Method

4.2.1 Participants

Eighty-six (79 females) University of Sussex undergraduate psychology students participated, aged 18-40 years (M = 19.70, SD = 3.00). Participants were volunteers and were remunerated with course credits.

4.2.2 Materials

Mood manipulation check.

Participants completed two 100-point visual analogue scales (VASs) assessing their mood: ‘Please mark a cross along the scale to indicate’ (i) ‘how sad you feel at the present moment’, and (ii) ‘how happy you feel at the present moment’.

Systematic processing facilitator scale.

The composite systematic processing facilitator measure was produced by compiling the four VASs assessing accountability, responsibility, desire for control, and NFC. As described above, these cognitive appraisals were chosen as they are linked with increased systematic processing, and emerge in the literature as dominant characteristics of individuals who systematically process (e.g. Cacioppo, et al., 1986; Harkins & Petty, 1982; Pittman & D'Agostino, 1989; Tetlock & Boettger, 1989). An individual’s processing sufficiency threshold is dictated by a number of factors, of which responsibility, accountability, NFC, and desire for control are four dominant examples in the literature (e.g. Chaiken, et al., 1989). As such, this

composite score is theoretically meaningful, as the co-occurrence of moderately high scores across these four systematic processing facilitators could increase an individual’s sufficiency threshold to the extent that they would persevere with their worrying. See Section 4.3.2 for statistical support for the unitary structure of the systematic processing facilitator measure. A higher score on the systematic processing facilitator measure represents an increased tendency to deploy systematic processing (Chaiken, et al., 1989). The VAS questions were developed by considering the definitions used in the literature, existing measures, and experimental manipulations of the constructs.

Tetlock (1983) defined accountability as “pressures to define one’s opinions to others” (p.74). Indeed, experimental manipulations involve informing the high accountability group that they will need to justify their ideas to others (e.g. Livingston & Sinclair, 2008). The VAS question measuring accountability was ‘Please indicate on the scale below the extent to which you feel that you may have to justify your worries to others’.

The VAS question measuring responsibility was ‘Please mark a cross along the scale to indicate how strongly you hold the belief that if you fail to anticipate (foresee) a potential negative outcome, because you did not worry sufficiently, then you are responsible for the negative outcome’. This was based upon the Responsibility Attitude Scale (Salkovskis, et al., 2000), the most widely used scale of clinically-relevant responsibility beliefs, containing items such as ‘If I don’t act when I can foresee danger, then I am to blame for any consequences if it happens’.

NFC is the tendency to engage in effortful cognitive endeavours (Cacioppo, Petty, & Kao, 1984; Cohen, et al., 1955). The question developed was ‘If you were to start worrying about something right now, to what extent would you want to think over the issue for a long time?’, and derived from its definition as a desire to generate thoughts about an issue, which is the basis of items in the Need for Cognition Scale (Cacioppo, et al., 1984).

The desire for control VAS was ‘Please mark a cross along the scale to indicate how strongly you hold the belief that it is important to have control over things you worry about’, and was based upon Burger and Cooper’s (1979) Desirability of Control Scale.

The cognitive appraisals can occur in the absence of worry, and consequently it is important to assess their relevance to a worry context. Accordingly, the VASs were couched in

terms of a hypothetical worry. Participants assessed their reactions to a hypothetical worry, rather than engaging in a worry bout.

Other measures.

Participants completed a VAS measuring deployment of the AMA stop rule (Davey, 2006b) (‘Please mark a cross along the scale to indicate how strongly you hold the belief that you will stop worrying when you have worried as much as possible’), as this is likely to be a proximal mechanism through which systematic processing is operationalised during the worry process. Participants completed the Penn State Worry Questionnaire (PSWQ; Meyer, et al., 1990, see Chapter 3 for more details), which is the most widely used valid measure of worry. As outlined in Chapter 3, the PSWQ has been used as an outcome measure to assess changes in worrying after a variety of interventions (e.g. Borkovec & Costello, 1993; Goldman, Dugas, Sexton, & Gervais, 2007; Treanor, Erisman, Salters-Pedneault, Roemer, & Orsillo, 2011). Similarly, the PSWQ was used in the present study as an outcome measure across the mood induction groups. The PSWQ consists of 16-items (e.g., ‘Many situations make me worry’), and has good test-retest reliability (Meyer, et al., 1990) and internal consistency (α = .90; Brown, et al., 1992).

4.2.3 Procedure

Stage 1.

After providing consent, participants were randomly assigned to one of three conditions: negative mood (n = 30), neutral mood (n = 30) and cognitive priming (CP; n = 26). Initially, the mood groups were split into high (n = 15) and low (n = 15) saliency. Mood induction saliency was manipulated as individuals may ignore the informational properties of mood if they attribute it to a source unrelated to the task at hand (Schwarz & Clore, 1983). To limit demand characteristics, participants were informed that the study was about mental imagery.

Stage 2 (mood manipulation).

