Comprobación de Hipótesis

While physiological measures have been previously used to assess promotional commercial marketing campaigns (e.g., Ohme, Reykowska, Wiener, & Choromanska, 2010b), these measures are less commonly used to assess road safety advertisements.

However, one physiological measure which has recently been applied to measure emotional

70 reactions towards emotional road safety advertisements is the skin conductance response

(SCR). SCR is a physiological measure assumed to reflect both positive and negative emotional arousal (Boucsein et al., 2012). To measure SCR, electrodes are attached to the palm of an individual’s hand or alternatively, on the tips of two fingers to measure arousal responses from the sweat glands.

One SCR study in a road safety advertising context found that SCR differed depending on the type of advertisement (Thornton, 2005). Thornton (2005) recruited 160 participants to view one of eight road safety advertisements. Of those advertisements, four were fear-only advertisements and four were fear-relief advertisements. The findings indicated that arousal levels differed depending on the content of the advertisement.

Specifically, when the initial shock of the advertisement was presented on screen (e.g., vehicle hitting a pedestrian) there was an increase in the arousal felt by the participants compared to their earlier arousal recordings at the beginning of the advertisement.

While the SCR can provide researchers with the precise moments that arousal occurs throughout one’s exposure to an advertisement, this physiological measure cannot provide information on the persuasiveness of the advertisement (Algie & Rossiter, 2004). Thus, more sensitive physiological measures of cognitive processes (beyond arousal), such as ERPs, are required to assess message processing and subsequent, message persuasiveness. To date, no published studies have applied neurological methods, such as ERPs, to examine processing of road safety messages. Therefore, the following section draws upon research in the health communication field that has applied neurological measures to assess processing and subsequent acceptance of health communication messages.

5.6.2 ERP and functional Magnetic Resonance Imaging (fMRI) and advertisements Only recently have researchers started to apply neuroimaging measures to examine brain activity in response to advertisement exposure. While an array of marketing studies

71 have used EEG to observe differences in neural activity towards television commercials that

promote product brands (e.g., Astolfi et al., 2008a,b; Ohme, Matukin, & Szczurko, 2010a;

Ohme, et al., 2009, 2010b; Vecchiato et al., 2010a,b), fewer studies have used ERPs or fMRI (a spatial resolution method whereby participants view stimuli whilst brain images are recorded) to examine processing of health communication messages (for exceptions see Chua, Liberzon, Welsh, & Strecher, 2009a; Chua, Polk, Welsh, Liberzon, & Strecher, 2009b;

Falk, Berkman, Mann, Harrison, Lieberman, 2010; Falk, Berkman, Whalen, & Lieberman, 2011; Kessels, Ruiter, Brug, & Jansma, 2011; Kessels, Ruiter, & Jansma, 2010; Ruiter, Kessels, Jansma, & Brug, 2006).

Ruiter et al. (2006), for instance, designed a dual-paradigm task to assess if message tailoring influenced attention and processing towards the messages. In this task, individuals were exposed to auditory stimuli while reading either a tailored (i.e., high personal relevance) or non-tailored (i.e., low personal relevance) nutrition education message. The findings revealed that individuals who viewed the non-tailored message demonstrated greater attention towards the auditory stimuli (as indicated by larger P300 amplitudes) compared to individuals who viewed the tailored message who in turn, assigned greater attention towards the

message. These findings are not only consistent with previous self-report findings that highlight the importance of message segmentation (e.g., Maheswaran & Meyers-Levy, 1990, Millar & Millar, 2000; see also: Kreuter & Wray, 2003), but also emphasises the utility of ERP methods for assessing message attention and/ or processing.

Similar to Ruiter et al. (2006), Kessels et al. (2011) devised an auditory dual-paradigm ERP study to further assess individuals’ attentive processes towards tailored and non-tailored nutrition messages. Kessels and colleagues reported that individuals

demonstrated greater attentive processes (measured by the P300 response) towards the tailored compared to the non-tailored nutrition messages. However, in contrast to the ERP

72 results, participant self-report ratings revealed that the participants perceived no differences

in their attention towards the two different message conditions. These findings reveal the potential discrepancies between measures of self-report and objective physiological measures of advertisement effects and highlight the superior sensitivity of objective measures for assessing the extent of message processing.

Similar to ERP studies of message attention and message processing, fMRI studies of message processing and message acceptance have emphasised the importance of using psychophysiological measures alongside traditional measures of self-report. For instance, Falk and colleagues (2010, 2011) conducted two studies, one which exposed participants to sun safety images (presented as print) while the other study exposed participants to anti-smoking messages (presented as televised public service announcements). The findings revealed that neural activity (as assessed via fMRI) could explain an additional 23% and 20%

of the variance in actual behaviour change that was unaccounted for by indirect measures of message acceptance for the sun safety print images and the anti-smoking television messages, respectively. Further, both studies found that participants who showed greater activity in the mesial prefrontal cortex and the precuneus brain regions (brain areas associated with

information processing; see reviews, Cavanna & Trimble, 2006; Etkin, Egner, & Kalisch, 2011) when viewing the stimuli were more likely to change their behaviour in line with the message.

Similar findings were also reported by Chua et al. (2009a). Using fMRI to assess message processing, participants were exposed to a tailored and non-tailored anti-smoking message, presented as an audio (radio-type) message. The findings revealed that when participants were exposed to the tailored message (compared to the non-tailored message), the rostal mesial prefrontal cortex and precuneous/ posterior were activated, indicating greater message processing. Thus, both Falk et al. (2010, 2011) and Chua et al. (2009a)

73 highlight the added benefits that brain imaging methods can offer in increasing understanding

of the underlying neural processes involved in message processing and subsequent message acceptance.

Applying physiological measures, such as ERPs to assess participants’ reactions to health messages is not well understood and further research is required in the health advertising field (Elliott, 2011). Based on previous ERP and fMRI findings that have examined health communication messages (e.g., Falk, 2010, 2011; Kessels et al., 2011), applying these measures in a road safety advertising context may lead to more reliable results, which can infer campaign designers in targeting high risk drivers, such as young adults. While ERPs and fMRIs have been used to assess anti-smoking, sun safety, and nutrition-related health communication messages, the current program of research is the first to use ERPs to assess message processing relating to road safety messages.

5.7 Chapter Summary

Chapter 5 reviewed the relevant literature on cognitive processing. Specifically, this chapter highlighted the utility of incorporating more objective measures, such as cognitive reaction-time based tasks (e.g., LDT) and neural processing measures (e.g., ERPs), to further understand the role of individual differences in the BAS and the FFFS traits in influencing message processing. This chapter reviewed previous research which has applied these measures in other health communication contexts (e.g., ERPs to further examine processing of nutrition education campaigns) and argued the benefits of applying these objective measures in the current program of research to further understand processing of road safety messages. To the best of the candidate’s knowledge, the current program of research has been the first to examine message processing via ERPs in a road safety advertising context and consequently, may provide important insights into how road safety advertisements may be

74 informed by using more objective measures to further understand how young drivers process

these campaigns.

75 Chapter 6. Study 1: Message Piloting and Manipulation Checks