Moreover, some of the behaviors are the outcomes of unconscious mental activities. In other words, mental processes are conscious and unconscious. But we don’t know which behavior is the outcome of the conscious or unconscious mental processes. So psychological studies based on mental processes alone may not be logical
In an experiment to determine whether a drug reduces anxiety, the experimenter manipulates who in the experiment gets the drug and who gets the placebo. The variable that is manipulated is the drug.
In a double-blind experiment, neither the individuals nor the researchers know who belongs to the control group and the experimental group. In the above experiment the experimenter knows which subjects are getting the drug and placebo. In order to make the above experiment a double blinded one the experimenter should also unaware of what is given to the subjects.
A psychologist decides to study whether Buddhist meditation reduces anxiety and interviews 20 people who meditate regularly and 20 people who do not meditate at all. The experimenter asks a series of questions designed to test anxiety level and finds that those who engage in meditation have less anxiety.
It is possible that people who are less anxious to begin with choose to meditate. Moreover it is not clear from the study that whether the subjects were suffering from anxiety disorders or not before the start of the meditation. It is also not clear that whether the subjects used any other medications at the time of testing the Buddhist meditations. The selection criteria of the subjects are also not evident from the study. It is quiet possible that some of the subjects might be children who usually experiences less anxiety compared to adults.
Identical twins come from same egg and sperm whereas the fraternal twins come from different eggs and sperms. Thus Fraternal twins develop