Why are psychological experiments often conducted under special controlled conditions that do not occur naturally outside the laboratory?

The reality are subjected to different and unexpected factors which are not present in a control environment, as a laboratory. Not only, the introduction of the study might change the behavior of the subject as well.

As explained by Kurt Lewin: “Experimentation in the laboratory occurs, socially speaking, on an island quite isolated from the life of society” (Lewin, 1944, p. 286).

Let's take a brief example. A group of scientists wants to test the generosity of people, the experiment once conducted in a laboratory might result in a higher generosity actions than in real life. Why? Because of the social pressure. In order to keep the natural behavior of the subjects in a laboratory, a significant number of factors have to be taken in consideration. Therefore, in such cases, the experiments outside a laboratory might result in more reliable data.

answer; the civil right act of 1964;