Saturday, December 13, 2014

A darker shade of pale


 
Subjects identified the left-hand image as a woman and the right-hand one as a man. Yet the two images differ only in skin tone. Study by Richard Russell, Sinha Laboratory for Vision Research, MIT.

 

Skin color differs by sex: women are fairer and men browner and ruddier. Women also exhibit a greater contrast in luminosity between their facial skin and their lip and eye areas. These differences arise from differing concentrations of three skin pigments: melanin (brown); hemoglobin (red); and carotene (yellow). The cause is ultimately hormonal, as shown by studies on castrated and ovariectomized adults, on boys and girls during puberty, and on digit ratios (Edwards and Duntley, 1939; Edwards and Duntley, 1949; Edwards et al., 1941; Frost, 2010; Kalla and Tiwari, 1970; Manning et al., 2004; Mesa, 1983; Omoto,1965; Porcheron et al., 2013). Women are fairer than men in all human populations. The difference is greatest in people of medium color and least in very dark- or very fair-skinned people, apparently because of "floor" or "ceiling" effects (Frost, 2007). 

This sex difference is used by the human mind for sex recognition. In fact, it's more important for this purpose than other visual cues, like face shape. When subjects are shown an image of a human face, they can tell whether it is male or female even if blurred and differing only in hue and luminosity. Hue provides a "fast channel" for sex recognition. If the facial image is too far away or the lighting too dim, the mind switches to the "slow channel" and relies on luminosity (Bruce and Langton, 1994; Dupuis-Roy et al., 2009; Frost, 2011; Hill et al., 1995; Russell and Sinha, 2007; Russell et al., 2006; Tarr et al., 2001; Tarr et al., 2002).


Age differences

Skin color also differs by age. It can be used to distinguish younger from older women, since the contrast in luminosity between facial skin and the lip/eye areas decreases with age (Porcheron et al., 2013). It can also be used to recognize infants. All humans are born with very little melanin, and the resulting pinkish-white skin is often remarked upon in different cultures.

This is especially so where adults are normally dark-skinned, in striking contrast to newborns. In Kenya, the latter are often called mzungu ('European' in Swahili), and a new mother may ask her neighbors to come and see her mzungu (Walentowitz, 2008). Among the Tuareg, children are said to be whitened by the freshness and moisture of the womb (Walentowitz, 2008). The situation in other African peoples is summarized by a French anthropologist: "There is a rather widespread concept in Black Africa, according to which human beings, before 'coming' into this world, dwell in heaven, where they are white. For, heaven itself is white and all the beings dwelling there are also white. Therefore the whiter a child is at birth, the more splendid it is" (Zahan, 1974, p. 385). A Belgian anthropologist makes the same point: "black is thus the color of maturity [...] White on the other hand is a sign of the before-life and the after-life: the African newborn is light-skinned and the color of mourning is white kaolin" (Maertens, 1978, p. 41). 

This infant/adult difference is evolutionarily old, being present in nonhuman primates. In langurs, baboons, and macaques, the newborn's skin is pink while the adult's is black. This visual cue not only helps adults to locate a wayward infant but also seems to induce a desire to defend and provide care (Jay, 1962). Humans may respond similarly to the lighter color of infants and women. This would be consistent with a tendency by the adult female body to mimic the newborn body in other ways: face shape; pitch of voice; amount of body hair; texture and pliability of the skin; etc. Over time, women may have come to resemble this 'infant schema' because it is the one that can best reduce aggressiveness in a male partner and induce him to assume a provider role.
 

The sun-tanning fad: An aesthetic revolution

The sex-specific aspects of skin color have influenced the development of cosmetics in many cultures. Even in ancient times, women would use makeup to increase the natural contrast in luminosity between their facial skin and their lip/eye areas (Russell, 2009; Russell, 2010). They would also make their naturally fair complexion even fairer by avoiding the sun and applying white powders or bleaching agents.

This feminine aesthetic changed radically in the 1920s with the sudden popularity of sun-tanning throughout the Western world, initially as a health fad. Tanned skin then entered women's fashion and became part of the flapper image, along with bobbed hair, broad shoulders, a relatively flat chest, narrow hips, and long legs. This fashion image was intended to be hermaphroditic, the aim being to energize the erotic appeal of the female body by masculinizing some of its key features (Bard, 1998; Segrave, 2005). 

