Now Is That Gratitude?

Now is that Gratitude,
Or is it really love?
Some kind of reality
That fits just like a glove

--Danny Elfman, Gratitude

Praise and condemnation serve a powerful purpose in our social and internal lives. They prop us up and tear us down. We reward ourselves (and others) when we perform good deeds, give a pat on the back for a job well done. Conversely, we punish bad behavior. Some people are more vengeful than others when they're wronged; other individuals might be more inclined to blame themselves, even when it's not their fault.

Laws and religions and etiquette and complex ethical systems enforce the rules of behavior. For most human beings of a certain age, moral emotions are the result of abiding by or violating these social norms. Moral emotions can be defined as “those emotions that are linked to the interests or welfare either of society as a whole or at least of persons other than the judge or agent” (Haidt, 2003). They can entail reacting to events that don't directly involve the self, as in the case of sympathy or contempt.

Zahn and colleagues (2013) refer to these feelings and reactions as moral sentiments, “following philosophers of the Scottish enlightenment who pointed to their role as key motivators of moral behaviour (Bishop, 1996).” In a recent study, they conceptualized four of these moral sentiments in a 2 x 2 grid, depending upon whether the emotion involved praise or blame, of oneself or of another (Zahn et al., 2013).

SELF        OTHER

PRAISE      Pride       Gratitude

BLAME      Guilt        Indignation

Their goal was to determine whether there are individual differences in regional gray matter volumes associated with self-reports on the Value-related Moral Sentiment Task, which attempts to quantify personally felt human emotions.


Moral Phrenology

Does the tendency to experience each of these moral sentiments correlate with the size of different regions of the brain? The strong form of this question assumes the brain is modular and divisible into separate regions that oversee distinct processes. It also reflects a belief in the “brain is like a muscle” analogy, with discrete regions growing larger with use and smaller with disuse. In Franz Gall's original formulation of phrenology, there were 27 “organs” or mental faculties that could be measured by palpating bumps on the skull. The list of faculties was further refined and developed by Spurzheim (1815), Combe (1834 & 1847), and Lundie (1844). ¹

Phrenological Chart, via Wikimedia Commons

For example, the organ of Benevolence is “situated at the upper part of the frontal bone... When it is large, the frontal bone rises with an arched appearance; when small, the forehead is low and retreating.”

Zahn et al. (2013) didn't palpate bumps on the skull, of course. Instead, they used voxel-based morphometry (VBM) to quantify regional gray matter (GM) volumes in 63 participants. In turn, these GM volumes were related to scores for each moral sentiment, controlled for positive and negative valence (Zahn et al., 2013):

We examined the effects of each moral sentiment measure (e.g. pride-proneness) on GM volume across the whole brain while using the other moral sentiment of equal valence (e.g. gratitude-proneness) as a covariate of no interest to control for effects of valence. We thus used two separate models to test for positive and negative emotions. All reported results were thus partial effects of one moral sentiment controlled for the adjusted effect of the equal-valence moral sentiment.

The Value-related Moral Sentiment Task (VMST) consists of 180 descriptions of positive or negative interactions between a participant and their best friend in which either they (self-agency, N=90), or their best friend (other-agency, N=90), acted in accord with (N=90) or counter to (N=90) social and moral values. The four conditions thus measured proneness to:

1. Pride (POS_SELF): positive self-agency (e.g. ‘Yourself acting in a generous way towards Sam [best friend]’)
2. Gratitude (POS_OTHER): positive other-agency (e.g. ‘Sam acting in a generous way towards you’)
3. Guilt (NEG_SELF): negative self-agency (e.g. ‘Yourself acting in a stingy way towards Sam’)
4. Indignation (NEG_OTHER): negative other-agency (e.g. ‘Sam acting in a stingy way towards you’)

The task was to choose the most fitting label (pride, gratitude, embarrassment [not examined here], guilt, indignation/anger, or none/other) for what they'd feel in response to each example. Participants then rated the unpleasantness or pleasantness of their projected feelings on a scale of -4 to +4.

Based on the authors' previous studies, the set of a priori brain regions of interest (ROIs) included anterior temporal lobes, posterior superior temporal sulcus/temporo-parietal junction, frontopolar cortex, dorsolateral prefrontal cortex (PFC), ventromedial PFC, lateral orbitofrontal cortex, dorsomedial PFC, insula, amygdala, basal ganglia, septum, hypothalamus, and ventral tegmental area.

However, there was no relationship at all between gray matter volumes in these predicted regions and any of the moral sentiments. Therefore, the correlations between 13 ROIs and scores for 4 moral sentiments yielded no significant results.

