- Published: 12 march 2014 -

Extraversion hand chart: 6 vertical factors.

- Extraversion Hand Chart: click HERE to see larger version -

Extraversion Hand Chart:

Six 'vertical' hand factors identified in Dutch study!

A breakthrough is reported here for the assessment of the Big Five personality dimension Extraversion through the hand. In this study 6 factors have been identified which all point towards a different set of 'vertical' patterns inside the hands of extraverts & introverts. A weighted combination of these 6 hand factors made it possible to present a histogram (resulting from a regression analysis) producing a success-score of 95.8% regarding the separation of a sample of extraverts (N=27) from a sample of introverts (N=21); the effect-size of this major result is found to be almost as large as the effect-size seen for the typical 'hand size' difference between males and females. An even higher success-score of 97.9% was found by using an additional control-mechanism.

The 6 hand factors involve three proportion ratios (finger length vs. palm breadth ratio, triradial ab vs ad ratio, and hypothenar vs. thenar ratio) & three aspects of the 2 major palmar transverse lines (disconnection of radial/proximal transverse line, twin line between both transverse lines, and curve of ulnar/distal transverse line). The results indicate that extroverts typically have a prominent set of features at the ulnar side of the hand (manifesting as: ulnar '+' factors & radial '-' factors), while introverts typically have a prominent sent of features at the radial side of the hand (manifesting as: ulnar '-' factors & radial '+' factors).

An 'Extroversion Hand Chart' is presented describing the typical 'vertical' hand patterns in extraverts & introverts (see the HAND CHART at the top- and bottom of this article). Additionally, a concept-chart has been developed, which illustrates how these typical 'vertical' tendencies can be understood in the perspectieve of various biological principles plus some typical male-female differences inside the hand.

Extraversion histogram: 6 hand factors. Concept for how to idenitify extraverts & introverts via the hand: a vertical approach to the hand.


EXTRAVERSION & THE HAND - CONTENTS:

- Research method & results:
• I - Extraversion & the hand: research method!
• II - Extraversion & the hand: 6 vertical hand factors!
• III -Extraversion & the hand: other hand factors!

- Background info & the hand reading literature:
• A - Extraversion & the Big Five model
• B - Extraversion defined by detail: 6 facets [according NEO PI-R]
• C - Extraversion fluctuates around the world
• D - Extraversion in the hand reading literature!






I - Extraversion & the hand: research method!

 The results presented here relate to the hands of 48 Dutch people: 27 extraverts + 21 introverts (including: 34 females & 14 males) - who were selected by age (19-54), ethnicity (white), IQ (above average) and high/low scores on the Extraversion dimension of the Dutch version of the NEO PI-R personality questionnaire. All materials were collected in 1997/1998, and all results are based on average measurements/assessments for both hands of each subject.

In a preceeding pilot-study 6 hand factors had been identified featured with strong, consistent results for both the male- and female group. The present study presents results for more hand factors, and from this larger sample of hand factors the 6 most significant hand factors have been identified/selected in order to study the theme 'Extraversion & the hand' by detail.

For each hand factor correlation results have been examined for the Big Five personality dimension Extraversion (extraverts vs. introverts compared) & sexe (males vs females compared). Then for the 6 most significant hand factors a regression analysis is presented with resulting histogram, which describes how many extraverts & introverts can be discriminated from each other with. Finally, an analysis of the results is used to produce a concept-chart describing how the 'vertical' sides of the hand vary between extraverts and introverts (+ how the quadrants vary between males and females).


II - Extraversion & the hand: 6 vertical hand factors!


 Extraversion hand chart: 6 vertical factors.

- Extraversion Hand Chart: click HERE to see larger version -

 The picture above describes the 6 hand factors which have produced the most significant result presented in this study (guidelines for the assessment of these indiviual hand factors are presented below the chart at the bottom of this article).

Table 1 below describes Pearson correlation coëfficients for these 6 hand factors with the Big Five personality dimension Extraversion (extraverts vs. introverts) & sexe (males vs. females). These 6 hand factors together represent a constellation that is highly significant for discriminating extraverts (N=27) & introverts (N=21) via the hand, which will be demonstrated below.


Table 1: Pearson correlation coëfficients for 6 hand factors with Extraversion & sexe.

