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Procedures

Subjects were fully informed at the outset of the experiment of the nature of the trials about to occur. They were given three EKG electrodes and the experimenter described their proper placement. The subject was instructed to take a diagram with them into the bathroom to put the electrodes on in private. Upon their return, the experimenter assisted the subject in properly putting on the GSR (the electrodes were attached to the distal phalanges of the index and middle fingers of the left hand) and BVP (secured to the ring finger of the left hand) sensor. After verifying that the signals being received were good, the experimenter started the program that presented a screen of consent to the subject. The screen of consent informed the subject that if they did not want their data used in the experiment they could retract it at any time, or abort the session if they so desired. All subjects freely consented.gif

All questions regarding the experiment, the sensors, or the instructions were answered before beginning the test. The experimenter reminded the subject again to remain still and not vocalize for the duration of the experiment, and to press the mouse firmly after each slide. They were informed of the 3 second blank screen delay before the appearance of each slide and instructed to relax and let their signals return to their baseline during this pause. Subjects were also reminded to allow themselves to feel the power of each emotional response before proceeding to the next slide.gif

Three seconds of blank screen followed the slider question page, and preceded the next stimulus. This was required to allow the time dependent body responses, namely HR and SC, to re-stabilize between slides. Additionally, only the first ten seconds of the signals for each slide was used in the HR and SC analysis, because the signal response dampened as the subject became de-sensitized to the stimulus.

The measured sentic data for each subject was compared against the collected self-reported data. In future work it should also be compared against theoretical IAPS results for each slide stimulus and against measured and theoretical HR acceleration. Comparing, sentic data against the Lang database would provide a method to corroborate the subject's self-reported measure of valence.

The null hypothesis, that there exists no relation between sentic data and valence, can be rejected if there exists a correlation.


next up previous
Next: Results Up: Method Previous: Design

Dana L Kirsch
Mon May 24 16:34:14 EDT 1999