Instead, larger right inferior temporal cortex volumes were associated with the propensity to experience Gratitude (Fig. 1c), while smaller precuneus and cuneus volumes were associated with greater Pride-proneness (Fig. 1d). This is very surprising, since the cuneus contains primary visual cortex (Area V1, aka Brodmann area 17 in primates). Why would humble people have larger primary visual cortices? Because they spend more time looking at the outside world?

The Guilt-proneness and Gratitude-proneness voxels in the dorsolateral PFC (Figs. 1a and 1b) were not significant after correction for multiple comparisons.

Fig. 1 (Zahn et al., 2013). Individual differences were depicted as increases (yellow) or decreases (blue) in GM volume that were associated with proneness to experience a specific moral sentiment on the experimental task in N=63 participants.


Since the straightforward VBM analyses were a complete bust, the authors did post-hoc analyses in the subset of subjects who participated in an earlier fMRI study, evaluating individual differences in  guilt-related BOLD responses and their relationship to GM volumes. I won't discuss that here.

How do the authors explain Figure 1? Clearly, their predictions did not pan out. ² After ruling out low statistical power as an issue, they put forth their best explanation: neuroanatomical differences cannot explain individual variation in responses on the VMST.

An alternative explanation which we favour is that structural variability in brain regions critical for specific moral sentiments is low between healthy participants, because high psychosocial functioning may not allow for large variations in structural anatomy within brain systems critical for moral motivations.

This doesn't stop them for offering highly speculative explanations for some of their findings (namely, the claim that gratitude might recruit visual imagery to a greater extent than pride):

We interpret the finding that individuals with higher GM volume within posterior cortical areas showed lower proneness to respond with pride and higher proneness to respond with gratitude as possibly being related to differences in reliance on visuo-spatial representations of morally salient scenes associated with these different types of feelings. A well-developed posterior cortical system may facilitate construction of detailed scenes which could play a more important role for experiencing gratitude than pride.

Now Is That Gratitude?

The present study illustrates the folly of modern-day moral phrenology. You can't measure the size of the anterior insula and determine whether someone is a self-righteously indignant person, or believe that the organ of gratitude is housed in the right inferior temporal cortex. Gratitude is a complex emotion that plays a huge role in positive psychology. You can be grateful for the weather or for your standard of living. Is praise of another person a valid operational definition of Gratitude as a moral sentiment? Or is this another form of wishful thinking, like the critical positivity ratio of 2.9013 (Brown et al., 2013)?


Footnotes

¹ For all phrenology all the time, see The History of Phrenology on the Web, by John van Wyhe.

² The authors made the following specific predictions:

...based on evidence from patient lesion studies (Moll et al., 2011) and fMRI (Takahashi et al., 2004; Moll et al., 2007; Kedia et al., 2008; Zahn et al., 2009b), we hypothesized associations of frontopolar GM volume with guilt-proneness. Based on recent studies, we further expected the importance of subgenual parts of the anterior cingulate (Zahn et al., 2009a, b) and the septal region (Zahn et al., 2009b; Moll et al., 2011) for individual variation on guilt-proneness. In contrast, we expected lateral orbitofrontal/insular areas to be associated with indignation-proneness based on an fMRI study directly probing indignation (Zahn et al., 2009b), a study in which this region showed activation for decisions based on moral anger (Moll et al., 2006), and evidence that a lateral orbitofrontal region was selectively more activated for other-critical feelings (anger and disgust) vs prosocial moral feelings including guilt (Moll et al., 2007). Our hypotheses for pride- and gratitude-proneness were less well supported due to a relative scarcity of evidence. Our main expectations were that pride-proneness and gratitude-proneness should be related to differences within mesolimbic and basal forebrain areas, specifically the hypothalamus, ventral tegmental area (VTA) and septal area (Zahn et al., 2009b).

References

Haidt, J. (2003). The moral emotions. In R. J. Davidson, K. R. Scherer, & H. H. Goldsmith (Eds.), Handbook of affective sciences. Oxford: Oxford University Press.(pp. 852-870).

Zahn R, Garrido G, Moll J, & Grafman J (2013). Individual differences in posterior cortical volume correlate with proneness to pride and gratitude. Social Cognitive and Affective Neuroscience PMID: 24106333

But when I think of you
And what you've done to me
You took away my hope
You took away my fantasy
I was set up for pride
The world was in my hands
I lived way at the top
In castles made of sand

--Danny Elfman, Gratitude

(Oooh) I dream of you sometimes
--ibid