Palmistry, or chiromancy (also spelled cheiromancy; from Greek kheir (χεῖρ, ός; “hand”) and manteia (μαντεία, ας; “divination”)), is the claim of characterization and foretelling the future through the study of the palm, also known as palm reading or chirology. The practice is found all over the world, with numerous cultural variations. Those who practice chiromancy are generally called palmists, palm readers, hand readers, hand analysts, or chirologists.
The belief behind Palmistry is that the hand mirrors the individual by measuring the following characteristics:
- Interactions with others
The information outlined below is briefly representative of modern palmistry; there are many ― often conflicting ― interpretations of various lines and palmar features across various schools of palmistry. These contradictions between different interpretations, as well as the lack of empirical support for palmistry’s predictions, contribute to palmistry’s perception as a pseudoscience among academics.
According to some, it had its roots in Hindu Astrology (known in Sanskrit as Jyotish), Chinese Yijing (I Ching), and Roma (Gypsy) fortune tellers. Several thousand years ago, the Hindu sage Valmiki is thought to have written a book comprising 567 stanzas, the title of which translates in English as “The Teachings of Valmiki Maharshi on Male Palmistry”. From India, the art of palmistry spread to China, Tibet, Egypt, Persia and to other countries in Europe. From China, palmistry progressed to Greece whereAnaxagoras practiced it. Aristotle (384–322 B.C.E.) discovered a treatise on the subject of palmistry on an altar of Hermes, which he then presented to Alexander the Great (356–323 B.C.E.), who took great interest in examining the character of his officers by analyzing the lines on their hands. Aristotle stated that “Lines are not written into the human hand without reason. They emanate from heavenly influences and man’s own individuality.”[this quote needs a citation] Accordingly, Aristotle, Hippocrates and Alexander the Great popularized the laws and practice of palmistry. Hippocrates sought to use palmistry to aid his clinical procedures.
During the Middle Ages the art of palmistry was actively suppressed by the Catholic Church as pagan superstition. In Renaissance magic, palmistry (known as “chiromancy”) was classified as one of the seven “forbidden arts,” along with necromancy, geomancy, aeromancy, pyromancy, hydromancy, and spatulamancy (scapulimancy).
It experienced a revival in the modern era starting with Captain Casimir Stanislas D’Arpentigny publication La Chirognomie in 1839.
The Chirological Society of Great Britain was founded in London by Katherine St Hill in 1889 with the stated aim to advance and systematise the art of palmistry and to prevent charlatans from abusing the art. Edgar de Valcourt-Vermont (Comte de St Germain) founded the American Chirological Society in 1897.
A pivotal figure in the modern palmistry movement was the Irish William John Warner, known by his sobriquet, Cheiro. After studying under gurus in India he set up a palmistry practice in London and enjoyed a wide following of famous clients from around the world, including famous celebrities like Mark Twain, W. T. Stead, Sarah Bernhardt, Mata Hari, Oscar Wilde, Grover Cleveland, Thomas Edison, the Prince of Wales, General Kitchener, William Ewart Gladstone, and Joseph Chamberlain. So popular was Cheiro as a “Society Palmist” that even those who were not believers in the occult had their hands read by him. The skeptical Mark Twain wrote in Cheiro’s visitor’s book that he had “…exposed my character to me with humiliating accuracy.”
Edward Heron-Allen, an English polymath, published various works including the 1883 book, Palmistry – A Manual of Cheirosophy which is still in print. There were attempts at formulating some sort of scientific basis for the art, most notably in the 1900 publication “The Laws of Scientific Hand Reading” by William G. Benham.
Chiromancy consists of the practice of evaluating a person’s character or future life by “reading” the palm of that person’s hand. Various “lines” (“heart line”, “life line”, etc.) and “mounts” (or bumps) (chirognomy) purportedly suggest interpretations by their relative sizes, qualities, and intersections. In some traditions, readers also examine characteristics of the fingers, fingernails, fingerprints, and palmar skin patterns (dermatoglyphics), skin texture and color, shape of the palm, and flexibility of the hand.
