Sunday, August 14, 2022

Comments by jinxer

Showing 13 of 13 comments.

  • Thanks for your reply!

    As to the above post, I too have been curious about the role of prenatal environment in personality formation. I am a professional in the maternity field, and know of the many studies relating to cortisol levels en utero and its affects on babies, along with testosterone levels and the supposed role elevated levels can play in shaping gender identity, etc. To some degree, I do believe that more positive and less stressed moms do have babies that are easier to calm, less anxious, etc, but that babies still are highly malleable and can also heavily influenced by their very early outside environment, to where it can override whatever biological influence their may be.

    Although I can appreciate the role of early prenatal nurturing in helping babies start out on the best foot possible as far as maximizing their abilities, I still rebel against the idea of hormones playing a huge, rigid role in personality development over nurture simply because it tastes a lot like determinism, as much as behavioral genetics does. I am curious on what your thoughts are on this topic, Jay, and if you see the early prenatal period as being a large factor in who we become.

  • Thank you for the great article!

    When I first looked into the MISTRA studies, I had a lot of questions. If they roughly calculate heritability estimates to be around 50% or more or less on many traits, than obviously many of the twins studied were not nearly so similar as the ones in the media. They studied a good number of twins raised apart, but only really focus on a handfull. Also, if we are going to call this a scientific study, discuss the differences too. (Ahem, researchers, your bias is showing.) Also, it is pretty obvious that any twins that were drawn to take part would have known beforehand of this bias, seeing the media attention similar pairs received, etc. Even if not done intentionally, and even in a case where two twins could have experienced complete separation, just the fact that they are meeting their identical twin would cause them to assume they would have lots of similarities, due to confirmation bias, and from the first meeting, a new shared perspective can start to emerge.

    I wish there were more concrete evidence of some of the things happening in the MISTRA studies that you mention, such as proof of lots of previous contact and not complete separation, lying to appear more similar, documentation of differences, but of course, that has not been released, so no blame put on you. Shame. Something smells fishy.

    Like the general public, I too can easily get caught up in all the similar details. But can how we hold a can, what key ring we wear, wearing rubber band on our wrists really be genetic? Do our genes have the time for all that? I can see some things, like how we walk or how we hold something or how we sit and cross our legs being somewhat genetic simply because it is influenced by our physical body characteristics. Seems sort of silly genes would dictate stuff as inconsequential as rubberbands on the wrists, etc. Ken Richardson has good points on those topics.

    Thanks again! If you know of any other places to find info on dissimilar twins, especially in regards to MISTRA, I would be interested. 🙂 But I am not hopeful. Those are locked in vault somewhere.

  • As a birth professional, I applaud this. In the hormonal swings that pregnancy and postpartum bring, support and good nutrition are what is needed. Prescribing antidepressants further the mom’s alienation and create a sense of her body being a lemon and a feeling of inadequacy in caring for herself or her baby without chemical help. Awesome postpartum therapists, support, rest, and nutrition are much better qualified for the job of building women up and empowering them

  • Thanks Jay! I love your past articles on reared apart twins, and gene illusions, and look forward to additional information that you may have not addressed in past articles. I think the anecdotes, rather than the data, is the biggest obstacle to those arguing against the genetic paradigm, and the more we can look at those extreme stories and report on the differences that are there but don’t get reported, we can chip away at the biased explanations we have been given. People are swayed by hearing of twins raised apart both flushing before they go, wearing rubber bands on their wrists, etc. I have heard Segal’s take on this extensively, and though I see glaring holes in her thinking (her study of non related look a likes, for instance, proves nothing because the lookalikes are not together and interacting with the same individuals together) she is quite convincing on her tangents of all these unique quirks and testing done.

    Thank you for being a balance in a much biased debate

  • Once again, a really great article. I was wondering if you could offer additional insight.

    When looking at the data in numbers and the way twin studies have been put together, I too cannot help to see the major flaws, such as the EEA and the cohort effect and the bias in how volunteers come to the studies. From the data, along with the fact that little to no actual genetic proof has been found, I am lead to believe that if genes play a role in such things like personality, mental disorders, etc, then it is a relatively small amount, and environment has great power in modifying whatever genetic contribution there would be.

    However, then I read these amazingly coincidental stories of twins raised apart. Stories like the Jim Twins. And the giggle sisters. And the New Jersey fire fighters. Some of it I can easily dismiss as physical attributes. Some of it purely due to chance out of their control. Some of it merely due to the era in which they were raised and other cohort effects. But then there is the heap of stuff like responding exactly the same on tests. Writing the same exact odd ball sentence in different rooms when asked to write a random sentence, and making a nervous typo in the same spot. Calling scrunching your nose with your hand “squidging.” Being almost indistinguishable personality wise. Doing the same four jobs throughout life in the same order. All of these could be called coincidence, but these stories truly seem to be so outrageous as to defy environment, genetics, and cohort effects. And all of a sudden I am confounded again and fall into the pit of thinking we are all merely acting out genetic legacies.

