ABSTRACT
Psychological research is mostly not observation but manipulation. 1 The human mind does not reveal its essential characters without researchers’ activity. Only by establishing the controlled connections between stimuli and responses does a rational analysis of human cognition become possible. The control of the connections between stimuli and responses may vary their intenseness, but observations can never be absolutely free. This means that the goals, presuppositions and intuitions of the researcher are necessarily intertwined in the operationalization of scientific ideas.