A reader usually begins by reading the person’s ‘dominant hand’ (the hand he or she writes with or uses the most, which is sometimes considered to represent the conscious mind, whereas the other hand is subconscious). In some traditions of palmistry, the other hand is believed to carry hereditary or family traits, or, depending on the palmist’s cosmological beliefs, to convey information about past-life or karmic conditions.
The basic framework for “Classical” palmistry (the most widely taught and practiced tradition) is rooted in Greek mythology. Each area of the palm and fingers is related to a god or goddess, and the features of that area indicate the nature of the corresponding aspect of the subject. For example, the ring finger is associated with the Greek god Apollo; characteristics of the ring finger are tied to the subject’s dealings with art, music, aesthetics, fame, wealth, and harmony.
Significance of the left and right hand
Though there are debates[by whom?] on which hand is better to read from, both have their own significance. It is custom[weasel words] to assume that the left hand shows potential in an individual, and the right shows realized personality. Some sayings about the significance include “The future is shown in the right, the past in the left”; “The left hand is the one we are born with, and the right is what we have made of it”; “The right hand is read for men, while the left is read for women”; “The left is what the gods give you, the right is what you do with it”; “The right hand is read for right-handed people, while the left is read for left-handed people“. The choice of hand to read is ultimately up to the instinct and experience of the practitioner.
- Left The left hand is usually controlled by the right brain (often believed to direct control pattern recognition, relationship understanding), reflects the inner person, the natural self, the anima, and the lateral thinking.
- Right The right hand is usually controlled by the left brain (often believed to direct logic, reason, and language), reflects the outer person, objective self, influence of social environment, education, and experience. It represents linear thinking.
Depending on the type of palmistry practiced, and the type of reading being performed, palmists may look at various qualities of the hand, including the shapes and lines of the palm and fingers; the color and texture of the skin and fingernails; the relative sizes of the palm and fingers; the prominence of the knuckles; and numerous other attributes of the hands.
In most schools of palmistry, hand shapes are divided into four or 11 major types, sometimes corresponding to the Classical elements or temperaments. Hand shape is believed to indicate character traits corresponding to the type indicated (i.e., a “Fire hand” would exhibit high energy, creativity, short temper, ambition, etc. – all qualities believed to be related to the Classical element of Fire).
Although variations abound, the most common classifications used by modern palmists:
- Earth hands are generally identified by broad, square palms and fingers, thick or coarse skin, and ruddy color. The length of the palm from wrist to the bottom of the fingers is usually equal to the length of the fingers.
- Air hands exhibit square or rectangular palms with long fingers and sometimes protruding knuckles, low-set thumbs, and often dry skin. The length of the palm from wrist to the bottom of the fingers is usually equal to the length of the fingers.
- Water hands are seeable by the long, sometimes oval-shaped palm, with long, flexible, conical fingers. The length of the palm from wrist to the bottom of the fingers is usually less than the width across the widest part of the palm, and usually equal to the length of the fingers.
- Fire hands are characterized by a square or rectangular palm, flushed or pink skin, and shorter fingers. The length of the palm from wrist to the bottom of the fingers is usually greater than the length of the fingers.
The number and quality of lines can also be included in the hand shape analysis; in some traditions of palmistry, Earth and Water hands tend to have fewer, deeper lines, while Air and Fire hands are more likely to show more lines with less clear definition.
The three lines found on almost all hands, and generally given most weight by palmists:
- The heart line is the first of the major lines examined by a reader and represents love and attraction. It is found towards the top of the palm, under the fingers. In some traditions, the line is read as starting from the edge of the palm under the little finger and flowing across the palm towards the thumb; in others, it is seen as starting under the fingers and flowing toward the outside edge of the palm. Palmists interpret this line to represent matters of the heart, that is, more literally, our emotional living; it is therefore believed to be an insight into how the emotional sides of our mindframes will act out and be acted upon during our lifetimes, and often said, to what extent we possess emotional reservoirs within us, for example, a chained or gridded heart line (or emotional line) is often seen in people who are highly strung, nervous and draw upon emotional strength and insight to attain their ambitions, i.e. they wear their ’emotions’ on their sleeves, often to draw strength. Such chaining or gridding on the heart line (emotional line) is often seen in intensely creative artists such as musicians and writers, as well as deeply driven scientists. Dealing with emotions, the line is also claimed to indicate romantic perspectives and intimate relationships, again, a chained or gridded heart line is said to point to a flirtatious attitude to love, and one which can be prone to fall in love easily. On a physical level, the heart line is indirectly associated with heart health, more so through the effects that emotions can have on the body such as with blood pressure. A chained heart line is often associated with high blood pressure, but also of an ‘adrenaline junkie’ attitude in life.
