The boy who knew too much: a child prodigy

This is the true story of scientific child prodigy, and former baby genius, Ainan Celeste Cawley, written by his father. It is the true story, too, of his gifted brothers and of all the Cawley family. I write also of child prodigy and genius in general: what it is, and how it is so often neglected in the modern world. As a society, we so often fail those we should most hope to see succeed: our gifted children and the gifted adults they become. Site Copyright: Valentine Cawley, 2006 +

Sunday, March 25, 2007

Ratio IQ and developmental markers

Ratio IQ is the ratio of the mental age to the chronological age multiplied by 100. It was the original measurement of IQ and provided very useful information since it acted as an indicator of something tangible: the mental age of the subject.

How do we calculate mental age? Well, the standard approach is to look for markers characteristic of particular ages and use these as a guide to the appropriate ratio. This was a technique frequently used to create estimates of a subjects mental age and thus ratio IQ. If the behaviour is typical of 10 years old and the subject is 5, then the ratio is 2 and the ratio IQ is 200. It is a simple and effective way to get an idea of how relatively bright a subject is.

In the prior post, I used the developmental markers of Ainan's academic interests, and abilities as well as his O level exam as markers of where he stands. Some people have made it clear that they don't understand the calculation. It is a straightforward one. All I have done is analyze what mental age a typical person would need to have to perform the tasks that Ainan performs. Then I have divided this by his actual age at the time he was doing the task, to get an estimate of his ratio IQ. This is a time-honoured technique and not one made up by me on the spot. It was used by psychometricians seeking an estimate of the IQs of dead geniuses, who could not be examined in other ways and has a long pedigree of producing interesting data about people.

Developmental markers of ALL kinds are typically advanced in gifted subjects. The gifted walk earlier, talk earlier, read earlier, do interesting things earlier than non-gifted subjects. In a very real sense this increased rate of development is fundamental to what it means to be gifted. A gifted child is, mentally speaking, an older child than their age might suggest. This is not readily understood by many people unfamiliar with the characteristics of the gifted child.

Ainan's developmental markers were all very advanced...suggesting a very high ratio IQ. There is no controversy about the ratio IQ estimate in the post below since it is in agreement with all of his other markers: time of first speech, time of crawling, time of walking, time of reading etc...are all suggestive of a high ratio IQ.

I hope that helps people understand ratio IQ a bit better.

Try the estimate for yourself. Look at the developmental markers of people you know either in person, or in history. Compare those markers to the average developmental time. Work out a ratio. Multiply it by 100 and you will have a ratio IQ.

I might post more on this topic another day.

Have a good day, all.

(If you would like to read more of Ainan Celeste Cawley, a scientific child prodigy, aged seven years and four months, or his gifted brothers, Fintan, three and Tiarnan, fourteen months, please go to: I also write of gifted education, IQ, intelligence, child prodigy, child genius, baby genius, adult genius, savant, the creatively gifted, gifted children and gifted adults in general. Thanks.)

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posted by Valentine Cawley @ 6:35 PM 


Anonymous Anonymous said...


You can use developmental markers to come up with an idea of what range of I.Q. a person could have. But you cannot really use a chemistry test to extrapolate an actual I.Q. number. It just doesn't work that way.

11:40 PM  
Blogger Valentine Cawley said...

I am as aware as you are, that the technique is an estimate...however, the logic is sound and the method will produce a fairly accurate result - in the sense that it can establish thresholds of IQ below which it would not have been possible to have been, to have accomplished the tasks in question.

To get an actual result we would need a large number of instances of achievement correlated to mental age, to derive a better picture of a person's IQ. It can be done - and has been done for historical geniuses, using their biographical evidence.

Yet, of course, it is not as "precise" as a test with wrong/right answers - but actually may in fact be MORE accurate because it won't display test score depression. I feel a post coming on...

Best wishes

7:04 AM  

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