Pearson Correlation Extraversion
(Introverts vs. Extraverts) 		Sexe
(Females vs. Males)
Factor 1:
Finger length to
palm width ratio
-0,378***
Females
-0,491*** 		Males
-0.300
-0,352***
Factor 2:
Triradial
ab vs. ad ratio
-0,400***
Females
-0,379** 		Males
-0.467**
-0,025
Factor 3:
Twin line between
transverse lines
-0,376***
Females
-0,422** 		Males
-0.277
-0,005
Factor 4:
Proximal transverse line
(dis)connection
-0,268**
Females
-0,332** 		Males
-0.102
-0,018
Factor 5:
Upper transverse line
curve / simian line
+0,356***
Females
+0,291** 		Males
+0.589**
+0,003
Factor 6:
Hypothenar vs.
thenar ratio
+0,377***
Females
+0,292** 		Males
+0.536**
-0,339***

* = sign. at p<0.10, ** = sign. at p<0.05, *** = sign. at p<0.01


The right column in table 1 show that various of these 6 hand factors correlate significantly with sexe. Therefore it became necessary to make a regression analysis for males and females seperately (in order to discriminate the extraverts from the introverts effectively!).

The best result was found resulting from a regression analysis focussed on the females only (the resulting female success-score = 94.1%); however, when a score of -0.5 is added to the male-scores then this (female-based) regression formula also produces a perfect result for the males (the resulting male success-score = 100%).

After adding -0.5 to the score of the individual males, the regression formula presented below produced a success-score of 95.8% for the studied population (leaving only two female introverts assessed incorrectly as 'false-extraverts'):

Extraversion-handfactor regression formula:

11.954 - (8.791 x A) - (7.499 x B) - (1.862 x C) - (0.124 x D) + (0.269 x E) + (0.094 x F)

A = finger length to palm width ratio [w = 26%];
B = triradial ab vs. ad ratio [w = 21%];
C = twin line between transverse lines (= head line + heart line) [w=20%];
D = proximal transverse line (= head line) (dis)connection [w = 7%];
E = distal transverse line (= heart line) curve / simian line [w = 18%];
F = hypothenar vs. thenar ratio [w = 8%].

NOTICE: W = indicative weight for the individual hand factor, the 6 factors together make a weight of 100%; interestingly, on top of the 'vertical' aspects the weights suggest that the hand factors associated with the distal-part of the hand (fingers + upper palm) have more weight than the hand factors associated with the proximal-part of the hand!


The histogram below displays the distribution of scores resulting from this 'Extraversion-handfactor regression formula' for the 21 introverts and the 27 extraverts (+ with featured below a distribution for the male- and female sub-population seperately). The results of the 'Extraversion-handfactor regression formula' produce a Pearson correlation result of +0,765 (sign. at p<0.001); the effect-size of this major result is found to be almost as large as the effect-size seen for the typical 'hand size' difference between males and females (see: hand factor 7 which is described in the next paragraph).


Histogram describing the distribution of scores resulting from the 'Extraversion-handfactor regression formula' for the introverts (N=21) & extraverts (N=27); click HERE to see a larger version of the picture.

Extraversion histogram: 6 hand factors.


For the purpose of illustration, the pictures below present in respective: (1) handprint samples from an extravert + an introvert, plus (2) a visual impression of how Extraversion personality scores & -handfactors scores may vary inside a single family.


- Handprints of an 'extravert' & an 'introvert': click HERE to see larger version -

 The hand print of an extravert + the handprint of an introvert.


- Extraversion family study: click HERE to see larger version -

 Extraversion family study.


Finally, a control-mechanism was developed (details are not shared in this report) with the use of two regression result analyses based on two groups of the most strongly connected hand factors, plus an additional analysis focussed on scores 'beyond standard deviation' for the six individual hand factors. This alternative more detailed analysis made it possible to use these as a control-mechanism on top of the 'Extraversion-handfactor regression formula'; it even became possible to idenitify why one of the two 'false-extraverts' was assessed incorrectly as an extravert through the 'Extraversion regression formula', because both aspects of the control mechanism together present a double contra-indicator for the result of the regression formula in one of these 'false-extraverts', while a double-contra-indicator was not seen in any of the other 47 subjects!