- The next line identified by palmists is the head line. This line starts at the edge of the palm under the index finger and flows across the palm towards the outside edge. Often, the head line is joined with the life line (see below) at inception. Palmists generally interpret this line to represent the person’s mind and the way it works, including learning style, communication style, intellectualism, and thirst for knowledge. It is also believed to indicate a preference for creative or analytical approaches to information (i.e., right brain or left brain).
- The life line is perhaps the most controversial line on the hand. This line extends from the edge of the palm above the thumb and travels in an arc towards the wrist. This line is believed to represent the person’s vitality and vigor, physical health and general well being. The life line is also believed to reflect major life changes, including cataclysmic events, physical injuries, and relocations. Contrary to popular belief, modern palmists generally do not believe that the length of a person’s life line is tied to the length of a person’s life.
- The combined length of these three main lines (heart, head, life) can also be used. If this combined length is longer than a persons foot they may be over bearing. However, if it is shorter they may give in too easily to other people. A similar length suggests a well balanced individual.
Additional major lines or variations include:
- A simian crease, or fusing of the heart and head lines, has special significance in that both emotional as well as reasoning nature have to be studied from this line alone. The peculiar line is thought to be a combination of the head and heart lines on such hands that are separately marked on the rest of the hands.
According to Cheiro, this line is thought to endow a person with an intensity of purpose or single-mindedness, the nature of which is decided upon by exact position of this line on the hand and the direction of any branches shooting from it, which is normally the case. In hands where such a line exists without any branches as a singular mark, it indicates an extremely intense nature and special care is needed for such persons. The normal position for the line is starting below the index finger and ending where normally the heart line terminates at the edge of the hand below the little finger, indicating average interests for the person and the intense side of the nature is decided purely by the direction of any branches shooting from it.
The upper half of the palm lying immediately below the fingers is considered to represent the higher or intellectual nature and the lower half of the palm to represent the materialistic side of the nature. If one of these halves is larger than the other as decided by the central placement of the head line or in this case the single transverse palmar crease it shows greater development of that aspect of the nature. Based on this general principle, if this line is placed below its normal position it indicates an intensely intellectual nature; if it is placed above its normal position it indicates an intensely materialistic nature and interests.
The direction in which any branches may be found shooting from this line have a significant impact on the nature of this line resulting in suitable modifications from the above defined results depending on the nature of the mounts on the hand. For instance, if a branch from this line shoots to the mount of Moon lying on the lower edge of the hand exactly opposite the thumb, it indicates an intensely vacillating nature and emotional temperament.
- The fate line runs from the bottom of the palm near the wrist, up through the center of the palm towards the middle finger. This line is believed to be tied to the person’s life path, including school and career choices, successes and obstacles. Sometimes this line is thought to reflect circumstances beyond the individual’s control, or alternately the person’s choices and their consequences.
Other minor lines:
- Sun line – parallel to the Fate Line, under the ring finger; believed to indicate fame or scandal
- Girdle of Venus – starts between the little and ring fingers, runs in a rough arc under the ring and middle fingers to end between the middle and pointer fingers; thought to relate to emotional intelligence and the ability to manipulate
- Union lines – short horizontal lines found on the percussive edge of the palm between the Heart Line and the bottom of the little finger; believed to indicate close relationships, sometimes – but not always – romantic.
- Mercury line – runs from the bottom of the palm near the wrist, up through the palm towards the little finger; purported to be an indicator of persistent health issues, business acumen, or skill in communication.
- Travel lines – these are horizontal lines found on the percussive edge of the palm between the wrist and the heart line; each line is said to represent a trip taken by the subject – the longer the line, the more important the trip is to the subject.
- Other markings – these include stars, crosses, triangles, squares, tridents, and rings under each of the fingers; their supposed impact and meaning varies by location on the palm and freedom from other interfering lines.
