[Campbell Biology P.1063] The experiment described in the text focused on the role of expecta... | Practice Question

The experiment described in the text focused on the role of expectation on ACTH secretion. However, like most experiments, there may be variables that were not explicitly controlled but could influence the results. Which of the following are potential uncontrolled variables in this experiment, based on the provided description?

  • A: Individual differences in subjects' natural sleep cycles or chronotypes.
  • B: Subjects' dietary intake or caffeine consumption prior to the experiment.
  • C: Environmental factors in the sleep laboratory, such as light or temperature.
  • D: The precise timing of blood sample collection relative to the moment of actual waking.
  • E: Subjects' stress levels or anxiety about the experiment itself.

Explanation

The experiment description does not mention controlling for individual variations in sleep patterns A , pre-experiment dietary or caffeine intake B , specific environmental conditions like light or temperature in the lab C , or the psychological state/anxiety of subjects E . These factors could influence ACTH levels and thus represent potential uncontrolled variables.