Through research, empirical evidence is obtained based on information obtained from experiments and scientific observations that validate current theories, modify them or launch new ones. In psychological research, certain criteria are taken into account: description of human behavior, explanation of the causes of behavior and making predictions about the conditions that determine human behavior. Thus, we can identify the purpose of scientific research in psychology as the explanation, understanding and prediction of human behaviors. The complexity of the object of study and the subjective nature of the psychic has consequences in terms of methodology, conditioning a succession of distinct, particular aspects. In psychological research, as in other areas of research, an established method for investigation is not constant, permanent. On the contrary, over time, it will undergo a series of corrections, modifications and improvements through which it will obtain an adequate and efficient use. Currently, specialists believe that a unique method used in psychological research is not sufficient for psychological and scientific knowledge of the human subject, which requires the development of a research strategy. The methods used in a research must be known by the psychologist and understood by the person-researched, valid, convenient to use, to provide possibilities for mathematical and standardized data processing. The methodologies, as well as the methodological practices associated with them, although extremely varied, even inconsistent with each other given the variety and non-concordance of schools and psychological orientations, can still be grouped according to their specificity. Lazăr Vlăsceanu (1982), referring to the dominant methodological guidelines in contemporary sociology, considers that they could be classified, according to the theoretical principles that generated a certain way of approaching social reality, into two main categories: objective methodologies and interpretive methodologies. With very small tweaks - the replacement of society with the individual in objective methodologies - these methodologies are also practiced in psychology, in addition, psychology contains a third type of methodologies, which we call mixed, which are its own.