Neural correlates of moral goodness & moral beauty judgments: Moral beauty judgment induced greater brain activity implicated in theory of mind, suggesting that it needs to understand the others' mental states, unlike moral goodness

Neural correlates of moral goodness and moral beauty judgments. Qiuping Cheng et al. Brain Research, Volume 1726, January 1 2020, 146534. https://doi.org/10.1016/j.brainres.2019.146534

Highlights
•    Moral goodness judgment and moral beauty judgment recruited the common brain activity in the left inferior OFC.
•    Moral goodness judgment mainly relied on the emotional facet of moral cognition, but moral beauty judgment relied on both the rational and emotional components of moral cognition.
•    Moral beauty judgment induced greater brain activity implicated in theory of mind (ToM), suggesting that it needs to understand the others` mental states but moral goodness judgment does not.
•    Moral beauty judgment also activated a cortical network that is considered mainly responsible for the processing of empathy, indicating that it involves empathic concerns for others.
•    The brain harbors neural systems for common and for domain-specific evaluations for moral goodness and moral beauty judgments.

Abstract: The objects of moral goodness and moral beauty judgments both generally refer to the positive moral acts or virtues of humans, and goodness must precede moral beauty. The main difference is that moral beauty, but not moral goodness, triggers emotional elevation. However, little is known about the neural mechanisms involved in both judgments. In the current study, 28 healthy female participants were scanned when they rated the good and beautiful extent of positive moral acts in daily life depicted in scene drawings to investigate the neural systems supporting moral goodness and moral beauty, specifically to test whether neural activity associated with moral beauty is same or different than moral goodness. The conjunction analysis of the contrasts between moral goodness judgment and moral beauty judgment identified the involvement of the left inferior orbitofrontal cortex (OFC), suggesting that the two judgments recruited the activity of a common brain region. Importantly, compared with the moral goodness judgment, the moral beauty judgment induced greater activity in more advanced cortical regions implicated in elevated emotions, including the anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC), superior frontal gyrus (SFG) and the left temporo-parietal junction (TPJ). These regions have been strongly correlated with the cognitive aspects of moral cognition, including theory of mind (ToM). In addition, moral beauty judgment also activated brain regions implicated in empathy including the midline structures and the anterior insula. Based on these results, the brain harbors neural systems for common and for domain-specific evaluations of moral goodness and moral beauty judgments. Our study thus provides novel and compelling neural evidence for the essence of moral beauty and advances the current knowledge of the neural mechanisms underlying the beauty-is-good stereotype.


1. Introduction

Imagine the following scenario: A young man is helping an elderly person cross the street. Now, please answer the first question: do you think this young man is morally good? Then, for the same behavior, please answer another question: do you think this young man displays inner beauty? Comparing these two questions, the first question is actually a moral goodness judgment in which an observer endows moral values to certain individual based on principles that have become a general law (Kant, (1785/1993), Haidt, 2007) and judges him a morally good person based on quick intuition – gut feelings (Haidt and Bjorklund, 2008, Hume, (1777/2006)., Greene, 2007, Greene, 2017). Meanwhile, the second question essentially reflects a moral beauty judgment in which an observer identifies a kind-natured person as displaying inner beauty based on an understanding of social rules and involves highly developed moral emotions (Diessner et al., 2006, Diessner et al., 2008, Haidt, 2003a, Haidt, 2003b, Haidt, 2007, Keltner and Haidt, 2003, Wang et al., 2015). Morality is considered as the sets of customs and values that are embraced by humans to guide social conduct (Moll et al., 2005) and is a product of evolutionary pressure that have shaped social cognitive and motivational mechanisms (Schulkin, 2000). Moral goodness and moral beauty judgments both belong to moral judgments, which are strongly influenced by emotional drives rooted in socio-emotional instincts (Darwin, 1874/1997), and they share a very important characteristic, that is, the object of both judgments is universal human virtues, for example, a kindness virtue of helping others in the scenario described above. These similarities prompt a critical question: Are the moral goodness judgment and moral beauty judgment the same? What about the neural correlates of two judgments?

