Question: A researcher assesses participants' attitude toward marijuana, presents them with a persuasive seminar favoring liberalization of marijuana laws, and then reassesses their attitude toward the drug. However, between assessment 1 and assessment 2, the President also advocates liberalization of marijuana laws. If the researcher does not use a control group, any differences observed are likely to be caused by ________ effects. Group of answer choices maturation testing history regression. Need Assignment Help?