Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

A neuropsychological assessment of dual-task costs in closed-head injury patients using Cohen’s effect size estimation method


A test of whether patients suffering from a severe closed-head injury (CHI) were affected by disproportionate dual-task costs compared to those of healthy control participants was carried out through a direct comparison of CHI effects on dual-task (psychological refractory period, or PRP) performance and on single-task performance. In the dual-task condition of the present experiment, independent choice-responses were required to two sequential stimuli presented at a variable stimulus onset asynchrony (SOA). A significant delay of the reaction time (RT) to the second stimulus was reported by both CHI patients and controls at short (SOA) compared to long SOA, i.e., a PRP effect. The PRP effect was more pronounced for CHI patients than controls. In the single-task condition, a single choice-response was required to a stimulus presented in isolation. The RT produced by CHI patients in the single-task paradigm was longer than the RT produced by controls. CHI effects on dual-task performance and on single-task performance were compared following (1) their transformation into Cohen’s ds, and (2) the application of a correction algorithm taking into account the different reliability of single-task and dual-task measures. The analysis of Cohen’s ds revealed that CHI effects on performance were, if anything, smaller in the dual-task condition than in the single-task condition. The results imply that CHI patient’s slower responding in single- and dual-task performance reflects a single common cause—slowing of the central processing.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2


  1. Brooks, D. N. (1984). Closed head injury: Psychological, social, and family consequences. New York: Oxford University Press.

  2. Cohen, J. (1988). Statistical power analysis for the behavioral sciences. Hillsdale (NJ): Lawrence Erlbaum Associates.

  3. Dell’Acqua, R., Stablum, F., Galbiati, S., Spannocchi, G., & Cerri, C. (2001). Selective effect of closed-head injury on central resources allocation: Evidence from dual-task performance. Experimental Brain Research, 136, 364–378.

  4. Dell’Acqua, R., Pashler, H, & Stablum, F. (2003). Multi-tasking costs in CHI-patients: A fine-grained analysis. Experimental Brain Research, 152, 29–41.

  5. Ferraro, F. R. (1996). Cognitive slowing in closed-head injury. Brain and Cognition, 32, 429–440.

  6. Gronwall, D. M. A., & Whrightson, P. (1975). Cumulative effect of concussion. Lancet, 2, 995–997.

  7. Hein, G., Schubert, T., & von Cramon, D. Y. (2005). Closed head injury and perceptual processing in dual-task situations. Experimental Brain Research, 160, 223–234.

  8. Hunter, J. E., & Schmidt, F. L. (1990). Methods of meta-analysis: Correcting error and bias in research findings. Newbury Park, CA: Sage Publications.

  9. Jennett, B., & Bond, M. (1975). Assessment of outcome after severe brain damage. Lancet, 1, 480–484.

  10. Jennett, B., Snoek, J., Bond, M. R., & Brooks, N. (1981). Disability after severe head injury: Observations on the use of the Glasgow Outcome Scale. Journal of Neurology, Neurosurgery, and Psychiatry, 44, 285–293.

  11. Leclercq, M., Couillet, J., Azouvi, P., Marlier, N., Martin, Y., Strypstein, E., & Rousseaux, M. (2000). Dual task performance after severe diffuse traumatic brain injury or vascular prefrontal damage. Journal of Clinical and Experimental Neuropsychology, 22, 339–350.

  12. Levin, H. S., & Grossman, R. G. (1979). The Galveston Orientation and Amnesia Test. A practical scale to assess cognition after head injury. Journal of Nervous and Mental Disease, 167, 675–684.

  13. McCann, R. S., & Johnston, J. C. (1992). Locus of the single-channel bottleneck in dual-task interference. Journal of Experimental Psychology: Human Perception and Performance, 18, 471–484.

  14. Miller, E. (1970). Simple and choice reaction time following severe head injury. Cortex, 6, 121–127.

  15. Park, N. W., Moscovitch, M., & Robertson, I. H. (1999). Divided attention impairments after traumatic brain injury. Neuropsychologia, 37, 1119–1133.

  16. Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory. Psychological Bulletin, 116, 220–244.

  17. Pashler, H., & Johnston, J. C. (1989). Chronometric evidence for central postponement in temporally overlapping tasks. Quarterly Journal of Experimental Psychology, 41A, 19–45.

  18. Pashler, H., & Johnston, J. C. (1998). Attentional limitations in dual-task performance. In H. Pashler (Ed.), Attention (pp. 155–189). Hove, UK: Psychology Press.

  19. Richer, F., Bédard, S., Lepage, M., & Chouinard, M.-J. (1998). Frontal lesions produce a dual-task deficit in simple rapid choices. Brain and Cognition, 37, 173–175.

  20. Ruthruff, E., Van Selst, M., & Johnston, J. C. (2005). How does practice reduce dual-task interference: Integration, automatization, or just stage-shortening? Psychological Research (in press).

  21. Schubert, T. (1999). Processing differences between simple and choice reactions affect bottleneck localization in overlapping tasks. Journal of Experimental Psychology: Human Perception and Performance, 25, 408–425.

  22. Spinnler, H., & Tognoni, G. (1987). Standardizzazione e taratura italiana di test neuropsicologici [Standardization for Italian of neuropsychological tests]. Journal of Neurological Sciences, Supplementum 8.

  23. Stablum, F., Leonardi, G., Mazzoldi, M., Umiltà, C., & Morra, S. (1994). Attention and control deficits following closed head injury. Cortex, 30, 603–618.

  24. Van Selst, M., & Jolicoeur, P. (1994) A solution to the effect of sample size and skew on outlier elimination. Quarterly Journal of Experimental Psychology, 47A, 631–650.

  25. Van Selst, M., & Jolicoeur, P. (1997). Decision and response in dual-task interference. Cognitive Psychology, 33, 266–307.

  26. Welford, A. T. (1959). Evidence of a single-channel decision mechanism limiting performance in a serial reaction task. Quarterly Journal of Experimental Psychology, 11, 193–210.

Download references

Author information

Correspondence to Roberto Dell’Acqua.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Dell’Acqua, R., Sessa, P. & Pashler, H. A neuropsychological assessment of dual-task costs in closed-head injury patients using Cohen’s effect size estimation method. Psychological Research 70, 553–561 (2006).

Download citation


  • Stimulus Onset Asynchrony
  • Psychological Refractory Period
  • Short Stimulus Onset Asynchrony
  • Psychological Refractory Period Effect
  • Colored Disk