For a data-based inference question, identify each variable, note what is held constant, and connect each experimental result to the narrowest supported conclusion. Reject choices that reverse relationships, ignore controlled evidence, or reduce a multifaceted result to one cause.
Hints
- Hint 1
Separate the measured features
Track the evidence about call tempo separately from the evidence about frequency.
- Hint 2
Examine the controlled comparison
Consider what remained different after approach speed and distance from shelter were matched.
- Hint 3
Connect calls with responses
Determine which feature affected how soon listeners fled and which feature affected where they looked.
Step-by-step
- Step 1
Distinguish the call features
Call tempo varied mainly with approach speed and the caller's distance from shelter, not with whether the predator was aerial or terrestrial.
- Step 2
Interpret the playback evidence
Faster-tempo calls caused listeners to flee sooner, supporting the inference that tempo communicates urgency. By contrast, the distinctive frequency pattern remained associated with aerial predators after other variables were controlled, and that pattern prompted upward scanning.
- Step 3
Combine the findings
The findings do not support a single-purpose interpretation of alarm-call variation. Instead, they indicate that different acoustic features can communicate different aspects of a threat.