Most objects of beauty judgments are pleasing to the eye and ear (Chatterjee and Vartanian, 2016), but another type of beauty, inner beauty, which is also delicately called moral beauty, has been identified (Haidt and Keltner, 2004). Moral beauty primarily addresses the natural beauty of persons and the beauty of their acts, states of character, and the like (Kosman, 2010), and emphasizes beauty as inherent to the individual’s inward appearance. It expresses several positive and culturally universal virtues that are independent of perceivable physical forms, such as wisdom, courage, humanity (love and kindness), and justice (Peterson and Seligman, 2004), similar to the object of moral goodness. Haidt and Keltner (2004) defined moral beauty as “the ability to find, recognize, and take pleasure in the existence of goodness in the social worlds” (p.537). Moral beauty and moral goodness are closely related, because the virtues of moral beauty are also generally considered signs of moral goodness (Diessner et al., 2006). According to Haidt and Keltner (2004), moral beauty is experienced when faced with displays of virtue or moral goodness in the social world (Haidt and Keltner, 2004, Güsewell and Ruch, 2012). Moral acts with virtues are “positive stimuli” and usually viewed as good and beautiful. Each is pleasant and offers potential for reward. According to Darwin, moral judgments are influenced by emotional processes, and these ‘social-emotional instincts’ are central for the feeling of pleasure when helping others and of unease when harming others (Darwin, 1874/1997). Individuals with inner beauty are not necessarily externally beautiful, but they must be morally good, because if beauty is not applied to a work of art, goodness must precede beauty and neither arises as a consequence of beauty nor is defined teleologically as a means to its accomplishment (Kosman, 2010). It seems that moral beauty and moral goodness are the same, at least, there is a partial overlap between the two judgments.

The remarks that “what is beautiful is good…” (Sappho, Fragments, No. 101) and that “physical beauty is the sign of an internal beauty, a spiritual and moral beauty…” (Schilier, 1882) indicates that the beauty-is-good stereotype is prevalent in human society (Berscheid and Walster, 1974, Dion et al., 1972, Tsukiura and Cabeza, 2011). For example, people with a better physical appearance receive more positive evaluations from others (Eagly et al., 1991, Feingold, 1992) and more preferential treatments in many aspects of life (Langlois et al., 2000), such as greater hiring opportunities (Marlowe et al., 1996) and earning a better income (Hamermesh and Biddle, 1994). Thus, beautiful individuals appear to be more positively associated with a socially desirable personality and moral traits (Dion et al., 1972, Eagly et al., 1991, Feingold, 1992, Langlois et al., 2000). The reliance on attractive features to infer moral character suggests a close relationship between beauty and moral valuation (Ferrari et al., 2017). One is capable of, at first sight, considering another human being attractive or unattractive while at the same time assigning values to that person. Tsukiura and Cabeza (2011) scanned participants with functional magnetic resonance imaging (fMRI) while they made attractiveness judgments about faces and goodness judgments about hypothetical acts to investigate the neural mechanisms underlying the relationship between beauty judgment and moral judgment. Both higher attractiveness ratings of faces and higher goodness ratings of moral acts correlated with increased activation of the orbitofrontal cortex (OFC). Takahashi et al., 2008, Wang et al., 2015 also observed relationships between the neural correlates of beauty judgment and moral feeling with the activation of the OFC. OFC is known as a region associated with processing positive emotions and reward, with its activity increasing as a function of beauty and moral goodness. These functional imaging studies support the idea of similar contribution of OFC to beauty and moral goodness judgments. However, no study has directly investigated whether the moral beauty judgment also shares the same neural correlate as the moral goodness judgment.

Although moral beauty objectively refers to the same human act or virtue as moral goodness, they differ in terms of the emotional response and motivation (Diessner et al., 2006, Diessner et al., 2008, Keltner and Haidt, 2003). Diessner et al. (2008) conceive “responsiveness to goodness and beauty” as a continuum, stretching from cognitive appreciation to deep engagement, with all imaginable intermediate degrees of emotional involvement. Cognitive appreciation without engagement is conceivable, but engagement without appreciation is not. When identifying a positive act of one person as moral goodness, an observer quickly assesses the morality of a certain behavior but remains emotionally unmoved and un-elevated (Diessner et al., 2006, Güsewell and Ruch, 2012). It seems that the emotional process influences the moral goodness and moral beauty judgments in the different patterns. An act of moral goodness is cognitively experienced as such without emotional involvement (Diessner et al., 2008). However, when judging the same act of moral goodness as moral beauty, the observer’s emotions are presumed to have been moved and elevated after observing manifest moral virtues in human act (Diessner et al., 2006, Haidt, 2003a, Haidt, 2003b, Haidt, 2007, Keltner and Haidt, 2003, Pohling and Diessner, 2016).