- “Apollo line” – the Apollo line means to have a fortunate life; it travels from the Mount of the Moon at the wrist to beneath the Apollo finger.
Criticism of palmistry often rests with the lack of empirical evidence supporting its efficacy. Scientific literature typically regards palmistry as a pseudoscientific or superstitiousbelief. Skeptics often include palmists on lists of alleged psychics who practice cold reading. Cold reading is the practice that allows readers of all kinds, including palmists, to appear psychic by using high-probability guessing and inferring details based on signals or cues from the other person.
In films and television
Palmistry has been shown in a number of films and television shows, including:
- Amaya (2011) – Through the use of Himalad (Palmistry) the priestess found out that Amaya is the chosen one – the girl with a twin snake who will kill the ferocious Rajah.
- Eat Pray Love (2010) – Julia Roberts‘ character goes in for a palmistry reading which transforms her life
- The Simian Line (2001) – Readings by a quirky psychic set in motion the main plot of the film
- Before Sunrise (1995) – Julie Delpy‘s character has her palm read, while Ethan Hawke‘s character is sidelined, leading to a cynical rant from his character
- Jacob’s Ladder (1990) – Tim Robbins‘ character has his palm read at a party, which acts as an ominous portent
- Teen Witch (1989) – While Robyn Lively‘s character has her palm read, the fortune teller recognizes her as reincarnated witch who will soon be coming into her powers
- The Simpsons – Palmistry is lampooned in the Season 4 Episode 8 New Kid on the Block.
- Fun and Fancy Free (1947) – In Mickey and the Beanstalk, Mickey reads the giant’s palm
- Are You Being Served? (1972-1985) – In the third series premiere (1975), Mr. Humphries (played by John Inman) reads an Asian customer’s hand, foretelling an accident. Later on, it does happen.
- The Hunchback of Notre Dame – When Quasimodo tells Esmeralda he’s a monster, she reads his palm and sees no “monster lines”.
- Harry Potter and the Prisoner of Azkaban – Harry takes a course in divination and dabbles in palmistry.
- Hands of Destiny (1954 film) – Palmist Dr Josef Ranald appears as himself. He had supposedly read the palms of the great and the good (and leading Nazis) in the mid C20 with huge accuracy!
Graphology has been controversial for more than a century. Although supporters point to the anecdotal evidence of positive testimonials as a reason to use it for personality evaluation, most empirical studies fail to show the validity claimed by its supporters.Graphology is the analysis of the physical characteristics and patterns of handwriting purporting to be able to identify the writer, indicating psychological state at the time of writing, or evaluating personality characteristics. It is generally considered a pseudoscience. The term is sometimes incorrectly used to refer to forensic document examination.
From grapho- (from the Greek γραφή, “writing”) and logos (from the Greek λόγος, “word”). There also exist many other words formed from the same root: graphopathology, graphomaniac, graphistic, graphopsychology, psychographology, graphometric, graphometry, graphoanalysis, graphotechnology, micrographia.
Jean-Charles Gille stated in 1991 that Juan Huarte de San Juan’s 1575 Examen de ingenios para las ciencias was the first book on handwriting analysis. In American graphology, Camillo Baldi‘s Trattato come da una lettera missiva si conoscano la natura e qualita dello scrittore is considered to be the first book.
Around 1830 Jean-Hippolyte Michon became interested in handwriting analysis. He published his findings shortly after founding Société Graphologique in 1871. The most prominent of his disciples was Jules Crépieux-Jamin who rapidly published a series of books that were soon published in other languages. Starting from Michon’s integrative approach, Crépieux-Jamin founded a holistic approach to graphology.
Alfred Binet was convinced to conduct research into graphology from 1893 to 1907. He called it “the science of the future” despite rejection of his results by graphologists.
After World War I, interest in graphology continued to spread in Europe as well as the United States. In Germany during the 1920s, Ludwig Klages founded and published his finding in Zeitschrift für Menschenkunde (Journal for the Study of Mankind). His major contribution to the field can be found in Handschrift und Charakter.
In 1929 Milton Bunker founded The American Grapho Analysis Society teaching graphoanalysis. This organization and its system split the American graphology world in two. Students had to choose between graphoanalysis or holistic graphology. While hard data is lacking, anecdotal evidence indicates that 10% of the members of International Graphoanalysis Society (IGAS) were expelled between 1970 and 1980.
