DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

**Martijn (admin)** Mon Oct 11, 2010 5:08 pm

Four example photographs of hands and arms scoring high or low on the 'Hand
Masculinity Index': (a) High masculinity male hand; (b) low masculinity male hand; (c)
high masculinity female hand; (d) low masculinity female hand. Color versions of
photographs were presented to judges.

AN ANALYSIS OF THE SEXUAL DIMORPHISM OF HANDS:
ATTRACTIVENESS, SYMMETRY AND PERSON
PERCEPTION

In december 2009 a student at the University of New Mexico presented the following dissertation study:
http://dspace.unm.edu/bitstream/handle/1928/10330/dissertationdane%20final.pdf?sequence=1"

The study e.g. presents a method providing an objective measure for the 'hand masculinity index', based on various hand- and forearm measures - specified to:

- wrist width;
- elbow width;
- finger lengths;
- body fat;
- and hairiness of arms

(with men hypothesized to have higher scores on all characteristics except body fat)

But the '2D:4D digit ratio', and 'fingerprint ridge counts' are included in this study as well!

I have spotted quite a few interesting results in this study, including e.g.:
1 - sexe difference for how '2D:4D digit ratio' correlates with 'fingerprint ridge counts' (see: table page 40);
2 - significant ethnic differences for 'hand masculinity index' (see: figures page 42)
3 - sex difference for how the 'hand masculinity index' correlates with FLUCTUATING ASYMMETRY;
4 - long fingers in women correlate higly with attractiveness (see: table page 55); in general, arms of both sexes were preferred it they were
less hairy and smaller in size. Younger women had attractive hands and in general
women’s hands with longer fingers were preferred;
5 - neither finger ridge counts nor 2D: 4D alone predicted
attractiveness, but sex-typical scores on the new masculinity index were associated with
attractiveness in photographs of hands including forearms;
6 - and the study reports... no sexe difference seen in finger length!**

(But I am sure that there are quite a few other points described in this study that could be mentioned here)

** PS. Last week I noticed the same conclusion from multiple other (international) studies: despite that people often assume that women have longer fingers, only the '(middle) finger length vs. palm width ratio' is higher in women.

See the discussion:
'Which country has the largest hands in the world?'
https://www.modernhandreadingforum.com/viiic-funny-stuff-f31/which-country-has-the-largest-hands-in-the-world-t245.htm

**Martijn (admin)** Tue Oct 12, 2010 2:24 pm

... I have been studying the details of this study a bit more. After some thinking, I think this study provides a very interesting hypothese regarding mate-choice, and especially regarding what women prefer to see in men!

I have written a short review of some details presented in this study:
http://handfacts.wordpress.com/2010/10/12/mate-choice-women-prefer-masculine-hands-but-not-masculine-men/

But basically, what I was able to conclude from this study is the following:

The study shows that women like men to have ‘masculine hands’… however, the study als demonstrates that women do not mind at all if a man’s body (arm + face) is a little bit less masculine than his hands!!

geek

... What is your thought? Surprizing???

I guess, we already knew that most women don't like 'bodybuilders'; this study provides a clear example of that most women are not like the woman in the photo below - instead: women usually prefer to appreciate the more 'subtile' elements in a man!

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Muscleman

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Muscleman

**Martijn (admin)** Tue Dec 21, 2010 12:13 am

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Hand

Here's another study (Mauritius, 2006) that focussed on the so-called 'hand index' (= the ratio between the hand width vs. the hand length):
http://www.ispub.com/journal/the-internet-journal-of-forensic-science/volume-1-number-2/determination-of-sex-by-hand-dimensions.html

The results are quite fascinating because they suggest:

1) that the studied men (N=125) typically have a 'hand index' higher than 44:
- in all five age groups of the males the average 'hand index' was higher than 44 (see the table 1 below); varying among the age groups from 44.02 to 45.05 (groups average = 44.64)

Table for the males:
DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Determination-of-sex-by-hand-dimensions.article-g03.ns

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Determination-of-sex-by-hand-dimensions.article-g03.ns

2) while the studied women (N=125) have a hand index lower than 44:
- in all five age groups of the females the average 'hand index' was lower than 44 (see the table 2 below), varying among the age groups from 42.65 to 43.79 (groups average = 43.28)

Table for the females:
DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Determination-of-sex-by-hand-dimensions.article-g04.ns

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Determination-of-sex-by-hand-dimensions.article-g04.ns

Actually... these results look slightly more impressive regarding the males vs. females difference: a difference of 3.1% (compared to the 2D:4D digit ratio studies where the average is usually close to 2%).

