Saturday, November 15, 2014

We are not equally empathic


 
The Child at Your Door (c. 1917-1919). We're not equally empathic toward strangers. This largely heritable trait varies continuously from psychopathy to extraordinary altruism (source: Wikicommons)

 

In a previous post, I discussed why the capacity for affective empathy varies not only between individuals but also between populations. First, its heritability is high: 68% (Chakrabarti and Baron-Cohen, 2013). So natural selection has had something to grab hold of. Second, its usefulness varies from one culture to another. It matters less where kinship matters more, i.e., where people interact mainly with close kin and where non-kin are likely to be enemies. The threat of retaliation from kin is sufficient to ensure correct behavior.

Affective empathy matters more where kinship matters less. This is a situation that Northwest Europeans have long known. Historian Alan Macfarlane argues that kinship has been weaker among the English—and individualism correspondingly stronger—since at least the 12th century and perhaps since Anglo-Saxon times (Macfarlane, 2012; Macfarlane, 1992, pp. 173-174). A weaker sense of kinship seems to underlie the Western European Marriage Pattern (WEMP), as seen by its defining characteristics: late age of marriage for both sexes; high rate of celibacy; strong tendency of children to form new households; and high circulation of non-kin among families. The WEMP has prevailed since at least the 12th century west of the Hajnal Line, a line running approximately from Trieste to St. Petersburg (Hallam, 1985; Seccombe, 1992, p. 94).

Can natural selection specifically target affective empathy?

So if affective empathy helps people to survive and reproduce, there will be more and more of it in succeeding generations. If not, there will be less and less.

But what exactly is being passed on or not passed on? A specific capacity? Or something more general, like pro-social behavior? If it's too general, natural selection could not easily make some populations more altruistic than others. There would be too many nasty side-effects.

Although pro-social behavior superficially looks like affective empathy, the underlying mental processes are different. Pro-social behavior is a willingness to help others through low-cost assistance: advice, conversation, a helping hand, etc. The logic is simple: give some help now and perhaps you'll receive a lot later from the grateful beneficiary. By the same logic, you may stop helping someone who seldom reciprocates.

Affective empathy is less conscious. It seems to have developed out of cognitive empathy: the ability to simulate what is going on in other people's minds, but not necessarily for the purpose of helping them. Con artists have plenty of cognitive empathy. Empathy is affective when you not only simulate how other people feel but also experience their feelings (Chakrabarti and Baron-Cohen,2013). Their wellbeing comes to matter as much as your own. 

Empathy of either sort relies on unconscious mimicry: "empathic individuals exhibit nonconscious mimicry of the postures, mannerisms, and facial expressions of others (the chameleon effect) to a greater extent than nonempathic individuals" (Carr et al., 2003). The ability to mimic is key to the empathic process of relaying information from one brain area to another via "mirror neurons":

- The superior temporal cortex codes an early visual description of another person's action and sends this information to posterior parietal mirror neurons.

- The posterior parietal cortex codes the precise kinesthetic aspect of the action and sends the information to inferior frontal mirror neurons.

- The inferior frontal cortex codes the purpose of the action.

- Parietal and frontal mirror areas send copies of motor plans back to the superior temporal cortex in order to match the visual description of the person's action to the predicted sensory consequences for that person.

- The mental simulation is complete when the visual description has been matched to the predicted sensory consequences (Carr et al., 2003).

By simulating the sensory consequences of what someone does or intends to do, we gain an understanding of that person that goes beyond what our senses immediately tell us. 

[...] we understand the feelings of others via a mechanism of action representation shaping emotional content, such that we ground our empathic resonance in the experience of our acting body and the emotions associated with specific movements. As Lipps noted, ''When I observe a circus performer on a hanging wire, I feel I am inside him.'' To empathize, we need to invoke the representation of the actions associated with the emotions we are witnessing. (Carr et al., 2003)

Affective empathy exists when this mental representation is fed into our own emotional state. We feel what the other person feels and we act appropriately. This is much more than pro-social behavior.

