Medical
students, Monterrey (credit: Daniel Adelrio, Wikicommons). Mexicans feel more
empathy if they have a university degree. Does university make people more
empathic?
We
differ from individual to individual in our capacity not only to understand how
others feel but also to experience their pain or joy. This “affective empathy”
also differs between the sexes, being stronger in women than in men. Does it
also differ between human populations? It should, for several reasons:
-
Affective empathy is highly heritable. A recent study put its heritability at
52-57% (Melchers et al. 2016).
-
It differs in adaptiveness from one cultural environment to another, being adaptive
in high-trust cultures and maladaptive in low-trust ones. There has thus been a
potential for gene-culture coevolution.
-
Such an evolutionary scenario would require relatively few genetic changes.
Affective empathy exists in all human populations, and most likely already
existed in ancestral hominids. Differences within our species are thus differences
in fine-tuning of an existing mechanism.
One
can imagine the following scenario:
1.
Initially, affective empathy existed primarily in women and served to
facilitate the mother-child relationship.
2.
Later, when human societies grew beyond the size of small kin groups, this
mental trait took on a new task: regular interaction with people who were not
necessarily close kin.
3.
Selection thus increased the capacity for affective empathy in both sexes but
more so in men.
4.
This gene-culture evolution went the farthest in high-trust cultures.
Affective empathy
and educational level in Mexico
To
measure differences in affective empathy between human populations we can
administer tests like "Pictures of Facial Affect" and the
"Cambridge Behavior Scale." The first test is a measure of the
ability to recognize emotion in human faces. The second test is a questionnaire
with responses on a 4-point scale ranging from "strongly agree" to
"strongly disagree."
In
a recent study from Mexico these tests confirmed that affective empathy is
stronger in women than in men. There were also differences by occupational
status:
[...] we sought to explore facial emotion recognition abilities and empathy in administrative officers and security guards at a center for institutionalized juvenile offenders. One hundred twenty-two Mexican subjects, including both men and women, were recruited for the study. Sixty-three subjects were administrative officers, and 59 subjects were security guards at a juvenile detention center. Tasks included "Pictures of Facial Affect" and the "Cambridge Behavior Scale." The results showed that group and gender had an independent effect on emotion recognition abilities, with no significant interaction between the two variables. Specifically, administrative officers showed higher empathy than security guards. Moreover, women in general exhibited more empathy than men. (Quintero et al. 2018)
Why
were the guards less able to recognize signs of distress or happiness on human
faces? The authors offer no explanation but do note that the two groups
differed in educational level: most of the administrative officers were
university graduates, whereas the guards had gone no farther than middle
school.
In
Mexico, educational level correlates with European admixture (Martinez-Marignac
et al. 2007). Is this group difference in empathy really an ethnic difference?
The amygdala and
political orientation in the U.S. and the U.K.
Tests
are subjective and thus suffer from biases that may produce different results
in different populations. To avoid this problem, a promising method is to
measure the size or activity of brain structures that are associated with
affective empathy. In the latest review of the literature, Tal Saban and Kirby
(2019) assign the amygdala a key role:
Neuroscientists have identified the brain regions for the "empathy circuit": 1) the amygdala, responsible for regulating emotional learning and reading emotional expressions; 2) the anterior cingulate cortex (ACC), activated during observed or experienced pain in the self or others; and 3) the anterior insula (AI), which responds to one's pain and the pain of a loved one (Carr, Iacoboni, Dubeau, Mazziotta, & Lenzi, 2003). In recent years the mirror neuron system (MNS), comprised of the inferior frontal gyrus and inferior parietal cortex, has been suggested to also be involved in empathy (Gazzola et al., 2006, Kaplan and Iacoboni, 2006, Pfeifer et al., 2008, Baird et al., 2011). The broad notion that empathy involves "putting oneself in another's shoes" by simulating what others do, think, or feel, has been linked to the properties of mirror neurons.
The
amygdala has been linked to affective empathy by MRI studies on healthy
individuals and on individuals with amygdala lesions (Bzdok et al. 2012;
Brunnlieb et al. 2013; Gu et al. 2010; Hurlemann et al. 2010; Leigh et al.
2013).
Two
studies have found group differences in amygdala size or activity. When brain
MRIs were done on 82 adults from the University of California at San Diego, the
right amygdala showed more activity in Republicans than in Democrats (Schreiber
et al., 2013). Similarly, a study of 90 adults from University College London
found that the right amygdala was larger in self-described conservatives than
in self-described liberals (Kanai et al., 2011).
Is
affective empathy stronger in conservatives than in liberals? Or are these labels
a proxy for something else? In both the United States and England, party
politics is increasingly identity politics. While it is true that non-European
minorities tend to be socially conservative, they nonetheless tend to be
politically liberal, often overwhelmingly so. In the American study, party
affiliation was undoubtedly the dimension being measured: participants were
asked whether they were Democrat or Republican. This is less evident in the
English study, where participants were asked about their "political
orientation."
Both
universities are ethnically diverse. University of California at San Diego is
36% Asian, 20% White, 19% non-resident alien, and 17% Latino (Anon 2019). There
is no ethnic breakdown of University College students, but we know that a third
of them come from outside the United Kingdom (Wikipedia 2019).
Conclusion
Brain
MRIs provide a means to measure affective empathy objectively. We can thus
evaluate differences between human populations, just as we have evaluated differences
between men and women, and from individual to individual. This kind of
comparative research will likely be done by accident rather than by design, as
with the above three studies.
Another
approach would be to identify alleles that correlate with a high level of
affective empathy. A polygenic score could then be created, thus providing an
objective yardstick for measuring this mental trait in any human population.
Particularly promising are two polymorphisms. Alleles at the OXTR gene correlate with
inter-individual differences in empathy, especially with affective empathy in
women (Huetter et al. 2016). Alleles at the GNAS
gene correlate with inter-individual differences in cognitive empathy, but only
in women (Huetter et al. 2018).
References
Anon.
(2019). University of California - San
Diego, Ethnic Diversity.
Bzdok,
D., L. Schilbach, K. Vogeley, et al. (2012). Parsing the neural correlates of
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Brunnlieb,
C., T.F. Munte, C. Tempelmann, and M. Heldmann. (2013). Vasopressin modulates
neural responses related to emotional stimuli in the right amygdala. Brain
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X., X. Liu, K.G. Guise, et al. (2010). Functional dissociation of the
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