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i think it's hereditary. i've always been told i'm a lot like my mom, who is an ESFP for sure. one of her sisters is esfp also, and a few of my cousins are too. again, this is all on my moms side of the family. the majority of my moms side are extraverted feelers, and on my dads side they're all introverted thinkers.

OR is it developed? i think your personality type is almost how your brain is programmed, but your personality itself is developed through the way your parents raised you and stuff like that.
 

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Depends on who you follow.

One of the great things i see on this forum is the slander of Dr keirsey on his skills and how useless he is and the oh so holy Carl jung. and yet Jung believed your type changed thru your life time. and that it wasn't static. So you get people who believe in Jungs original works and find Keirsey and useless idiot, yet believe in keirseys ideas on it static and never changing.

When your a child your brain learns thru making neurological pathways in the brain. the more that same pathway is used the stronger it is, and the more safe you feel. Trying to use a different pathway is harder and can sometimes produce fear like symptoms.

Now to me logic would suggest every human when born has the ability to use and think in whatever way it wants. it has the ability to learn everything and anything. But once you learn something and it feels and becomes easy. you tend to stick to that method. you also apply that method to other things. Over many years, it becomes who you are. you feel safe the way you think and the way to do things. and when you are forced to do things that are not in the way you would usually do them. you have problems, you feel unable to do so. and you also stray away from those feeings more.

So i believe as a child your personality is shaped, by the way you learn to do and see things. it's what makes you who you are. I dont think your born a sensor...or a thinker...or feeler. you become them in the fact that your brain and neurological pathways have seen this as the most simple and trouble free way of dealing with things

Sort of like behaviorism really.
 

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Wow that was very insightful, I'm inclined to agree with you to a point, I would say Judging, Perceiving, Sensing and Intuition never change although as far I can tell over the years I've swung between introvert and extrovert, Feeling and thinking I've always been a P and N I think these are the least flexible of all our functions because while we can learn to use the opposite function we never quite stray from the initial way of thinking and handling situations.
 

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i think it's hereditary. i've always been told i'm a lot like my mom, who is an ESFP for sure....

OR is it developed? i think your personality type is almost how your brain is programmed, but your personality itself is developed through the way your parents raised you and stuff like that.
Depends on who you follow.

One of the great things i see on this forum is the slander of Dr keirsey on his skills and how useless he is and the oh so holy Carl jung. and yet Jung believed your type changed thru your life time. and that it wasn't static. So you get people who believe in Jungs original works and find Keirsey and useless idiot, yet believe in keirseys ideas on it static and never changing.
Jung is like a box of chocolates.... What he thought about something often depends on which paragraph you happen to grab.

Although it's true Jung said it was possible for a person's type to change, and he certainly thought it was relatively normal for the strength of a person's preferences (and the corresponding degree of "one-sidedness") to fluctuate to some degree, I think it's fair to say he thought a complete change of type (e.g., from an extravert to an introvert) was much more the exception than the rule.

Jung also thought type was largely inborn. Here are a few selections:

Jung said:
In the same family one child is introverted, the other extraverted. Since the facts show that the attitude-type is a general phenomenon having an apparently random distribution, it cannot be a matter of conscious judgment or conscious intention, but must be due to some unconscious, instinctive cause. As a general psychological phenomenon, therefore, the type antithesis must have some kind of biological foundation.
Jung said:
The fact that children often exhibit a typical attitude quite unmistakably even in their earliest years forces us to assume that it cannot be the struggle for existence in the ordinary sense that determines a particular attitude. ... [The argument] that the mother's influence leads to specific reactions in the child, ... while supported by incontestable evidence, becomes rather flimsy in face of the equally incontestable fact that two children of the same mother may exhibit contrary attitudes at an early age, though no change in the mother's attitude can be demonstrated. Although nothing would induce me to underrate the incalculable importance of parental influence, this familiar experience compels me to conclude that the decisive factor must be looked for in the disposition of the child. Ultimately, it must be the individual disposition which decides whether the child will belong to this or that type despite the constancy of external conditions. Naturally I am thinking only of normal cases. Under abnormal conditions, i.e., when the mother's own attitude is extreme, a similar attitude can be forced on the children too, thus violating their individual disposition, which might have opted for another type if no abnormal external influences had intervened. As a rule, whenever such a falsification of type takes place as a result of parental influence, the individual becomes neurotic later, and can be cured only by developing the attitude consonant with his nature.
Jung said:
Experience shows us that complexes are infinitely varied, yet careful comparison reveals a relatively small number of typical primary forms, which are all built upon the first experiences of childhood. This must necessarily be so, because the individual disposition is already a factor in infancy; it is innate, and not acquired in the course of life. The parental complex is therefore nothing but the first manifestation of a clash between reality and the individual's constitutional inability to meet the demands it makes upon him. ... The existence of a parental complex therefore tells us little or nothing about the peculiar constitution of the individual. Practical experience soon teaches us that the crux of the matter does not lie in the presence of a parental complex, but rather in the special way in which the complex works itself out in the individual's life. And here we observe the most striking variations, though only a very small number can be attributed to the special nature of the parental influence. There are often several children who are exposed to the same influence, and yet each of them reacts to it in a totally different way.
And meanwhile, in the world of actual data... Decades of twin studies strongly suggest that genes account for around half (or more) of the kinds of relatively stable temperament dimensions measured by the MBTI and Big Five. Note, however, that the genetic side of things is complicated: an introvert's twin brother would probably be an introvert, but they might have two extraverted parents.

