Brief Report: Information Processing Speed is Intact in Autism but not Correlated with Measured Intelligence

  • Gregory L. WallaceEmail author
  • Mike Anderson
  • Francesca Happé
Brief Report


Speed of information processing, as measured by inspection time (IT), is a robust predictor of intellectual functioning. However, among individuals with autism and low IQ scores, IT has been reported to be discrepantly fast, and equal to that of high IQ typically developing children (Scheuffgen et al. in Dev Psychopathol 12: 83–90, 2000). The present investigation replicates and extends this study by examining IT and its relationship to IQ in a higher functioning (average range mean IQ) group of children with autism spectrum disorders (ASD) versus matched controls. Though IT was not significantly faster in the ASD group than in the matched control group, the relationship between IT and IQ was uniquely discrepant for the ASD group, partially corroborating and extending previous findings.


Autism Asperger’s syndrome Processing speed Inspection time Intelligence IQ 



The authors would like to thank the Baily Thomas Charitable Fund for providing funding to complete this research and the schools and children who participated in this research. This work was carried out in partial fulfillment of the first author’s PhD.


  1. American Psychiatric Association. (1994). The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). Washington, DC: Authors.Google Scholar
  2. Anderson, M. (1988). Inspection time, information processing and the development of intelligence. The British Journal of Developmental Psychology, 6, 43–57.Google Scholar
  3. Anderson, M. (2001). Annotation: Conceptions of intelligence. Journal of Child Psychology and Psychiatry and Allied Disciplines, 42, 287–298. doi: 10.1017/S0021963001007016.CrossRefGoogle Scholar
  4. Anderson, M., & Miller, K. L. (1998). Modularity, mental retardation, and speed of processing. Developmental Science, 1, 239–245. doi: 10.1111/1467-7687.00037.CrossRefGoogle Scholar
  5. Anderson, M., O’Connor, N., & Hermelin, B. (1998). A specific calculating ability. Intelligence, 26, 383–403. doi: 10.1016/S0160-2896(99)00007-0.CrossRefGoogle Scholar
  6. Cyr, J. J., & Brooker, B. H. (1984). Use of appropriate formulas for selecting WAIS-R short forms. Journal of Consulting and Clinical Psychology, 52, 903–905. doi: 10.1037/0022-006X.52.5.903.CrossRefGoogle Scholar
  7. Dawson, M., Soulières, I., Gernsbacher, M. A., & Mottron, L. (2007). The level and nature of autistic intelligence. Psychological Science, 18, 657–662. doi: 10.1111/j.1467-9280.2007.01954.x.PubMedCrossRefGoogle Scholar
  8. Ericsson, K. A., & Charness, N. (1994). Expert performance: Its structure and acquisition. The American Psychologist, 49, 725–747. doi: 10.1037/0003-066X.49.8.725.CrossRefGoogle Scholar
  9. Eysenck, H. J. (1988). The concept of “intelligence”: Useful or useless? Intelligence, 12, 1–16. doi: 10.1016/0160-2896(88)90019-0.CrossRefGoogle Scholar
  10. Goldstein, G., Allen, D. N., Minshew, N. J., Williams, D. L., Volkmar, F., Klin, A., et al. (2008). The structure of intelligence in children and adults with high functioning autism. Neuropsychology, 22, 301–312.PubMedCrossRefGoogle Scholar
  11. Golombok, S., & Rust, J. (1992). The UK Revision. In D. Wechsler (Ed.), The manual of the Wechsler intelligence scale for children—3rd Revision (WISC-III UK). The Psychological Corporation: London.Google Scholar
  12. Grudnik, J. L., & Kranzler, J. H. (2001). Meta-analysis of the relationship between intelligence and inspection time. Intelligence, 29, 523–535. doi: 10.1016/S0160-2896(01)00078-2.CrossRefGoogle Scholar
