Perhaps the most famous person to doubt Oprah’s head size was Stephen Spielberg. When he cast her to be in The Colour Purple, Oprah tried to warn him that finding a wig would be impossible but Spielberg, having worked with some of the biggest headed men in show business, was having none of it, believing Oprah’s head would easily fit into their jumbo sized wigs. He couldn’t have been more wrong, according to this quote from Oprah in the May 14, 1996 National Enquirer.
Of course Oprah knew wigs were a problem from when she went bald back in Baltimore (from the same article).
Independent confirmation for Oprah’s colossal cranium comes from an internet comment by a David Letterman fan named Helen Read who on Dec 6, 2007 reported that Letterman was told that Oprah has a hat size of 8.
Since hat size equals the diameter of a perfectly spherical head, dividing circumference by pi (3.14) gives hat size, thus a hat size of 8 perfectly corroborates her 25.25″ head.
The late Gene Siskel went hat shopping with Oprah and the salesman said Oprah’s was the largest head he’d ever seen.
Using the late J.P. Rushton’s idea of using the formula for calculating the volume of a hemisphere (V = circumfence3/118.4) Oprah would have a cranial capacity of 2229 cm3 but this formula overestimates the brain size of black women because they tend to have relatively long heads and thick hair. For example young black American women in the 1980s had larger head circumferences than White or Asian women, but smaller cranial capacity (though cranial capacity was estimated from an extremely old regression equation that assumed a linear relationship between head dimensions and volume when the true relationship is cubic)
To allow for cubic effects, a better way might be to use the hemisphere formula and then adjust for the degree of over or underestimation in a particular demographic group.
For example, if their heads were perfectly spherical and there was no inflation for hair, skull thickness or fat and skin around the skull, black women would average a 1398 cm3 cranial capacity based on their 54.9 cm circumference, but in reality, as of the 1980s they had a mean age 25 brain weight of 1291 g.
If the samples in the army data and autopsy study are comparable, this implies their brain weights are 0.923 as large in grams as the hemisphere formula puts them in cubic centimeters (for simplicity I’m ignoring any putative post-mortem weight gain). Thus multiplying Oprah’s hemisphere formula head size of 2229 cm3 by 0.923 gives an estimated age 25 brain weight of 2057 g, which is at least 6.4 standard deviations above the mean for U.S. black women and at least 5.7 standard deviations above the mean of U.S. white women. Given the much smaller population size of well nourished peak age women of all races when Oprah was 25, this would have mad her arguably the World’s biggest brained woman at least until some younger woman from the better nourished generations that followed took her place. Decades later she would be the World’s most influential woman.