Nature vs Nurture debate

[Mr Rayon]

Does nature or nurture (hereditary or environment) influence the development of one's identity more?

 

Scientifically, what are the arguments presently for each stance?

[thinker_jeff]

Does nature or nurture (hereditary or environment) influence the development of one's identity more?

 

Scientifically, what are the arguments presently for each stance?

To science, this debate has been over for years. The conclusion is that both of nature and nurture influence the development of a human being.

[Mr Rayon]

To science, this debate has been over for years. The conclusion is that both of nature and nurture influence the development of a human being.

 

But what are the arguments that both influence the development of a human being? Was this conclusion based on any experimental analysis? I am writing an essay and need some points/evidence/rebuttals etc to plan out as I am completely ignorant about the whole debate.

[Ringer]

Look for twin studies.

[thinker_jeff]

But what are the arguments that both influence the development of a human being? Was this conclusion based on any experimental analysis? I am writing an essay and need some points/evidence/rebuttals etc to plan out as I am completely ignorant about the whole debate.

Ringer's suggestion is correct. Here is one you can start with.

http://www.pages.drexel.edu/~rm35/#NVN

 

 

 

 

[zapatos]

But what are the arguments that both influence the development of a human being? Was this conclusion based on any experimental analysis? I am writing an essay and need some points/evidence/rebuttals etc to plan out as I am completely ignorant about the whole debate.

http://en.wikipedia.org/wiki/Nature_versus_nurture

[SamTheSkeptic]

Does nature or nurture (hereditary or environment) influence the development of one's identity more?

 

 

When you use the word "identity," I assume that you are referring to an individual's personality or character, rather than their physical appearance.

The study of personalities and character is Psychology, which really isn't a science... it is an attempt to understand and explain the human mind (which can't be accurately done as of present day). No one can scientifically explain human behavior - why we act the way we do, feel the emotions we feel, and take on the personalities which define us - despite what you might have read in the latest pop-science newspaper article or best selling psychology book. There is no chemical test, for example, that can be ran to detect certain types of personalities. You can't take a blood test and find out if you are positive for homosexuality. As ridiculous as this may seem, this is exactly what proponents of the "nature AND nurture" delusion are implying. If nature (genes) were at all involved in the formation of "character" and "personality," then it would be theoretically possible to have such tests to detect them. They simply don't exist, because personalities and character are not genetically predetermined.

 

Think of it this way: genes provide you with your physical brain (the organ itself) and its components... so in this sense, I suppose that genes are 'partially responsible for behavior', which is the phrase you so often hear parroted today. But really, what you do with your brain after it reaches its physical genetically predetermined growth limit, is not determined at all by genes. After this point, you begin crafting your own personality and emotional scale based on the people and things you see and hear around you. This is 0% genetics, and 100% environment.

 

 

Scientifically, what are the arguments presently for each stance?

 

It isn't evidence, but a lack thereof that you should be concerned with when it comes to the position that personality is genetic. There is already plenty of scientific evidence out there regarding hereditary physical traits. . .certainly tests can be done to determine them and it really doesn't take a scientist to see striking similarities between some children and their parents (I look just like my father for example). There is no question that I look the way I do because it was genetically predetermined.

 

But there is no such undeniable conclusive evidence regarding the responsibility of genes in the development of one's character. If there were, it would be big news!

What you do see are lots of speculative and misleading articles and books, published each year, bombarding us with a plethora of new opinions and hunches but never a conclusive and testable theory.

 

With that being said, here are some sources I can offer up for your research paper. I hope you find some useful stuff, good luck.

 

AVPR1a and SLC6A4 Gene Polymorphisms Are Associated with Creative Dance Performance

 

http://www.plosgenet...al.pgen.0010042

 

Bad News for the Genetics of Personality

 

http://neurocritic.b...ersonality.html

 

The Personality Paradox

 

http://www.wired.com...nality-paradox/

 

The heritability of personality is not always 50%: gene-environment interactions and correlations between personality and parenting.

 

http://www.ncbi.nlm....pubmed/19012656

[thinker_jeff]

The study of personalities and character is Psychology, which really isn't a science...

I can't believe someone arguing this again over here.

Please find the exact topic in the panel "Psychiatry and Psychology".

[SMF]

SamTheSkeptic:

 

You appear to be a relatively strong adherent of the Tabula Rasa (http://en.wikipedia....iki/Tabula_rasa) side of the nature/nurture question. If you don't think that ones genetic background has any effect on the development of complex personality and other character traits, I presume you believe that, in a thought experiment, a group of children from diverse genetic backgrounds that were all raised in exactly the same environment would become a group of adults that would all be, essentially, the exact same person. Is this true? Also, what is the deal with your citing two studies that disagree with you contentions.?

