In the study of the emotion, a great diversity of procedures exists to induce emotion, each one with different grade of effectiveness. The traditionally used procedures have some inconvenience and different critical: a) in general, they have not been designed starting from any sums up theoretical position, but rather in to heuristic way (Vicens and Andrés, 1997); b) while in some techniques those "effects of the demand" on the task they are so evident that they constitute an important methodological problem, in other techniques the reliability and effectiveness to induce emotions in the laboratory are more than doubtful (Martin, 1990; Westermann, Spies, Stahl and Hesse, 1996), and; c) their lack of objectivity, since in almost all the methods take place some type of cognitive manipulation and the investigator doesn't only have a scarce control on the stimuli, but rather, also, it cannot control what the fellow revives more than through self-assessment.
Trying to overcome all these critics, Peter's team Lang, being based on the results obtained when analyzing the emotional structure in the space defined by three big dimensions; arousal, affective valence, and control, in the pattern bioinformacional (Lang, 1979), and paying the problems that outline other methods, is developing different material to stimulate standardized and procedures of emotional induction of great repercussion in the empiric investigation (Bradley and Lang, 2000). These instruments are based on a theory that guides their construction (model bioinformacional), they have objective, controllable stimuli and they are relatively free of the "effect of the demand." They are ethical, rapids of administering and they possess a high ecological validity.
In this context the following study is presented that tries of getting the attention about the importance that acquires the election of the procedure used the being a critical variable, to which the investigator should lend a lot of attention.