Has the tanning fad un-gendered skin color? Not wholly, to judge by the above studies on sex recognition. There still seems to be a tendency to prefer a lighter skin tone for women than for men. This was the conclusion of a recent study on how people perceive two skin pigments: melanin (brown) and carotene (yellow). When shown facial images with varying concentrations of melanin and carotene, the subjects had a greater preference for carotene than for melanin. This preference was stronger for female faces than for male faces, irrespective of the observer's sex. Nonetheless, for both male and female faces, the preferred skin color was much darker than it would have been a century ago (Lefevre and Perrett, 2014).

Again, this aesthetic norm has darkened only in the Western world. The tanned look had some popularity among Japanese women in the postwar era up to the 1970s, but it has since gone out of fashion (Ashikari, 2005). It never did catch on elsewhere in Asia (Li et al., 2008). In North America and Europe, the tanned look seems much more persistent, and this persistence suggests that it is locked into place by something else in our cultural environment.

Such as ...? One factor may be the conscious effort to promote images of dark-skinned people in advertising and, more generally, in popular culture. Another factor may be a half-conscious desire in popular culture for more aggressive, "harder" forms of eroticism. This is something that fair skin is less effective at delivering, having been originally part of the infant schema and thus less conducive to that kind of emotional response.

 

References


Ashikari, M. (2005). Cultivating Japanese whiteness. The 'whitening' cosmetics boom and the Japanese identity, Journal of Material Culture, 10, 73-91. 

Bard, C. (1998). Les Garçonnes. Modes et fantasmes des Années folles, Flammarion, Paris. 

Bruce, V., and S. Langton. (1994). The use of pigmentation and shading information in recognising the sex and identities of faces, Perception, 23(7), 803-822.

Dupuis-Roy, N., I. Fortin, D. Fiset, and F. Gosselin. (2009). Uncovering gender discrimination cues in a realistic setting, Journal of Vision, 9(2), 10, 1-8.
http://journalofvision.org/9/2/10/

Edwards, E.A. and S.Q. Duntley. (1949). Cutaneous vascular changes in women in reference to the menstrual cycle and ovariectomy, American Journal of Obstetrics and Gynecology, 57, 501-509.

Edwards, E.A. and S.Q. Duntley. (1939).The pigments and color of living human skin, American Journal of Anatomy, 65, 1-33.

Edwards, E.A., J.B. Hamilton, S.Q. Duntley, and G. Hubert. (1941). Cutaneous vascular and pigmentary changes in castrate and eunuchoid men, Endocrinology, 28, 119-128. 

Frost, P. (2011). Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks, Human Ethology Bulletin,
http://www.researchgate.net/publication/256296588_Hue_and_luminosity_of_human_skin_a_visual_cue_for_gender_recognition_and_other_mental_tasks/file/72e7e5223eb2c3eb3b.pdf

Frost, P. (2010). Femmes claires, hommes foncés. Les racines oubliées du colorisme, Québec: Les Presses de l'Université Laval, 202 p.

Frost, P. (2007). Comment on Human skin-color sexual dimorphism: A test of the sexual selection hypothesis, American Journal of Physical Anthropology, 133, 779-781.

Hill, H., Bruce, V., and S. Akamatsu. (1995). Perceiving the sex and race of faces: The role of shape and colour, Proceedings of the Royal Society B: Biological Sciences, 261, 367-373. 

Jay, P.C. (1962). Aspects of maternal behavior among langurs, Annals of the New York Academy of Sciences, 102, 468-476.
http://onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.1962.tb13653.x/abstract

Kalla, A.K. and S.C. Tiwari. (1970). Sex differences in skin colour in man, Acta Geneticae Medicae et Gemellologiae, 19, 472-476. 

Lefevre, C.E. and D.I. Perrrett. (2014). Fruit over sunbed: Carotenoid skin colouration is found more attractive than melanin colouration, The Quarterly Journal of Experimental Psychology,
http://www.tandfonline.com/doi/full/10.1080/17470218.2014.944194#tabModulehttp://www.tandfonline.com/doi/full/10.1080/17470218.2014.944194#tabModule

Li, E.P.H., H.J. Min, R.W. Belk, J. Kimura, and S. Bahl. (2008). Skin lightening and beauty in four Asian cultures, Advances in Consumer Research, 35, 444-449.