When this control-mechanism is applied on top of the 'Extraversion-handfactor regression formula' it became therefore even possible to produce a success-score of 97.9% (still based on only the 6 'vertical' hand factors); leaving only one single (female) introvert to be assessed as a 'false-extravert', while all other introverts & extroverts became assessed correctly by combining the 'Extraversion-handfactor regression formula' with the control-mechanism.

Because of these impressive results (success-scores varying from 95.8% tot 97.9%) it became a sensible opportunity to develop a concept-chart that describes how all 6 'vertical' hand factors together manifest in a pattern of hand-dynamics that provides a better understanding how the Big Five personality dimension Extraversion tends to become manifest inside the morphology & structure of the hand.

The concept-chart displayed below describes how vertical patterns of hand dynamics - related to (1) vertical hand shape proportions [= hand factors 1, 2 & 6] and (2) the two major transverse creases [= hand factors 3, 4 & 5] - tend to correlate with the Big Five personality dimension Extraversion.

Additionally, the concept-chart also displays how the 4 quadrants vary with sexe: males tend to have a more dominant upper ulnar & lower radial quadrants, while females tend to have more dominant upper radial & lower ulnar quadrants!

NOTICE: In the next paragraph various results will be presented for six other hand factors; special attention should be directed at the '2d:4d digit ratio', because it's results provide additional support for the pattern of 'vertical' hand dynamics described by the picture below!


Concept for how to idenitify extraverts & introverts: a vertical approach to the hand; click HERE to see a larger version of the picture.

Concept for how to idenitify extraverts & introverts via the hand: a vertical approach to the hand.


III - Extraversion & the hand: other hand factors!

 Beyond the 6 'vertical' hand factors that have produced the most significant results in this study, results are presented for another set of 6 hand factors [= hand factor 7 to 12] in table 2 below. These results are presented seperately because a statistical analysis has pointed out that in the studied sample of individuals none of these additional 6 hand factors contributes an effect to the combination of the first 6 (vertical) hand factors.

Table 2 e.g. describes that hand index (= hand factor 8), palm length vs. palm width (= hand factor 10), and 2d:4d digit rato (= hand factor 12) correlate significantly with Extraversion. 2d:4d digit rato provides additional support for the concept-chart presented in the previous paragraph.

The right column in table 2 describes how hand size & palm size correlate significantly with sexe; which perfectly makes sense in the perspective of the fact that males tend to have larger bodies (and thus larger hands) than females. Also, in the studied sample 2d:4d digit ratios turns out to be lower in males, which confirms the sexe-stereotypical result that is usually reported in 2d:4d digit ratio studies around the world (males typically tend to have slightly lower 2d:4d digit ratios than females, which reflects prenatal hormonal oestrogen-testosterone balance).

Additionally, one can take notice of the fact that the largest effect-sizes of the individual hand factors regarding Extraversion (highest correlation is significant at p<0.01) is much smaller than the largest effect-size regarding sexe (highest correlation is significant at p<0.001). This illustrates how subtile the differences in the hands of extraverts and introverts really are: assessing the 'sexe' of an individual from the hand is much more easy than assessing the Big Five dimension Extraversion from the hand!

NOTICE: The final 4 paragraphs A to D only provide additional background info related to this study.


Table 2: Pearson correlation coëfficients for 6 hand factors with Extraversion and Sexe.

Pearson Correlation Extraversion
(Introverts vs. Extraverts) 		Sexe
(Females vs. Males)
Factor 7:
Hand size
[= (finger length + palm length)
x palm width]
-0,042
Females
+0,010 		Males
+0.098
+0,790****
Factor 8:
Hand index
[= palm width /
(finger length + palm length)]
+0,335**
Females
+0,428*** 		Males
+0.256
+0,289**
Factor 9:
Palm size
[= palm length x palm width]
-0,033
Females
+0,025 		Males
+0.103
+0.793****
Factor 10:
Palm length vs.
palm width ratio
-0,255**
Females
-0,309** 		Males
-0.197
-0,190*
Factor 11:
Finger length vs.
palm length ratio
-0,052
Females
-0,066 		Males
-0.048
+0,003
Factor 12:
d2:d4 ratio
-0,189*
Females
-0,109 		Males
-0.510**
-0,274**

* = sign. at p<0.10, ** = sign. at p<0.05, *** = sign. at p<0.01, **** = sign. at p<0.001




Personality according the Big Five dimensions: subdimensions.