So, maybe combining this 'hand index' with the Manning's 'digit ratio'... could be an interesting combination of indices (though: contrary to the '2D:4D' the 'hand index' is NOT established before birth).

EDIT 1: But we have to be aware of population differences...

John Napier published in 1980 in his book 'Hands (page 26)' likewise data for a much larger sample including Europeans & Americans (which describe a difference also larger than 3%... which is indeed higher than the sexe-difference usually seen in 'digit ratio' studies!!!):
- average 'hand index' of 9883 males (very large majority were army personnel): 45.8
- average 'hand index' of 8848 females (all army personnel): 44.4

EDIT 2: ... I remember, I created some likewise considerations for the hand shapes of various nations in an earlier discussion:
Which country has the largest hands in the world?

happy move

Originally I created that topic created 'just for fun'... but now it becomes very useful! => People in the US appear to have the highest 'hand index' (close to 45); UK and China are less wider (close to 44); Mauritius just below that (43.8 )... and people from Japan have the narrowest hands (close to 43).

Rock on!

One could wonder... have army personnel a higher 'hand index' than non-army people? (Napier's data suggests that this difference is likely very small, so compared with the data from Mauritius likely Americans & Europeans appear to have a high 'hand index' than people in Mauritius... maybe there is a link with body mass index and/or body length???)

PS. scratch

Anyway, very, very, interesting stuff...

In both of my hands have a relatively normal '2D:4D finger ratio'... but in both hands I have a female-like 'hand index' (the average for both of my hands appears to be close to 43).

Now... what is your 'hand index'?

sgm2010 Tue Dec 21, 2010 4:06 am

Hey Martijn,

My palm width is 3.4 inches and length is 7.1 from (first rascette to tip of middle finger). That gives me a ratio of almost 4.8. So it means either I'm an unsually weird dude or an unusually intelligent one. What are you thoughts ?

**Martijn (admin)** Tue Dec 21, 2010 11:59 am

sgm2010 wrote:Hey Martijn,

My palm width is 3.4 inches and length is 7.1 from (first rascette to tip of middle finger). That gives me a ratio of almost 4.8. So it means either I'm an unsually weird dude or an unusually intelligent one. What are you thoughts ?

Hello sgm2010,

Variations are only natural: a male 'hand index' of 4.8 is very well possible.
It means that you have a relatively wide hand - which is a typically 'male-like' characteristic.

Sorry, if there is any connection between 'hand index' and intelligence... I have various reasons to assume that a 'narrow hand' could more likely indicate a high (verbal) intelligence.

EDIT: I can present 2 indicative examples which are indicative for a likely negative correlation between hand length & IQ:

1 - Down syndrome & fragile-X syndrome which are the 2 most common causes for a low intelligence is usually featured with a relatively wide palm, which implicates a high 'hand index'.

2 - And this negative correlation has actually been confirmed for normal, healthy people as well:

This study from the former Yugoslavia (1980) reports that hand width produced negative correlations with all 10 cognitive tests (on 540 men) that were included in the study:
Canonical relations of morphological characteristics and intellectual abilities

Thanks!

sgm2010 Tue Dec 21, 2010 2:02 pm

Thanks for this reply Martin. Will read through the link you've given.

Now I know what I've suspected all along. It's my brain that's the problem.

Martijn,

A followup question: For the width, I took the measurement from the crease where the thumb joins the palm to the opposite edge of the palm (Moon mount edge). I drew an imaginary line between these two points parallel to the rascettes and measured that dimension.

Is this correct ?

**Martijn (admin)** Tue Dec 21, 2010 2:18 pm

sgm2010 wrote:A followup question: For the width, I took the measurement from the crease where the thumb joins the palm to the opposite edge of the palm (Moon mount edge). I drew an imaginary line between these two points parallel to the rascettes and measured that dimension.

Is this correct ?

Hello sgm2010,

Your follow-up question is essential!

Sounds like you have not used the correct method in your first effort, so I can only advice to measure your 'hand width' (you can take the average of both hands) as described by the picture below.

NOTICE: As far as I know in all scientific studies 'hand width' is measured at the metacarpals just below the fingers (you should strive for finding the smallest palm width in that particular palmar zone).

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Hand-w10

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Hand-w10

sgm2010 Wed Dec 22, 2010 2:04 am

I did take a fresh measurement as shown in the diagram. The width is aprrox. bet. 3.1 and 3.2. So that's makes my hand index about 4.36 - 4.5. Probably average ?

Phew...that's a relief !!!

Thanks Martijn.

**Martijn (admin)** Wed Dec 22, 2010 2:42 am

Hello sgm2010,

Okay, thanks for your feedback... and it Iooks like my picture became helpful for you to make a more precise measurement. Great!