Maertens, J-T. (1978). Le dessein sur la peau. Essai d'anthropologie des inscriptions tégumentaires, Ritologiques I, Paris: Aubier Montaigne. 

Manning, J.T., P.E. Bundred, and F.M. Mather. (2004). Second to fourth digit ratio, sexual selection, and skin colour, Evolution and Human Behavior, 25, 38-50.
http://www.ehbonline.org/article/S1090-5138(03)00082-5/abstract 

Mesa, M.S. (1983). Analyse de la variabilité de la pigmentation de la peau durant la croissance, Bulletin et mémoires de la Société d'Anthropologie de Paris, t. 10 series 13, 49-60.
http://www.persee.fr/web/revues/home/prescript/article/bmsap_0037-8984_1983_num_10_1_3882 

Omoto, K. (1965). Measurements of skin reflectance in a Japanese twin sample, Journal of the Anthropological Society of Nippon (Jinruigaku Zassi), 73, 115-122.
http://ci.nii.ac.jp/naid/130003726811/http://ci.nii.ac.jp/naid/130003726811/ 

Porcheron, A., E. Mauger, and R. Russell (2013). Aspects of facial contrast decrease with age and are cues for age perception, PLoS ONE 8(3): e57985
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0057985 

Russell, R. (2010). Why cosmetics work. In R. Adams, N. Ambady, K. Nakayama, and S. Shimojo. (eds.) The Science of Social Vision, New York: Oxford.
http://public.gettysburg.edu/~rrussell/Russell_SocialVision_cosmetics_chapter.pdf 

Russell, R. (2009). A sex difference in facial contrast and its exaggeration by cosmetics, Perception, 38, 1211-1219
http://public.gettysburg.edu/~rrussell/Russell_2009.pdf

Russell, R. (2003). Sex, beauty, and the relative luminance of facial features, Perception, 32, 1093-1107.

Russell, R. and P. Sinha. (2007). Real-world face recognition: The importance of surface reflectance properties, Perception, 36, 1368-1374.

Russell, R., P. Sinha, I. Biederman, and M. Nederhouser. (2006). Is pigmentation important for face recognition? Evidence from contrast negation, Perception, 35, 749-759.

Segrave, K. (2005). Suntanning in 20th Century America, Jefferson (North Carolina), McFarland & Co. 

Tarr, M. J., Kersten, D., Cheng, Y., and Rossion, B. (2001). It's Pat! Sexing faces using only red and green, Journal of Vision, 1(3), 337, 337a
http://journalofvision.org/1/3/337/

Walentowitz, S. (2008). Des êtres à peaufiner. Variations de la coloration et de la pigmentation du nouveau-né, in J-P. Albert, B. Andrieu, P. Blanchard, G. Boëtsch, and D. Chevé (eds.), Coloris Corpus, (pp. 113-120), Paris: CNRS Éditions, 2008.

Zahan, D. (1974). White, Red and Black: Colour Symbolism in Black Africa, in A. Portmann and R. Ritsema (eds.) The Realms of Colour, Eranos 41 (1972), 365-395, Leiden: Eranos.

Saturday, December 6, 2014

Are Chinese babies more docile?

 


Navaho woman with a child on cradleboard.
see video on cross-cultural differences in newborn behavior, Daniel Freedman, 1974 (posted by hbd chick)

 

In my last post I discussed recent research on mental differences between Europeans and Chinese people. The latter are less prone to boredom. They think less abstractly and more relationally. They're less individualistic, and less likely to punish friends for dishonesty. Mental differences also seem to exist within China, depending on whether one comes from a region that historically grew rice or one that historically grew wheat. Chinese from wheat-growing regions are closer to Europeans in mentality.

Are these differences inborn? Or are they due to upbringing? The second explanation is hard to reconcile with the fact that the regional differences within China involved urban residents who had never lived on a farm of any sort.

Almost a half-century ago, these questions interested the American psychologist Daniel Freedman and his wife Nina Chinn Freedman. They examined 24 Chinese-American and 24 Euro-American newborns whose parents were otherwise similar in age, economic class, and number of previous children. The two groups nonetheless behaved differently. The Euro-American babies cried more easily, were harder to console, and would immediately turn their faces aside if placed face down on a sheet. In contrast, the Chinese-American babies accepted almost any position without crying or resisting. When a light was shone in their eyes, the Euro-American babies would continue to blink long after the Chinese-American babies had stopped blinking (Freedman and Freedman, 1969; Freedman, 2004).