The most counterintuitive conclusion that's been drawn from the cumulative data is that how your parents raise you has almost no influence on your basic temperament — e.g., whether you'll end up an INTJ. Identical twins raised in the same household are not significantly more alike (in terms of temperament) than identical twins raised in separate households.

Now, at this point you may well be thinking to yourself that, if non-genetic factors account for a third to a half of temperament, it seems awfully strange that how your parents raise you — not to mention all the other "environmental" influences that will be more or less similar for two twins growing up together — has virtually no effect on your temperament. How could that be?

If you want my personal view, I'm inclined to think that the lion's share of the explanation is probably that the data substantially understates the genetic component of temperament, and here's why:

Anytime you're doing studies where the results take the form of correlations, most sources of error are going to introduce noise into the data that has the effect of reducing the magnitude of the reported correlations. And personality typing involves multiple sources of significant error, starting with the fact that they haven't even figured out exactly what the nature of the temperament dimensions they should be measuring are, and also including multiple forms of human error in any self-assessment test that can cause the taker to answer a question "incorrectly." What's more, the more you assume (as Jung did, and as various studies suggest) that a relatively large percentage of the population is in or near the middle on one or more of the dimensions, the more mistyped people you should expect as a result of relatively small testing errors.

Assuming that the four MBTI dimensions — or, if you prefer, the eight cognitive functions — aren't just arbitrary theoretical constructs and really do correspond to something real that could theoretically be accurately measured (by, say, directly measuring biological markers of some kind), I strongly suspect that, if every subject was accurately typed, the data would show that a substantially greater proportion of temperament is genetic. And the fact that twins raised in the same household aren't any more alike than twins raised separately would obviously seem a lot less strange if the proportion of temperament that results from "environmental" factors turned out to be very small.
 

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Jung is like a box of chocolates.... What he thought about something often depends on which paragraph you happen to grab.

Although it's true Jung said it was possible for a person's type to change, and he certainly thought it was relatively normal for the strength of a person's preferences (and the corresponding degree of "one-sidedness") to fluctuate to some degree, I think it's fair to say he thought a complete change of type (e.g., from an extravert to an introvert) was much more the exception than the rule.

Jung also thought type was largely inborn. Here are a few selections:







And meanwhile, in the world of actual data... Decades of twin studies strongly suggest that genes account for around half (or more) of the kinds of relatively stable temperament dimensions measured by the MBTI and Big Five. Note, however, that the genetic side of things is complicated: an introvert's twin brother would probably be an introvert, but they might have two extraverted parents.

The most counterintuitive conclusion that's been drawn from the cumulative data is that how your parents raise you has almost no influence on your basic temperament — e.g., whether you'll end up an INTJ. Identical twins raised in the same household are not significantly more alike (in terms of temperament) than identical twins raised in separate households.

Now, at this point you may well be thinking to yourself that, if non-genetic factors account for a third to a half of temperament, it seems awfully strange that how your parents raise you — not to mention all the other "environmental" influences that will be more or less similar for two twins growing up together — has virtually no effect on your temperament. How could that be?