 

SM

Edited March 22, 2011 by SMF

[SamTheSkeptic]

SamTheSkeptic:

 

You appear to be a relatively strong adherent of the Tabula Rasa (http://en.wikipedia....iki/Tabula_rasa) side of the nature/nurture question.

 

 

I am indeed. I think it is important to point out though, that although the 'nature vs. nurture' debate is largely considered to be a philosophical one, real science does play an important role as well. Just how does science play into it? Well, science prevents the proponents of the "nature" side from ever validating their claims. In essence, the whole debate revolves around their claim - that human behavior is (at least partially) genetically predetermined - and the lack of scientific evidence to support that claim. The proponents of the "nurture" side don't need scientific evidence to validate their position because they are aware that personality and character cannot be explained scientifically!

 

If you don't think that ones genetic background has any effect on the development of complex personality and other character traits, I presume you believe that, in a thought experiment, a group of children from diverse genetic backgrounds that were all raised in exactly the same environment would become a group of adults that would all be, essentially, the exact same person. Is this true?

 

No. The problem with trying to apply this hypothetical 'thought experiment' (which I have heard presented before) is that there is no objective scientific measurement for character or personality (because they are non-scientific concepts). So, even if this this experiment were to be properly conducted on a sufficient enough sample to yield meaningful findings, in the end there would be no reliable test to determine whether or not the individuals in the study actually turned out "the same." Who would decide how much "alike" any two given individuals are? What would that decision be based on? Surely, it would be a self-reporting problem...and in the realm of psychology, not science.

 

 

Also, what is the deal with your citing two studies that disagree with you contentions.?

 

SM

 

I figured I'd give a few examples from each viewpoint, since the poster implied that they were writing an essay on both sides of the debate. Maybe I should have pointed that out to avoid confusion. With that being said, I did pick out the dancing gene study because I find it to be particularly amusing. . .

[SMF]

SamTheSkeptic:

 

I am very surprised at your statements regarding “scientific measurement for character or personality” being impossible. For example, it is common to say that somebody is excitable, or a risk taker, or is trusting, or tends to be melancholy and the meaning is clear to others. The fact that we all are able to communicate these complex character traits to one another indicates that they are real and verifiable behaviors. The point is that they are behaviors and are easily measured. A behavior geneticist studying heritability of complex behavior traits will reduce these descriptions to operational definitions for research purposes.

 

 

Some of the best evidence for the heritability of complex behavioral traits can be found in twin studies. There are two big ones, the Minnesota twin study- http://mctfr.psych.umn.edu/ where you can find links to research from their database and the Swedish twin study for which I couldn’t find a website, but you can see an enormous amount of research for both by putting the twin study name in the search field in Google Scholar. The reason this is such good research is that it is relatively easy to statistically measure heritability from behavioral comparisons of identical twins reared together and apart and non-identical twins reared together and apart. There is a very large research literature on this topic.

 

Here are some links to good research. I have tried to provide full text links where possible.

 

T.J. Bouchard twin study- http://www.sciencemag.org/content/250/4978/223.abstract, full text- http://www.psych.umn.edu/courses/fall06/yoonh/psy3135/articles/bouchard_1990.pdf

 

Behavior study using Swedish twin data, the full text link is on this page- http://www.pnas.org/content/105/10/3721.short

 

Heritability of personality dimensions- http://www.psych.umn.edu/courses/fall06/yoonh/psy3135/articles/Jang%20et%20al_1996.pdf

 

Here is one on homosexuality- http://faculty.bennington.edu/~sherman/sex/samesex%202010.pdf

 

You might also be interested in Robert Plomin’s work- http://www.sciencemag.org/content/264/5166/1733.short

 

As for my thought experiment, your answer is very confusing. You seem to be saying that personality and character are completely determined by experience, as opposed to inheritance, but that you couldn’t tell. If you can’t tell the difference then you also can’t assign these traits to either cause.

 

SM

 

 

[SamTheSkeptic]

SamTheSkeptic:

 

I am very surprised at your statements regarding "scientific measurement for character or personality" being impossible.

 

Well, I'm not surprised that you're surprised. Most people don't realize this, but it really is at the foundation of the entire debate. At the same time, you shouldn't be surprised that it is impossible to scientifically measure a concept that only exists inside our minds. . .

 

For example, it is common to say that somebody is excitable, or a risk taker, or is trusting, or tends to be melancholy and the meaning is clear to others. The fact that we all are able to communicate these complex character traits to one another indicates that they are real and verifiable behaviors. The point is that they are behaviors and are easily measured.