These findings were partially replicated by another American psychologist, Jerome Kagan, who found that Chinese 4-month-olds cried, fretted, and vocalized less than Euro-American infants. At older ages, however, the pattern reversed with Chinese Americans fretting and crying more when separated from their mothers (Kagan et al., 1978; Kagan et al., 1994).

Is this response specific to Chinese? Or does it apply to East Asians in general? In a study of Euro-American, Japanese, and Chinese 11-month olds, the last group was the least expressive one, being least likely to smile or cry. The Japanese babies either fell between the two other groups or were like the Euro-American babies (Camras et al., 1998). When another study looked at Japanese and British newborns, the latter actually showed more self-quieting activity (Eishima, 1992).

On the other hand, Navaho babies are even calmer and more adaptable than Chinese babies (Freedman, 2004). Some anthropologists have attributed this finding to a traditional practice of tying the baby to a cradleboard. As Freedman pointed out, however, this practice is now only sporadic among the Navaho.

Freedman attributed his Chinese and Navaho findings to a general Mongoloid temperament. If that were the case, infants should behave similarly in other North American native peoples. A study of Alaskan Inupiaq found young children to be shy but otherwise no different from Euro-American children. These subjects were, however, older than Freedman’s, being 3 to 6 years of age (Sprott, 2002).

It may be that the Navaho differ from other North American native peoples in this respect. Perhaps, in the past, mortality was higher among those babies who resisted the cradleboard; over time, they and their temperament would have been steadily removed from the gene pool. As Freedman noted, "most Navaho infants calmly accept the board; in fact, many begin to demand it by showing signs of unrest when off." When Euro-American mothers tried using the cradleboard, "their babies complained so persistently that they were off the board in a matter of weeks" (Freedman, 2004).

Infant calmness can thus arise in relatively simple societies, and not just in advanced ones as I had argued in my last post. In the Navaho case, there may have been some kind of parental selection, i.e., through their child-rearing practices, parents influence what sort of children survive and what sort don't. In other simple societies, such as among the Australian Aborigines, infant behavior is much less calm and compliant (Freedman, 2004).

Behavior can likewise differ between infants from different complex societies. We've seen this with Chinese-American and Euro-American babies, the latter having a less easy temperament. A difficult temperament (colic, excessive crying) is also much more common in babies of Greek or Middle Eastern origin than in babies of Northwest European or Asian Indian origin (Prior et al., 1987).

In the future, it would be interesting to find out whether infants differ in temperament within China, such as between rice-growing and wheat-growing regions.
 

But will there be more research?

There seems to be less and less interest in this area of research, particularly within the United States. I can point to several reasons:

- The behavioral differences between Chinese and Japanese babies must have arisen over a relatively short span of evolutionary time. Many researchers, even those who are receptive to HBD thinking, have trouble accepting fast behavioral evolution, especially below the level of large continental races.

- American researchers are increasingly interested in the possibility that early parental interaction, such as reading to children, can stimulate brain development. Although it is doubtful that parental interaction can explain differences in newborn behavior, this assumption seems to make people dismissive of Freedman's work. 

- Since the 1970s, and throughout the Western world, academia has become more hostile to the possibility of genetic influences on human behavior. This trend is self-reinforcing, since hiring decisions are biased toward candidates who believe in environmental determinism.

The last two points apply much less to East Asian scholars ... or American ones who are willing to do some of their work offshore. 

Right now, we need to identify the genetic causation for these differences in infant behavior. One cause may be the 7R allele of the D4 dopamine receptor gene, which is associated with Attention-Deficit/Hyperactivity Disorder (ADHD) and is very rare in East Asians (Leung et al., 2005). Nonetheless, as with differences in intellectual capacity, we're probably looking at an accumulation of small effects at many different genes. Natural selection acts on what genes produce, and not directly on genes, so there is no reason to believe that a single behavioral outcome has a single genetic cause. That would be too convenient.

