Is 2D:4D finger ratio research misleading?

Is 2D:4D finger ratio research misleading?

Is finger ratio research misleading / deceptive?

This week Czech researchers presented a revision of their earlier reported results: “previously published results on the 2D:4D ratio are biased by its covariation with finger length”. But the Czech researchers also reported very explicitely: “We do not claim that the previous results for the finger length ratio are wrong”.

What can we conclude from the latests step in finger ratio research?

What are the essentials of the Czech research? The Czech researchers claim that the fundamentals of the male-female 2D:4D finger length ratios can be related to male-female differences in finger length. Men usually have longer fingers (larger hand) than women – and there appears to be a negative correlation between finger length in general and the 2D:4D finger ratio.

The Czech research was presented under the title: ‘Differences in the 2nd to 4th digit length ratio in humans reflect shifts along the common allometric line’ – some quotes from the researchers about their finger ratio findings:

“Most studies agree that 2D:4D is sexually dimorphic.”

“Sexual differences in 2D : 4D are mainly caused by the shift along the common allometric line with non-zero intercept, which means 2D : 4D necessarily decreases with increasing finger length, and the fact that men have longer fingers than women.”

“We do not claim that the previous results for the finger length ratio are wrong”

“We conclude that previously published results on the 2D : 4D ratio are biased by its covariation with finger length. We strongly recommend regression-based approaches for comparisons of hand shape among different groups.”

Finger length measurements.

Are you tall, short, or got a small head?
Don’t forget to take a look at your fingers!

Recently Roger Dobson – author at MailOnline.co.uk presented an informative article with the title: ‘Tall, short – or got a small head? Here’s what your physique reveals about your health’. The article describes how various body dimensions – varying from body length to foot size – can indicate useful information about your risk of developing certain conditions, varying from cancer through to dementia & heart disease.
The continuation presents a quote from Roger Dobson’s article about the 2D:4D digit length ratio – the hand characterstic that has become very well-known in the past few years through the work and the 2 books of ‘the finger’ Professor John T. Manning

Roger Dobson wrote in his article about the hand:

“IF YOU HAVE LONG FINGERS

Autism and ADHD, mental illness/depression

A range of disorders has been linked to the length of fingers, and in particular the ratio between index and ring fingers. The ratio is thought to be a marker of what was happening hormonally in the womb when the foetus developed.

It’s thought a relatively long ring finger is a sign that the foetus was exposed to higher levels of the male hormone testosterone, while a relatively long index finger is a marker of the female hormone, oestrogen.

Conditions associated with a long ring finger compared to the index include autism and ADHD. Those associated with a longer index include depression.

Males, who are more likely to develop autism and ADHD, tend to have a longer ring finger relative to their index finger.

Exposure to certain hormones might increase or reduce the risk of certain conditions and traits.

‘It has been suggested that autism may arise as the result of exposure to high concentrations of prenatal testosterone,’ say researchers at Liverpool University.”