If you want my personal view, I'm inclined to think that the lion's share of the explanation is probably that the data substantially understates the genetic component of temperament, and here's why:

Anytime you're doing studies where the results take the form of correlations, most sources of error are going to introduce noise into the data that has the effect of reducing the magnitude of the reported correlations. And personality typing involves multiple sources of significant error, starting with the fact that they haven't even figured out exactly what the nature of the temperament dimensions they should be measuring are, and also including multiple forms of human error in any self-assessment test that can cause the taker to answer a question "incorrectly." What's more, the more you assume (as Jung did, and as various studies suggest) that a relatively large percentage of the population is in or near the middle on one or more of the dimensions, the more mistyped people you should expect as a result of relatively small testing errors.

Assuming that the four MBTI dimensions — or, if you prefer, the eight cognitive functions — aren't just arbitrary theoretical constructs and really do correspond to something real that could theoretically be accurately measured (by, say, directly measuring biological markers of some kind), I strongly suspect that, if every subject was accurately typed, the data would show that a substantially greater proportion of temperament is genetic. And the fact that twins raised in the same household aren't any more alike than twins raised separately would obviously seem a lot less strange if the proportion of temperament that results from "environmental" factors turned out to be very small.
Any chance of any papers published that i can read. I have been told so many times about this twins thing and the only research i found, said that 60% were of different type. that is twins living in the same family.

Also know more twins with different personalities than same ones. Now i am not using this as proof, but the law of averages shud of kicked in by now
 

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Depends on who you follow.

One of the great things i see on this forum is the slander of Dr keirsey on his skills and how useless he is and the oh so holy Carl jung. and yet Jung believed your type changed thru your life time. and that it wasn't static. So you get people who believe in Jungs original works and find Keirsey and useless idiot, yet believe in keirseys ideas on it static and never changing.

When your a child your brain learns thru making neurological pathways in the brain. the more that same pathway is used the stronger it is, and the more safe you feel. Trying to use a different pathway is harder and can sometimes produce fear like symptoms.

Now to me logic would suggest every human when born has the ability to use and think in whatever way it wants. it has the ability to learn everything and anything. But once you learn something and it feels and becomes easy. you tend to stick to that method. you also apply that method to other things. Over many years, it becomes who you are. you feel safe the way you think and the way to do things. and when you are forced to do things that are not in the way you would usually do them. you have problems, you feel unable to do so. and you also stray away from those feeings more.

So i believe as a child your personality is shaped, by the way you learn to do and see things. it's what makes you who you are. I dont think your born a sensor...or a thinker...or feeler. you become them in the fact that your brain and neurological pathways have seen this as the most simple and trouble free way of dealing with things

Sort of like behaviorism really.

Would make a lot of sense, when I was a kid especially, I was taught very closely by my: Mother INTJ uncle INTJ and granda ISTJ. Pretty much explains a lot I suppose.
 

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Any chance of any papers published that i can read.
Here's Hans Eysenck, writing over 20 years ago, on the subject of parental influence on the core dimensions of temperament:

Eysenck said:
Eysenck, H.J., "Genetic and Environmental Contributions to Individual Differences: The Three Major Dimensions of Personality." Journal of Personality, 58, 245, 1990.

"Six major recent studies, all of which are characterized by being based on sufficiently large numbers of twin pairs, as well as being analyzed by means of modern statistical methods, provide more reliable evidence for genetic influence on personality change." (248)

"[T]he data show that the family environment, ... as distinct from the unique experiences of the individual, makes only a trivial contribution to personality differences. ... If correct (and there seems little doubt about a conclusion replicated so many times, on so many large samples and using many different methods of testing and analysis), these close correlations disprove the importance of family environmental influence on personality and call into question the validity of traditional personality theories discussed by Hall and Lindzey (1970) and in personality textbooks in general." (251)
I assume this article may be one of the studies Eysenck was referring to.

I'm not aware of any more recent studies that have thrown any significant doubt on Eysenck's conclusion.

ADDED: The Heritability section of the Big Five article at Wikipedia cites a couple more articles.
 

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Here's Hans Eysenck, writing over 20 years ago, on the subject of parental influence on the core dimensions of temperament:



I assume this article may be one of the studies Eysenck was referring to.

I'm not aware of any more recent studies that have thrown any significant doubt on Eysenck's conclusion.

ADDED: The Heritability section of the Big Five article at Wikipedia cites a couple more articles.
Sorry i cannot take this paper seriously. There are soooooooooooo many flaws, For 1 there are 4 pairs of twins that they could get for 1 test.....another pair of twins in the mix showing completely different results would ruin the % they found.


Also these are not children seperated at birth. But after spending a few months...or years together before being adopted. Which is when i suggest the begining of development of the cognitive functions.