Big Five dimensions + 30 accessory facets according NEO PI-R personality inventory.
A - Extraversion & the Big Five model

 In the 2nd half of the 20 century various independent personality researchers have concluded that human personality can best be described using five broad factors. This explains why during the past few decades the Big Five factors (e.g. described by Costa & McCrae, 1985) became recognized as representing the standard in academic psychology today.

Despite that most people can best be described as 'ambiverts', the dimension Extraversion-Introversion is generally considered as a key-dimension of human personality. The terms 'extraversion' and 'introversion' were first popularized by Carl Jung (1913) and became later included in many personality theories; today some speak even about the so-called 'extravert ideal' (a term recently introduced in 2012 by American author Susan Cain).


The Big Five factors are:

Extraversion - Neuroticism - Conscientiousness
Agreeableness - Openness to Experience


 Costa & McCrae's BIG FIVE dimensions: Extraversion, Neuroticism, Openness, Agreeableness, Conscientiousness.

Wondering about your Big Five personality profile? There are various credible online Big Five online tests available (IPI NEO, Atof Inc. Big Five inventory); the picture below presents 2 Big Five profiles resulting from the BBC Big Five test

NOTICE: 'low' scores for Extroversion can be associated with introversion; 'medium' scores with ambiversion; and 'high' scores with extraversion.

Two BBC Big Five test profile results.

 BBC test Big Five profiles.



B - Extraversion defined by detail: 6 facets [according NEO PI-R] -

 The verb 'extraversion' has become an element in the daily lives of many people, but sometimes it appears as if individuals tend to atribute different meaning to the word. This is probably due to the various associations with the verb in different contexts.

The terms 'introversion' and 'extraversion' were first popularized by psychologist Carl Gustav Jung (after Freud had adopted the terms in his 'libido' psychology); however, both the popular understanding and psychological usage differ from his original intent!

The trait-dimension of 'extraversion-introversion' is now known as a central dimension of human personality theories:

Extraversion tends to be manifested in outgoing, talkative, energetic behavior, whereas introversion is manifested in more reserved, quiet, shy behavior. Virtually all comprehensive models of personality have adopted these concepts in various forms; the most well-known examples are: the Big Five model, Jung's analytical psychology, Hans Eysenck's three-factor model, Raymond Cattell's 16 personality factors, the Minnesota Multiphasic Personality Inventory, and the Myers Briggs Type Indicator.

The picture below presents an overview of six facets of Extraversion according the Big Five model (inside the NEO PI-R personality inventory each facet is measured through eight multiple-choice questions).

Six facets of extraversion: introverts - ambiverts - extraverts.


NOTICE: "Although many people view being introverted or extroverted as a question with only two possible answers, most contemporary trait theories measure levels of extraversion-introversion as part of a single, continuous dimension of personality, with some scores near one end, and others near the half-way mark. Ambiversion is a term used to describe people who fall more or less directly in the middle and exhibit tendencies of both groups. An ambivert is normally comfortable with groups and enjoys social interaction, but also relishes time alone and away from the crowd." (cited from Wikipedia)


Susan Cain’s definition is that introverts have a preference for a quiet, more minimally stimulating environment.


In 2012 Susan Cain's argues in her bestseller, 'Quiet: The Power of Introverts in a World That Can't Stop Talking', how modern Western culture misunderstands and undervalues the traits and capabilities of introverted people, leading to "a colossal waste of talent, energy, and happiness." Cain defines the introvert-extrovert spectrum in terms of preferences for different levels of stimulation. Her definition for Introversion is: "introverts have a preference for a quiet, more minimally stimulating environment" (see also picture above).


C - Extraversion fluctuates around the world

 Extraversion around the world. Studies around the world have indicated that the distribution of mean Extraversion factor scores fluctuates around the world - see pictures (McCrae, 2004; 23andMe, 2011; MyPersonality, 2008).

The data reveals that people from Europe & US tend to score higher for Extraversion than people from Asia (Allik & McCrae, 2004).

Extraversion map Europe. Extraversion map US.



D - Extraversion concepts inside the hand reading literature!