Moral elevation is the emotional response to witnessing acts of moral beauty and is particularly elicited by moral beauty. It triggers a distinctive feeling in the chest of warmth and expansion and causes a generalized desire to become a better person oneself and creates a tendency toward prosocial actions that trigger similar good behaviors in a similar scenario (Algoe and Haidt, 2009, Diessner et al., 2013, Haidt, 2003a, Haidt, 2003b, Haidt and Keltner, 2004, Schnall et al., 2010, Shiota et al., 2014, Van de Vyver and Abrams, 2015, Greene, 2017). Moral elevation directs the focus on others (Haidt, 2003) by understanding their mental states (i.e., theory of mind, ToM) and vicariously experiencing similar feelings (i.e., empathy). With regard to cognitive changes, it was assumed (Haidt, 2003) and found (Freeman et al., 2009) that elevation induces optimistic thoughts of people and humanity (Pohling and Diessner, 2016). Researchers have observed the recruitments of brain regions often implicated in mentalizing (ToM and empathy) behavior (Bzdok et al., 2012, Farrow et al., 2001, Han and Northoff, 2008, Harenski et al., 2012, Johnson et al., 2002, Maratos et al., 2001, Moll et al., 2002, Moll et al., 2005, Reniers et al., 2012, Saxe and Kanwisher, 2003) under the condition of moral elevation, including the medial prefrontal cortex (mPFC) and bilateral temporo-parietal junction (TPJ) implicated in ToM; the midline structures (anterior and posterior cingulate, precuneus) and the anterior insula implicated in empathy (Bzdok et al., 2012, Englander et al., 2012, Immordino-Yang et al., 2009, Lewis, 2014, Piper et al., 2015). According to recent neuropsychological evidence, moral beauty not only involves the OFC (Takahashi et al., 2008), which is activated in both external beauty and moral goodness judgments (Tsukiura and Cabeza, 2011), but also recruits the activity of similar brain regions as moral elevation, including the mPFC, anterior cingulate cortex (ACC), precuneus/PCC, insula and TPJ (Luo et al., 2019, Wang et al., 2015, Wen et al., 2017). However, researchers did not directly conclude a correlation between the activation of these brain regions involved in moral beauty with emotional elevation.

The beauty-is-good stereotype has been the topic of many social cognition studies, however, most focused on the dynamic relationship between the external beauty judgment and moral goodness judgment. The similarity and differences in the neural correlates between the moral beauty judgment and moral goodness judgment remain unknown. To the best of our knowledge, no previous study has directly compared brain activity during both judgments. Therefore, we designed an fMRI experiment to address this issue. During the scan, scene drawings depicting positive moral acts with different behavioral levels in daily life were presented on the computer screens while participants rated the extent of moral goodness (MG) and moral beauty (MB) presented by the main character in scene drawings. Then, we input the rating scores of each participant into the parametric modulators in SPM12 to identify regions in which the activity changed as a function of behavioral ratings. With this parametric approach, we were able to locate the brain regions involved in the moral beauty judgment and the moral goodness judgment and further explore the similarities and differences between them. Correspondingly, two hypotheses were generated. According to the findings reported in the previous literature, the brain activity in the OFC overlapped not only in the external beauty and moral goodness judgments (Tsukiura and Cabeza, 2011) but also in external beauty and moral beauty judgments (Luo et al., 2019, Wang et al., 2015). We initially hypothesized that the OFC would also be a shared brain region associated with moral beauty and moral goodness judgments, because both judgments refer to the same virtuous acts that have been approved by social culture. Virtue acts are “positive stimuli”, which usually lead to positive emotions and then facilitate appropriate behavioral responses to potential rewards (Fredrickson, 1998). According to neuroimaging studies, abstract rewards induced by social approval from others recruit the OFC (Haber and Knutson, 2010). Additionally, because moral beauty triggers emotional elevation and moral elevation activates brain regions involved in ToM and empathic process, we hypothesized that the moral beauty judgment would also recruit these advanced brain regions that are responsible for processing others mental states including mPFC and TPJ, and responsible for sharing others emotions including ACC, precuneus/PCC, and anterior insula.