DOES THE ATD ANGLE CORRELATE WITH INTELLIGENCE?

Does the ATD angle correlate with intelligence?

Yes! Various studies have indicated that there is indeed a link between the ATD angle and intelligence, but one should be aware that most of these studies were focussed on the hands of people who are featured with a low IQ (including: mentally retarded subjects and/or people who have Down syndrome).

One should also be aware that the IQ can vary from 25^o to 75^o (values outside this range are very rare). Which also implicates that principally these can all be found among invididuals of high IQ and low IQ. 

However, the following studies present strong evidence that the ATD angle correlates with IQ:
- [2010] Axial triradius as a preliminary diagnostic tool in patients of mental retardation
- [1996] Quantitative dermatoglyphic analysis in persons with superior intelligence
Plus the following Chinese report:
- [2006] Report on study of multivariate intelligence

What do these reports generally indicate?

A few general guidelines that can be derived from these reports are:

- ATD > 60^o = typical for Down syndrome [trisomy 21] (+ some other trisomy disorders);
- ATD > 55^o = often seen in people who have mental retardation (IQ below 70);
- 40^o < ATD < 55^o = normal;
- 30^o < ATD < 40^o = often seen in intelligent people (IQ above 120);
- ATD < 30^o = often seen in people who have mental retardation (IQ below 70).