 What does the hand reading literature report about extraversion/introversion?

Various authors have presented attempts to define 'extraversion' and/or 'introversion' through a combination of hand characteristics:


PDC Chirologist Arnold Holtzman



Arnold Holtzman:

* 'Applied Hand Reading' (1983):

• page 41:
- EXTRAVERTS: hard hands;
- INTROVERT: soft hands;
• page 68/69:
- EXTRAVERSION: flattened lower part of hypothenar (mount of moon);
• page 69:
- INTROVERSION: swelled lower hypothenar (mount of moon) and dropping into the wrist.

* 'Psychodiagnostic Chirology in Analysis and Therapy' (2004):

• page 41:
- EXTRAVERT: an extrovert formula would be the rule when the life instinct (area just below the point of origin of the upper transverse crease) is the driving influence;
- INTROVERT: an introvert formula would be the rule when the death instinct (= pronounced plunge of the hypothenar eminence into the wrist) holds sway over an individual's program of survival;
• page 68:
- EXTRAVERT: hard hand;
- INTROVERT: soft hand.


Chirologist Johnny Fincham



Johnny Fincham:

* 'The Spellbinding Power of Palmistry' (2005):

• page 37
- EXTRAVERT: thumb angle: 90 degrees;
- INTROVERT: thumb angle: 20 degrees or less;
• page 42:
- INTROVERT: all fingers leaning to little finger side;
• page 113:
- INTROVERT: fragmented girdle of venus;
• page 117:
- INTROVERT: very strong sun/apollo line.

* 'Palmistry: From Apprentice to Pro in Twenty-Four Hourse' (2007):

• page 197
- INTROVERT: closed fingers tightly together; skin quality: either silk or course; lines: faint and fine or thick and trench-like; head line: curves deeply (downward);
• page 198:
- INTROVERT: head line: tied to vitality line; long 2nd finger;
-EXTRAVERT: 'naturally hold their fingers wide spread'; 4th finger: long; head line: straight; lines: strong and bold; large gap between head line and life line.

NOTICE: It's rather remarkable that in the perspective of Extraversion/Introversion Fincham appears to talk about completely different hand features in each of his books.


Palmist Nathaniel Altman




Nathaniel Altman:

* 'Sexual Palmistry' (1986):

• page 20:
- EXTRAVERT: spatulate hands;
• page 67:
- INTROVERSION: small, deficient lower mount of mars;
• page 80
- EXTRAVERSION: head line seperate from life line;
• page 132:
- EXTRAVERSION: angle between index finger and thumb;
• page 137:
- EXTRAVERSION: flexible hands, generous thumb.



 NOTICE: The concepts listed above raise the question whether these are supported by the findings reported inside this Extraversion-study?

Fincham's references to a 'long 2nd finger' in introverts and a 'long 4th finger' in extraverts provides direct support for the 2d:4d digit ratio findings. However, all three authors appear to have described at least one concept that is actually contradicted by the reported results. But maybe it is even more worth mentioning that it is stricking to see that the overlap between the concepts used by these authors is not very large; so this might indicate that untill recently there was not much common agreement inside the hand reading literature about how the dimension trait 'extraversion-introversion' tends to manifests inside the hand! Therefore the new research findings presented inside this report (e.g. featured with success-scores reported varying from 94.1% for the larger sample of females to 100.0% for the smaller sample of males) present a solid new basis!




Extraversion Hand Chart: 6 typical hand signs in extraverts & introverts (+ expected hand signs in ambiverts);
this combination produced a discriminative success-score of 95.8% in 27 Dutch extraverts and 21 Dutch introvert.

- Full size picture available: HERE -

Phantom hands describing hand signs for extraversion / introversion.


- Appendix: Guidelines for the assessment of the six individual 'vertical' hand factors (+ more results) -


• Hand factor 1 - 'finger length vs. palm width ratio':

This hand factor requires a measurement of (1) the length of the middle finger [from tip to the crease that separates this finger from the palm], and (2) the palm width [shortest distance measured at the metacarpals]; then the ratio of both measurements is used (finger length quotient to palm width); take the average score of both hands.

Inside the studied Dutch sample scores vary for hand factor 1 from +0.94 to +1.13, with an average value of +1.029 featured with a standard deviation of 0.043; average values for the sub-populations => extraverts: +1.015, introverts: +1.048, males: +1.006, females: +1.039.

