La explicación desde diversas miradas

Chapter 3 successfully manipulated negative mood, but failed to find any significant difference in rule-based or non-rule-based category learning performance. Chapter 2 measured negative mood as well as depressive symptoms, but negative mood did not correlate significantly with performance. Current depressive symptoms did correlate negatively with complex rule-based performance, but when positive mood was taken into account this correlation was no longer significant.

Prior research on the influence of negative mood on cognitive processing has been mixed, with some research demonstrating that negative mood narrows attention (Baumann & Kuhl, 2005; Gasper & Clore, 2002; Mikulincer, Kedem, & Paz, 1990a; Mikulincer, Paz, & Kedem, 1990b), some research demonstrating it broadens attention (Gable & Harmon- Jones, 2010), and other research reporting null findings (Isen, Daubman, & Nowicki, 1987; Murray, Sujan, Hirt, & Sujan, 1990). Overall the literature suggests it is more common for manipulated negative mood to result in null effects. Several possibilities might explain my results as well as previous results.

Isen (1985) suggests that people are motivated to maintain positive mood states, and motivated to resist negative states. The resistance of negative mood is called mood repair. A related explanation is that even successful negative mood manipulations do not last long enough to have an influence on performance in many tasks. This could be due to mood repair strategies or it could be due to a lack of rehearsal of the negative information (which could be construed as part of the mood repair process). For instance Baumann and

Kuhl (2005) reported that negative mood resulted in slower responses on trials that required a global response. What is noteworthy about their manipulation is that

participants in the negative mood condition were primed with a negatively valenced word before each trial, unlike most experiments where the mood manipulation precedes and does not continue into the experimental task. Similarly, Gable and Harmon-Jones (2010) primed participants before each response trial with a neutral or negatively valenced picture. In both cases the mood manipulations were maintained on a trial-by-trial basis, and resulted in significant results.

A third related possibility to explain why manipulated negative mood did not negatively influence rule-based category learning performance is that for most participants it is unusual to focus on negative events/feelings evoked by mood manipulations to the extent that it takes up space in working memory for a prolonged period of time, in other words, most people are able to regulate their emotions such that they do not experience negative mood for very long in an experimental situation. The hallmark of anxiety is worry, which can be defined as persistent, relatively uncontrollable negative thoughts (Borkovec, Robinson, Pruzinsky, & Depree, 1983), and a symptom of depression is rumination, which can be defined as repetitive, negative, and self-focused thoughts about the future impact of current depressive feelings (Nolen-Hoeksema, 1991). It can be argued that anxiety and depression each represent an impaired ability to regulate one’s emotions, particularly negative ones, although paradoxically both worry and rumination are considered to represent attempts to regulate one’s negative emotions (Borkovec et al., 1983; Gross, 1999). Rumination is linked to increased negative mood and depressive symptoms (Nolen-Hoeksema & Morrow, 1991), and people high in trait rumination are more likely to become depressed (Just & Alloy, 1997). Likewise worry is related to increased anxiety (Borkovec et al., 1983). Worry and rumination both involve a

significant verbal component (Fresco, Frankel, Mennin, Turk, & Heimberg, 2002; Stober, Tepperwien, & Staak, 2000). It is possible that for most individuals, an experimental manipulation of negative mood does not result in the persistent negative thoughts associated with anxiety and depressive disorders that are related to impaired executive functions (see Austin, Mitchell, & Goodwin, 2001; and Castaneda, Tuulio-Henriksson, Marttunen, Suvisaari, & Lönnqvist, 2008 for reviews). Again, it is noteworthy that two

successful negative mood inductions that resulted in significantly altered performance used trial-by-trial exposure to negatively valenced stimuli (Baumann & Kuhl, 2005; Gable & Harmon-Jones, 2010). However Gasper and Clore (2002) did not use trial-by- trial maintenance of negative mood, and reported significant results. Participants in the experiment wrote about a “sad experience” and then completed a brief global-local processing task. It is possible that because writing about a sad experience resulted in a negative mood state that persisted throughout the brief task.

Thus it is possible that a trial-by-trial negative mood induction might result in a significant reduction in rule-based category learning performance. In contrast positive mood inductions are posited to result in a release of dopamine in frontal brain regions and the effects of this release have been found to last about 30 minutes (Ashby et al., 1999). Thus successful positive mood inductions should not require maintenance in the way that negative mood inductions appear to. Evidence in support of the idea that negative mood inductions do not last as long as positive mood inductions argument comes from Kliegel et al. (2005), who reported significant performance differences between negative and neutral mood conditions in the first five minutes of the experimental task following the mood induction procedures.