From psychopaths to extraordinary altruists

The capacity for affective empathy varies from one person to the next. It is least developed in psychopaths:

Psychopathy is a heritable developmental disorder characterized by an uncaring nature, antisocial and aggressive behavior, and deficient prosocial emotions such as empathy, guilt, and remorse. Psychopaths exhibit consistent patterns of neuroanatomical and functional impairments, such as reductions in the volume of the amygdala and in the responsiveness of this structure to fear-relevant stimuli. These deficits may underlie the perceptual insensitivity to fearful facial expressions and other fear-relevant stimuli observed in this population. (Marsh et al., 2014)

Mainstream opinion accepts that psychopaths are heritably different because they are "sick." Heritable differences are thus thought to be unusual and even pathological. "Normal" individuals may vary in their capacity for affective empathy, but surely that sort of variability is due to their environment, isn't it?

No it isn't. That variability, too, is largely genetic. Affective empathy varies over a largely heritable continuum, and an arbitrary line is all that separates psychopaths from "normal" individuals. There may be many psychopaths or there may be few; it depends on where you set the cut-off point.

At the other end of this continuum is another interesting group: extraordinary altruists. A research team has recently looked at the brains of such people, specifically individuals who had donated one of their kidneys to a stranger:

Given emerging consensus that psychopathy is a continuously distributed variable within the general population and that psychopaths represent one extreme end of a caring continuum, we hypothesized that extraordinary altruism may represent the opposite end of this continuum and be supported by neural and cognitive mechanisms that represent the inverse of psychopathy; in particular, increased amygdala volume and responsiveness to fearful facial expressions. (Marsh etal., 2014)

In extraordinary altruists, the right amygdala is larger and responds more to fearful facial expressions. This is the inverse of what we see in psychopaths, who have smaller amygdala and are less responsive to fearful facial expressions.

Affective empathy is thus a specific mental trait, like psychopathy. It is not a form of pro-social behavior any more than psychopathy is a form of antisociality:

[...] it is important to distinguish between antisociality that results from psychopathy, which is specifically associated with reduced empathy and concern for others, as well as with reduced sensitivity to others' fear and distress, and antisociality that results from any of a variety of other factors, such as impulsivity or trauma exposure, that are not closely related to empathy. (Marshet al., 2014)

Marsh et al. (2014) cite a number of studies to show the relative independence of these two behavioral axes: prosociality / antisociality and affective empathy / psychopathy.

Conclusion

Affective empathy is specific and largely heritable. People differ continuously in their innate capacity for affective empathy, and it is only by setting an arbitrary cut-off point that we classify some as "psychopaths" and others as "normal," including extraordinary altruists who may be a small minority.

Affective empathy is an intricate adaptation that must have evolved for some reason. Initially, it may have served to facilitate the relationship between a mother and her children, this being perhaps why it is stronger in women than in men (Baron-Cohen and Wheelwright, 2004). In some cultures, natural selection may have increased this capacity in both sexes and extended it to a wider range of social interactions. This scenario would especially apply to Northwest Europeans, who have long had relatively weak kinship. They have consequently relied more on internal means of behavior control, like affective empathy (Frost, 2014).
 

References 

Baron-Cohen, S. and S. Wheelwright. (2004).The Empathy Quotient: An investigation of adults with Asperger Syndrome or high functioning autism, and normal sex differences. Journal of Autism and Developmental Disorders, 34, 163-175.
http://ftp.aspires-relationships.com/the_empathy_quotion_of_adults_with_as.pdf 

Carr, L., M. Iacoboni, M-C. Dubeau, J.C. Mazziotta, and G.L. Lenzi. (2003). Neural mechanisms of empathy in humans: A relay from neural systems for imitation to limbic areas, Proceedings of the National Academy of Sciences (USA), 100, 5497-5502.
http://www.ucp.pt/site/resources/documents/ICS/GNC/ArtigosGNC/AlexandreCastroCaldas/7_CaIaDuMaLe03.pdf  

Chakrabarti, B. and S. Baron-Cohen. (2013). Understanding the genetics of empathy and the autistic spectrum, in S. Baron-Cohen, H. Tager-Flusberg, M. Lombardo. (eds). Understanding Other Minds: Perspectives from Developmental Social Neuroscience, Oxford: Oxford University Press.
http://books.google.ca/books?hl=fr&lr=&id=eTdLAAAAQBAJ&oi=fnd&pg=PA326&ots=fHpygaxaMQ&sig=_sJsVgdoe0hc-fFbzaW3GMEslZU#v=onepage&q&f=false 

Frost, P. (2014). Affective empathy. An evolutionary mistake?  Evo and Proud, September 20
http://evoandproud.blogspot.ca/2014/09/affective-empathy-evolutionary-mistake.html

Hallam, H.E. (1985). Age at first marriage and age at death in the Lincolnshire Fenland, 1252-1478, Population Studies, 39, 55-69. 