Lack of validity
Although graphology had some support in the scientific community before the mid-twentieth century, more recent research rejects the validity of graphology as a tool to assess personality and job performance, and today it is considered to be a pseudoscience. Graphology is primarily used as a recruiting tool to screen candidates during the evaluation process. Many studies have been conducted to assess its effectiveness to predict personality and job performance. Recent studies testing the validity of using handwriting for predicting personality traits and job performance have been consistently negative.
In a 1987 study, graphologists were unable to predict scores on the Eysenck Personality Questionnaire using writing samples from the same people. In a 1988 study, graphologists were unable to predict scores on the Myers-Briggs test using writing samples from the same people. A 1982 meta-analysis drawn from over 200 studies concludes that graphologists were generally unable to predict any kind of personality trait on any personality test.
Measures of job performance appear similarly unrelated to the handwriting metrics of graphologists. Professional graphologists using handwriting analysis were just as ineffective as lay people at predicting performance in a 1989 study. A broad literature screen done by King and Koehler confirmed dozens of studies showing the mechanical aspects of graphology (slant, slope, etc.) are essentially worthless predictors of job performance.
Rowan Bayne, a British psychologist who has written several studies on graphology, summarized his view of the appeal of graphology: “[i]t’s very seductive because at a very crude level someone who is neat and well behaved tends to have neat handwriting”, adding that the practice is “useless… absolutely hopeless”. The British Psychological Society ranks graphology alongside astrology, giving them both “zero validity”.
Overall, despite a few studies that support handwriting analysis, such as Crumbaugh and Stockholm (1977), the large majority of studies such as Ben-Shakar, Bar-Hillel, Blum, Ben-Abba, & Flug and many others supply evidence against its predictive validity.
There is some evidence of a relationship between gender and handwriting style, though the correlation is weak.
Additional specific objections
- The Barnum effect (the tendency to interpret vague statements as specifically meaningful) and the Dr. Fox effect (the tendency for supposed experts to be validated based on likeability rather than actual skill) make it difficult to validate methods of personality testing. These phenomena describe the observation that individuals will give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically for them, but are in fact vague and general enough to apply to a wide range of people. See, for example, Tallent (1958). Non-individualized graphological reports give credence to this criticism.
- Effect Size: Dean’s (1992) primary argument against the use of graphology is that the effect size is too small. Regardless of the validity of handwriting analysis, the research results imply that it is not applicable for any specific individual, but may be applicable to a group.
- Vagueness: Some important principles of graphology are vague enough to allow a lot of room for a graphologist to skew interpretations to suit a subject or preconceived conclusion. For example, one of the main concepts in the theory of Ludwig Klages is form-niveau (or form-level): the overall level of originality, beauty, harmony, style, etc. of a person’s handwriting—a quality that, according to Klages, can be perceived but not measured. According to this theory, the same sign has a positive or negative meaning depending on the subject’s overall character and personality as revealed by the form-niveau. In practice, this can lead the graphologist to interpret signs positively or negatively depending on whether the subject has high or low social status.
Systems of handwriting analysis
Integrative graphology focuses on strokes and their relation to personality. Graphoanalysis was the most influential system in the United States, between 1929 and 2000. The Sistema de Xandró is another method of integrative graphology. Holistic graphology is based on form, movement, and use of space. The psychogram is another method which uses specific diagrams to analyze handwriting. The Personal Worth Chart is one such method developed by the Handwriting Consultants of San Diegoduring the early eighties. The psychograph is an additional psychogram method. was developed by Leslie King during the seventies.The Wittlich Character Diagram,and the Muller – Enskat Protokol are other psychogram methods.Each approach to handwriting analysis has spawned several different systems.
Four academic institutions around the world currently offer an accredited degree in handwriting analysis:
- The University of Urbino, Italy: MA (Graphology)
- Instituto Superior Emerson, Buenos Aires, Argentina: BA (Graphology)
- Centro de Estudios Superiores (CES) Buenos Aires, Argentina: BA (Graphology)
- Autonomous University of Barcelona, Barcelona: Spain: MA (Graphology)
The majority of material in the field is oriented towards the Latin writing system. Courses offered in the subject reflect that bias.
