- Top of page
- EXPERIMENT 1
- EXPERIMENT 2
- GENERAL DISCUSSION
Previous studies indicate that people respond defensively to threatening health information, especially when the information challenges self-relevant goals. The authors investigated whether reduced acceptance of self-relevant health risk information is already visible in early attention allocation processes. In two experimental studies, participants were watching high- and low-threat health commercials, and at the same time had to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (odd ball paradigm). The amount of attention allocation was measured by recording event-related brain potentials (i.e., P300 ERPs) and reaction times. Smokers showed larger P300 amplitudes in response to the auditory targets while watching high-threat instead of low-threat anti-smoking commercials. In contrast, non-smokers showed smaller P300 amplitudes during watching high as opposed to low threat anti-smoking commercials. In conclusion, the findings provide further neuroscientific support for the hypothesis that threatening health information causes more avoidance responses among those for whom the health threat is self-relevant.
An important goal of health education messages is to encourage and motivate people to engage in health-promoting and disease-preventive behaviours. One way of achieving this goal is to confront target groups with fear-arousing information to promote self-protective action (e.g., smoking kills, quit now). However, randomized controlled studies suggest that these so-called fear appeals are less effective than often assumed by health education researchers and practitioners (Ruiter & Kok, 2005, 2006). A large body of experimental research suggests that threatening health messages are met with defensive responses especially by those for whom the health threat is most personally relevant (for an overview, see Van't Riet & Ruiter, 2013).
Previous studies into the cognitive nature of defensive reactions towards fear appeals were restricted to self-report measures such as risk denial, biased information processing, re-appraisal strategies and message derogation (Van't Riet & Ruiter, 2013). In addition, self-report measures of cognitive effort (Liberman & Chaiken, 1992) and more implicit measures of reading time (Brown & Locker, 2009) and response time (Klein & Harris, 2009) have been used to provide an index of the amount of attention that is allocated to threatening health information. These latter studies suggest that most people at risk react defensively by attending away from the threatening message. However, these measures do not allow a direct observation of the amount of attention that is allocated to the threatening information during message processing (Kessels, Ruiter, & Jansma, 2010).
Here we aim to explain people's defensive reactions to threatening health messages by studying early cognitive processes during message exposure. In two previous studies, we addressed this question by studying attention-allocation processes in response to pictures and written messages that depict the negative health consequences of smoking and unhealthy nutrition, respectively (Kessels, Ruiter, Brug, & Jansma, 2011; Kessels et al., 2010). In this study, we extend our line of research with two experimental studies that study attention-allocation processes in response to threatening health commercials (instead of pictures or written messages) by recording event-related potentials (ERPs).
The relationship between mental resources of attention and ERPs has been discussed especially with regard to one target ERP component, namely the P300. The P300 shows larger amplitudes whenever the target stimulus is attended to compared with when there is less or no attention to the target with a maximum peak around 300 ms (Kok, 1997). The P300 may reflect controlled attention processes and as such provides an index for a cognitive attention allocation and update of stimulus processing with working memory information (Polich, 2007).
This study used almost the same experimental setup as was used in our previous study (Kessels et al., 2011). While watching health commercials, participants need to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (oddball paradigm). In studying defensive reactions to threatening health information, we thus focus on a shift of attention away from threatening contents and towards a distracting source. Based on the underlying rational of resource allocation, we assume that the observed auditory attention effects in P300 ERP can be used as an inverted index of the amount of attention allocated to watching the commercials (cf. Kessels et al., 2010; Ruiter, Kessels, Jansma, & Brug, 2006). Therefore, based on the recent fear appeal literature findings that people show defensive reactions to personal relevance, high-threat information (i.e., they shift their attention away from relevant but negative information), we predicted that in the high personal relevance conditions attention to the high tones is increased during watching high-threat health commercials compared with watching low-threat health commercials, resulting in faster reaction times and higher mean amplitudes of the P300 in response to the auditory targets for the high-threat condition than for the low-threat condition (H1).
