Critical Reasoning

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

A. When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.

B. In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.

C. The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

D. If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.

E. When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.

OA C

My explanation

Tiger beetles are such fast runners that they can capture virtually any nonflying insect.
However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack.
Theory1: Perhaps they cannot maintain their pace and must pause for a moment's rest;
Theory2: while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

A. When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(Does not fit as insect is moving towards the beetle. OFS)

D. If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
Ending a pursuit is neither mentioned nor favorable to any one of the thesis.

E. When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.
(Response to suddenly introduced obstacles is out of scope.)

I got struck between B and C.

B. In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(I chose B as I felt it pauses because of its visual blurr)

C. The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(This supports the first theory but how can think we that the beetle increases its speed after its next pause. )

can someone explain why B is wrong and C is right?

Mechmeera wrote: My explanation

Tiger beetles are such fast runners that they can capture virtually any nonflying insect.
However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack.
Theory1: Perhaps they cannot maintain their pace and must pause for a moment's rest;
Theory2: while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

A. When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(Does not fit as insect is moving towards the beetle. OFS)

This goes against both. If the beetle were not able to see without pausing it would not immediately turn. If it needed to rest it would pause when it runs away as it does when it runs toward.

D. If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
Ending a pursuit is neither mentioned nor favorable to any one of the thesis.

E. When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.
(Response to suddenly introduced obstacles is out of scope.)

I got struck between B and C.

can someone explain why B is wrong and C is right?

B. In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(I chose B as I felt it pauses because of its visual blurr)

If beetle responds immediately to changes in the insect's direction, it must not have trouble seeing. If it had trouble seeing, it would often only after pausing respond to changes in direction. So this goes against both.

C. The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(This supports the first theory but how can think we that the beetle increases its speed after its next pause. )

This goes against the first theory, because the beetle must not need rest or it would need more frequent pauses at higher speed. It supports the second theory, because the beetle does not change pace until pausing, possibly indicating that not until the beetle pauses does it see that the insect has started to flee.

Sorry. I kind of misread the topic.

I had this question in OG 2016. they changed the correct answer to
"In pursuing a swerving insect, a beetle alters its course while running and its pauses become more frequent as the chase progresses.
I don't understand how this strengthens the second hypothesis and undermines the first one. Can someone help?

selina.yang wrote:I had this question in OG 2016. they changed the correct answer to
"In pursuing a swerving insect, a beetle alters its course while running and its pauses become more frequent as the chase progresses.
I don't understand how this strengthens the second hypothesis and undermines the first one. Can someone help?

In pursuing a swerving insect, a beetle alters its course while running.
Since the beetle is able to ALTER ITS COURSE in response to a SWERVING insect, the hypothesis that running tiger beetles are unable to process rapidly changing visual information is WEAKENED.

Its pauses become more frequent as the chase progresses.
Here, the beetle finds it increasingly difficult to maintain its pace as the CHASE PROGRESSES, with the result that its pauses become MORE FREQUENT -- information that STRENGTHENS the hypothesis that beetles cannot maintain their pace and must pause for a moment's rest.

GMATGuruNY wrote:

selina.yang wrote:I had this question in OG 2016. they changed the correct answer to
"In pursuing a swerving insect, a beetle alters its course while running and its pauses become more frequent as the chase progresses.
I don't understand how this strengthens the second hypothesis and undermines the first one. Can someone help?

In pursuing a swerving insect, a beetle alters its course while running.
Since the beetle is able to ALTER ITS COURSE in response to a SWERVING insect, the hypothesis that running tiger beetles are unable to process rapidly changing visual information is WEAKENED.

Its pauses become more frequent as the chase progresses.
Here, the beetle finds it increasingly difficult to maintain its pace as the CHASE PROGRESSES, with the result that its pauses become MORE FREQUENT -- information that STRENGTHENS the hypothesis that beetles cannot maintain their pace and must pause for a moment's rest.

Thanks, but seems the explanation in OG is opposite. It says, this one strengthens the second hypothesis: the beetle's pauses increase as the variety of visual information that it needs to deal with increases. This makes me confused.

selina.yang wrote:Thanks, but seems the explanation in OG is opposite. It says, this one strengthens the second hypothesis: the beetle's pauses increase as the variety of visual information that it needs to deal with increases. This makes me confused.

The explanation in the OG seems faulty.
According to the OA, a beetle in pursuit of a swerving insect is able to alter its course WHILE RUNNING.
This information undermines the second hypothesis, which contends that rapidly changing visual information causes tigers beetles to GO BLIND AND STOP.
A blind beetle cannot alter its course while running.