Also they say "a significant contribution of shared enviroment is found for the personality trait of social closeness and possibly religious interests and values" I found that very witty to be honest. There are far too many parameters that have not been taken into account for reliable results. ANd social closeness as a personailty trait is quite a simplistic personality trait. rather reminiscent of a psychics "cold reading" techniques

I am not claiming that it is wrong, or my theory i hold onto is right. But this seriously needs so much more research than what has been done here to come to any conclusion of such a scale. It is rather primitive and lacks any clear cut connections or things that can be stated as fact. Every single thing they mentioned can be explained by something else. something they have not tested for.

I Would love to see some new recent research done on this. But as i have read the lack of people for testing is obviously due to the lack of twins that have lived in such conditions. And althou it does look quite good, it is still pretty much mostly guess work from the point of showing certain validity into these claims
 

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Sorry i cannot take this paper seriously. There are soooooooooooo many flaws, For 1 there are 4 pairs of twins that they could get for 1 test.....another pair of twins in the mix showing completely different results would ruin the % they found.
I'm not sure what you're referring to, but if it's the Wikipedia sentence that includes the phrase "four recent twin studies," that's a reference to four separate studies, not four sets of twins.

And the Eysenck and Bouchard articles all cite multiple studies in support of their conclusions. And, FYI, Eysenck and Bouchard are both what you might call heavyweights.

You can still choose to disbelieve all their data if you like, but it sounds like maybe you just need to have a cup of coffee and read a little more carefully. :tongue:

ADDED: I should also mention that all the stuff I've linked to is just the stuff I happen to have handy links to. As Eysenck mentioned, there have been many more studies. Eysenck's 1990 article referred to "six recent studies," and noted that they basically confirmed the conclusions that were already reasonably evident from many years of previous studies.
 

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Paternal G/father ESTJ, Paternal G/mother ESFP - Maternal G/father ESTJ, Maternal G/mother ISFJ
Father INTJ - Mother ESFJ
Myself ENTP


So, No.
 
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I'm not entirely sure what question your "No" is a response to, but my understanding is that, to the extent that there's any kind of majority view on genes and the kinds of personality dimensions involved in the MBTI and Big Five, it's that the genetic influence involves combinations of genes, rather than the kind of single-gene transmission where you end up matching one parent or the other.

So the fact that you don't match any particular relative (other than an identical twin brother) doesn't really speak to the extent to which your type may be inborn.
 

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I'm not sure what you're referring to, but if it's the Wikipedia sentence that includes the phrase "four recent twin studies," that's a reference to four separate studies, not four sets of twins.

And the Eysenck and Bouchard articles all cite multiple studies in support of their conclusions. And, FYI, Eysenck and Bouchard are both what you might call heavyweights.

You can still choose to disbelieve all their data if you like, but it sounds like maybe you just need to have a cup of coffee and read a little more carefully. :tongue:

ADDED: I should also mention that all the stuff I've linked to is just the stuff I happen to have handy links to. As Eysenck mentioned, there have been many more studies. Eysenck's 1990 article referred to "six recent studies," and noted that they basically confirmed the conclusions that were already reasonably evident from many years of previous studies.
I'll just put this right here.......Get a pot of coffee brewing it time to learn boy