Every system of handwriting analysis has its own vocabulary. Even though two or more systems may share the same words, the meanings of those words may be different. The technical meaning of a word used by a handwriting analyst, and the common meaning is not congruent. Resentment, for example, in common usage, means to feel or exhibit annoyance. In Graphoanalysis, the term indicates a fear of imposition.
A report by the Hungarian Parliamentary Commissioner for Data Protection and Freedom of Information says that handwriting analysis without informed consent is a privacy violation.
In the United States
Gender and handwriting
There have been a number of studies on gender and handwriting. Uniformly the research indicates that gender can be determined at a significant level. The published studies on ethnicity, race, age, nationality, gender orientation, weight, and their relationship to handwriting have had mixed results.
Americans with Disabilities Act of 1990
One of the rules of thumb in human resources is that if an individual who has an ADA-defined disability cannot take a test, then nobody can. As a result, tests that cannot be adapted for use by those individuals will not be used by a company.
Handwriting clearly falls into the group of tests that cannot be adapted to be administered to individuals who fall within one or more ADA-defined disabilities. Blind people, for example, do not develop the required fluency in handwriting, for the writing to be correctly analyzed.
Questions that handwriting analysts ask before doing an analysis can be illegal under this act.
Graphology in court testimony
In Carroll v. State [276 Ark 160; 634 SW 2d 99, 101-102 (1982)] the opposing handwriting analysts showed unprofessionalism.
A company takes a writing sample provided by an applicant, and proceeds to do a personality profile, matching the congruency of the applicant with the ideal psychological profile of employees in the position.
A graphological report is meant to be used in conjunction with other tools, such as comprehensive background checks, practical demonstration or record of work skills. Graphology supporters state that it can complement but not replace traditional hiring tools.
Research in employment suitability has ranged from complete failure to guarded success. The most substantial reason for not using handwriting analysis in the employment process is the absence of evidence of a direct link between handwriting analysis and various measures of job performance.
Graphology has been used clinically by European counselors and psychotherapists. When it is used, it is generally used alongside other projective personality assessment tools, and not in isolation. It is often used within individual psychotherapy, marital counseling, or vocational counseling.
In its simplest form only sexual expression and sexual response are examined. At its most complex, every aspect of an individual is examined for how it affects the other individual(s) within the relationship. The theory is that after knowing and understanding how each individual in the relationship differs from every other individual in the relationship, the resulting marriage will be more enduring.
Medical graphology is probably the most controversial branch of handwriting analysis. Strictly speaking, such research is not graphology as described throughout this article but an examination of factors pertaining to motor control. Research studies have been conducted in which a detailed examination of handwriting factors, particularly timing, fluidity, pressure, and consistency of size, form, speed, and pressure are considered in the process of evaluating patients and their response to pharmacological therapeutic agents. The study of these phenomena is a by-product of researchers investigating motor control processes and the interaction of nervous, anatomical, and biomechanical systems of the body.
The Vanguard Code of Ethical Practice, amongst others, prohibits medical diagnosis by those not licensed to do diagnosis in the state in which they practice.
This is the practice of changing a person’s handwriting with the goal of changing features of his or her personality. It originated in France during the 1930s, spreading to the United States in the late 1950s. The purported therapy consists of a series of exercises which are similar to those taught in basic calligraphy courses, sometimes in conjunction with music or positive self-talk
The digit ratio is the ratio of the lengths of different digits or fingers typically measured from the midpoint of bottom crease where the finger joins the hand to the tip of the finger. It has been suggested by some scientists that the ratio of two digits in particular, the 2nd (index finger) and 4th (ring finger), is affected by exposure to androgens e.g. testosterone while in the uterus and that this 2D:4D ratio can be considered a crude measure for prenatal androgen exposure, with lower 2D:4D ratios pointing to higher prenatal androgen exposure. The 2D:4D ratio is calculated by dividing the length of the index finger of the right hand by the length of the ring finger of the right hand. A longer index finger will result in a ratio higher than 1, while a longer ring finger will result in a ratio of less than 1.
The 2D:4D digit ratio is sexually dimorphic: while the second digit is typically shorter in both females and males, the difference between the lengths of the two digits is greater in males than in females.
