John Ray (M.A.; Ph.D.)
The best article on Leftism that I have ever read is by George Irbe. Irbe says pretty much what I say about the nature of Leftism but says it with greater brevity and clarity. Irbe's name for Leftists is "Coercive Utopians" and he diagnoses their dismal motivations most persuasively. I liked this epigram: "One will usually discover that behind the Robin Hood image hides just a plain hood." I like his article so much that I have copied it to one of my sites so that it will remain available even if it gets taken down at its original source.
He is strongly of the view that Leftism is an inborn tendency but seems unaware that there is now good evidence from the twin studies by behaviour geneticists such as Martin and others confirming that. The behaviour genetics work is mainly published in obscure and highly technical academic journals (that even I find a bit challenging to follow in detail) rather than being available online but one early summary by Eaves, Martin, Heath, Schieken, Silberg & Corey that IS available online is particularly fascinating. The authors found that your politics in your youth are mainly the product of the social influences around you (school and college indoctrination, for instance) but as you get older your genetically inherited political tendencies come to the fore.
The most striking behaviour genetics finding, however, is the 1999 finding by Eaves et al. showing that conservatism/Leftism is even more hereditary than how tall you are.
And the early (1986) article by Martin & Jardine showed that heredity is a particularly strong influence (around 50% of the variance) in women. Presumably because women tend to take less interest in the details of politics, their political reactions are much more likely to be purely instinctive.
And another article by Martin, Eaves, et al. (1986) showed that data on the transmission of conservative attitudes could in fact be explained by a model which assigned ZERO influence to the social environment and ALL influence to heredity. Putting it another way, the correlation between the conservatism of twins was high but not perfect but what similarity there was could be accounted for entirely by the extent to which the twins shared genes. Shared family environment was of no significance in determining the degree of twin similarity. Putting it yet another way, genetics is one (strong) influence on how conservative you are but your home environment is not. This runs entirely contrary to what the human race has believed for thousands of years but many other variables studied in genetics research also show little influence from family environment and strong influence from genetics. The facts are no respecter of preconceptions and assumptions. If parent and child have similar attitudes or similar personalities, that similarity is due to their shared genes, not to family teaching or indoctrination. Indoctrination from outside the family could however have some influence. All the influences on attitudes and personality have not yet been studied.
Bouchard, Segal, Tellegen, McGue, Keyes, & Krueger (2003) have also reported findings similar to those of Eaves, Martin and their associates.
Finally, there is an article in the 2005 American Political Science Review by John R. Alford, Carolyn L. Funk, and John R. Hibbing under the heading "Are Political Orientations Genetically Transmitted?". The whole article is not online but there is a summary of it in the NYT. Excerpt:
"As found in previous studies, attitudes about issues like school prayer, property taxes and the draft were among the most influenced by inheritance, the researchers found. Others like modern art and divorce were less so. And in the twins' overall score, derived from 28 questions, genes accounted for 53 percent of the differences.... Although the two broad genetic types, more conservative and more progressive, may find some common ground on specific issues, they represent fundamental differences that go deeper than many people assume, the new research suggests."
Bouchard, T.J., Segal, N. L., Tellegen, A, McGue, M, Keyes, M. and Krueger, R. (2003) Evidence for the construct validity and heritability of the Wilson-Patterson conservatism scale: a reared-apart twins study of social attitudes. Personality and Individual Differences, 34 (6), April 2003, 959-969.
Eaves L, Martin N, Heath A, Schieken R, Meyer J, Silberg J, Neale M, Corey L. (1997) Age changes in the causes of individual differences in conservatism. Behavior Genetics 1997, 27(2), 121-124.
N. G. MARTIN, L. J. EAVES, A. C. HEATH, ROSEMARY JARDINE, LYNN M. FEINGOLDT, AND H. J. EYSENCK (1986) Transmission of social attitudes. Proceedings of the National Academy of Sciences, USA Vol. 83. pp. 4364-4368.
Martin, N. & Jardine, R. (1986) Eysenck's contribution to behaviour genetics. In: S & C. Modgil (Eds.) Hans Eysenck: Consensus and controversy. Lewes, E. Sussex: Falmer
Eaves, L.J., Martin, N.G., Meyer, J.M. & Corey, L.A. (1999) Biological and cultural inheritance of stature and attitudes. In: Cloninger, C.R., Personality and psychopathology. Washington, D.C.: American Psychiatric Press.
A small update:
Renner's 2011 study also showed conservatism as primarily genetically determined. The abstract below just for fun:
Whereas a substantial genetic component of Conservatism and Religiosity is well documented, there is little evidence with respect to the behavior genetics of other aspects of human values. A sample of 157 monozygotic and 74 dizygotic twins reared together received the Austrian Value Questionnaire (AVQ), which measures a broad variety of value domains and their facets, found by the lexical approach in the German language. Family resemblance of Intellectualism, Harmony, Materialism, and Conservatism was best explained by additive or dominance genetic and non-shared environmental effects, whereas the influence of the environment shared by twins was negligible. In contrast, Religiosity was transmitted by additive genetic, shared and non-shared environmental influences. At the level of facets, the Intellectualism and Harmony showed a homogenous etiology while Religiosity, Materialism, and Conservatism were etiologically heterogeneous.
Personality and Individual Differences. In Press, Corrected Proof - doi:10.1016/j.paid.2011.09.003