 

References
 

Camras, L.A., H. Oster, J. Campos, R. Campos, T. Ujiie, K. Miyake, L. Wang, and Z. Meng. (1998). Production of emotional facial expressions in European American, Japanese, and Chinese infants, Developmental Psychology, 34, 616-628.
http://www-psych.stanford.edu/~carl/isl/PDFPublications/Production%20of%20emotional%20facial%20expressions%20in%20European%20American,%20Japanese,%20and%20Chinese%20infants..pdf  

Eishima, K. (1992). A study on neonatal behaviour comparing between two groups from different cultural backgrounds, Early Human Development, 28, 265-277.
http://www.sciencedirect.com/science/article/pii/037837829290172D  

Freedman, D.G. (2004). Ethnic differences in babies, in L. Dundes (ed.). The Manner Born: Birth Rites in Cross-Cultural Perspective, pp. 221-232, AltaMira Press.
http://books.google.ca/books?hl=fr&lr=&id=ZSizAQAAQBAJ&oi=fnd&pg=PA221&dq=freedman+chinese+american+newborns&ots=qmXzqhaNE3&sig=eIEw-KCGcciDEDpIiqgdxX9PxJk#v=onepage&q&f=false

Freedman, D.G., and N.C. Freedman. (1969). Behavioural differences between Chinese-American and European-American newborns, Nature, 224, 1227. 

Kagan, J., D. Arcus, N. Snidman, W. Feng, J. Hendler, and S. Greene. (1994). Reactivity in infants: A cross-national comparison, Developmental Psychology, 30, 342-345.
http://pzacad.pitzer.edu/~dmoore/1994_Kagan%20et%20al_Reactivity%20in%20infants_DP.pdf

Kagan, J., R. Kearsley, and P. Zelazo. (1978). Infancy: Its place in human development, Cambridge, MA: Harvard University Press. 

Leung, P.W.L., C.C. Lee, S.F. Hung, T.P. Ho, C.P. Tang, et al. (2005). Dopamine receptor D4 (DRD4) gene in Han Chinese children with attention-deficit/hyperactivity disorder (ADHD): Increased prevalence of the 2-repeat allele, American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics, 133B, 54-56.
http://webcontent.hkcss.org.hk/rh/rpp/HKPaediatricSociety20050630DRD4ADHDChinese.pdf

Prior, M., E. Garino, A. Sanson, and F. Oberklaid. (1987). Ethnic influences on "difficult" temperament and behavioural problems in infants, Australian Journal of Psychology, 39, 163-171.
http://www.tandfonline.com/doi/abs/10.1080/00049538708259045#.VIMoKuktDcs

Sprott, J.E. (2002). Raising Young Children in an Alaskan Iñupiaq Village: The Family, Cultural, and Village Environment of Rearing, Greenwood Publishing Group.
http://books.google.ca/books?hl=fr&lr=&id=FjBxXAFqD3QC&oi=fnd&pg=PR13&dq=%22alaskan+inupiaq+newborns+temperament&ots=JfwfOrluQq&sig=B3RSdAUzYqcBPIJyJMS65LGy-Zo#v=onepage&q=temperament&f=false

Friday, November 28, 2014

Do Chinese people get bored less easily?


 
Boy in a café (S. Yao, Wikicommons)

 

All humans were once hunter-gatherers. Back then, versatility came with the territory. There were only so many game animals, and they differed a lot in size, shape, and color. So you had to enjoy switching back and forth from one target animal to another. And you had to enjoy moving from one place to another. Sooner or later you'd have to.

Beginning 10,000 years ago, farmers made their appearance. Now monotony came with the territory. A plot of land wasn't something you could forget while you took off somewhere else. It needed constant care. The tasks were also more repetitive: ploughing, sowing, harvesting ...

Things worsened as farming became more advanced. You had to focus on one crop and a limited number of key tasks.

Different means of subsistence have selected for different mental traits, and this selection has had genetic consequences. Monotony avoidance has a heritability of 0.53 (Saudino, 1999). This predisposition has usually been a handicap in modern societies, so much so that it often leads to criminality. Males with a history of early criminal behavior tend to score high on monotony avoidance, as well as on sensation seeking and low conformity (Klinteberg et al., 1992).

Today, if you have trouble fitting into your society, you might still survive and reproduce. In the past, you probably wouldn’t. Other people would take your place in the gene pool and, over successive generations, their mental makeup would become the norm.

That’s gene-culture co-evolution. We have reshaped the world we live in, and this human-made world has reshaped us. After describing how our ancestors radically changed their environment, Razib goes on to write: "We were the authors of those changes, but in the process of telling that story, we became protagonists within it" (Khan, 2014).