 

Let's delve a bit deeper into your example. Sure, we have all heard the term "risk taker." I don't disagree that we all know the general concept of what it means to be a 'risk taker' - obviously, it is a term given to those who take risks. But how much risk does a person have to take in order to be considered a "risk taker" ? I mean, we all take risks in our life at some point or another. ..indeed, from driving in cars to flying in airplanes to even taking a shower! This then begs the question, "what constitutes a risk?" And then, if this question were to somehow be universally answered and agreed upon, how many risks would one have to take in order to be deemed a "risk taker? The problem is coming up with a scale that exists objectively to measure the risk; that's the impossible part. There are pH tests to measure acidity and blood tests to measure HIV, but no such tests to measure "risk."

 

 

And many 'behavioral scientists' do attempt to create standardized scales for such concepts. Intelligence (another concept that exists only in our minds and not objectively) is an example, along with the IQ tests intended to assess it. I'm sure many would even consider IQ tests to be scientific, but in reality they are not. I won't get into the origins of the test itself, but the standards used on the test are certainly arbitrary. . . And that isn't to say anything about the uselessness of the results. A person's IQ score many times seems to be in stark contrast with how others perceive their abilities and accomplishments. If it were a scientific measurement, this would never happen.

 

 

You say that the meaning of these concepts are "clear to others," but I think you might be surprised at the amount of disagreement you may come to with others pertaining them. One's trust might be viewed by another as being "weak," and what you may consider to be melancholy may not feel like melancholy at all to someone else. True science doesn't change at all from person to person. . .something either IS or it ISN'T, and there are ways to test/disprove it.

 

 

 

 

Some of the best evidence for the heritability of complex behavioral traits can be found in twin studies. There are two big ones, the Minnesota twin study- http://mctfr.psych.umn.edu/ where you can find links to research from their database and the Swedish twin study for which I couldn't find a website, but you can see an enormous amount of research for both by putting the twin study name in the search field in Google Scholar. The reason this is such good research is that it is relatively easy to statistically measure heritability from behavioral comparisons of identical twins reared together and apart and non-identical twins reared together and apart. There is a very large research literature on this topic.

 

Here are some links to good research. I have tried to provide full text links where possible.

 

T.J. Bouchard twin study- http://www.sciencema...78/223.abstract, full text- http://www.psych.umn...uchard_1990.pdf

 

Behavior study using Swedish twin data, the full text link is on this page- http://www.pnas.org/...5/10/3721.short

 

Heritability of personality dimensions- http://www.psych.umn...t%20al_1996.pdf

 

Here is one on homosexuality- http://faculty.benni...esex%202010.pdf

 

You might also be interested in Robert Plomin's work- http://www.sciencema...5166/1733.short

 

 

I have seen these studies before, and they all lack the same scientific validity because they never actually explain the causes they study! For example, taken from the

Minnesota twin study website, "While we still use and have much to learn from twin and adoption study techniques, the successful mapping of the human genome now provides scientists with an exciting opportunity to build on these important findings. Your DNA sample, when related to the extensive behavioral information you have also provided, will lead to a better understanding of how and why genetic factors appear to shape human behavior. "

 

I've put the important parts in bold, lol. They still "have much to learn from study techniques," and the "exciting opportunity to build.. . .Genetic factors appear to shape human behavior." What this really means is that they have no conclusive explanation or proof for genetics playing any role whatsoever in human personality. They might have lots of correlations and observations, but no cohesive theory that actually explains the phenomenon. Do you think NASA could send people to space if it "appeared" that they would be able to re-enter the earth's atmosphere without incinerating? Could an engineer design a bridge that "appeared" to be safe? Of course not. . rigid and strict precision is required for accomplishing such great tasks. . and real science provides this.

 

 

As for my thought experiment, your answer is very confusing. You seem to be saying that personality and character are completely determined by experience, as opposed to inheritance, but that you couldn't tell. If you can't tell the difference then you also can't assign these traits to either cause.

 

SM

 

Yes, I am saying that personality and character are completely determined by experience and environment...they are merely concepts which although can be generally agreed upon in terms of their definition, have different meanings for different people. Science has the same meaning for everyone. I can't drive this point home enough.

[SMF]

SamTheSkeptic. You say-

 

Well, I'm not surprised that you're surprised. Most people don't realize this, but it really is at the foundation of the entire debate. At the same time, you shouldn't be surprised that it is impossible to scientifically measure a concept that only exists inside our minds. . .

 

This statement is nonsensical. Personality and character constructs are based on the output of our complex biological computers (brains). There is no representation of “risk taker” in the brain, but it is a demonstrable component of behavior. This behavior is well defined in culture and by scientists who wish to study it (in the studies I have cited) so I challenge you to provide scientific evidence, no more opinions, of any representation of this concept "inside our minds." Don't imply that this is obvious because this is just your opinion. Both genetics and experience affect the processor and, thereby, the output, and this has been reliably measured by researchers.