Macfarlane, A. (1992). On individualism, Proceedings of the British Academy, 82, 171-199.
http://www.alanmacfarlane.com/TEXTS/On_Individualism.pdf 

Macfarlane, A. (2012). The invention of the modern world. Chapter 8: Family, friendship and population, The Fortnightly Review, Spring-Summer serial
http://fortnightlyreview.co.uk/2012/07/invention-8/ 

Marsh, A.A., S.A. Stoycos, K.M. Brethel-Haurwitz, P. Robinson, J.W. VanMeter, and E.M. Cardinale. (2014). Neural and cognitive characteristics of extraordinary altruists, Proceedings of the National Academy of Sciences, 111, 15036-15041.
http://www.pnas.org/content/111/42/15036.short

Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe, London: Verso.

5 comments:

Anonymous said...

Interesting. When it comes to affective empathy, Northern Europeans come at the top, followed by maybe Africans and south americans.
Arab countries and the Indian subcontinent would be pretty low on affective empathy becaue of tribalism and a caste system.
And then there's a difference between affective empathy for one' group and outsiders. Arabs would do pretty well on giving to their 'own' but India would still perform worse.

Mergen

http://www.cafonline.org/pdf/worldgivingindex2012web.pdf

Anonymous said...

Good stuff

Imo the explanation is there are two sets of genes contesting:

1) genes that produce a dose of happy chemicals when their carrier hurts someone

2) genes that produce a dose of sad chemicals when their carrier hurts someone and happy chemicals when they help someone

and it's the balance between the two that causes the spectrum.

You see evidence of this in CCTV of things like stabbings and killings. The attacker will often have a big grin on their face and look high as a kite - because they are high as a kite.

If the average person was 80/20 on the balance of good genes vs evil genes then the sergeant's mess in any infantry barracks would be mostly somewhere in the 60/40 range.

Luke Lea said...

As I asked on Unz.com, wouldn't this suggest that the amygdala of individuals in clan-based societies should be smaller on average than those in NW Europe? Is there any evidence for this (yet)?

Peter Fros_ said...

Anon,

It's important to distinguish here between empathy and pro-social behavior. Arabs seem to be better at pro-social behavior than Western Europeans. I'm not saying this is hardwired. It's just that when most people around you are not very empathic, you have to invest more effort in being pro-social, i.e., offering hospitality, making friendly conversation, giving free advice, little presents, flattery, etc. If you don't, the consequences are more serious than in a high-empathy society.

Anon,

I'll discuss this more in another post. There's good evidence that enjoyment of violence has a heritable basis.

Luke,

For what it's worth, self-described conservatives have bigger amygdalas than self-described liberals.

http://www.psychologytoday.com/blog/the-human-beast/201104/conservatives-big-fear-brain-study-finds

This finding is interpreted as meaning that conservatives are needlessly anxious and fearful.

surfaceyourrealself.com said...

Regarding the PNAS study cited, I was disappointed that the researchers stopped short of causal explanations. I think that it would have been within the scope of the study had the researchers continued on to examine what may have happened in the subjects’ lives to possibly cause their neurobiological and psychological attributes.

An accompanying PNAS commentary from a Harvard researcher made some interesting points. However, the author showed his biases that the thinking brain rules human behavior with an out-of-left-field question at the end of a paragraph in which he developed specious reasoning.

He was completely off base when he stated: “Could it be that extraordinary altruists such as Maupin [a study participant] and the 19 individuals studied by Marsh et al. [the researchers] are special, not only because of how they feel when they see people in distress, but because of how they think?” I don’t imagine that the brilliant commentator’s attempt to upstage the study’s subjects and get the spotlight on himself for some brilliant idea was much appreciated by anyone involved.

The amygdala is the central hub of a person’s feeling brain. The study’s findings had very little to say about the subjects’ thinking brains.

To postulate that the researchers missed that there was something different about the subjects’ thinking brains was out of touch with the realities of both the researchers’ scientific bases and the subjects. It’s another example of the current research mindset/social meme of thinking brain dominance.

http://surfaceyourrealself.com/2015/05/14/a-larger-amygdala-in-people-who-donated-a-kidney-to-strangers-surfaceyourrealself/