Participants were tested individually in a quiet room in either their own homes or the Affective Neuroscience Laboratory at the University of Melbourne, or in a silent reading area of a public library. They were given a plain language statement describing the experimental procedure (Appendix L), and signed a consent form (Appendix C) prior to the commencement of experimentation.
Self-Report Assessment of Affect, Metacognitive Processing, and Executive Function. The participant was next administered the BDI, BAI, PANAS, RRS, MAAS, and DBS. The experimenter stayed in the room, readying the DMDX task for the next part of the procedure, while the participant filled in the questionnaires, clarifying any points of uncertainty which the participant raised concerning any of the items.
Neutral Switching Task. The participant was next told that they would be presented with words, one at a time, in the middle of the computer screen, and were asked to maintain a silent mental count of how many they saw during each trial (set of words) from each of the two semantic categories, "food" and "household objects". They were instructed to press the spacebar when they had updated their mental count and were ready for the next word. Further, they were requested to do this as quickly as possible, while maintaining accuracy. At the end of each trial, they were asked to report this count to the experimenter. Errors were not assessed as a dependent variable, but were used to ensure that the participants properly understood the task.
Affective Switching Task. The participant was then asked to perform exactly the same task again, only this time with words from different semantic categories. They were told that the words were now words which described them, and were asked to think about whether, if they were described this way, they considered each word to be a positive or negative descriptor. They were asked to therefore maintain a silent mental count of how many "positive" and "negative" words they saw during each trial, reporting this count at the end of each trial. Again, they were instructed to press the spacebar when ready for the next word, and were asked to do this as quickly as possible, while maintaining accuracy. As before, errors were not recorded, but were used to assess understanding of the task.
At the conclusion of the experiment, the participant was debriefed (Appendix M). In addition, at the conclusion of the second testing period (T2), the participant was provided with an opportunity to ask questions regarding the nature of the experimental procedure.