 

Let's delve a bit deeper into your example. Sure, we have all heard the term "risk taker." I don't disagree that we all know the general concept of what it means to be a 'risk taker' - obviously, it is a term given to those who take risks. But how much risk does a person have to take in order to be considered a "risk taker" ? I mean, we all take risks in our life at some point or another. ..indeed, from driving in cars to flying in airplanes to even taking a shower! This then begs the question, "what constitutes a risk?" And then, if this question were to somehow be universally answered and agreed upon, how many risks would one have to take in order to be deemed a "risk taker? The problem is coming up with a scale that exists objectively to measure the risk; that's the impossible part. There are pH tests to measure acidity and blood tests to measure HIV, but no such tests to measure "risk."

 

This bit demonstrates your lack of understanding of how science works. Most phenomena, and especially biological ones, can be represented by the ubiquitous normal (bell) curve. Scientists who study behavior can define a trait, such as risk taker, operationally for research. This typically might be behavior tested to be two standard deviations from the mean. This operational definition is more than adequate for performing a study that relates heritability to behavior. Defining risk is actually very easy. It is based on how often the behavior results in a bad outcome. If you think that there is disagreement about this prove it with science, not opinion.

 

 

As for the rest of your missive- Science is always building on past knowledge. Many questions, such as evolutionary theory, are a long term continuing project. Because of the nature of the scientific enterprise the findings absolutely do not have the same meaning for everyone. You are confusing science with nature. Finally, NASA did send people into orbit knowing that they might burn up on reentry, and some did. SM

[SamTheSkeptic]

SamTheSkeptic. You say-

 

 

 

This statement is nonsensical. Personality and character constructs are based on the output of our complex biological computers (brains). There is no representation of "risk taker" in the brain, but it is a demonstrable component of behavior.

 

My statement makes perfect sense, you are just failing to understand it. As I said before, show me a falsifiable theory that fully explains how genetics exactly predetermine one's personality, and I will accept your claims. But the truth is that you can't. . .none of the studies you have provided (and there are indeed none out there at all) provide conclusive evidence for this.

 

This behavior is well defined in culture and by scientists who wish to study it (in the studies I have cited) so I challenge you to provide scientific evidence, no more opinions, of any representation of this concept "inside our minds." Don't imply that this is obvious because this is just your opinion. Both genetics and experience affect the processor and, thereby, the output, and this has been reliably measured by researchers.

 

Again, you fail to understand that observing human behavior (including representing the observations with bell curves, graphs, constructed scales, etc.) does not make it science. You need to have a falsifiable theory, I'll say it time and time again. Here's a particular example that I enjoy from an article written by Paul Lutus:

 

" Let's say I am an astrologer, and I want to carry out a research project — I want to statistically break down the U.S. population by astrological sign. That way, I can order supplies intelligently and focus my efforts appropriately, with an evidence-based idea of who my clients will be. So I consult a statistical database of U.S. births by date, process the data, and break it down by the astrological "signs" (this result is for U.S. births in 2003):

Aries 334,893 8.19%

Taurus 347,647 8.50%

Gemini 348,053 8.51%

Cancer 342,726 8.38%

Leo 381,064 9.32%

Virgo 363,278 8.88%

Libra 349,643 8.55%

Scorpio 345,045 8.44%

Sagittarius 312,977 7.65%

Capricorn 314,750 7.70%

Aquarius 327,456 8.01%

Pisces 322,418 7.88%

-------------------------------

Total 4,089,950 100.00%

Okay. I have created a scientifically valid statistical result in astrology, and the study turns out to have practical value in the daily activities of astrologers. Does this scientifically valid result make astrology itself scientific? No, of course not. Why? Because, regardless of its practical significance, my research doesn't address or potentially falsify the core theories of astrology."

 

Please drive this principle into you head. These studies you are citing do not make your argument scientific!

 

This bit demonstrates your lack of understanding of how science works. Most phenomena, and especially biological ones, can be represented by the ubiquitous normal (bell) curve. Scientists who study behavior can define a trait, such as risk taker, operationally for research. This typically might be behavior tested to be two standard deviations from the mean. This operational definition is more than adequate for performing a study that relates heritability to behavior. Defining risk is actually very easy. It is based on how often the behavior results in a bad outcome. If you think that there is disagreement about this prove it with science, not opinion.

 

Funny that even after I have explained (and pointed out that it is often overlooked) the fact that you are the one who is making the claim and you are the one who needs evidence, you still overlook it. You asking me for evidence is like asking an atheist for proof that god doesn't exist...it is a fallacious argument.