 
China: a case study

Advanced farming—intensive land use, task specialization, monoculture—has profoundly shaped East Asian societies, particularly China. This is particularly so for rice farming. Because the paddies need standing water, rice farmers must work collectively to build, dredge, and drain elaborate irrigation networks. Wheat farming, by comparison, requires no irrigation and only half as much work.

Advanced farming seems to have favored a special package of predispositions and inclinations, including greater acceptance of monotony. This has been shown in two recent studies.

The first one was about boredom and how people experience it in their lives. The results from the 775 Chinese participants were then compared with the results from a previous survey of 572 Euro-Canadians. It was found that the Chinese participants were less likely to feel bored in comparable situations. They seemed to value low-arousal (calm, relaxation) versus high arousal (excitement, elation) in the case of Euro-Canadians (Ng et al., 2014). 

The authors attributed their findings to cultural learning. One may wonder, however, why preference for low arousal persists in the face of China’s massive influx of high-arousal Western culture.


Relational thinking, collectivism, and favoritism

The second study had the aim of seeing whether the sociological differences between rice farmers and wheat farmers have led to differences in mental makeup. When 1,162 Han Chinese performed a series of mental tasks, the results differed according to whether the participants came from rice-farming regions or wheat-farming regions (Talhelm et al., 2014).

When shown a list of three items, such as “train”, “bus”, and “tracks”, and told to choose two items that pair together, people from rice-farming regions tended to choose "train and tracks," whereas people from wheat-farming regions tended to choose "train and bus." The former seemed to be more relational in their thinking and the latter more abstract. This pattern held up even in neighboring counties along China's rice-wheat border. People from the rice side of the border thought more relationally than did people from the wheat side.

A second task required drawing pictures of yourself and your friends. In a prior study, Americans drew themselves about 6 mm bigger than they drew their friends, Europeans drew themselves 3.5 mm bigger, and Japanese drew themselves slightly smaller. In the present study, people from rice regions were more likely than people from wheat regions to draw themselves smaller than they drew their friends. On average, people from wheat regions self-inflated 1.5 mm, and people from rice regions self-deflated -0.03 mm.

A third task required imagining yourself doing business with (i) an honest friend, (ii) a dishonest friend, (iii) an honest stranger, and (iv) a dishonest stranger. This person might lie, causing you to lose money. Or this person might be honest, causing you to make money. You could reward or punish this person accordingly. A previous study found that Singaporeans rewarded friends much more than they punished them. Americans were much more likely to punish friends for bad behavior. In this study, people from rice regions were more likely to remain loyal to friends regardless.

Interestingly, these findings came from people with no connection to farming at all. They grew up in a modern urban society, and most were too young to have known the China that existed before the economic reforms of the late 1970s.  It looks like rice regions have favored hardwiring of certain psychological traits: less abstract thinking and more relational thinking, less individualism and more collectivism, and less impartiality toward strangers and more favoritism toward kin and friends.

 
Why farming sucks, for you but not for me

These findings corroborate the ethnographic literature on the differences in mentality between hunter-gatherers and farmers. Hunter-gatherers typically see farming as a kind of slavery, and they have trouble understanding well-meaning outsiders who want to turn them into land-slaves.

Yes, for the same land area, farming can produce much more food. But it's hard work, not only physically but mentally as well. Humans had to undergo a change in mentality before they could make the transition from hunting and gathering to farming

Those humans ended up transforming not just their physical landscape but also their social and cultural landscape … and ultimately themselves. By creating new values and social relations, they changed the rules for survival and reproduction, thereby changing the sort of mentality that future generations would inherit.

Humans transformed the world through farming, and the world returned the favor.

  
References
 

Khan, R. (2014). Our cats, ourselves, The New York Times, The Opinion Pages, November 24
http://www.nytimes.com/2014/11/25/opinion/our-cats-ourselves.html

Klinteberg, B., K. Humble, and D. Schalling. (1992). Personality and psychopathy of males with a history of early criminal behaviour, European Journal of Personality, 6(4), 245-266.
http://psycnet.apa.org/psycinfo/1993-18051-001
 
Ng, A.H., Y. Liu, J-Z. Chen, and J.D. Eastwood. (2014). Culture and state boredom: A comparison between European Canadians and Chinese, Personality and Individual Differences, 75, 13-18.
http://www.sciencedirect.com/science/article/pii/S0191886914006321
 
