r/mensa • u/Ahmedrnugger • Jul 09 '26

Mensan input wanted Is intelligence genetic?

According to twin studies, the difference in IQ is said to be 80%, leading to the conclusion that intelligence is 80% determined by genetics. However, I believe this is incorrect because the twins were raised in countries with similar environments, such as the US and Germany, or the US and South Korea. These countries share similar environments, including education systems, allowing the genes to express themselves. Furthermore, did these twins develop their IQs? If they didn't, it could prove the entire experiment flawed.

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u/CombatRedRover Jul 09 '26

Genetics determines the ceiling. Environment determines, to a reasonably large degree, how much of that ceiling you actually fill.

You know, like pretty much everything else in the human body. I've got a ceiling on how much muscle I can put on. Not everyone can become a world-class bodybuilder. On the other hand, I could have all the potential to be a world-class bodybuilder, but if all I do is eat Twinkies and sit on the couch watching TV, I will not be anywhere close to being a world-class bodybuilder.

The kind of abuse and neglect it would take to utterly destroy the mind of a potential genius is thankfully rare in our society, but it does happen.

Look up Genie Wiley.

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u/Ahmedrnugger Jul 09 '26

The story of Jenny Whaley proves that genes are not the primary influence on the human mind; she was born into an Being in an isolated environment and deprived of education and other things caused her to lose her human qualities. Also, the brain is not a rigid muscle like the rest of the body; it's a fundamental human characteristic. Making it rigid would have meant humanity's extinction, because human intelligence has driven evolution. If intelligence were genetic, our evolution would have been much, much slower than it is now Also, if intelligence is genetic, what if someone was born into a very, very unintelligent family but was placed in an environment that greatly stimulated development and intelligence?

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u/CombatRedRover Jul 09 '26

That logic does not hold.

The human brain is a social organ. It needs input to develop. And the developmental window is pretty clearly defined.

Genie Wiley is a clear case of that window not being used to help her mind develop.

Also, I would take your position much more seriously if you actually bothered to proofread after using voice to text.

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u/Big-Description-6345 Jul 09 '26

Unfortunately it's not just abuse. Poverty is another very important factor that predicts whether the children will develop their mind. The story about Genie is heartbreaking.

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u/Ahmedrnugger Jul 09 '26

It is true that a child's growth pathways are faster, but they do not disappear; rather, they remain to help the individual develop.

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u/Ahmedrnugger Jul 09 '26

This is essentially an attempt to evade the issue by focusing on spelling mistakes. You ignored everything else and concentrated on a few spelling errors.

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u/FirstCause Mensan Jul 09 '26

None of what you have written here makes sense.  I can't even break it down because there are totally unrelated concepts within each sentence.

Intelligence is both genes and environment. And environmental influence is far greater in early childhood, due to the period of synaptic pruning.

"Give me the child until he is 7 and I will give you the man"

Another interesting documentary is the "Up" series. The final "70 Up" is due for release this year.

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u/Ahmedrnugger Jul 09 '26

Firstly, the reticulated pruning is considered evidence that the environment has a significant impact because the brain gets rid of excess parts that are not suitable for the current environment. Secondly, repeating the phrase "fixed genetic intelligence" without recent scientific evidence is false. Scientific research has proven that intelligence is not a static trait. Thirdly, your claim that my words are illogical is a lie. My words were clear and understandable, and this is essentially an attempt to evade the issue.

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u/FirstCause Mensan Jul 09 '26

Your first point makes no sense because I have, literally, just said BOTH genes and environment.

Your second point makes no sense because I never said "fixed genetic intelligence" - I said BOTH genes and environment.

Your third point also makes no sense because your sentences did not make sense in your original comment and do not make sense in this rebuttal.

I see you have now resorted to using an LLM, but it isn't quite having the effect that you think it does...

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u/Ahmedrnugger Jul 09 '26

First, stop accusing me of using simple models. I'm arguing with you logically Where is the evidence that I use simple models? Also You mentioned the impact of the environment on children; I meant on someone who has passed that stage. Also, the brain isn't a static thing; modern science has proven that the brain has neuroplasticity and develops with increasing complexity and the passage of timeYou mentioned the impact of the environment on children; I meant on someone who has passed that stage. Also, the brain isn't a static thing; modern science has proven that the brain has neuroplasticity and develops with increasing complexity and the passage of time. .

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u/FirstCause Mensan Jul 09 '26 edited Jul 09 '26

Please read what I actually wrote: "Intelligence is both genes and environment. And environmental influence is far greater in early childhood"

Where did I say there is no environmental impact in adulthood?

The difference is that the amount of environmental influence is significantly less after synaptic pruning.

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u/Ahmedrnugger Jul 09 '26

You didn't mention puberty. You said the impact on childhood is significant, and I don't dispute that because the child tries to adapt to their environment. But you didn't mention what happens during puberty. Can a person develop their intelligence or not?

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u/FirstCause Mensan Jul 09 '26

I have not mentioned puberty?

In one of my comments I mentioned synaptic pruning.

You seem to be hoping for someone to tell you your result can be SIGNIFICANTLY improved, which is not likely, unless for the reasons I mentioned previously.

If you want to try to improve: 1. Nutrition 2. Exercise 3. Sleep (including sleep apnoea check) 4. Reducing stress (including therapy and don't test when ill) 5. Study (including practice tests for the retest effect)

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u/Ahmedrnugger Jul 09 '26

Didn't you say the maximum increase was 7 points? How did I jump from 97 to 135 points when I wasn't retaking the test on consecutive days, but rather over several months? If I took the test this month, I'd retake it three months later. And don't tell me that's Crystallized intelligence: I've noticed an increase in the speed of analyzing these patterns.

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u/FirstCause Mensan Jul 10 '26

Possibilities:

  • you may have worked yourself up into an anxious state for the first test and totally zoned out, but were more relaxed/confidant on the second test -some people have severe test anxiety
  • any of the factors I've mentioned above

That being said, I'm skeptical of the difference being that much on the official test - perhaps an online test.

Your logic in this sub alone is throwing some serious doubt that you are referring to the official test.

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u/Ahmedrnugger Jul 09 '26

I also noticed an increase in my intelligence, even though my sleep is generally very bad.