 

You make a claim, I am skeptical of that claim - but you can't turn around and then label my disbelief as being a belief in itself! I hope you see that you're falling into this simple fallacy.

[SMF]

SamTheSkeptic:

 

My statement makes perfect sense, you are just failing to understand it. As I said before, show me a falsifiable theory that fully explains how genetics exactly predetermine one's personality, and I will accept your claims. But the truth is that you can't. . .none of the studies you have provided (and there are indeed none out there at all) provide conclusive evidence for this.

The obvious falsifiable theory that is being tested is- Heritability can explain some percentage of the variance of some specific complex human behaviors. This theory has been verified repeatedly and is being refined. The more comprehensive theory that involves the specific underlying genetic and brain mechanisms is currently being researched. If science progressed in the manner you think it should then we would not have evolutionary theory, modern physics, modern neuroscience, and who knows what else because the researchers didn't have a complete theory at the beginning.

 

Just for accuracy, no scientists are claiming that "genetics exactly predetermines one's personality" and this is a straw man argument.

 

Okay. I have created a scientifically valid statistical result in astrology, and the study turns out to have practical value in the daily activities of astrologers. Does this scientifically valid result make astrology itself scientific? No, of course not. Why? Because, regardless of its practical significance, my research doesn't address or potentially falsify the core theories of astrology."

 

Please drive this principle into you head. These studies you are citing do not make your argument scientific!

 

Descriptive statistics of human behavior is quite valuable both in and of itself and because they can be related to some other variable, such as genetics. This is science. Behavior geneticists have demonstrated a relationship and, along with neuroscientists, are looking for biological mechanisms. Astrologers have not demonstrated a relationship between astrological sign and behavior and are not looking for a mechanism, and scientists can't even think of a research direction for this. This is another straw man argument.

 

Funny that even after I have explained (and pointed out that it is often overlooked) the fact that you are the one who is making the claim and you are the one who needs evidence, you still overlook it. You asking me for evidence is like asking an atheist for proof that god doesn't exist...it is a fallacious argument.

 

You make a claim, I am skeptical of that claim - but you can't turn around and then label my disbelief as being a belief in itself! I hope you see that you're falling into this simple fallacy.

 

In this statement, you have presented a fallacious argument. It is perfectly valid for me to ask you to support any assertion you make. It sounds to me that you don't think science regarding the nature nurture question is valid at all. Perhaps you should check out astrology for an answer. No? Then answer this- Why do you think that if "personality and character cannot be explained scientifically," that experience explanations (nurture) are valid, but genetic explanations (nature) are not? No more hand waving please.

 

I find your repeated orders to "drive this principle into your head" very annoying and condescending. I suggest that you take your own advice for the following- It is scientifically valid to study how variability in the genetics of any organism affects variability in resulting body structure, function, and behavior. If you don't believe this, please explain. No more hand waving please.

 

I think this thread should be moved to the Speculations section. SM

Edited March 24, 2011 by SMF

[SamTheSkeptic]

SamTheSkeptic:

 

 

The obvious falsifiable theory that is being tested is- Heritability can explain some percentage of the variance of some specific complex human behaviors. This theory has been verified repeatedly and is being refined.

 

No, this is a speculation, not a falsifiable theory. How can it be falsifiable if you can't even give specific measurements? Heritability can explain "some" percentage of "some" human behaviors? Exactly how much? What specific behavior(s)? Could you possibly be any more vague? Do you think that such a sloppy "Theory" could provide us with any reliable information? The answer is no.

 

In order for this to be falsifiable, you would need to define an exact percentage and an exact behavior first. This would be your hypothesis. Then you would have to be able to reproduce the results over and over again to confirm this hypothesis. If you came out with a different result even once, you know that the theory couldn't be the best way to explain the phenomenon.

 

Really what you mean to say is that extensive observational studies (which fall into the realm of psychology and not science) have been done which show correlations between genes and behavior. But this is far from a scientific theory.

 

If science progressed in the manner you think it should then we would not have evolutionary theory, modern physics, modern neuroscience, and who knows what else because the researchers didn't have a complete theory at the beginning.

 

No, you're mistaking a theory with a hypothesis...as I explained above. In order to come up with a scientific theory, you need a specific hypothesis first that can be precisely defined. The sloppy evidential standards you proposed in your 'theory' above are quite simply insufficient to produce quality results.

 

 

Descriptive statistics of human behavior is quite valuable both in and of itself and because they can be related to some other variable, such as genetics. This is science. Behavior geneticists have demonstrated a relationship and, along with neuroscientists, are looking for biological mechanisms. Astrologers have not demonstrated a relationship between astrological sign and behavior and are not looking for a mechanism, and scientists can't even think of a research direction for this. This is another straw man argument.

