The MBTI is an amazing tool and it's really helped me over the years to understand myself and others.
In mainstream academic psychology (at least, the American version), they don't put much stock in the MBTI (at least, officially), but they have something very similar called the Five Factor Model of Personality, by Costa and McCrae.
It looks at five dimensions of personality, not four as the MBTI does. It's been tested a lot and validated by academic psychologists, which the MBTI hasn't so much been (but that doesn't mean the the MBTI isn't powerful too - it really is great, in my opinion).
I have been skimming through old Phoenix Rising threads tonight and I came across this one... I noticed that folks in this thread were talking about genetics and personality types/MBTI results --
and I thought I'd mention that some of the Five Factor Model of Personality crowd (and lots of others) are researching this very issue: genetics and personality types.
Further information and some examples of published studies:
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Basics of the Five Factor Model of Personality
http://en.wikipedia.org/wiki/Five_factor_model
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"McCrae and... Costa.... have developed the Five-Factor Theory, which says that personality traits themselves are genetically based, but that characteristic adaptations--habits, beliefs, values, self-concepts, roles, relationships, skills--are shaped jointly by genetically determined traits and the environment."
from the article "Searching for Genes that Explain our Personalities"
American Psychological Association publication, September
2002
http://www.apa.org/monitor/sep02/genes.aspx
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"The NEO-Five-Factor Inventory divides human personality traits into five dimensions: neuroticism, extraversion, openness, conscientiousness and agreeableness. In this study, we sought to identify regions harboring genes with large effects on the five NEO personality traits by performing genome-wide linkage analysis of individuals scoring in the extremes of these traits.... Our findings imply that there may be genes with relatively large effects involved in personality traits"
"A genome-wide linkage study of individuals with high scores on NEO personality traits"
Mol Psychiatry. 2012 Oct;17(10):1031-41. doi: 10.1038/mp.2011.97. Epub 2011 Aug 9.
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"Personality traits are summarized by five broad dimensions with pervasive influences on major life outcomes, strong links to psychiatric disorders, and clear heritable components. To identify genetic variants associated with each of the five dimensions of personality we performed a genome wide association (GWA) scan of 3,972 individuals from a genetically isolated population within Sardinia, Italy."
"Genome-wide association scan for five major dimensions of personallity"
Mol Psychiatry. 2010 June; 15(6): 647–656.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874623/
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"The first candidate gene studies of human personality promised much but, in the fifteen years since their publication, have delivered little in the way of clear evidence for the contribution of specific genetic variants to observed variation in personality traits. This is most likely due to the very small effects conferred by individual loci. The advent of genome-wide association studies has brought growing awareness that high levels of statistical stringency, very large sample sizes, and independent replication will be minimum requirements for future genetic studies of personality. At the same time, evidence from other fields indicates that the genetic architecture of personality is likely to consist of the combined effect of many hundreds, if not thousands, of small effect loci."
"Dissecting the Genetic Architecture of Human Personality"
Trends Cogn Sci. 2011 Sep;15(9):395-400. doi: 10.1016/j.tics.2011.07.007. Epub 2011 Aug 9.
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"Common SNPs explain some of the variation in the personality dimensions of neuroticism and extraversion."
Transl Psychiatry. 2012 Apr 17;2:e102. doi: 10.1038/tp.2012.27.
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(Oops, I meant to put the Pubmed hyperlinks to all of those, but forgot and then closed the links. These and similar articles are available there.)