A cognitive psychologist designs an experiment to test whether a new mnemonic technique improves list recall. Group 1 is taught the mnemonic and is tested individually in a silent laboratory. Group 2 is not taught the mnemonic and is tested in a busy university library. The researcher measures the number of words correctly recalled by each participant.
In this experimental design, the difference in the testing environment (silent laboratory vs. busy library) is best described as:
the independent variable, because it is the primary factor that the researcher intentionally manipulates to observe its direct effect on memory.
the dependent variable, because it is the quantitative metric used to measure each participant's recall performance.
a confounding variable, because it varies systematically alongside the independent variable and could explain the difference in recall scores.
a controlled extraneous variable, because the researcher has successfully kept the environment constant for all participants.