Problems with the twin study method

One of the fundamental assumptions of the twin study method is that closer resemblance in monozygotic twins is due to closer genetic similarity rather than more shared environment, i.e. that monozygotic and dizygotic twins share environment to the same extent. However, there is considerable evidence that the common environment is not the same for the two types of twins; the 'twinning reaction', or mutual dependence between twins, is greater between identical twins than between fraternal twins (e.g. Farber 1981, Eysenck 1979). Kamin notes that identical twins tend to be treated very similarly by parents, teachers etc., spend more time together, have more mutual friends, and so on, than do fraternal twins. Conversely, identical twins may, possibly unconsciously, try to make themselves slightly different from their cotwins in appearance, manner etc., in order to achieve a greater degree of individuality. Farber suggests that such "minute interpersonal and intrapsychic events may be the most potent in altering at least some traits fundamentally linked to the somatic blueprint of the individual." Such tendencies of monozygotic twins to differentiate themselves from each other are, of course, related to their initial degree of similarity. However, a small proportion of monozygotic twins are not strikingly similar in appearance (see, e.g. Eysenck & Kamin 1981). If a twin study relies purely on physical similarity to determine the zygosity of twins, then it is likely that a number of monozygotic twins will therefore be misclassified as dizygotic. This criticism can be applied to some of the earlier twin studies in many fields, but more recent research has utilised more reliable techniques for zygosity determination (e.g. blood-group matching, fingerprint ridge counts etc.).
Roughly two-thirds of identical twins are monochorionic, that is, they shared the same chorion, and hence the same blood supply, during prenatal development. In such an arrangement, one twin receives the maternal blood supply after it has passed through the other, and is therefore at a severe competitive disadvantage regarding oxygen supply, hormone supply, etc.. The consequences of this on the later development of the twins can include gross phenotypic differences, even before postnatal influences of the family are considered (Mesnikoff et al. 1963). Such a process can lead to an over-estimation of the proportion of variance attributable to the specific postnatal environment of the twins.
Conversely, if we consider the production of hormones by the foetus as opposed to those supplied by the mother, the quantity of hormones produced, along with the absolute and relative timing of production, is controlled by the genetic code of the developing individual. Therefore, monozygotic twins experience higher similarity in foetal hormone production, both in timing and in amount, than do dizygotic twins. This has the effect of increasing the similarity for prenatal-hormonally determined traits in monozygotic twins relative to dizygotic twins.
Considering the penultimate point, even monozygotic twins, sharing exactly the same genes, may display phenotypic differences due to their different prenatal environment. Things becomes even more complicated, however, when one considers that not all of an individual's genes are active at any point in his or her life. Gottesman (1974) states that "it cannot be over-emphasized that it is environmental factors through such extracellular metabolic intermediates as hormones, vitamins and toxins that determine which genes get switched on and how long they function . . . Since only a small portion of the genome (perhaps 5-20%) is activated at any one time, the effective genotype upon which environmental factors are acting is constantly changing." Farber (1981) points out that such genetic 'timetables' of vulnerability to environmental influence may be more similar among identical twins than fraternal twins, and more similar among fraternal twins than non-twins. She therefore suggests that "some of the similarity in specific traits is not so much because the trait itself is strongly predetermined, but because the twins were susceptible to environmental influence when they were in similar stages of psychological and maturational organisation." Such factors would lead to an overestimate of heritability estimated from twin studies.
It is, in fact, generally found that twin studies of a particular trait suggest higher estimates of heritability than do adoption studies (Plomin, 1990). In addition to Farber's proposed process, this may also be explained by nonadditive genetic variance, such as epistasis, which covaries completely for identical twins, but contributes little to the resemblance of first-degree relatives.
In many twin studies it is likely that at least two types of bias operate in the selection of twins pairs for inclusion in the sample from all possible twins in the population who meet the criteria for the study. One such bias is concordance dependent ascertainment, where the probability of twin pairs being included in a study of a particular trait is dependent on whether they are concordant or discordant for that trait. Such a bias can occur in a number of ways, even when a voluntary recruitment procedure is adopted. Another bias that may occur is that of non-independent ascertainment, where ascertainment probability depends on the combination of within-pair similarity and the type of relative (e.g. monozygotic or dizygotic twins); for example, it may happen that concordant monozygotic twins are more likely to be included in a particular study than are concordant dizygotic twins.
If a twin sample is obtained which has avoided all such biases, then we still have to ask whether any sample of twins can be representative of the population from which they were drawn. For example, the probability of a twin birth increases with the age of the mother until about the age of 39 (see Farber 1981, chapter 1). This leads to an increased chance of chromosomal anomalies in twins which could affect the concordance rate for traits associated with that chromosomal locus. Farber also points out that there is a high frequency of premature births in multiple deliveries. She suggests the possibility that prematurity can make an individual differently susceptible to the environment than a full-term individual is.
Gottesman and Carey (1983) suggest several internal checks that may be performed on twins sample data so that some confidence may be felt regarding their representativeness. These include checking the proportion of the two sexes, the proportion of various zygosities, and whether twins are over-represented in the reference population of the trait in question. Of course, such checks require knowledge of the corresponding figures for the reference population, which are often uncertain.
All of the above represent formidable, if not insurmountable, problems for the experimental design of a twin study from which we can hope to obtain any meaningful, generalizable results. This has not, as we have seen, prevented a substantial number of researchers from conducting such studies. But even if we assume that these problems have been overcome, the interpretation of the results of twin studies, usually given in terms of concordance rates for monozygotic and dizygotic twins, is problematic.
The ratio of concordance in identical twins to that in fraternal twins may seem like a promising statistic, but is, in fact, not very informative. For example, such a ratio is sensitive to the base rate of the trait in the given population, and will usually have a considerable associated standard error (Kendler, 1989). Also, Gottesman and Carey (1983) demonstrated that quite different concordance rates between the sexes can reduce to the same estimates of underlying heritability.
For a better understanding of the results of twin studies, Gottesman and Carey recommend "that appropriate population risks be determined and that the concordance rates be converted into correlations in the liability toward developing the disorder." They end their report on twin studies on an optimistic note, by listing recent innovations and developments which should assist twin research. Such developments include multivariate analysis, longitudinal twin study analysis, brain scan differences, the use of data on other relatives to check on the assumptions of twin strategies, and a renewal of interest in identical twins reared apart.
Specific problems with the twin studies of homosexuality