 

Descriptive statistics are valuable to psychologists, not so much for scientists. And no, "behavior geneticists" and neuroscience have not scientifically defined or explained the relationship. . they simply have said "our observations seem to suggest a link." And in many cases, they even use those exact words!

 

In this statement, you have presented a fallacious argument. It is perfectly valid for me to ask you to support any assertion you make. It sounds to me that you don't think science regarding the nature nurture question is valid at all. Perhaps you should check out astrology for an answer. No? Then answer this- Why do you think that if "personality and character cannot be explained scientifically," that experience explanations (nurture) are valid, but genetic explanations (nature) are not? No more hand waving please.

 

Incorrect. Sure it would be valid for you to ask me to support my assertion. . but I haven't made any assertions (as I've explained earlier numerous times). My skepticism of your claim is not in itself an assertion or a claim!!! THIS is the fallacious argument. No hand waving necessary, it really is as simple as that.

 

I suggest that you take your own advice for the following- It is scientifically valid to study how variability in the genetics of any organism affects variability in resulting body structure, function, and behavior. If you don't believe this, please explain. No more hand waving please.

 

Body structure yes. Behavior, no. I've already explained plenty. . but in a nutshell, you are attempting to sell (poorly disguised) psychology as a science, and I'm not buying.

 

I think this thread should be moved to the Speculations section. SM

 

Great idea, considering that behavior being determined by genes is really a speculation.

[SMF]

SamTheSkeptic:

 

You are at least consistent. You refuse to bring any science to the conversation. You refuse to answer questions. You only offer negative opinions to the conversation. You can’t support anything you assert. Your way of looking at science has little relationship with reality. You are trashing a lively and legitimate area of research with your uninformed opinion. In short, you are trolling.

 

I highly recommend that others here don’t engage SamThe (Pseudo) Skeptic on this topic. His disruptive intrusion here is a shame because there is a lot of interesting research regarding heritability of behavioral traits in both humans and other creatures. SM

 

 

[swansont]

!

Moderator Note

SamTheSkeptic, I have to concur that you are making straw man arguments, and using them to engage in appeal to ridicule. Logical fallacies are not valid arguments and are not permitted. "Nature vs nurture" studies exist (e.g. with twins) and broad dismissals of them is unfounded.


Note: If you wish to discuss any issues with a moderator, please send them a private message. Do not argue here; you will merely drive the thread off-topic.

I find your repeated orders to "drive this principle into your head" very annoying and condescending.
…
I think this thread should be moved to the Speculations section. SM

!

Moderator Note

SMF, please refrain from making this personal.

The OP seems to be legitimate, so I think it would be a disservice to move it to speculations based on the actions of a responder.


Note: If you wish to discuss any issues with a moderator, please send them a private message. Do not argue here; you will merely drive the thread off-topic.

[Mr Skeptic]

Does nature or nurture (hereditary or environment) influence the development of one's identity more?

 

Scientifically, what are the arguments presently for each stance?

 

I think heredity can make the difference between someone with the intelligence of an amoeba or a human genius. How said individual is nurtured can have some effect on that too. I'll let you work out which effect is the larger.

 

However, if you restrict the question to only the genetic variability within H Sapiens, nature and nurture have approximately equal effects, with one or the other being more important depending on the specific context. Twin studies are the gold standard to tell the difference for any particular attribute.

[SamTheSkeptic]

SamTheSkeptic, I have to concur that you are making straw man arguments, and using them to engage in appeal to ridicule. Logical fallacies are not valid arguments and are not permitted.

 

I'm sorry, but my argument is not fallacious at all. All of my points are valid and have been based in logic. Nowhere have I constructed a straw man. If you'd like to be specific, I certainly can explain further on anything I've said to clarify. . .

 

And my point is certainly not to ridicule or anger anyone. . .this is a forum for scientific discussions - and although this one may seem a bit heated, everyone here is playing by the rules and I'm sure someone can take something useful away from this thread. My position is very simple and consistent. I refuse to accept speculations as scientific theories (hence my screen name).

 

 

"Nature vs nurture" studies exist (e.g. with twins) and broad dismissals of them is unfounded.

 

I never said that I "broadly dismiss" these studies; but I certainly do question the validity and significance of their results and implications. This is the very nature of science - until something is explained definitely and absolutely, we must consider with equal importance all other possibilities. How could you consider this to be "unfounded?"

 

SMF, let me say firstly that I have no personal feelings against you. . .believe it or not I have enjoyed having this exchange with you and I appreciate your replies. Hopefully the OP and others have pulled something from this as well.

 

You are at least consistent. You refuse to bring any science to the conversation.