A number of studies have shown a correlation between the 2D:4D digit ratio and various physical and behavioral traits.
History of digit ratio research
That a greater proportion of men have shorter index fingers than ring fingers than do women was noted in the scientific literature several times through the late 1800s, with the statistically significant sex difference in a sample of 201 men and 109 women established by 1930, after which time the sex difference appears to have been largely forgotten or ignored. In 1983 Dr Glenn Wilson of King’s College, London published a study examining the correlation between assertiveness in women and their digit ratio. This was the first study to examine the correlation between digit ratio and a psychological trait within members of the same sex. Wilson proposed that skeletal structure and personality were simultaneously affected by sex hormone levels in utero. In 1998, John T. Manning and colleagues reported the sex difference in digit ratios was present in two-year-old children and further developed the idea that the index was a marker of prenatal sex hormones. Since then research on the topic has burgeoned around the world.
A 2009 study in Biology Letters argues: “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,” which may be the basis for the sex difference in digit ratios and/or any putative hormonal influence on the ratios.
A 2011 paper by Zhengui Zheng and Martin J. Cohn reports “the 2D:4D ratio in mice is controlled by the balance of androgen to estrogen signaling during a narrow window of digit development.” The formation of the digits in humans, in utero, is thought to occur by 13 weeks, and the bone-to-bone ratio is consistent from this point into an individual’s adulthood. During this period if the fetus is exposed to androgens, the exact level of which is thought to be sexually dimorphic, the growth rate of the 4th digit is increased, as can be seen by analyzing the 2D:4D ratio of opposite sex dizygotic twins, where the female twin is exposed to excess androgens from her brother in utero, and thus has a significantly lower 2D:4D ratio.
Importantly, there has been no correlation between the sex hormone levels of an adult and the individual’s 2D:4D, which implies that it is strictly the exposure in utero that causes this phenomenon.
A major problem with the research on this topic comes from the contradiction in the literature as to whether the testosterone level in adults can be predicted by the 2D:4D ratio, but male sexual traits that are stereotypically attributed to testosterone levels have been found in correlation with the 2D:4D. So there should be a correlation with one or the other but not both.
Digit ratio distribution
From a study of 136 males and 137 females:
- Males: mean 0.947, standard deviation 0.029.
- Females: mean 0.965, standard deviation 0.026.
Assuming a normal distribution, the above lead to 95% confidence intervals for 2D:4D ratio of 0.889-1.005 for males and 0.913-1.017 for females.
Evidence of androgen effect on digit ratio
Women with congenital adrenal hyperplasia (CAH), which results in elevated androgen levels before birth, have lower, more masculinized 2D:4D on average. Other possible physiological effects include an enlarged clitoris and shallow vagina.
Males with CAH have more masculine (smaller) digit ratios than control males, which also suggests that prenatal androgens affect digit ratios, since amniocentesis samples show that prenatal levels of testosterone are in the high normal range in males with CAH, while levels of the weaker androgen androstenedione are several fold higher than in control males. These measures indicate that males with CAH are exposed to greater prenatal concentrations of total androgens than are control males.
Digit ratio in men with Klinefelter’s syndrome, who have reduced testosterone secretion throughout life compared to control males, are greater (i.e., more feminine) than in their fathers or control males.
Digit ratio in men correlates with genetic variation in the androgen receptor gene. Men with genes that produce androgen receptors that are less sensitive to testosterone (because they have more CAG repeats) have greater, more feminine, digit ratios. There are reports of a failure to replicate this finding. However, men carrying an androgen receptor with more CAG repeats compensate for the less sensitive receptor by secreting more testosterone, probably as a result of reduced negative feedback on gonadotropins. Thus, it is not clear that 2D:4D would be expected to correlate with CAG repeats, even if it accurately reflects prenatal androgen.
XY individuals with androgen insensitivity syndrome (AIS) due to a dysfunctional gene for the androgen receptor present as women and have feminine digit ratios on average, as would be predicted if androgenic hormones affect digit ratios. This finding also demonstrates that the sex difference in digit ratios is unrelated to the Y chromosome per se.
