RESOLUCIONES Y PRECEDENTES DEL TRIBUNAL REGISTRAL

The relationships between the measures will be examined to determine the characteristics of the sample. Newby and Moulds (2011a) found no significant between group differences in the number days on which currently depressed, recovered depressed and never depressed individuals had experienced an intrusive memory over the previous week, although the never depressed group had experienced the memory fewer times within a day than the currently depressed group. Therefore, it is unclear whether the correlation between the memory frequency (retrospective or diary rating) and BDI-II score will be significant on a continuous measure of

depressive symptomatology. Previous research suggests that the frequency of intrusive memories does not correlate with intrusive memory-related distress, as measured on a 100-point scale (Starr & Moulds, 2006; Williams & Moulds, 2007c). However, previous research does suggest there is a significant positive correlation between subjective distress, as measured by the IES, which is the measure of subjective distress to be used in current study, and BDI-II scores (Hauer, Wessel, & Merckelbach, 2006). This is consistent with the suggestion that negative cognitive biases in low mood individuals are also reflected in the experience of both involuntary and voluntary memories (Watson et al., 2012). A significant correlation between trait rumination and intrusion-related distress (measured by the IES) is also expected to be significant based on previous research, which used a 100-point rating scale for

distress (Starr & Moulds, 2006; Williams & Moulds, 2008b), rather than the IES used in the current study. A positive significant correlation between RRS and BDI-II is also expected also on the basis of existing research (Nolen-Hoeksema, 1991; Spasojević & Alloy, 2001).

Methods: Participants:

The study was given ethical approval by the University Teaching and Research Ethics Committee (UTREC). Participants volunteered for the study through the SONA system (which is open to students and the local community) on the basis of having recently experienced intrusive memories and being fluent English speakers. Participation involved two sessions (1 hour and 30 minutes total).In total 38 participants took part, 1 of whom was excluded due to reporting a frequency of

intrusive memories more than 3 SDs above the mean (= 54 memories, details below)

SDs above the mean, therefore no other data were excluded. Consequently, 35 participants remained for data analysis (26 female, 9 male, age range 18-29). Power analysis revealed that a sample size of 34 would be required to detect a medium effect size at the 95% confidence interval using the .05 criterion of statistical significance. Therefore, the sample size was relatively small. Participants were reimbursed £10 total for their time.

Stimuli were single letters presented 40 mm x 40 mm in size, presented in black font and presented centrally on a white screen. The cue letter consisted either of an A or a B, and target letters consisted either of an X or a Y. The target-letter X required a ‘target’ response (keyboard press: z) only if preceded by the letter A. Any other combination of cue-target letter pairs (i.e. AY, BX, BY trials) required a ‘non-target’ response (keyboard press: m). Each trial began with a fixation cross on screen (300 ms), followed by the cue-letter (300 ms), followed a blank screen (SOA: 700 ms or 4700 ms), followed by the target-letter (presented until response) and finally a blank screen was presented (300 ms). See Figure 4.1 for an example of a single trial. The task was made up of 4 blocks, each containing 100 cue-target-pair trials. The SOA was randomly chosen, and each SOA was presented equally often in each block. 70% of trials were AX trials, the rest were divided equally between AY, BX and BY trials (10% each), with trial order randomly chosen within each block. At the end of each block, participants were shown their mean accuracy rate for the previous block (as a %) and could take a short break before continuing. Participants first completed 2 practice blocks (of 10 cue-target pairs), and were given the mean accuracy rate after each practice block and the opportunity to ask the researcher any questions before beginning the experimental trials.

Figure 4.1. Example of a single trial on the AX-CPT.

Procedure:

Participants first completed the AX-CPT task, lasting approximately 30 minutes. Participants were then taken through the Intrusive Memory Interview and completed the IES, BDI-II and the RRS self-report questionnaires in a randomized order. Participants were then given the instructions for keeping the diary over the next 7 days, after which they returned to the research laboratory to hand in their diaries, to be debriefed and to be reimbursed.

Results:

Firstly, the overall task data will be presented, followed by the group comparisons. The overall task data will be analysed using a 1-way repeated-measures ANOVA with the within-subjects factor SOA (short, long) for the ‘target’ trials. For the ‘non-target’ trials, a repeated-measures ANOVA with the within-subjects factors SOA (short, long) and condition (AY, BX, BY) will be conducted. The following group splits will then be conducted; retrospective, diary, IES, RRS and BDI-II. The group ‘target’ trial comparison will comprise of a 1-way repeated-measures ANOVA with the within-

subjects factor SOA (short, long) and the between-subjects factor (as defined in the following sections). For the ‘non-target’ trials, this will comprise of a repeated- measures ANOVA with the within-subjects factors SOA (short, long) and condition (AY, BX, BY) and the between-subjects factor. For the between-group analyses, only effects involving the factor group will be reported. Bonferroni corrections were made to post-hoc comparisons to minimise the risk of a Type II error. However, given the relatively small sample size, Bonferroni corrections were not made to the initial between-group comparisons.