    I know you are familiar not only with these studies, but of others as well, and I have read all of your articles where you attempt to debunk them. And like I said, I think you do to a certain extent.

    Obviously, if the Minnesota studies came up with hertibility estimates of roughly .50, I am guessing that either the twins mentioned above had a vast number of unreported dissimilarities, or that the few pairs mentioned were rare exceptions, despite the fact that Nancy Segal says they happen with reared apart twins more often then not. Do you know for a fact if non-similar twin data was dropped or not included? Or do you have any insight regarding how similar twin brain wiring seems to be when it comes to the thought process? (Writing the same sentence?).

    In summary, I really want to believe that I am not merely a product of my biological heritage, and that i have some degree of “free will” and that the many unique parts of who I am (my humor, quirky habits, original thoughts) do not simply lie in some gene expression, and that if I had a twin, I’d be looking in an identical mirror of the soul. That’s why I think your work is so important, since media and researchers can be quoted saying outrageous lies not grounded on anything resembling good science. (Showing how all data was extrapolated, interpreted, and fully open to peer review with solid proof of the mechanism that shows how the phenomena happens). Thoughts? Ideas? Other conspiracies you have proof of?

  • Thanks Jay! So, to clarify, any somatic mutations would most likely not affect personality either (slight differences that fall within the “normal” range)

    I agree about mental disorders. So much of what I see in my family and in others has pretty strong correlations to major environmental factors.

    I look forward to future posts, and thank you for putting up with my questions. 🙂

  • Thanks! Makes sense to me! Thoughts about my other question below? Do you think somatic mutations within an MZ pair could account for some of the differences, or do you see them as negligible? I’m not informed enough to know if 300 copy errors could cause a big enough difference to affect personality traits or larger mental illnesses like Schizophrenia

  • Another question–do you think somatic mutations between identical twins could account for displayed differences within a pair, whether mental illness, personality? Researchers have found on average, one MZ twin may have just over 300 variations in their genome from somatic mutation early on. In my understanding, a majority of these mutations will never have any affect, but when they do, it can lead to differences like schizophrenia and other disorders. Therefore providing a genetic link. What I can find in somatic mutation is that it does not always do anything, but when it does, it’s usually a negative affect. Just a question on how you take this into account. I

  • Another great read. I feel like I can tell someone what heritability versus heredity is, but then when I try to explain it beyond that, I have to shrug my shoulders.

    Have there been MZTRA studies done that show how different identical twins can be too? The Minnesota study is slow to mention those. Of course those would never be publicized, since they don’t have the same shock and awe factor. That really is the only compelling thing for me are the anecdotal stories of identical twins, both raised together and apart, that are so alike in every little mundane way (even past where I would think genetics could even touch)

    I have recently been really struggling with the fact that personality is being boiled down to a mix of genetics and womb environment. And the idea of shared environment counting as almost nothing vs. non-shared environment (Judith Harris’ work) really gets my goat, since it seems so contrary to what I see and changes people make. As parents, we can take the innate tendencies and then help guide kids to healthy lifestyle choices that can make them realize their full potential. Maybe this is the Christian part of me speaking, but I believe many non-Christians would agree, and many phsychologists see it every day in their work. They see kids have disorders from parents/environments that get mended, they see disorders that may be genetic get mended, etc. They see how environment can drastically affect a person’s well being by either being positive or negative towards their tendencies. I always have personally believed (off mere observation, no formal education in genetics or psychology or the like) that personality is made up of a mix of both that definitely interact, but if you had to find a percentage, maybe 20% genes, the rest all types of environment. Completley arbitrary, I know, and based on nothing scientific. 🙂

    Anyway, thanks for being a differing voice. Why are there not more of you?

  • I have long been bothered about the notion of us being mere genetic robots. It didn’t seem to fit what I observe in the everyday world. For years I have agreed that genetics may play a part in temperament, but a small one. This new meta analysis study had me delving into articles, and I stumbled upon the Minnesota Twin study. With the Minnesota twin study, I too was victim of the shock and awe of the raised apart twins that were reunited after several years. The minute details (wearing rubber bands on wrists, flushing toilets before and after, same name of wives and kids) stunned me into thinking maybe heredity plays 100%. I mean, how can you account for all those similarities? I later found a summary of your first book chapter by chapter, which helped address some of my own laymen concerns.

    I do appreciate your cohort argument, and I had not realized the “behind the scenes” work with the photographs. I have been wondering: they highlighted 5-7 or so identical twins reared apart that had amazing similarities, but don’t say anything about the other pairs. Were any completely different in personality in regards to observation and the test? I forget how many they had in the study, (MZRA) but it seemed quite a few. Do you have insight into those?

    I agree that it seems money tends to flow toward genetic studies, which in turn leads to biased results. Money does not flow towards family/environment studies.

    Just for fun, with all scientific data aside and just from your own informed opinion, what would you conjecture to be the genetic component of personality?