In contrast, we expected that for those of whom the threat has low personal relevance, threat information follows the general pattern of the effect of emotional information on attention-allocation processes with more attention for high-threat information than for low-threat information (Kessels et al., 2010). Therefore, in the low personal relevance conditions, we expected that in response to the auditory target tones reaction times are slower and the mean amplitudes of P300 are lower for the high-threat health commercials than for the low-threat commercials (H2).
The experimental studies received approval from the Ethical Committee Psychology and Neuroscience at Maastricht University, the Netherlands.
- Top of page
- EXPERIMENT 1
- EXPERIMENT 2
- GENERAL DISCUSSION
Our findings support recent findings in the fear appeal literature which suggest that people react defensively to threatening health information. In addition to the findings of earlier studies that used pictures (Kessels et al., 2010, 2011), this study found neuroscientific evidence that threatening health commercials cause more attentional avoidance among those for whom the health threat is self-relevant. In two experiments, smokers showed an increased P300 amplitude in response to an auditory target while watching high-threat as opposed to low-threat commercials about the negative health consequences of smoking. This threat-induced moderation of the P300 was not found in smokers who watched non-smoking related commercials (Experiment 1) and was not found in non-smokers (Experiment 2). Further support for our defensive avoidance hypothesis for whom the threat information was self-relevant was found in the reaction time data in Experiment 1. Smokers responded faster to the auditory target while watching high-threat as opposed low-threat anti-smoking commercials.
The P300 findings for the smoking participants are in line with the view that people are motivated to reduce feelings of cognitive dissonance (Festinger, 1957; Kunda, 1990). According to the cognitive dissonance theory (Festinger, 1957) and Kunda's (1990) argument for motivated reasoning, people experiencing dissonance because of their self-image are threatened (e.g., smokers exposed to threatening health commercials about smoking) are motivated to reduce it by changing one of the implicated cognitive or behavioural elements, for example through avoidant and biased processing of presented information (e.g., Kessels et al., 2010; Liberman & Chaiken, 1992). While previous studies used self-report measures or implicit measures of reading time and response time (Brown & Locker, 2009; Klein & Harris, 2009), this study provided support for motivated reasoning through the use of attention measures during message processing. The P300 findings thus indicate that avoidance responses can arise during the early process of attention allocation at the interface between sensory and memory processing.
In the first session of Experiment 2 we also found support for an attention advantage of high-threat information over low-threat information when the health information was supposed to be less self-relevant. From an evolutionary perspective, an attention preference mechanism for imminent threat was expected, but only for those for whom the information was not self-relevant (Kessels et al., 2010).
A limitation of this study is that the indirect nature of the experimental paradigms do not exclude the possibility that the enhanced P300 during high-threat Vs. low-threat anti-smoking commercials was the result of better task performance due to increased levels of attentional capacity because of higher levels of arousal in the high-threat conditions (Proctor & Van Zandt, 1994). Also, our selections of health commercials in the two studies do not allow for a comparison between high-threat commercials and neutral commercials on processes of attention allocation. Some of the commercials in the low-threat conditions in both experiments included humouristic scenes. Humour has been associated with increased attention and recall. Therefore, to the extent that the low-threat commercials were indeed evaluated as humouristic, the effects on the P300 could have been further enhanced by using humouristic rather than neutral commercials in the low-threat conditions (Schmidt & Williams, 2001).
Another possible limitation is that use of the auditory oddball might have interacted and be affected by the auditory component of the commercials. In future research we might use the technique of event-related desynchronization (ERD) to measure approach and withdrawal every second while watching commercials (Pfurtscheller & Aranibar, 1977).
Our results complement those reported by Kessels et al. (2010) and provide further neuroscientific support to findings in the fear appeal literature that suggest that people react defensively to threatening health information, especially if this information is able to question self-relevant health behaviours such as smoking among daily smokers. In addition, the findings strongly suggest that threatening commercials are not an effective tool in motivating people to attend to health messages, but instead decrease chances of successful persuasion.