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It is like how rising tides lift all boats. A good environment helps people without the right genetics; but this does not mean that this group can beat another

It is like how rising tides lift all boats. A good environment helps people without the right genetics; but this does not mean that this group can beat another set with right genetics in the same good environment.

noobermin 8y ago
What you just said sounds like a misunderstanding of the words "average" and "variance". Usually when things like intelligence is modeled, it is modeled as a normal distribution. Moving the average for a normal distribution moves the majority of people in the distribution. Variance just expresses how wide the distribution is, or how far you can expect people to deviate from the average. What you're saying seems to suggest the distribution is multimodal. I'm not sure that's what they said.
forapurpose 8y ago
> A good environment helps people without the right genetics; but this does not mean that this group can beat another set with right genetics in the same good environment. I think that's backwards from what Plomin is saying in that quote. He's saying that, regardless of genetics, a better environment will cause the average performance of the group experiencing it to outperform the average performance of a group experiencing a worse environment. And he's saying that DNA influences the amount of each group's variation around that average performance. For example, if we were looking at height, * There are two groups, 1 and 2; people in Group 1 have one kind of tallness DNA (tDNA, something I just made up), and people in Group 2 have another kind of tDNA; also, Group 1 grows up in an environment with better nutrition and exercise than Group 2. Both groups are one gender, let's say women, to simplify height statistics. * Group 1 averages a height of 5'7" due to their relatively better environment, and due to their tDNA their variance is that 50% are between 5'5" and 5'8", a 3-inch range, and 95% are between 5'3" and 5'10", a 7-inch range. * Group 2 averages a height of 5'5" due to their relatively worse environment, and due to their different tDNA their variance is larger: 50% score between 5'3" and 5'9", a 6-inch range, and 95% are between 5'0" and 5'11", an 11-inch range.

noobermin 8y ago

What you just said sounds like a misunderstanding of the words "average" and "variance". Usually when things like intelligence is modeled, it is modeled as a normal distribution. Moving the average for a normal distribution moves the majority of people in the distribution. Variance just expresses how wide the distribution is, or how far you can expect people to deviate from the average. What you're saying seems to suggest the distribution is multimodal. I'm not sure that's what they said.

forapurpose 8y ago

> A good environment helps people without the right genetics; but this does not mean that this group can beat another set with right genetics in the same good environment. I think that's backwards from what Plomin is saying in that quote. He's saying that, regardless of genetics, a better environment will cause the average performance of the group experiencing it to outperform the average performance of a group experiencing a worse environment. And he's saying that DNA influences the amount of each group's variation around that average performance. For example, if we were looking at height, * There are two groups, 1 and 2; people in Group 1 have one kind of tallness DNA (tDNA, something I just made up), and people in Group 2 have another kind of tDNA; also, Group 1 grows up in an environment with better nutrition and exercise than Group 2. Both groups are one gender, let's say women, to simplify height statistics. * Group 1 averages a height of 5'7" due to their relatively better environment, and due to their tDNA their variance is that 50% are between 5'5" and 5'8", a 3-inch range, and 95% are between 5'3" and 5'10", a 7-inch range. * Group 2 averages a height of 5'5" due to their relatively worse environment, and due to their different tDNA their variance is larger: 50% score between 5'3" and 5'9", a 6-inch range, and 95% are between 5'0" and 5'11", an 11-inch range.