  13. Happé, F., & Frith, U. (1996). The neuropsychology of autism. Brain, 119, 1377–1400. doi: 10.1093/brain/119.4.1377.PubMedCrossRefGoogle Scholar
  14. Heaton, P., & Wallace, G. L. (2004). Annotation: The savant syndrome. Journal of Child Psychology and Psychiatry and Allied Disciplines, 45, 899–911. doi: 10.1111/j.1469-7610.2004.t01-1-00284.x.CrossRefGoogle Scholar
  15. Jensen, A. R. (1982). Reaction time and psychometric g. In H. J. Eysenck (Ed.), A model for intelligence (pp. 93–132). Berlin: Springer-Verlag.Google Scholar
  16. Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2, 217–250.Google Scholar
  17. Kranzler, J. H., & Jensen, A. R. (1989). Inspection time and intelligence: A meta-analysis. Intelligence, 13, 329–347. doi: 10.1016/S0160-2896(89)80006-6.CrossRefGoogle Scholar
  18. Minshew, N. J., Turner, C. A., & Goldstein, G. (2005). The application of short forms of the Wechsler intelligence scales in adults and children with high functioning autism. Journal of Autism and Developmental Disorders, 35, 45–52. doi: 10.1007/s10803-004-1030-x.PubMedCrossRefGoogle Scholar
  19. Nettelbeck, T. (1987). Inspection time and intelligence. In P. A. Vernon (Ed.), Speed of information processing and intelligence (pp. 295–346). Norwood, NJ: Ablex.Google Scholar
  20. Plaisted, K. C., O’Riordan, M., & Baron-Cohen, S. (1998). Enhanced discrimination of novel, highly similar stimuli by adults with autism during a perceptual learning task. Journal of Child Psychology and Psychiatry and Allied Disciplines, 39, 765–775. doi: 10.1017/S0021963098002601.CrossRefGoogle Scholar
  21. Rumsey, J. M. (1992). Neuropsychological studies of high-level autism. In E. Schopler & G. Mesibov (Eds.), High-functioning individuals with autism (pp. 41–64). New York: Plenum.Google Scholar
  22. Sattler, J. M. (1992). Assessment of Children (3rd ed.). Jerome M Sattler Publisher, Inc: San Diego.Google Scholar
  23. Scheuffgen, K., Happé, F., Anderson, M., & Frith, U. (2000). High “intelligence”, low “IQ”? Speed of processing and measured IQ in children with autism. Development and Psychopathology, 12, 83–90. doi: 10.1017/S095457940000105X.PubMedCrossRefGoogle Scholar
  24. Siegel, D. J., Minshew, N. J., & Goldstein, G. (1996). Wechsler IQ profiles in diagnosis of high-functioning autism. Journal of Autism and Developmental Disorders, 26, 389–406. doi: 10.1007/BF02172825.PubMedCrossRefGoogle Scholar
  25. Taylor, M. M., & Creelman, C. D. (1967). PEST: Efficient estimates on probability functions. The Journal of the Acoustical Society of America, 41, 782–787. doi: 10.1121/1.1910407.CrossRefGoogle Scholar
  26. Treffert, D. A., & Wallace, G. L. (2002). Islands of genius. Scientific American, 286, 76–85.PubMedCrossRefGoogle Scholar
  27. Wallace, G. L., Happé, F., & Giedd, J. N. (2009). A case study of a multiply-talented savant with an autism spectrum disorder: Neuropsychological functioning and brain morphometry. Philosophical Transactions of the Royal Society: Section B: Biological Sciences. (in press).Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Gregory L. Wallace
    • 1
    • 2
    Email author
  • Mike Anderson
    • 3
  • Francesca Happé
    • 1
  1. 1.Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, King’s CollegeUniversity of LondonLondonUK
  2. 2.Laboratory of Brain & CognitionNational Institute of Mental HealthBethesdaUSA
  3. 3.Neurocognitive Development Unit, School of PsychologyUniversity of Western AustraliaPerthAustralia

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