Final answer:
In a between-subjects design, researchers randomly assign participants to different treatments or conditions, ensuring any lurking variables are equally distributed and that the observed differences are due to the treatments, thus allowing for cause-and-effect analysis.
Step-by-step explanation:
In a between-subjects design, the researcher aims to ensure that the separate groups of participants are equivalent at the outset of the experiment, except for the different conditions or treatments they receive. By randomly assigning participants to treatment conditions, all of the potential lurking variables are spread equally among the groups. This ensures that the only difference between the groups is the one imposed by the researcher. As a result, any different outcomes observed in the response variable must be solely attributed to the effect of the treatments or conditions. If a study is designed correctly with control groups and random assignment, these measures facilitate establishing a cause-and-effect connection between the independent (explanatory) and dependent (response) variables, eliminating the influence of confounding variables.