Smile

**Martijn (admin)** Wed Aug 01, 2012 1:41 am

... I wonder what will become visible when 'hand index' is mapped in a chart against 'finger length index' (as defined in the chart below)???

(Beause the 'hand index' gives an impression of the palm breadth compared to finger length and palm length together, while the 'finger length index' gives an impression of finger length relative to palm length + palm breadth... so it must result in a completely different chart compared to when fl/pb gets mapped to fl/pl)

Anyway, a new article about finger length differences between men and women (around the world) is now available here:
http://www.handresearch.com/diagnostics/sexual-dimorphism-finger-length-males-females-gender-differences.htm

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Finger-length-variations-males-females

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands' Finger-length-variations-males-females

**Martijn (admin)** Wed Aug 01, 2012 3:57 pm

Martijn (admin) wrote:
... I wonder what will become visible when 'hand index' is mapped in a chart against 'finger length index' (as defined in the chart below)???

The answer is simple: the result sort of looks the same as in the chart above (with changed position for the axes).

By the way, for recognizing gender via 'hand index' or 'finger length index' the results are similar (and my picture shows that combining both indices does produce a slightly better result, but the Japanese male sample continues to be positioned close to the female average of all 6 populations).

But it looks like combining the '2D:4D digit ratio' with the 'finger length index' produces a formula which is highly discriminating measure for gender in individuals.... because then all 6 male populations would have lower (average) scores for the 'finger length index + 2D:4D digit ratio' measure than the 6 female populations!

(Regarding combining the 'finger length index' + '2D:4D digit ratio': scores lower than 1.40 are typical for males - with an average close to 1.38; and higher scores are typical for females - with an average close to 1.42)

Patti Wed Aug 01, 2012 4:05 pm

.459

7.9/17.2 right hand

**Martijn (admin)** Wed Aug 01, 2012 4:14 pm

Patti wrote: .459

7.9/17.2 right hand

Hi Patti,

I assume that your '0.459' is referring to your hand index? (EDIT 2: Well, actually... your hand index is then 45.9, which on it's self is sort of a more masculine feature than a feminine feature - because values above 44.0 are typical for males... though the numbers for Americans indicate that the average female 'hand index' is 44.00, so this partly explains your relatively higher value)

However, I would like to invite you to add your '2d:4d digit ratio' on top of your 'finger length index' value (= fl/(pb+pl)... and I expect that you hand then clearly belongs to the female category.

(In my former post I described how combining both indices will typically result in higher values for females: higher than 1.40, with an average of about 1.42... while the male average is proprobably to 1.38)

I hope this makes sense?

wave

EDIT: PS. Combining the 'hand index' with '2d:4d digit ratio' would require to distract both measures (because the 'hand index' gets larger for smaller 'finger length index' values)... so one can not replace the 'hand index' for the 'finger length index' in the formula which I described in my former post.

Patti Wed Aug 01, 2012 4:26 pm

Martijn (admin) wrote:
Patti wrote: .459

7.9/17.2 right hand

Hi Patti,

I assume that your '0.459' is referring to your hand index? (EDIT 2: Well, actually... your hand index is then 45.9, which on it's self is sort of a more masculine feature than a feminine feature - because values above 44.0 are typical for males... though the numbers for Americans indicate that the average female 'hand index' is 44.00, so this partly explains your relatively higher value)

However, I would like to invite you to add your '2d:4d digit ratio' on top of your 'finger length index' value (= fl/(pb+pl)... and I expect that you hand then clearly belongs to the female category.

(In my former post I described how combining both indices will typically result in higher values for females: higher than 1.40, with an average of about 1.42... while the male average is proprobably to 1.38)

I hope this makes sense?

EDIT: PS. Combining the 'hand index' with '2d:4d digit ratio' would require to distract both measures (because the 'hand index' gets larger for smaller 'finger length index' values)... so one can not replace the 'hand index' for the 'finger length index' in the formula which I described in my former post.

No. How do you 'combine' the 2D:4D?

**Martijn (admin)** Wed Aug 01, 2012 5:45 pm

Patti wrote:
Martijn (admin) wrote:
Patti wrote: .459

7.9/17.2 right hand

Hi Patti,

I assume that your '0.459' is referring to your hand index? (EDIT 2: Well, actually... your hand index is then 45.9, which on it's self is sort of a more masculine feature than a feminine feature - because values above 44.0 are typical for males... though the numbers for Americans indicate that the average female 'hand index' is 44.00, so this partly explains your relatively higher value)

However, I would like to invite you to add your '2d:4d digit ratio' on top of your 'finger length index' value (= fl/(pb+pl)... and I expect that you hand then clearly belongs to the female category.