Many of the criticisms of twin studies mentioned in the previous section apply to the twin studies of homosexuality. Rosenthal (1970) has severely criticised Kallman's 1952 study for the high incidence of psychiatric disorders among the probands and their cotwins. He comments that "only 10 of the 80 monozygotic twins and 18 of the entire sample (170 individuals) were thought to be 'sufficiently adjusted' emotionally and socially." There is a possibility that the homosexuality shown by some of the twins is secondary and reactive to their psychopathology, or vice versa. Kallman's study could also be subject to non-independent ascertainment and concordance-dependent ascertainment, although the exact method of recruitment is not explained in his report. As for the 100% concordance rate reported among monozygotic twins, Kallmann himself regarded this as a "statistical artifact" (see his discussion at the end of Rainer et al.'s 1960 report), and was not surprised when monozygotic twins discordant for sexual orientation were reported. Lykken et al. (1987) point out that many twin studies have a disproportionate number of monozygotic probands compared to the given population. This criticism applies to Kallman's report, which included 40 monozygotic pairs and 45 dizygotic pairs. The proportion of monozygotic to dizygotic twins in American and European populations is roughly 1:2 (see Lykken et al. 1987). For these reasons, Kallman's study cannot be considered as representative of the American population as a whole, but is best looked upon as a useful and provocative preliminary publication that has prompted much subsequent research.
Heston and Shields (1968) explain their recruitment and interview techniques in more detail. They emphasize that twins recruited through the Maudsley Twin Register are unselected as regards concordance and zygosity, and attempt to show that monozygosity per se is not associated with homosexuality, and that the incidence of homosexuality in members of same-sexed male twins is no greater than in the parent Maudsley population. Their data may therefore reasonably be considered as representative of this population (but note the small numbers of probands involved), but, again, we see a high incidence of psychiatric disorders in probands and their cotwins. Hence, there is difficulty in generalizing the results of this study onto a larger population.
As Bailey and Pillard point out, their 1991 investigation falls short of the ideal recruitment procedure of systematic sampling from a well-specified population. They admit that concordance-dependent ascertainment (which they term type 1 bias) might have occurred, but note that "concluding that sexual orientation is partially heritable based on different patterns of monozygotic and dizygotic twin concordance is equally valid whether or not type 1 bias occurred." Non-independent bias may also have affected the results; probands with heterosexual adoptive brothers were significantly less likely to consent to have their relative contacted than probands with heterosexual twins, whereas cooperation did not differ notably if relatives were homosexual. Bailey and Pillard suggest that this could lead to an underestimation of the proportion of heterosexual relatives in the adoptive brothers, compared with the twin subsamples, resulting in an underestimation of heritability. They also found that, contrary to the predictions of a simple genetic hypothesis, the rate of homosexuality in nontwin brothers was lower than that of dizygotic cotwins, and roughly equal to that of adoptive brothers. Two possible explanations for this finding were suggested, as described in the previous section, one being merely fluctuations in sampling. Hence, the desirability of replicating the findings is emphasized. Despite these shortcomings, this study clearly represents the most significant research in twin studies of homosexuality conducted to date, and its findings suggest many questions which should be addressed by future studies.
The smaller case studies of homosexuality in twins may be useful in highlighting similarities or differences in the environment experienced by each twin of a pair that have lead to their concordance or discordance for sexual orientation. However, by their very nature (e.g. small sample sizes, bias in recruitment etc.) they cannot produce results which can be generalised to a wide population. It should be noted that many of these reports are of a psychoanalytic nature, and the combined results of many such cases have lead to the development of psychoanalytic theories of homosexuality (see Freud 1953, Friedman 1988, Lewes 1989, and next section). However, such theories can, at best, only be generalised onto the population of individuals receiving psychoanalytic treatment.
The only study of homosexuality in identical twins reared apart is that of Eckert et al. (1986). Some of the problems associated with the data were discussed in the previous section. Although the Minnesota study maintains notably stringent criteria for inclusion of twins, such studies can never fulfil all of the theoretical assumptions upon which heritability calculations are based. It has been suggested (see, e.g. Farber 1981) that even an awareness of twinship in separated twins can affect their development. Even twins separated at birth have shared the prenatal environment of the uterus, which, according to recent theories, may have a critical role in the development of sexual orientation (see next section). Therefore, if separated identical twins show concordance for a particular trait, this cannot, in practice, be directly attributed entirely to their shared genes.
Conclusions from the studies conducted to date