Saudino, K.J., J.R. Gagne, J. Grant, A. Ibatoulina, T. Marytuina, I. Ravich-Scherbo, and K. Whitfield. (1999). Genetic and environmental influences on personality in adult Russian twins, International Journal of Behavioral Development, 23, 375-389.
http://jbd.sagepub.com/content/23/2/375.short
 
Talhelm, T., X. Zhang, S. Oishi, C. Shimin, D. Duan, X. Lan, and S. Kitayama. (2014). Large-scale psychological differences within China explained by rice versus wheat agriculture, Science, 344, 603-607.
http://internationalpsychoanalysis.net/wp-content/uploads/2014/05/RiceversusWheatScience-2014-Talhelm-603-8.pdf

Saturday, November 22, 2014

Are liberals and conservatives differently wired?


 
Anti-UKIP protest in Edinburgh (source: Brian McNeil, Wikicommons). "Conservative" increasingly means pro-white.

 

Are liberals and conservatives differently wired? It would seem so. When brain MRIs were done on 90 young adults from University College London, it was found that self-described liberals tended to have more grey matter in the anterior cingulate cortex, whereas self-described conservatives tended to have a larger right amygdala. These results were replicated in a second sample of young adults (Kanai et al., 2011).

The amygdala is used to recognize fearful facial expressions, whereas the anterior cingulate cortex serves to monitor uncertainty and conflict (Adolphs et al., 1995; Botvinick et al., 1999; Critchley et al., 2001; Kennerley et al., 2006). Perhaps unsurprisingly, these findings were changed somewhat in the popular press. "Conservatives Big on Fear, Brain Study Finds," ran a headline in Psychology Today. The same article assured its readers that the anterior cingulate cortex "helps people cope with complexity" (Barber, 2011).

A study on 82 young American adults came to a similar conclusion. Republicans showed more activity in the right amygdala, and Democrats more activity in the left insula. Unlike the English study, the anterior cingulate cortex didn't differ between the two groups (Schreiber et al., 2013).

It would seem, then, that conservatives and liberals are neurologically different. Perhaps certain political beliefs will alter your mental makeup. Or perhaps your mental makeup will lead you to certain political beliefs. But how can that be when conservatism and liberalism have changed so much in recent times, not only ideologically but also electorate-wise? A century ago, English "conservatives" came from the upper class, the middle class, and outlying rural areas. Today, Britain's leading "conservative" party, the UKIP, is drawing more and more of its members from the urban working class—the sort of folks who routinely voted Labour not so long ago. Similar changes have taken place in the U.S. Until the 1950s, white southerners were overwhelmingly Democrats. Now, they're overwhelmingly Republicans.

Of course, the above studies are only a few years old. When we use terms like "conservative" and "liberal" we refer to what they mean today. Increasingly, both terms have an implicitly ethnic meaning. The UKIP is becoming the native British party, in opposition to a growing Afro-Asian population that votes en bloc for Labour. Meanwhile, the Republicans are becoming the party of White Americans, particularly old-stock ones, in opposition to a Democrat coalition of African, Hispanic, and Asian Americans, plus a dwindling core of ethnic whites.

So are these brain differences really ethnic differences? Neither study touches the question. The English study assures us that the participants were homogeneous:

We deliberately used a homogenous sample of the UCL student population to minimize differences in social and educational environment. The UK Higher Education Statistics Agency reports that 21.1% of UCL students come from a working-class background. This rate is relatively low compared to the national average of 34.8%. This suggests that the UCL students from which we recruited our participants disproportionately have a middle-class to upper-class background. (Kanai et al., 2011)

Yes, the students were largely middle-class, but how did they break down ethnically? Wikipedia provides a partial answer:

In 2013/14, 12,330 UCL students were from outside the UK (43% of the total number of students in that year), of whom 5,504 were from Asia, 3,679 from the European Union ex. the United Kingdom, 1,195 from North America, 516 from the Middle East, 398 from Africa, 254 from Central and South America, and 166 from Australasia (University College London, 2014)

These figures were for citizenship only. We should remember that many of the UK students would have been of non-European origin. 

We know more about the participants in the American study. They came from the University of California, San Diego, whose student body at the time was 44% Asian, 26% Caucasian, 10% Mexican American, 10% unknown, 4% Filipino, 3% Latino/Other Spanish, and 2% African American (Anon, 2010). This ethnic breakdown mirrors the party breakdown of the participants: 60 Democrats (72.5%) and 22 Republicans (27.5%).