(In my former post I described how combining both indices will typically result in higher values for females: higher than 1.40, with an average of about 1.42... while the male average is proprobably to 1.38)

I hope this makes sense?

EDIT: PS. Combining the 'hand index' with '2d:4d digit ratio' would require to distract both measures (because the 'hand index' gets larger for smaller 'finger length index' values)... so one can not replace the 'hand index' for the 'finger length index' in the formula which I described in my former post.

No. How do you 'combine' the 2D:4D?

Patti, you can do that by simply summarizing your 'finger length index' with your 2D:4D digit ratio (for your left hand: digit ratio is close to 0.97, 'finger length index' is close to 0.43, combined the result is: 1.40 - which is at the borderline between masculine hand-finger shape and femine hand-finger shape).

I think this application for combining hand shape with digit ratio could become a very interesting topic... with potential practical purposes (for example as a measure for the 'masculinity' factor, because both the hand shape and finger length ratio do not represent a reliable measure in isolation).

I will see if I can present a picture with all necessary guidelines.

Patti Wed Aug 01, 2012 6:40 pm

Martijn (admin) wrote:
Patti wrote:
Martijn (admin) wrote:
Patti wrote: .459

7.9/17.2 right hand

Hi Patti,

I assume that your '0.459' is referring to your hand index? (EDIT 2: Well, actually... your hand index is then 45.9, which on it's self is sort of a more masculine feature than a feminine feature - because values above 44.0 are typical for males... though the numbers for Americans indicate that the average female 'hand index' is 44.00, so this partly explains your relatively higher value)

However, I would like to invite you to add your '2d:4d digit ratio' on top of your 'finger length index' value (= fl/(pb+pl)... and I expect that you hand then clearly belongs to the female category.

(In my former post I described how combining both indices will typically result in higher values for females: higher than 1.40, with an average of about 1.42... while the male average is proprobably to 1.38)

I hope this makes sense?

EDIT: PS. Combining the 'hand index' with '2d:4d digit ratio' would require to distract both measures (because the 'hand index' gets larger for smaller 'finger length index' values)... so one can not replace the 'hand index' for the 'finger length index' in the formula which I described in my former post.

No. How do you 'combine' the 2D:4D?

Patti, you can do that by simply summarizing your 'finger length index' with your 2D:4D digit ratio (for your left hand: digit ratio is close to 0.97, 'finger length index' is close to 0.43, combined the result is: 1.40 - which is at the borderline between masculine hand-finger shape and femine hand-finger shape).

I think this application for combining hand shape with digit ratio could become a very interesting topic... with potential practical purposes (for example as a measure for the 'masculinity' factor, because both the hand shape and finger length ratio do not represent a reliable measure in isolation).

I will see if I can present a picture with all necessary guidelines.

Thanks! It's interesting to think about my hand having masculine ratios. In high school I was placed in advanced science and math classes which are more male dominated, especially the time period I attended school. Later in other tests related to entrance to the military, I scored highest scores to that date in the unit I was in and I was their first female. Same time period I played competitive chess at cafes. Yet emotionally and in appearance I'm very obviously feminine.

**Martijn (admin)** Wed Aug 01, 2012 8:34 pm

Hi Patti, thanks for sharing that. Interesting!

(Regarding the military: quite fascinating to hear that you have been employed in that profession for some time)

By the way, regarding the '1.40 borderline' that I mentioned... I have done some further study and found that the borderline for the combined measure (digit ratio + finger length index) should be estimated at 1.385 (because the six international populations that I have studied so far show that all average scores are for the males are 1.381 or lower, and for the females 1.389 or higher - for US females I found an average score of 1.408 and for US males score is 1.374).

So, this implicates that in this combined measure your score is on the feminine side.

(I will make some efforts in order to see if this '1.385 borderline' works as well regarding the averages for males and females in other countries)

**Martijn (admin)** Fri Aug 03, 2012 12:35 am

(I have tried to find hand anthropometry data for populations from other countries than China, Japan, India, Turkey, UK and the US; I only found useful data for people from Malaysia... which confirms that the 1.385 might work well.

Interestingly, the Malaysian data also indicated that the 'hand index' is far above 0.44 for Malasian men and women - and I found another study for Malasian elderly which confirmed that. So, it looks like the combination of the 'finger length index' + '2D:4D digit ratio' is a more accurate discriminator that the combi 'hand index' + '2D:4D digit ratio'.

To be continued!)

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

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Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

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Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

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Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'

Re: DISSERTATION STUDY: 'An Analysis of the Sexual Dimorphism of Hands'