For the many reasons mentioned in the previous section, it is inappropriate to pool the data from the studies to perform some type of meta-analysis (e.g. Rosenthal 1984, Oakes 1986). In their paper on the analysis of twin data, Gottesman and Carey (1983) emphasize the importance of only comparing data pertaining to common population risk and diagnostic criteria. The studies summarised are of inconsistent quality, with biased and limited samples. Lykken et al. (1987) suggest that the "only wholly dependable method of avoiding errors of recruitment bias may be to employ an incentive or method of recruitment that is about equally effective with dizygotic as with monozygotic twins, preferably a method that is successful with most (>80%) of pairs solicited." Unfortunately, such methods are seldom, if ever, available.
The greatest problem for studies of this type remains that of recruiting large numbers of non-institutionalised probands due to the social ostracism of homosexuals. This problem is gradually diminishing, as evidenced by Bailey and Pillard's 1991 study, but is still far from being negligible.
As for the theory behind twin studies, it has been shown that there are flaws in many people's understanding of the concept of heritability. For example, Bouchard et al. (1990) point out that heritability must increase as V(E), the variance affected by the environment, decreases. Hence, the heritability of a psychological trait reveals as much about the culture as it does about human nature.
Bailey and Pillard's 1991 study is clearly superior to any of its predecessors in terms of experimental design and analysis of results. Although it, too, has its weak points, it is notable that the estimates of heritability derived from the data were significant under a wide range of assumptions concerning the base rate of homosexuality and the degree of ascertainment bias. In contrast, estimates of the proportion of phenotypic variance explained by shared environmental differences were not significant under the same range of assumptions.
These results give reason to believe that there is some constitutional component to male homosexuality. However, the twin data are consistent not only with a purely genetic explanation, but also with one involving possible differences in the degree of shared prenatal environment between monozygotic and dizygotic twins (as explained earlier, monozygotic twins experience higher similarity in foetal hormone production, both in timing and in amount, than do dizygotic twins). Some recent theories of the genesis of homosexuality, to be mentioned in the next section, place critical importance on hormone levels in the prenatal environment of an individual. If such theories are true, then the difference in concordance rates between monozygotic and dizygotic twins could be explained largely in these terms (see next section). It should be noted that such an explanation still relies on genetically controlled prenatal hormone production to account for observed differences in concordance between monozygotic and dizygotic twins.
 

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My latest personality type came from timeless's cognitive functions quiz.
 
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The only thing that I have noticed about my family is that the fathers inferior function seems to be the daughters dominant function. Here is an example of my family below:

Great Grandfather: INFP (Fi-Ne-Si-Te)
Grandmother: ESTJ (Te-Si-Ne-Fi)

Grandfather: ISTP (Ti-Se-Ni-Fe)
Mother: ENFJ (Fe-Ni-Se-Ti)

Father: ISTJ (Si-Te-Fi-Ne)
Me: ENFP (Ne-Fi-Te-Si)

I found that discovery pretty interesting.
 

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My childhood was so disfunctional I was not taught - i reacted. I think a lot of that formed my some of my INFJ characteristics- but my deep concern for people? that had to come from my sporatic religious training - and a few people who I encountered along the way. I think there is a hard-wiring component and nurture component -but I am not an INFJ - that is the profile of characteristics from a specific limited set of test data. I am me, a creature with free will.
 

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I'll just put this right here.......Get a pot of coffee brewing it time to learn boy

Problems with the twin study method ...
Um, yeah, thanks for the uncredited cut-and-paste. *rolls eyes*

And here's a more balanced overall perspective from Wikipedia if you're interested.

