An experiment was designed to test the effects of rehearsal on memory. In order to hold the extraneous variable "time of day" constant, the experimenter decides to run two groups simultaneously. The rehearsal group is given the instructions live and the other non-rehearsal group sees the same instructions in the next room via closed-circuit television. Live-versus- television is
A) an extraneous variable, but not a confounding variable.
B) a confounding variable, but not an extraneous variable.
C) neither an extraneous nor a confounding variable.
D) both an extraneous and a confounding variable.

Question

Quizplus · Accepted Answer

Live-versus-television instruction delivery introduces a difference in the experimental conditions beyond the intended independent variable (rehearsal), potentially affecting the outcome (memory). This makes it both an extraneous variable (an unwanted variable that might affect the results) and a confounding variable (a variable that varies along with the independent variable, making it difficult to discern the effect of the independent variable alone).

An Experiment Was Designed to Test the Effects of Rehearsal