Affective empathy and ethnicity

In my last post, I cited a study showing that the amygdala is larger in extraordinary altruists—people who have donated one of their kidneys to a stranger. In that study, we were told that a larger amygdala is associated with greater responsiveness to fearful facial expressions, i.e., a greater willingness to help people in distress. Conversely, psychopaths have a smaller amygdala and are less responsive to fearful faces (Marsh et al., 2014).

Hmm ... That's a tad different from the spin in Psychology Today. Are liberals the ones who don't care about others? Are they ... psychopaths?

It would be more accurate to say that "liberals" come from populations whose capacity for affective empathy is lower on average and who tend to view any stranger as a potential enemy. That's most people in this world, and that's how most of the world works. I suspect the greater ability to monitor uncertainty and conflict reflects adaptation to an environment that has long been socially fragmented into clans, castes, religions, etc. This may explain why a larger anterior cingulate cortex correlated with "liberalism" in the British study (high proportion of South Asian students) but not in the American study (high proportion of East Asian students).

As for "conservatives," they largely come from Northwest Europe, where a greater capacity for affective empathy seems to reflect an environment of relatively high individualism, relatively weak kinship, and relatively frequent interactions with nonkin. This environment has prevailed west of the Hajnal Line since at least the 12th century, as shown by the longstanding characteristics of the Western European Marriage Pattern: 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. This zone of weaker kinship, with greater reliance on internal means of behavior control, may also explain why Northwest Europeans are more predisposed to guilt than to shame, whereas the reverse is generally the case elsewhere in the world (Frost, 2014).

All of this may sound counterintuitive. Doesn't the political left currently stand for autonomy theory and individualism? Doesn't it reject traditional values like kinship? In theory it does. The reality is a bit different, though. When Muslims vote Labour, it's not because they want gay marriage and teaching of gender theory in the schools. They expect something else.

The same goes for the political right. When former Labourites vote UKIP, it's not because they want lower taxes for the rich and offshoring of manufacturing jobs. They expect something else. Are they being delusional? Perhaps. But, then, are the Muslims being delusional? 

Perhaps neither group is. Perhaps both understand what politics is really about.

 

References
 

Adolphs, R., D. Tranel, H. Damasio, and A.R. Damasio. (1995). Fear and the human amygdala, The Journal of Neuroscience, 15, 5879-5891.
http://www.emotion.caltech.edu/papers/AdolphsTranel1995Fear.pdf 

Anon (2010). Racial breakdown of the largest California public colleges, The Huffington Post, May 4
http://www.huffingtonpost.com/2010/03/04/racial-breakdown-of-the-l_n_485577.html 

Barber, N. (2011). Conservatives big on fear, study finds, Psychology Today, April 19
http://www.psychologytoday.com/blog/the-human-beast/201104/conservatives-big-fear-brain-study-finds

Botvinick, M., Nystrom, L.E., Fissell, K., Carter, C.S., and Cohen, J.D. (1999). Conflict monitoring versus selection-for-action in anterior cingulate cortex, Nature, 402, 179-181.

Critchley, H.D., Mathias, C.J., and Dolan, R.J. (2001). Neural activity in the human brain relating to uncertainty and arousal during anticipation, Neuron, 29, 537-545. 

Frost, P. (2014). We are not equally empathic, Evo and Proud, November 15
http://www.evoandproud.blogspot.ca/2014/11/we-are-not-equally-empathic.html 

Kanai, R., T. Feilden, C. Firth, and G. Rees. (2011). Political orientations are correlated with brain structure in young adults, Current Biology, 21, 677 - 680.
http://www.cell.com/current-biology/abstract/S0960-9822(11)00289-2

Kennerley, S.W., Walton, M.E., Behrens, T.E., Buckley, M.J., and Rushworth, M.F. (2006). Optimal decision making and the anterior cingulate cortex. Nat. Neurosci. 9, 940-947.

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

Schreiber, D., Fonzo, G., Simmons, A.N., Dawes, C.T., Flagan, T., et al. (2013). Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans. PLoS ONE 8(2): e52970.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0052970 

University College London. (2014). Wikipedia
http://en.wikipedia.org/wiki/University_College_London#Student_body

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.