Daniel McCartney

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Daniel McCartney
Born (1817-09-10)September 10, 1817
Died November 15, 1887(1887-11-15) (aged 70)
Nationality American
Known for having HSAM--Highly Superior Autobiographical Memory
Portrait daniel mccartney.jpg

Daniel McCartney (September 10, 1817 – November 15, 1887) was an American who had what is now known as HSAM--Highly Superior Autobiographical Memory, formerly Hyperthymesia.

McCartney was born in Westmoreland County, Pennsylvania. He was legally blind and lived with relatives throughout his lifetime. For a large part of his life, he resided in Morrow County, Ohio, before his final days in Muscatine, Iowa. He never married.

McCartney was famous for his mental ability in two specific areas. First, he remembered every single day in his life from the age of nine until his death. Given any specific calendar date, McCartney in seconds could give the day of the week, describe the weather conditions, describe what he did during the day, describe what he ate during the day, and could provide details of local, regional and national events on that day. In a similar case as McCartney's, noted neurobiologist James McGaugh of the University of California, Irvine, one of the world's leading experts on human memory, reports on a woman, Jill Price, with the astonishing ability to clearly remember events that happened to her decades ago. McGaugh labels this one-of-a-kind ability as Hyperthymesia (National Public Radio, 2006). McCartney's mental aptitude appears to be nearly identical to this recent case reported in McGaugh's study. McCartney, however, had an additional mental ability: mathematical computation.

McCartney could mentally compute difficult mathematical computations in seconds, and extremely difficult ones in minutes. McCartney was tested several times by panels of university mathematicians in which he was given a battery of mathematical questions. On one such examination in July 1870 in Salem, Ohio, McCartney was asked to take 89 to the sixth power, which he mentally computed in ten minutes, giving the correct answer of 496,981,290,961. On another examination he was asked to provide the cube root of 4,741,632 for which he answered correctly in three minutes-(168); and 389,017 for which he answered correctly in fifteen seconds-(73).

On occasion, special sessions for the general public were held to witness mental examinations of McCartney's unique abilities. During these public exhibitions, he was always correct in his responses, and would provide a response in a matter of seconds to the amazement of audiences.

He died at the age of 70 in Wilton, Iowa. McCartney was reported to be one of a number of great mental calculators (Henkle, 1871).


  • "Arithmetical Prodigies", American Journal of Psychology, April 1891, v. IV, no. 1, pg. 38-39.
  • "Great Memories: Phenomenal powers developed by some men", The Budget, vol. 1, no. 43, October 27, 1886, Milburn, N.J.
  • Creighton, J.H. (1888). "A Prodigy of Memory". Knowledge. vol. 11, p. 274.
  • Henkle, W. D. (1871). A Sketch of the Life of Daniel McCartney, the Man with the Remarkable Memory. Columbus, Ohio: Ohio State Journal Job Rooms. ISBN B0008BLVY0.
  • Henkle, W. D. (1871). "Remarkable Cases of Memory", Journal of Speculative Philosophy. vol. V, no. 1, pg. 6-26.
  • Howe, H. (1902). "Historical collections of Ohio in two volumes: An encyclopedia of the state", vol. II. Cincinnati, Ohio: C.J. Krehbiel & Co., pg. 319-321.
  • LePort, A.K. (2014) Behavorial, cognitive and neural correlates of Highly Superior Autobiographical Memory. (Doctoral Dissertation, University of California, Irvine, CA).
  • Smith, S. B. (1983). The great mental calculators: The psychology, methods, and lives of calculating prodigies, past and present. New York: Columbia University Press. ISBN 0-231-05641-9.
  • "Woman's Long-Term Memory Astonishes Scientists". (April 20, 2006). National Public Radio. (Part 2 includes "AJ" in her own words.)