 

I am not refusing to bring science into the situation; rather, science is refusing to explain your claims. In the same way that science can't be applied to uniquely human concepts such as deities, neither can it be used to explain human emotions. This is the field of psychology.

 

Your way of looking at science has little relationship with reality.

 

Actually, "my way of looking at science" is completely necessary for achieving the best available understanding of reality. There is no debate about the theory of gravity for example, because the evidence is overwhelming and physically available for anyone who inquires to confirm it. Indeed, if a single person were to ever conduct a test or produce a situation in which gravity "broke down" or didn't hold true, then the theory would be falsified and no longer considered to be the best understanding of reality.

 

But your position lacks this kind of testability. There is no definite theory which can be used to fully explain and accurately predict future outcomes. It is only a speculation; and there are many exceptions to your speculation, even in the very studies (twin studies) you have cited. For example, according to your claim that "genes partially influence human behavior," it should prove true that "two identical twins should, theoretically, be exactly the same in all respects, even if reared apart. But a number of studies show that they are never exactly alike, even though they are remarkably similar in most respects. " If your claim was truly a scientific theory (and not just a speculation), then this single finding alone would be sufficient to falsify it.

 

You are trashing a lively and legitimate area of research with your uninformed opinion. In short, you are trolling.

 

I never have "trashed" anyone's attempt to document and/or understand reality, as long as it has valid scientific relevance and significance. Part of my reasoning for being so critical of the "nature" side of the debate is because of the legal implications that it may have. If eventually your view (which is currently the most popular) becomes generally accepted, then how many people will be able to get off the hook for murder because they were "genetically prone to violent behavior" ? How many sex offenders will have their sentences reduced because they had the "sex offender gene" ? Also, disagreeing with you doesn't equate to trolling.

[SMF]

SamTheSkeptic:

 

I will try again. Please explain the following. I will try to make this as simple as possible:

 

Both genes and behaviors are measurable, quantifiable, and measurements are repeatable. They are both legitimate topics of scientific investigation. If one gets a repeatable correlation between a specific genetic background and a behavioral measure, then this is a legitimate scientific result. You might argue that the name of the behavioral construct isn't accurate, but you cannot deny the principle that genes have been shown to relate to complex behavior. When twins reared apart are compared to twins reared together then the comparison of these conditions rule out the criticism of "correlation does not equal causation" because, unless someone is invoking pseudoscience, genes and environment are pretty much the whole show.

 

You say-

 

For example, according to your claim that "genes partially influence human behavior," it should prove true that "two identical twins should, theoretically, be exactly the same in all respects, even if reared apart. But a number of studies show that they are never exactly alike, even though they are remarkably similar in most respects. " If your claim was truly a scientific theory (and not just a speculation), then this single finding alone would be sufficient to falsify it.

 

The logic of what you say is very difficult to follow. In my statement my use of the word "partially" is clear and refers to the behavior genetics truism that Phenotype = genotype X environment (P = G X E) and it unequivocally does not follow, as you say, that identical twins should be identical when reared apart (or together, for that matter). Behavior genetics research specifically tries to partition effects into environment and genetic components. Your "identical" assertion is illogical and a strawman argument.

 

You have refused to answer the following. You have made the claim that complex human behaviors, such as personality, are totally due to experience with no genetic component and have stated that

 

The proponents of the "nurture" side don't need scientific evidence to validate their position because they are aware that personality and character cannot be explained scientifically!

 

This suggests the simple and straightforward question- How does your statement logically exclude genetics but not environment as a scientifically verifiable causative factor? In other words, if there is no way to define it, there is also no way to make a choice. Please respond to this.

 

 

SM

Edited March 26, 2011 by SMF

[Ringer]

Part of my reasoning for being so critical of the "nature" side of the debate is because of the legal implications that it may have. If eventually your view (which is currently the most popular) becomes generally accepted, then how many people will be able to get off the hook for murder because they were "genetically prone to violent behavior" ? How many sex offenders will have their sentences reduced because they had the "sex offender gene" ? Also, disagreeing with you doesn't equate to trolling.

 

Since when do legal implications have anything to do with scientific accuracy?

[SamTheSkeptic]

SamTheSkeptic:

 

I will try again. Please explain the following. I will try to make this as simple as possible:

 

Both genes and behaviors are measurable, quantifiable, and measurements are repeatable.

 

I don't agree with you that human behavior is quantifiable, scientifically measurable, or repeatable. I am sure that I'm not the only person with this view. . .Sure, one can observe human behavior, chart it, graph it, compile statistics on it, but that doesn't mean that the phenomenon is actually explained or understood. As I said before, there exists no objective scientific scale for "love" or "risk taker." And if human behavior tests were truly "repeatable," then the same exact results would appear every time without any exceptions. This clearly is not the case, as human behavior is highly unpredictable.