The sex difference in 2D:4D is present before birth in humans, which rules out any social influences that might affect digit growth differentially in the two sexes. Because all somatic sex differences in mammals to date have been found to be due to either androgenic masculinization or effects of the sex chromosomes, and as the AIS finding rules out a role for sex chromosomes in the sex difference in digit ratios, the prenatal sexual dimorphism also indicates that androgens act before birth to affect digit ratios.
Studies in mice indicate that prenatal androgen acts primarily by promoting growth of the fourth digit.
The level of estrogen in the amniotic fluid is not correlated with higher 2D:4D, and when examined researchers found no difference in estrogen levels between males and females.
Explanation of the digit ratio effect
It is not clear why digit ratio ought to be influenced by prenatal hormones. There is evidence of other similar traits, e.g. otoacoustic emissions and arm-to-trunk length ratio, which show similar effects. Hox genes responsible for both digit and penis development have been implicated in affecting these multiple traits (pleiotropy). Direct effects of sex hormones on bone growth might be responsible, either by regulation of Hox genes in digit development or independently of such genes. Likewise, it is unclear why digit ratio on the right hand should be more responsive than that on the left hand, as is indicated by the greater sex difference on the right than the left.
Geographic and ethnic variation in 2D:4D
Manning and colleagues have shown that 2D:4D ratios vary greatly between different ethnic groups. This variation is far larger than the differences between sexes; in Manning’s words, “There’s more difference between a Pole and a Finn, than a man and a woman.”
Correlation between digit ratio and traits
Some authors suggest that digit ratio correlates with health, behavior, and even sexuality in later life. Below is a non-exhaustive list of some traits that have been either demonstrated or suggested to correlate with either high or low digit ratio.
|Low digit ratio||High digit ratio|
|Physiology and disease|
|Physical and competitive behavior|
|Cognition and personality|
Male-to-female transsexual women
A study in Germany has found a correlation between digit ratio and male-to-female transsexualism. Trans women were found to have a higher digit ratio than cisgender males, but one that was comparable to control females.
Digit ratio and development
There is some evidence that 2D:4D ratio may also be indicative for human development and growth. Ronalds et al. (2002) showed that men who had an above average placental weight and a shorter neonatal crown-heel length had higher 2D:4D ratios in adult life. Moreover, studies about 2D:4D correlations with face shape suggest that testosterone exposure early in life may set some constraints for subsequent development. Prenatal sex steroid ratios (in terms of 2D:4D) and actual chromosomal sex dimorphism were found to operate differently on human faces, but affect male and female face shape by similar patterns. Fink et al. (2004) found that men with low (indicating high testosterone) and women with high (indicating high estrogen) 2D:4D ratios express greater levels of facial symmetry. However, exposure to very high levels of testosterone and/or estrogen in the womb may have negative effects as well.
Digit ratio and palaeolithic hand stencils
Digit ratio research in animals
- Dennis McFadden and collaborators have demonstrated sexual dimorphism in hind limb digit ratio in a number of great apes, including gorillas and chimpanzees.
- Emma Nelson and Susanne Shultz are currently investigating how 2D:4D relates to primate mating strategies and the evolution of human sociality.
- Sexual dimorphism in hind limb 2D:4D has been demonstrated in mice by two studies by both John Manning and Marc Breedlove‘s research groups. There is some evidence to suggest that this effect is not seen in all mouse strains.
- Nancy Burley’s research group has demonstrated sexual dimorphism in zebra finches, and found a correlation between digit ratio in females and the strength of their preference for sexually selected traits in males.
- Front limb D2:D3 has shown to be influenced by prenatal alcohol exposure in female rats.
- Alžbeta Talarovičová and collaborators found in rats that elevated testosterone during the prenatal period can influence 4D length, the 2D:4D ratio, and open field motor activity.
- Peter L. Hurd, Theodore Garland, Jr., and their students have examined hindlimb 2D:4D in lines of mice selectively bred for high voluntary wheel-running behavior (seeexperimental evolution). These high-runner mice exhibit increased 2D:4D. This apparent “feminization” is opposite to the relation seen between 2D:4D and physical fitness in human beings, and is difficult to reconcile with the idea that 2D:4D is a clear proxy for prenatal androgen exposure in mice. The authors suggest that 2D:4D may more accurately reflect effect of glucocorticoids or other factors that regulate any of various genes.