Researchers conditioned a group of flies to associate a particular odor with a weak electric shock. Twenty-four and forty-eight hours later the researchers conducted tests on the flies, both individually and in groups, to determine whether the flies retained the conditioning. When tested individually, the flies were significantly less likely to avoid areas marked with the odor. The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor.
The researchers’ hypothesis requires which of the following assumptions?
A. The flies do not give off odors as alarm signals.
B. Flies that did not avoid the odor when tested individually were not merely following other flies’ movements when tested in a group.
C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
D. Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.
E. An electric shock was used during the flies’ conditioning and during the later tests.
SOLUTION
Passage Analysis:
| Text from Passage | Analysis |
| Researchers conditioned a group of flies to associate a particular odor with a weak electric shock. | What it says: Scientists trained flies to connect a specific smell with getting shocked What it does: Sets up the experimental foundation for what’s coming next What it is: Study setup/methodology |
| Twenty-four and forty-eight hours later the researchers conducted tests on the flies, both individually and in groups, to determine whether the flies retained the conditioning. | What it says: Scientists tested the flies 1-2 days later in two different ways to see if they still remembered the training What it does: Describes the testing phase that builds on the initial conditioning What it is: Study methodology/procedure |
| When tested individually, the flies were significantly less likely to avoid areas marked with the odor. | What it says: Solo flies mostly forgot their training and didn’t avoid the smell anymore What it does: Reveals a key finding that contrasts with what we’d expect from the conditioning What it is: Study finding Visualization: Individual flies: 20-30% avoid the odor (vs expected 70-80%) |
| The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor. | What it says: Scientists think that when flies are together, one fly that remembers sends out a warning signal that helps other flies remember to avoid the smell What it does: Provides the researchers’ explanation for why group vs individual testing might show different results What it is: Researchers’ hypothesis Visualization: Group scenario: Remembering fly (10%) ā sends alarm signal ā other flies (90%) ā retriggered memory ā all avoid odor |
Argument Flow:
We start with an experiment setup where flies learn to fear a certain smell. Then we get the testing procedure and a surprising result – individual flies don’t avoid the smell much anymore. Finally, researchers propose their explanation for this unexpected finding.
Main Conclusion:
Researchers believe that flies in groups help each other remember conditioning through alarm signals, which explains why individual flies perform worse than expected.
Logical Structure:
This isn’t a complete argument yet – it’s presenting a hypothesis that attempts to explain an experimental observation. The researchers use the unexpected individual test results as evidence that suggests flies might need social cues (alarm signals from other flies) to maintain their conditioned responses.
Prethinking:
Question type:
Assumption – We need to find what must be true for the researchers’ hypothesis to work. The hypothesis claims that flies in groups avoid the odor better because some flies that remember send alarm signals to help other flies remember.
Precision of Claims
The key claims involve behavioral differences (individual vs group fly responses), memory retention (some flies remembering conditioning), and communication mechanisms (alarm signals between flies).
Strategy
To find assumptions, we need to identify what could make this hypothesis fall apart while keeping the given facts intact. The hypothesis has several moving parts: some flies must retain memory, they must be able to send signals, other flies must receive these signals, and this must cause avoidance behavior. We’ll look for what’s necessary for this chain to work.
Answer Choices Explained
A. The flies do not give off odors as alarm signals.
This choice states ‘The flies do not give off odors as alarm signals.’ This actually contradicts what we need for the hypothesis to work. The researchers’ hypothesis specifically mentions that flies give off ‘alarm signals’ to help other flies remember. While the hypothesis doesn’t specify that these signals must be odors, saying flies definitely don’t use odors as signals isn’t necessary for the hypothesis. The researchers just need some form of alarm signal to exist – it could be odors, sounds, movements, or other forms of communication.
B. Flies that did not avoid the odor when tested individually were not merely following other flies’ movements when tested in a group.
This choice states ‘Flies that did not avoid the odor when tested individually were not merely following other flies’ movements when tested in a group.’ This is exactly what the hypothesis requires. If the flies who forgot individually were just copying other flies’ movements in groups (without their memory actually being retriggered), then the researchers’ explanation about alarm signals reactivating conditioned associations would be wrong. The hypothesis assumes that the group avoidance behavior represents genuine memory retriggering through alarm signals, not just behavioral mimicry.
C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
This choice states ‘Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.’ This isn’t necessary for the hypothesis. The researchers’ explanation could work even if all flies in groups showed similar avoidance rates. What matters is that the alarm signal mechanism helps flies remember – it doesn’t require that previously forgetful flies remain less responsive than others in group settings.
D. Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.
This choice states ‘Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.’ The researchers’ hypothesis doesn’t depend on the flies’ initial reaction to the odor. Whether flies originally liked, disliked, or were neutral about the odor doesn’t affect whether alarm signals can help them remember their conditioning. The conditioning process and alarm signal mechanism work independently of pre-experiment odor preferences.
E. An electric shock was used during the flies’ conditioning and during the later tests.
This choice states ‘An electric shock was used during the flies’ conditioning and during the later tests.’ The hypothesis doesn’t require shocks during the testing phase. The passage tells us shocks were used during initial conditioning, but the later tests were just about whether flies avoided the odor – no mention of continued shocking. The alarm signal explanation works based on the original conditioning, regardless of what happened during testing.