For a review of mood induction procedures, see Chapter 3. This experiment utilized vignettes to induce mood because they allowed for the construction of a convincing cover story that the experiment was investigating imagery, and also enabled the inclusion of a cognitive priming control condition. Vignettes (based on Scott & Cervone, 2002) were played through headphones. The negative mood vignette lasted for 5 min 25 s. Participants in the negative mood group were asked to imagine memories they shared with their best friend, and

their friend becoming terminally ill. The CP group listened to a modified version of the negative vignette, which was slightly shorter at 3 min 42 s because it did not include a few sentences which emphasized that the participant should imagine that the following sentences were happening to them. In the CP vignette, all first person pronouns were substituted by two hypothetical characters, Bill and Joe. So, for example, in the negative mood condition, participants heard the sentence ‘Now think about your best friend’, while the CP group heard ‘Bill and Joe have been good friends’. When the negative mood group heard ‘Now imagine that your friend has become progressively ill over the past few months’, the CP group heard ‘Joe has been feeling progressively ill over the past few months’. Additionally, the CP group rated on a five-point Likert scale the extent that 15 target words were similar to sentences in the vignette. So, for example, the participants were required to rate how similar the sentence ‘Bill and Joe have been good friends’ is to the word ‘comrade’, and how closely the sentence ‘Joe has been feeling progressively ill over the past few months’ is to the word ‘sickly’. Participants in the CP group made their ratings in this similarity task on a 5-point Likert scale (1 = ‘Not at all similar; 5 = ‘very similar’). These ratings were not analysed. Consequently, the CP group heard the same negative words as the negative mood group, but did not experience it in a personally relevant manner. Thus, individuals in the CP group were not expected to show the same level of negative mood or subsequent worry perseveration, forming a control for priming effects. Participants in the neutral mood group were guided to imagine various pieces of their bedroom furniture, for example ‘Visualise where your desk is – look at all the objects that are on your desk’. The neutral mood vignette was 3 min 47 s.

Stage 3 (saliency manipulation).

After the vignette, the high saliency groups were told “It can sometimes change your mood listening to vignettes like that”. The low saliency and the CP groups were not told anything about the possibility of the vignette affecting their mood. A manipulation of the saliency of the mood induction was included as some research suggests that individuals ignore the informational properties of mood if they attribute it to a transient external source of little relevance to the task at hand (Schwarz & Clore, 1983). The saliency manipulation was designed to ensure that mood awareness was not a determining factor and that participants were not simply responding to demand characteristics.

Stage 4 (VAS questionnaire).

Participants completed the 100-point VASs described in section 4.2.2 measuring mood (sadness, happiness), systematic processing facilitators (responsibility, accountability, desire for control, NFC), and AMA deployment.

Stage 5 (worry measures).

Participants took part in the CI to provide a behavioural measure of perseverative worry (Davey, 2006a; Vasey & Borkovec, 1992), see Chapter 3 for details. Use of the CI alongside the PSWQ allows for both behavioural and self-reported worry, respectively, to be examined. The experimenter begins by asking “what is it that worries you about X?” where X is the participant’s current main worry. The experimenter repeats the question, substituting X with the participant’s answer to the first question, and so on. Participants are told there is no right or wrong time to end the interview, and they should end the interview when they choose to. The number of steps generated is taken as a measure of perseveration at the worry task. Afterwards, participants completed the PSWQ.

Stage 6 (debrief).

During the debrief participants were asked what they thought the purpose of the vignette was (saliency manipulation check). Participants were debriefed about the experiment’s aims and provided with the university’s Counselling Service details.

4.2.4 Statistical Analyses

Preacher and Hayes’ (2008) script for conducting mediation with multiple mediators was used. In assessing mediation, it is possible to calculate the direct effect of an independent variable (IV) on a dependent variable (DV) (weight c'), and the indirect effect (weight a × b; where a is the effect of the IV on the mediator, and b is the effect of the mediator on the DV) of the IV on the DV through the proposed mediator, which together make up the total effect. When multiple mediators are hypothesized, one multiple mediator model can be used to estimate total indirect effects (i.e. sum of a × b weights for all mediators) and specific indirect effects (i.e. a × b effect for each mediator).

To estimate indirect effects, bootstrapping was used with n = 5000 resamples. Bootstrapping is a nonparametric resampling technique that takes n samples from the full data and calculates the indirect effects in the resamples; it is preferable to the Sobel test due to its greater power (Preacher & Hayes, 2004). For a further discussion of bootstrapping, see

Preacher and Hayes (2008). Percentile confidence intervals (95%) were constructed as they had the best overall performance on Monte Carlo simulations in terms of controlling Type 1 error rates, and exhibiting reasonable power (Biesanz, Falk, & Savalei, 2010). Indirect effects were considered significant in the case that zero was not contained in the confidence intervals (e.g. Roelofs, Huibers, Peeters, Arntz, & van Os, 2008).