Sunday, 12 May 2013

The e-mails from 2008 when I had the idea of using historical reaction time data to measure trends in intelligence


Two e-mails to Richard Lynn (Emeritus Professor, University of Ulster) 

5th July 2008 14:43 

Richard,

I've just this morening got Dysgenesis from the ILL service - I've so far just looked through the contents and headings.

I think I have an idea for measuring dysgenic change which doesn't seem to be in the book - by using reaction times.

Since reaction time correlates with IQ, and since I believe it is an old physological measurement, it is possible that there are representative data on national population reaction times over the past 100 or so years.

Since high IQ people have a fertility considerably below replacement level, my prediction would be that average reaction time would have become longer, and that the standard deviation would have become smaller (due to selective loss of shorter reaction times).

Do you think this makes sense as an hypothesis?

Maybe somebody has already done it, or if not - do you know of any databases of reaction times (or somebody whom I might contact about this?)

Best wishes, Yours, Bruce

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9th July 2008 09:28h 

Dear Richard,

Thanks for this. Yes - I was assuming/ hoping that RT might be a way to look at genotypic IQ, but as you say this is not known.

I haven't been able to find any old population measures of RT so far (I have only spent a couple of hours on the job, admittedly) - but I think that _if_ reaction times had lengthened throughout the twentieth century, then that would be an interesting observation. On the other hand, average RTs had stayed the same (like inspection times in the paper you mentioned) or if they had shortened throughout the 20th century, then neither of _those_ results would be interesting.

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Two e-mails to Ian Deary (Professor, University of Edinburgh): 

Monday 7th July 2008 09:51h

Dear Ian,


I'm sorry to badger you when you are still catching up but I have had an idea for measuring dysgenic change by using reaction times which I am keen to follow-up.


Since reaction time correlates with IQ, and since reaction time is an old physiological measurement, it is possible that there are representative data on national population reaction times over the past 100 or so years.


Because high IQ people have a fertility considerably below replacement level, my prediction would be that average reaction time in developed countries should have become longer, and that the standard deviation would have become smaller (due to selective loss of shorter reaction times).


But probably somebody has already done it (perhaps your group?)?


Or maybe reaction time correlates with 'phenotypic' (or measured) IQ (and therefore gets enhanced by the Flynn effect) rather than correlating with underlying 'genotypic' IQ? - I don't know.


If it hasn't already been done - do you know of any databases of reaction times (or somebody whom I might contact about this?


Best wishes, Yours, Bruce


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7th July 2008 20:11h

Dear Ian

That is *extremely* helpful of you (as ever).

So you have a modern average simple reaction time of 358 ms from Deary et al 2001. And the inspection time paper suggests that RT may be 'genotypic' intelligence - and not comtaiminated by the Flynn effect.

One would imagine it should be simple, in principle, to compare this with older estimates of RT - but so far I have failed to find any - either due to the papers not quoting any actual numbers, or different measure, or not being able to access the paper.

Hmm - I shall keep digging.  

With best wishes, Yours, Bruce
 

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NOTE: It was not until 28 February 2012 when - as a result of an e-mail interchange we had earlier that day - Michael A Woodley found that data which answered this question: Silverman IW. Simple reaction time: it is not what it used to be. American Journal of Psychology. 2010; 123: 39-50. As can be seen, Silverman's review and analysis had not been published in July 2008, when I made my failed attempt to discover some relevant evidence. 

http://charltonteaching.blogspot.co.uk/2012/02/convincing-objective-and-direct.html

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