Banos, R.M.(1); Botella, C. (2); Liaño. V. (2); Rey, B. (3); Guerrero, B. (2) & Alcaniz, M. (3)
(1) Universitat de Valencia (Spain)
(2) Universitat Jaume I (Spain)
(3) Universidad Politécnica de Valencia (Spain)
Address contact:
Rosa M.Baños, Ph.D.
Dpto. Personalidad, Evaluación y Tratamientos Psicológicos (Facultad de Psicología)
Avda. Blasco Ibáñez, 21, 46010-Valencia (Spain)
e-mail: banos@uv.es
Phone: + 34 96 3 86 44 76
Fax: +34 96 3 86 46 69
In the lasts decades, it has been developed a set of experimental procedures able to induce emotional changes in participants in a controlled way, manipulating variables inside the laboratory. The initial objective has been to go more deeply into the knowledge of emotions and their relations with cognitions. This set of procedures, called "Mood Induction Procedures" (MIPs), includes a broad diversity of methods (Martin, 1990; Westermann, Spies y Stahl, Hesse 1996) and they can be defined as "strategies whose aim is to provoke in an individual a transitory emotional state in a non natural situation and in a controlled manner; the mood induced tries to be specific and pretends to be an experimental analogue of the mood that would happen in a certain natural situation" (García-Palacios & Baños, 1999, p. 16). MIPs have proven to be efficient in achieving these changes in the target mood. However, the magnitude and the specificity of the change vary according to the specific MIP used.
The meta-analyses made by Martin (1990), Gerrards-Hesse and cols. (1994) and Westermann and cols. (1996) review the different MIPs characteristics and their effectiveness. In these works, the following different MIPs have been pointed out: Self-statements or Velten procedure, music, music "in crescendo", hypnotic suggestion, facial expression, game feedback, social feedback, autobiographical recall, social recall, imagery, empathy, experimenter behaviour, films, threat, public speaking, gift, drugs, social interaction, combination of MIPs. We have selected four of them:
"Self-statements or Velten procedure" has been developed by Velten in 1968. The induction is achieved by means of 60 statements relative to the mood, written in first person. Subjects are asked to read the statements, and to try to feel a mood similar to the one described in the statement.
Music has been used the first time by Sutherland, Newman and Rachman in 1982. Subjects are asked to use the music piece as a base to enter themselves into a mood, and they are told that music alone can't induce the mood automatically and that they must follow their own strategies to reach the mood.
"Autobiographical recall" was developed by Brewer, Doughtie and Lubin (1980). Subjects are asked to remember autobiographical events that provoke in them a certain mood, e.g. that makes them feel alone, rejected, frustrated or hurt.
"Films" (or fragments of films) have been used by the James Gross group (e.g. 1995). Subjects are asked to feel all the emotions provoked by the film as intensely as possible, without trying to content themselves or hide their feelings.
To get a more effective induction, some authors combine different kinds of MIPs. Some of the procedures seem especially appropriate for these combinations. That is the case of very similar procedures, for example the Velten and the Imagery procedures that can be applied simultaneously, like the Velten and the Music procedures.
Effectiveness or success rate: There is a considerable variability in the success rate of the different mood induction procedures. Some successful techniques induce the required mood in more than 75% of cases (Music, Autobiographical Recall, Solitary Recall, Films) and other procedures achieve approximately 50% success (Velten, Social Recall, Facial Expression, Social Feedback) (Martin, 1990). Other studies show similar results (Gerrards-Hesse et al., 1994; Westermann et al., 1996).
Intensity of the induced moods: There are several criteria to assess the intensity of the induced moods, one of them being the time of duration of the induction effects. Some studies talk about 10-15 minutes (Frost y Green, 1982). Another criterion has been to compare the experimentally induced moods with people suffering from a mood disorder (e.g., depression). When both moods are compared (from clinical depressed patients and from induced subjects) the results show that MIPs provoke a medium-sized level of reported depression equivalent to a intermediate clinical level (Clark, 1983; Clark & Teasdale, 1982, 1985).
Range of induced moods: Mostly, MIPs have been used to induce depression and happiness, but there are also some MIPs to induce anxiety, anger, and "no mood", that means a "neutral condition" (Martin 1990).
We think Virtual Reality (VR) may overcome some of the limitations of traditional MIPs. For instance, the duration of the induced mood could be longer (more than 15 minutes) and the mood intensity could be higher. Furthermore, it could be useful to induce a range of different moods.
EMMA project (IST-2001-39192) has developed a MIP using VR in order to induce sadness, happiness, anxiety and relax. We have also included a neutral condition, where no changes in mood are expected. The virtual environment is a park. It has been chosen because it is a "natural" place where other elements (e.g. cinema, music) can be integrated in a believable way. In all five conditions, the virtual environment starts with a narrative, which is different according to the mood to be induced. The user listens to a woman voice (representation of the EMMA avatar) that gives to the user an introduction of the environment and of the mood state. Once inside the environment, the user starts walking by the park. The initial appearance of this virtual environment is the same for all users. However, the aspect changes soon depending on the mood. For example, in the case of sadness, the park is grey, it is a cloudy day, the trees have no leaves, there are no people in the park and the music that is heard is a very sad piece.
After two minutes walking by the park, the user has to go to a band stand. He/she finds an statement located in the lower side of five walls of the stand (it is an eight-faced polyhedron). The five statements are from Velten technique, and they change depending on the mood condition. EMMA asks the user to think about the personal meaning of each statement. At the same time, a piece of music related to the message is heard, and also four images (from IAP, Lang et al., 2001) are shown over the sentence. User has to select one image.
When "Velten technique" have finished, the user continues walking around the park for two minutes. EMMA voice invites the user to go to a summer cinema and see a movie. The aspect of this cinema changes according to the specific mood. The movies are film scenes of short duration with sad, happy, anxious, neutral and relaxing contents. Finally, after having finished the movie visualization, EMMA asks the user to think about a similar personal situation (autobiographical recall) and to explain the experience/situation in loud voice.
At the end, EMMA congratulates the user for his/her experience. In the case of negative moods (i.e., sadness and anxiety), users are invited to walk again around the park with positive (happy or relaxing) content, in order to return to the "reality" with positive moods.
The fist task we are doing at this moment is to validate all the material used in this MIP-VR. Some of this work is just finished In order to assess mood induction and presence, several measures will be used.
Baños, R.M., Botella, C., García-Palacios, A., Villa, H., Perpiñá, C. & Alcañiz, M. (2000) Presence and Reality Judgment in virtual environments: A unitary construct? Cyberpsychology and Behavior, 3 (3), 327-335.
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Clark, D, M. & Teasdale, J.D. (1982). Diurnal variation in clinical depression and accessibility of memories of positive and negative experiences. Journal of Abnormal Psychology, 91, 87-95.
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Frost, R.O. and Green M.L. (1982). Duration and post-experimental removal of Velten mood induction procedure effects. Personality and Social Psychology Bulletin, 8, 341-347.
García-Palacios y Baños (1999). Eficacia de dos procedimientos de inducción del estado de ánimo e influencia de variables moduladoras. Revista de Psicopatología y Psicología Clínica, 4 (1), 15-26.
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