflect this argumentative stance and focus on the central claim about stationary object perception.
Answer Choices Explained
A
discuss experimental data on the correlation of microsaccades with peripheral visual perception
Why It's Wrong:
• This choice focuses too narrowly on just the experimental portion at the end of the passage
• It treats the experiment as the main focus rather than as supporting evidence for a larger argument
• It ignores the evolutionary background, visual neuron explanation, and the author's central theory
Common Student Mistakes:
1. Does the experiment take up the most space in the passage?
→ Remember that length doesn't determine importance - the experiment supports the main argument rather than being the main point
1. Isn't the experimental data the most concrete part?
→ Focus on what the concrete evidence is used to prove, not just the evidence itself
• This choice focuses too narrowly on just the experimental portion at the end of the passage
• It treats the experiment as the main focus rather than as supporting evidence for a larger argument
• It ignores the evolutionary background, visual neuron explanation, and the author's central theory
Common Student Mistakes:
1. Does the experiment take up the most space in the passage?
→ Remember that length doesn't determine importance - the experiment supports the main argument rather than being the main point
1. Isn't the experimental data the most concrete part?
→ Focus on what the concrete evidence is used to prove, not just the evidence itself
B
explain how visual neurons generate electrochemical impulses in response to microsaccades
Why It's Wrong:
• The passage doesn't explain HOW neurons generate impulses in response to microsaccades
• This choice focuses on a technical mechanism that isn't actually detailed in the passage
• The passage mentions that neurons respond to motion but doesn't explain the electrochemical process itself
Common Student Mistakes:
1. Doesn't the passage mention electrochemical impulses?
→ Yes, but only briefly as background information, not as the main focus of explanation
1. Isn't this about how microsaccades work with neurons?
→ The passage is about WHY microsaccades exist (their function), not HOW they create neural responses
• The passage doesn't explain HOW neurons generate impulses in response to microsaccades
• This choice focuses on a technical mechanism that isn't actually detailed in the passage
• The passage mentions that neurons respond to motion but doesn't explain the electrochemical process itself
Common Student Mistakes:
1. Doesn't the passage mention electrochemical impulses?
→ Yes, but only briefly as background information, not as the main focus of explanation
1. Isn't this about how microsaccades work with neurons?
→ The passage is about WHY microsaccades exist (their function), not HOW they create neural responses
C
describe the evolution of microsaccades in visual systems
Why It's Wrong:
• The passage doesn't trace how microsaccades evolved over time
• Evolution is mentioned only as background to explain why visual systems detect motion
• The focus is on the current function of microsaccades, not their evolutionary development
Common Student Mistakes:
1. Doesn't the passage talk about evolution and predators/prey?
→ Yes, but this explains why motion detection evolved, not how microsaccades themselves evolved
1. Isn't the comparison with frogs about evolution?
→ The frog example illustrates current visual system differences, not evolutionary development of microsaccades
• The passage doesn't trace how microsaccades evolved over time
• Evolution is mentioned only as background to explain why visual systems detect motion
• The focus is on the current function of microsaccades, not their evolutionary development
Common Student Mistakes:
1. Doesn't the passage talk about evolution and predators/prey?
→ Yes, but this explains why motion detection evolved, not how microsaccades themselves evolved
1. Isn't the comparison with frogs about evolution?
→ The frog example illustrates current visual system differences, not evolutionary development of microsaccades
D
argue that microsaccades likely play a role in the perception of stationary objects
Why It's Right:
• This directly matches the author's central claim stated in sentence 4: "But it is likely that microsaccades enable perception of stationary objects"
• The entire passage structure supports this argument through background explanation and experimental evidence
• The word "argue" correctly identifies that the author is taking a position, not just describing or explaining
Key Evidence: "But it is likely that microsaccades enable perception of stationary objects... The reason humans see stationary objects better than do frogs may be that human eyes create their own motion, prompting visual neurons to keep firing."
• This directly matches the author's central claim stated in sentence 4: "But it is likely that microsaccades enable perception of stationary objects"
• The entire passage structure supports this argument through background explanation and experimental evidence
• The word "argue" correctly identifies that the author is taking a position, not just describing or explaining
Key Evidence: "But it is likely that microsaccades enable perception of stationary objects... The reason humans see stationary objects better than do frogs may be that human eyes create their own motion, prompting visual neurons to keep firing."
E
compare two competing hypotheses about microsaccades, one generated by evolutionary theory and the other by experimental evidence
Why It's Wrong:
• The passage doesn't present two competing hypotheses - it presents one negative view and argues against it
• There's no comparison between evolutionary theory and experimental evidence as separate competing approaches
• The evolutionary background and experimental evidence both support the same hypothesis rather than competing with each other
Common Student Mistakes:
1. Aren't there different theories mentioned about microsaccades?
→ Yes, but the author clearly advocates for one theory and uses both evolution and experiments to support it
1. Don't evolution and experiments represent different types of evidence?
→ They're different types of support for the same hypothesis, not competing explanations
• The passage doesn't present two competing hypotheses - it presents one negative view and argues against it
• There's no comparison between evolutionary theory and experimental evidence as separate competing approaches
• The evolutionary background and experimental evidence both support the same hypothesis rather than competing with each other
Common Student Mistakes:
1. Aren't there different theories mentioned about microsaccades?
→ Yes, but the author clearly advocates for one theory and uses both evolution and experiments to support it
1. Don't evolution and experiments represent different types of evidence?
→ They're different types of support for the same hypothesis, not competing explanations
Rate this Solution
Tell us what you think about this solution
Forum Discussions
Start a new discussion
Post
Load More