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Estimated IQs of 301 Geniuses
 of the 15th - 19th Centuries
by Catharine Morris Cox, PhD


Based on Catharine Morris Cox. (1926) The early mental traits of three hundred geniuses.
Genetic Studies of Genius
(Vol. II). Stanford University Press.

20 Selected Geniuses... [More]


Dates Years Lived



Average Reliability Grade** Obtained Est. IQ* Corrected Est. IQ*
Adams, John Quincy 1767-1848 81 American statesman 3.0 165 175
Balzac, Honoré de 1799-1850 51 French writer 3.5 145 155
Beethoven, Ludwig van 1770-1827 57 German musician 5.5 140 165
Copernicus, Nicolas 1473-1543 70 Prussian*** scientist 5.5 130 160
Da Vinci, Leonardo 1452-1519 67 Italian artist 6.0 150 180
Descartes, René 1596-1650 54 French philosopher 4.5 160 180
Emerson, Ralph Waldo 1803-1882 79 American writer 3.5 145 155
Franklin, Benjamin 1706-1790 84 American statesman 4.5 145 160
Goethe, Johann Wolfgang von 1749-1832 83 German writer 3.0 200 210
Handel, George Frideric 1685-1759 74 German musician 4.5 155 170
Jefferson, Thomas 1743-1826 83 American statesman 4.0 150 160
Johnson, Samuel 1709-1784 75 English writer 4.0 155 165
Kant, Immanuel 1724-1804 80 German philosopher 5.5 145 175
Lincoln, Abraham 1809-1865 56 American statesman 4.0 140 150
Mill, John Stuart 1806-1873 67 English philosopher 3.0 170 180
Napoleon Bonaparte 1769-1821 52 French soldier 3.5 140 145
Newton, Isaac 1642-1727 85 English scientist 4.5 170 190
Pascal, Blaise 1623-1662 39 French scientist 3.5 180 195
Rembrandt van Rijn 1606-1669 63 Dutch artist 5.5 135 155
Spinoza, Baruch de 1632-1677 45 Dutch philosopher 5.5 145 175
Voltaire, Arouet de 1694-1778 84 French writer 3.5 180 190

* IQ scores are based on ratings of individual case histories of the behavior and performance of 301 eminent young men and women, between 17 and  26 years of age, born 1450 to 1850, prepared from 1,500 biographical sources, reported as estimated intelligence quotients based on The Stanford Revision of the Binet-Simon Intelligence Scale, and corrected for regression to the mean. (See Genius: An Overview)

** These are the  average grades assigned by raters who rated the reliability of the data of each of the cases on the following seven point scale:

Grade 1. Rating based on data equal to a Stanford-Binet test.

Grade 2. Rating based on data for which standardize norms are available or which are closely correlated with Stanford-Binet norms. (Example: Galton.)

Grade 3. Rating based on documentary evidence combined with diagnostic descriptive material. (Example: John Quincy Adams.)

Grade 4. Rating based on less satisfactory documentary evidence and descriptive material, or on descriptive material (definite statements as to school rank, etc.) without documents. (Example: Melanchthon.)

Grade 5. Rating based on general descriptive material. General statements of superiority (or inferiority) or of school standing, intellectual interests, etc. (Example: Fénelon.)

Grade 6. Rating based on slight evidence. Standing of the family combined with a statement as to school attendance. (Example: Bernadotte.)

Grade 7. Guess, based on no data. (Example: Drake.)
*** Cox listed Copernicus' nationality as Prussian, a designation that is not without controversy, since he is regarded today as one of Poland's greatest geniuses. His birthplace, Torun (Thorn), was in Royal Prussia, now Poland, and was part of the Prussian Confederation at the time of his birth. According to Wikipedia, his native language was German, his working language was Latin, and there are no extant letters written by Copernicus in Polish, only German and Latin.

Sources: Copernicus' Nationality  and  Royal Prussia

 More Tables


The Flynn Effect
Charles Graham and Jonathan Plucker
Indiana University

In his study of IQ tests scores for different populations over the past sixty years, James R. Flynn discovered that IQ scores increased from one generation to the next for all of the countries for which data existed (Flynn, 1994). This interesting phenomena has been called "the Flynn Effect."  Many of the questions about why this effect occurs have not yet been answered by researchers. This site attempts to explain the issues involved in a way that will better help you to understand the Flynn Effect. It also provides references for further inquiry.

More on the Flynn Effect

Renorming IQ tests due to Flynn effect may have unintended consequences

Making IQ tests harder has educational, financial, legal and military recruiting implications

WASHINGTON -- The steady rising of IQ scores over the last century – known as the Flynn effect – causes IQ tests norms to become obsolete over time. To counter this effect, IQ tests are "renormed" (made harder) every 15-20 years by resetting the mean score to 100 to account for the previous gains in IQ scores. But according to new research, such renorming may have unintended consequences, particularly in the area of special education placements for children with borderline or mild mental retardation. The findings are reported on in the October issue of American Psychologist, a journal of the American Psychological Association (APA).

More on Renorming IQ Tests

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