The Relationship Between Ideology and Disgust Sensitivity

The aim of the current paper is to examine the association between ideology and disgust sensitivity. Studying disgust offers psychologists an opportunity to assess how judgments have evolved over time due to a “gut” sense of danger. This emotion also plays a role in moral judgment: individuals label moral wrongdoings as disgusting which elicits a specific facial expression. For this reason, disgust has recently been found to be a plausible emotion involved in political decision-making. Studies indicate that liberals and conservatives rely on respective moral foundations that influence their choices. Haidt et al. (2009) argue that liberals’ views on morality are based primarily on harm/care and fairness/reciprocity, whereas conservatives’ views on morality show a more even distribution across the foundations, including those endorsed by liberals, as well as ingroup/loyalty, authority/respect and purity/sanctity. Schnall et al. (2008) suggest a causal relationship between feelings of disgust and moral convictions. People often rely on moral reasoning when they do not have an intuitive response or when their intuition is conflicting. The current study examined this complex relationship by assessing disgust sensitivity while simultaneously manipulating emotional state through the use of emotionally disgusting and neutral pictures. Electroencephalographic (EEG) eventrelated brain potentials (ERPs) were used as the primary index of emotional processing. The results indicated a main effect for electrode site location and for picture image, as IDEOLOGY AND DISGUST SENSITIVITY 2 expected. Results did not show an interaction between disgust sensitivity and ideology, or any mediating factors, suggesting that there may be no statistically significant differences in disgust sensitivity between liberals and conservatives. These results suggest that the core differences between conservatives and liberals may be exaggerated. Limitations and directions for future research are discussed. IDEOLOGY AND DISGUST SENSITIVITY 3 CHAPTER I Statement Of The Problem Disgust is commonly recognized among researchers as a core emotion (Tybur, Lieberman, & Griskevicius, 2009). Schnall (2008) and Haidt’s (2007; 2004) studies posit that when people make an intuitive judgment they also have an emotional “gut” feeling, referred to as disgust. Historically, disgust has been thought of and studied as an essential process involved in distinguishing harmful substances for purpose of survival (Rozin, Haidt, & Fincher, 2009). A detailed definition and discussion of disgust is provided in Chapter II. More recent research has shown how disgust influences morality through the avoidance or deviation from social norms (Royzman & Kurzban, 2011; Rozin et al., 2009; Russell & Giner-Sorolla, 2013). While studies suggest a link between disgust sensitivity and morality, less is known about how disgust sensitivity impacts political decision-making and self-reported ideology. To better understand the relationship between disgust and ideology, it helps to look at research on moral values. John Haidt applied his theory on moral foundations to ideology and found that conservatives and liberals rely on a different set of morals (Graham, Haidt, & Nosek, 2009; Haidt & Graham, 2007). While Haidt provides insights into core differences between ideologies, his research does not explore the role disgust might play as a core/physiological factor. Fortunately, Inbar et al. (2008) took this theory a step further by applying self-reported ideology to the disgust emotional process. His studies found that via questionnaires conservatives report more disgust sensitivity than liberals; and further, that induced disgust influences judgments (Inbar, Pizarro, & Bloom, 2008, 2012; Inbar, Pizarro, Knobe, & Bloom, 2009). IDEOLOGY AND DISGUST SENSITIVITY 4 These results raise interesting questions regarding the relationship between disgust and moral decision-making, particularly concerning how and why people vote along party lines. Do people make political decisions based on complex decision-making, a higher ordered cognitive process, or do they go with their “gut” reaction? How much does an emotional physiological reaction such as disgust influence peoples’ decisions? Moral decision-making is a complex process as there is sometimes a discrepancy between intention and following through with planned behavior (Ajzen, 2001). Information presented outside of consciousness can still influence decisions (Greene & Haidt, 2002). Ong et al. (2014) found that disgust sensitivity moderates the relationship between priming disgust and moral judgments, showing how both reason and higher order thinking, as well as more subliminal facets such as emotions, affect moral judgments. Therefore, disgust could be thought of as a more subliminal influence on decision-making. For this reason it is important to not only consider how people view themselves, but also to examine implicit attitudes and emotions in connection with actual behavior that may influence judgments. While individuals self-identify as liberal or conservative, less is known about what informs this self-identification and how it maintains stability over time. Research on contrasting political views has been disputed for as long as politics has been studied. Most assume that political orientation is related to environmental factors such as socialization (Hibbing, Smith, & Alford, 2014); children often have values and voting patterns similar to their parents. In contrast, more recent research has shown parental socialization and sociodemographic variables have only a small effect on political orientation (Hibbing et al., 2014; Plutzer, 2002). Research has begun to postulate that IDEOLOGY AND DISGUST SENSITIVITY 5 psychophysiological differences influence superficial correlates between conservatives and liberals (Hibbing et al., 2014). This makes a good argument for why research should then focus on psychophysiological differences in order to determine underlying variables between ideological identifications. Physiological differences are reasonably stable over a life span (Cohen & Hamrick, 2003; De Weerth & Van Geert, 2002) similar to political orientation; this stability is unlike socialization, which changes with environment and age. Due to disgust’s influence on moral decision-making and its ability to be tested using psychophysiological measures, it is an appropriate physiological area to study. Disgust can be examined in various ways, including: self-report, facial expression or through psychophysiological means such as brain measures. Various studies have looked into disgust responses, most using self-report measures and few using the latter psychophysiological measures. Psychophysiological measures have the ability to capture a response faster and therefore more implicitly when compared to how individuals think or evaluate themselves (Luo et al., 2013; Moll et al., 2005). Through electroencephalogram (EEG), studies can examine the strength of a person’s response over time, unlike other brain measures. Neuroimaging such as fMRIs have had difficulty measuring specific and complex brain processes such as cognition, while event-related potentials (ERPs) use a continuous measure that permits researchers to examine these complex pathways (Luo et al., 2013). Luo et al. (2013) examined the difference between core disgust and moral disgust through ERP components using individuals’ reactions to lexicon images. This study found that core disgust was a more sensitive measure than moral disgust alone. Luo et al. used words in order to measure disgust, and while emotional words trigger a larger ERP response than neutral words, images have been IDEOLOGY AND DISGUST SENSITIVITY 6 shown to be an even more sensitive measure (Azizian, Watson, Parvaz, & Squires, 2006; Simos & Molfese, 1997). Therefore, measuring core disgust sensitivity through an ERP component is a promising method to determine whether disgust is an underlying difference between self-identified ideologies. Research Goals and Questions There are few empirical studies that examine the relationship between disgust and ideology, and even fewer that show these influences through psychophysiological measures. The integration of social psychology with neuroscience is a rising area to be studied. This study proposed to examine how a brain measure, specifically ERP response, was influenced by disgust sensitivity and how that could be moderated by ideological factors. The first objective of this study was to examine whether disgust sensitivity differs based on ideology using different EEG electrodes. Figure 1 illustrates the interaction model. Was there a main effect for ideology? Was there a main effect for disgust sensitivity? Was there an interaction between disgust sensitivity and level of ideology shown from EEG electrode locations? IDEOLOGY AND DISGUST SENSITIVITY