The first thing to note is that all that stuff in the Taylor article you pasted — ignoring the problems specific to the homosexuality studies, not to mention the stuff in the first section on heritability (parent-to-child) issues that has (unless I'm misunderstanding) nothing to do with twin studies — is basically on the order of quibbles. It's a collection of reasons why you might want to end up mildly tweaking certain twin study results to account for the fact that, e.g., identical twins aren't perfectly identical (because of different womb experiences, etc.), shared living environments aren't really the "same" environment for both children, etc.

But more importantly, the second thing to note is that the majority of those imperfections in what you might call the background assumptions behind twin studies mean that, if you assume introversion, for example, is substantially genetic, the reported results from twin studies are likely to understate, rather than overstate, the genetic influence as a result of the imperfections — because, for example, you're measuring how alike two identical twins are and the different experiences in the womb end up making them less alike, not more alike.

So, as I understand it, any overall net negative impact of the issues raised in that article on the robustness of Eysenck's and Bouchard's (among many others') conclusions is likely to be small at best. In my first post in the thread I mentioned what I view as the large magnitude of error (from multiple causes) that plagues self-assessment personality tests, and I'll add here that, compared to those, Taylor's issues sound like very small potatoes.
 

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Um, yeah, thanks for the uncredited cut-and-paste. *rolls eyes*

And here's a more balanced overall perspective from Wikipedia if you're interested.

The first thing to note is that all that stuff in the Taylor article you pasted — ignoring the problems specific to the homosexuality studies, not to mention the stuff in the first section on heritability (parent-to-child) issues that has (unless I'm misunderstanding) nothing to do with twin studies — is basically on the order of quibbles. It's a collection of reasons why you might want to end up mildly tweaking certain twin study results to account for the fact that, e.g., identical twins aren't perfectly identical (because of different womb experiences, etc.), shared living environments aren't really the "same" environment for both children, etc.

But more importantly, the second thing to note is that the majority of those imperfections in what you might call the background assumptions behind twin studies mean that, if you assume introversion, for example, is substantially genetic, the reported results from twin studies are likely to understate, rather than overstate, the genetic influence as a result of the imperfections — because, for example, you're measuring how alike two identical twins are and the different experiences in the womb end up making them less alike, not more alike.

So, as I understand it, any overall net negative impact of the issues raised in that article on the robustness of Eysenck's and Bouchard's (among many others') conclusions is likely to be small at best. In my first post in the thread I mentioned what I view as the large magnitude of error (from multiple causes) that plagues self-assessment personality tests, and I'll add here that, compared to those, Taylor's issues sound like very small potatoes.
So you admit that there are problems. But that in your personal opinion they are only "small potatoes" if only you were a credible source for information....one of the heavyweights. never mind then
 

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So you admit that there are problems. But that in your personal opinion they are only "small potatoes" if only you were a credible source for information....one of the heavyweights. never mind then
I admit that "there are problems" in the "nothing's perfect" sense. Yes indeed.

And I understand that difficulty distinguishing significant imperfections from relatively insignificant perfections is something of an INTP trademark. :tongue:
 

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I admit that "there are problems" in the "nothing's perfect" sense. Yes indeed.

And I understand that difficulty distinguishing significant imperfections from relatively insignificant perfections is something of an INTP trademark. :tongue:
http://jayjoseph.net/yahoo_site_admin/assets/docs/Twin_2002_pdf.15583400.pdf

More evidence if you wish to read, i would be interested in your views on it.

i see your classic INTJ trait of "even when it is a theory and not actually proven scientifically, you still believe it" because someone important told you so


http://www.slate.com/articles/life/twins/2011/08/double_inanity.html some more people questioning the validity of what you claim.

you will love this one "Fortunately for the future of our democracy, the study's conclusions far outpace its evidence. Three years after the Alford study came out, a Duke political scientist named Evan Charney (PDF) and Harvard geneticists Jon Beckwith and Corey Morris examined the flaws in the Alford study—and showed why all the other twin studies on heritability can't possibly show what they purport to show.



Twin studies rest on two fundamental assumptions: 1) Monozygotic twins are genetically identical, and 2) the world treats monozygotic and dizygotic twins equivalently (the so-called "equal environments assumption"). The first is demonstrably and absolutely untrue, while the second has never been proven."

look 2 heavy weight geneticists....and who do you trust more about the genetics of twins.... psychologists or 2 geneticists :D
 
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