In this infamous study, employees at the Hawthorne Works in Cicero, Illinois were told ahead of time that they were part of an experiment designed to measure, among other things, worker productivity. Initial results looked very promising; however, subsequent research and investigation revealed that the novelty of being part of an experiment likely caused worker productivity to rise. As a result, this confounded results and inflated (albeit unintentionally) the data. Today, the use of deception or post-experimental debriefing is encouraged if a Hawthorne effect is expected in a research design.

Subjects can be deceived on the absolute true nature of the experiment if these two conditions have been met:

1) It is not feasible to use alternates to deception

2) The potential findings justify the use of deception due to their scientific, educational, or applied value

In order to do ethical research, researchers must obtain informed consent from research participants. Informed consent is sometimes obtained verbally rather than using a written form. Researchers usually need to have their way of obtaining informed consent approved by an institutional review board.

According to the ethic laws for psychological experiments and studies, all participants must be debriefed after the study. 

Using deception in research is covered by the American Psychiatric Association's (APA) ethics code. Standard 8.07 of the code states “psychologists do not deceive prospective participants about research that is reasonably expected to cause physical pain or severe emotional distress.” Dr. R's study involves both deception and physical pain; therefore, her study is unethical.

An "institutional review board" (IRB), also known as an ethical review board (ERB), is a committee that has been formally designated to approve, monitor, and review psychological research involving human subjects. In the United States, IRBs are governed by Title 45 Code of Federal Regulations Part 46. 

As the intake of sugars increases, the activity of the mice increases. If this were to be graphed, it would indicate a positive correlation from a line with a positive slope. It is important to note that this would be a correlation; furthermore, correlation simply reveals possible relationships and does not necessarily indicate causation, which may be the result of a lurking or confounding variable.

Almost every experiment has a control group, along with one or more experimental groups. A control group must be included to serve as a baseline comparison in contrast to the experimental group. This allows experimenters to determine whether the treatment (the independent variable) creates significant change. The control group is not given experimental treatment, but may be given a placebo. Any differences between the experimental group and control group can be attributed solely to the experimental variable, as this is meant to be the only distinguishng feature between the experimental and control groups.

Longitudinal studies retest the same subjects multiple times over a long period of time. Some longitudinal studies can span several decades, depending on the type of data being collected. These types of studies are especially popular in the field of developmental psychology.

Applied research is always conducted with the end goal of trying to solve practical problems. The other choices may seek to help solve various issues, but this is not always the case.