• Hand factor 2 - '(triradial) ab vs. ad ratio':

This hand factor relates to the palmar triradii below the index finger (= triradius a), middle finger (= triradius b), and pinky finger (= triradius d). the distance between triradius a and triradius b (= ab) is measured, and the distance between triradius a and triradius d (= ad) is measured; then the ratio of both measurements is used (distance ab quotient to distance ad); take the average score of both hands.

Inside the studied Dutch sample scores vary for hand factor 2 from +0.29 to +0.53, with an average value of +0.426 featured with a standard deviation of 0.046; average values for the sub-populations => extraverts: +0.410, introverts: +0.447, males: +0.424, females: +0.427.

• Hand factor 3 - 'Twin line between transverse lines (= head line + heart line)':

This hand factor requires an assessment regarding the presence of an incomplete extra transverse crease between both transverse creases; optional assessement scores are: 0 = twin line is missing, 1/2 = doubtful or presence of a very small twin line, 1 = twin line is present; take the average score of both hands.

Inside the studied Dutch sample scores vary for hand factor 3 from 0 to +0.5, with an average value of +0.047 featured with a standard deviation of 0.143; average values for the sub-populations => extraverts: +0.000, introverts: +0.107, males: +0.357, females: +0.512.

• Hand factor 4 - 'Proximal transverse line (= head line) disconnection':

This hand factor requires an assessment regarding the radial termination of the proximal transverse line (a.k.a. the head line); optional assessement scores are: 0 = long connection, 1 = doubtful/very short connection, 2 = no connection; take the average score of both hands.

Inside the studied Dutch sample scores vary for hand factor 4 from 0 to +2.0, with an average value of +0.594 featured with a standard deviation of 0.797; average values for the sub-populations => extraverts: +0.407, introverts: +0.833, males: +0.571, females: +0.603.

• Hand factor 5 - 'Distal transverse line (= heart line) curve / simian line':

This hand factor requires an assessment regarding the curve of the distal transverse line (a.k.a. the heart line); optional assessement scores are: 0 = simian line, 1 = flat curve + simian line branch, 2 = flat curve or normal curve with a simian line branch, 3 = normal curve, 4 = strong/abrupt upward curve; take the average score of both hands.

Inside the studied Dutch sample scores vary for hand factor 5 from 0 to +4.0, with an average value of +2.531 featured with a standard deviation of ???; average values for the sub-populations => extraverts: +2.???, introverts: +2.???, males: +2.???, females: +2.???.

• Hand factor 6 - 'Hypothenar (= mount of moon) vs. thenar (= mount of venus) ratio':

This hand factor requires an assessment of the developement of the hypothenar (a.k.a. mount of moon) relative to the thenar (a.k.a. mount of venus). For the hypothenar the upper- and lower part needs to be assessed seperately. Also, it is important to be aware that the thenar tends to have a natural tendency to manifest slightly more pronounced because of the muscules involved with thumb movement; so, when a hypothenar appears to have a likewise development to the thenar this usually means that the hypothenar is 'overdeveloped' (compared to the thenar).

The scores attributed to the individual parts (thenar, upper hypothenar & lower hypothenar) vary from: +1 (= excessive development), 0 (= normal development), and -1 (= weak development). The assessment score is then found by first summarizing the upper hypothenar score and the lower hypothenar score, and then substract the thenar score twice; take the average score of both hands (assessment scores can vary between -4 and +4).

Inside the studied Dutch sample scores vary for hand factor 6 from -3.5 to +4.0, with an average value of -0.063 featured with a standard deviation of 1.315; average values for the sub-populations => extraverts: +0.037, introverts: -0.619, males: -0.750, females: +0.221.



Finger length index: extraverts versus introverts (+ international averages for males and females). De 'dots'
show that the finger length variation between introverts and extraverts are larger regarding palm breadth
than palm length - which indicates that in this perspective the 'hand index' is probably the best discriminator!

Finger length index: extraverts versus introverts.

You might want to explore hand charts for the Big Five personality dimensions:
Agreeableness, Conscientiousness, Extraversion & Neuroticism!


Martijn van Mensvoort - Hand Research

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