Question 9·Hard·Inferences
Researchers studying "embodied perception" have argued that physical effort alters visual judgments: hills look steeper to fatigued hikers, and distances look longer to people carrying heavy backpacks. To test whether such effects reflect changes in perception or in how people choose to respond, psychologists Claire Zedaker and Minh Tran ran three experiments. In the first, participants either wore a heavy backpack or no backpack and gave verbal estimates of a hill’s steepness. In the second, the same groups adjusted a handheld aperture to match the hill’s slope—a sensorimotor task presented as unrelated to the backpack. The heavy-backpack group reported steeper angles verbally in the first experiment, but the groups showed no difference in the aperture-matching task. In a third experiment, participants were offered bonuses for accuracy and were told the backpack was a "physiological monitoring vest"; under those conditions, the verbal difference also disappeared. These findings most strongly suggest that _____
Which choice most logically completes the text?
For inference questions about scientific studies, first identify the researchers’ stated goal (what competing explanations they are testing). Then track results across conditions and tasks, looking for patterns that hold up when methodology or instructions change. Eliminate choices that explain only one experiment or that require assumptions not supported by the text. Choose the option that best accounts for all reported findings.
Hints
Clarify the purpose of the experiments
Look back at the sentence that explains why Zedaker and Tran ran their experiments. What two possibilities were they trying to distinguish between?
Compare the tasks across experiments
One experiment uses verbal estimates and another uses aperture matching. In which task did the backpack make a difference, and in which did it not?
Focus on the effect of changing instructions and incentives
In the third experiment, how was the backpack described, and how were participants rewarded? What happened to the verbal difference?
Look for an answer that explains all three findings
Pick the choice that explains (1) the initial verbal difference, (2) the lack of difference in the aperture task, and (3) why the verbal difference disappears when expectations/incentives change.
Step-by-step Explanation
Identify the researchers’ main question
The passage states that the psychologists wanted to test “whether such effects reflect changes in perception or in how people choose to respond.” So the key issue is: does physical effort truly change what people visually perceive, or does it just change their reports/answers?
Understand what happened in Experiments 1 and 2
In Experiment 1, with verbal estimates, backpack wearers reported steeper hills.
But in Experiment 2, participants used aperture matching, a more sensorimotor task presented as unrelated to the backpack. There was no difference between backpack and no-backpack groups.
If the backpack were changing perception itself, you would expect the effect to carry over beyond a single reporting method; the fact that it does not suggests the effect may be tied to how participants respond in a verbal setting.
Use Experiment 3 to refine the conclusion
In Experiment 3, participants were told the backpack was a “physiological monitoring vest” and were paid bonuses for accuracy. Under these conditions, the verbal difference between backpack and no-backpack groups disappeared.
When expectations about the backpack’s purpose are altered and accuracy is emphasized, participants stop giving the “steeper with backpack” verbal response. That points to response tendencies/expectations rather than altered perception.
Match the overall pattern to the best conclusion
Putting it all together:
- The backpack effect shows up in verbal reports under standard conditions.
- It does not show up in an ostensibly more objective, backpack-irrelevant matching task.
- It also disappears in verbal reports once demand characteristics are reduced and accuracy is incentivized.
These results most strongly support the conclusion that previous reports of effort-influenced perception largely reflect participants’ expectations about how they should respond.