Response to Snyder’s “Comments on Priming Skills of Autistic Twins and Yamaguchi (2006) Letter to the Editor: ‘Questionable Aspects of Oliver Sacks’ (1985) Report,’” Journal of Autism and Developmental Disorders

Dear Editor I am responding to Professor Synder’s Letter to the Editor addressing my statement concerning Oliver Sacks’ use of prime numbers. Snyder is not convincing. He insists that Sacks did not claim to have confirmed primality of 8, 9, or 10 digit numbers. This interpretation should be new in the literature. It seems even inconsistent with his own earlier writing. (‘‘Sacks (1985) observed autistic twins who could exchange prime numbers in excess of eight figures, possibly even 20 figures’’, Snyder & Mitchell, 1999). He could ask Sacks about his interpretation before submitting his comments. In addition, what is relevant is not whether such a book is logically conceivable, but whether such a book was published and available in 1966. The burden of proof rests with Snyder or Sacks. A few leading researchers commented on the target letter before publication. Stanislas Dehaene said that he talked to Sacks about the issue about 10 years ago in the hope of obtaining exact prime numbers generated by the twins, and that he felt the whole story was greatly exaggerated. Brian Butterworth claimed he too had already been skeptical about Sacks’ report because it seemed inconsistent with earlier reports of the twins by other researchers (Horwitz, Deming, & Winter, 1969; Horwitz, Kestenbaum, Person, & Jarvik, 1965). Furthermore, I point out that another feat reported by Sacks, instant perception of large numerosities, and also the subject of Snyder, Bahramali, Hawker, and Mitchell (2006), met with skepticism. See Dehaene (1997, 2001). Snyder et al.’ new data only show approximate perception, not exact one as reported by Sacks. Before we have convincing evidence, we should be careful in including these abilities in the list of reported abilities associated with savant syndrome. It is worrying that sometimes the list also contains other questionable abilities like extrasensory perception (Treffert, 1989).