 

They are both legitimate topics of scientific investigation.

 

They are legitimate topics of investigation; just in my opinion, not scientific investigation. I never meant to imply that there lies no value in attempting to understand and explain human behavior, I only contend that it presents an inherent impossible feat for science. Science will never be able to "dis-prove" your claims just as science can never "dis-prove" that God exists.

 

If one gets a repeatable correlation between a specific genetic background and a behavioral measure, then this is a legitimate scientific result.

 

This just simply isn't true. Under this logic, because African-Americans statistically show to be more violent and commit more crime (behavioral traits) than Caucasians, it would be 'scientifically legitimate' to attribute this behavior to their genetic background? Of course not. A correlation is just a correlation, nothing more. Once you are able to explain the phenomenon with a cohesive and testable theory, then you will have legitimate science.

 

You might argue that the name of the behavioral construct isn't accurate, but you cannot deny the principle that genes have been shown to relate to complex behavior.

 

I don't argue that the name of the behavioral construct isn't accurate, but that it is merely a construction of our minds in an attempt to understand the unexplainable phenomenon of our thoughts and emotions. This concept is a subjective one, not concretely defined, one that changes a bit from person to person. . .therefore, it is not a scientific principle.

 

Also I do deny that genes have been shown to relate to complex behavior. Nothing at all has been "shown" here. . . It takes more than correlations to show (prove) something in science.

 

 

 

The logic of what you say is very difficult to follow. In my statement my use of the word "partially" is clear and refers to the behavior genetics truism that Phenotype = genotype X environment (P = G X E) and it unequivocally does not follow, as you say, that identical twins should be identical when reared apart (or together, for that matter). Behavior genetics research specifically tries to partition effects into environment and genetic components. Your "identical" assertion is illogical and a strawman argument.

 

 

First off, not all scientists agree that behavior should be included within the definition of "phenotype," but this is another issue. Even then, my example is far from illogical. In your 'behavior genetics truism' (P=G X E), imagine two individuals (twins) with the exact same genes and environment (G and E). Then, the phenotype, or P, (which includes behavior according to your definition) should be exactly the same. But in reality, they are not. There are always at least slight differences, which because we already know that their Genes are exactly the same, must be attributed to environment.

 

 

 

You have refused to answer the following. You have made the claim that complex human behaviors, such as personality, are totally due to experience with no genetic component....This suggests the simple and straightforward question- How does your statement logically exclude genetics but not environment as a scientifically verifiable causative factor? In other words, if there is no way to define it, there is also no way to make a choice. Please respond to this.

 

SM

 

 

I have already answered this many times. My position logically excludes genetics because I am aware that human emotion/thoughts/behaviors are outside of the realm of science. Would I spend my time "scientifically researching" the existence of God? No, because I understand that God, like the ideas of Love or Hate or Intelligence, are in essence only constructs of the human mind and they cannot be objectively measured or quantified.

I also understand that attempting to do so may be interesting and fun, but ultimately will not yield results which lead to their scientific explanation.

 

The last part of your statement is a fallacy, as I have also specifically pointed out before. I have heard this argument used a million times, I specifically remember Bill O'Reily trying to use it in his interview with Richard Dawkins. I will use God as an example again. . .my disbelief in God is not a "choice" in itself. Rather, those who believe in God are the ones actually making a choice. They are taking the leap of faith - without conclusive supporting evidence - not me. When they try to turn around and say that "atheism" is itself a belief, this is simply illogical. Yet this is exactly what you are doing here. . .

 

Since when do legal implications have anything to do with scientific accuracy?

 

Ever heard of Forensics? Scientific Expert testimonies? CSI !?!?

 

Scientific accuracy couldn't be any more important when it comes to human lives and/or freedom.

[swansont]

!

Moderator Note

SamTheSkeptic you might want to reconsider the strategy of ignoring staff warnings, including the part about not derailing the thread with responses.

Note: If you wish to discuss any issues with a moderator, please send them a private message. Do not argue here; you will merely drive the thread off-topic.

[SMF]

Although I am not an expert in this area I think I have pretty much made my assertions regarding behavior genetics as a discipline, and also how science progresses, very clear and will let this stand on its merits. I hope that others will add to the discussion of this fascinating area of research. As I mentioned above, there are two large databases that have studied both fraternal and identical twins reared both together and apart. Those interested can enter "Minnesota" or "Sweden" plus "twin" plus whatever you might think is interesting or appropriate into your favorite search engine, or especially in Google Scholar for just the scientific literature, to probe the science in this research area. There is much more than behavior and all kinds of diseases and other traits have been studied to determine what can be attributed to ones inheritance. SM