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How does practice reduce dual-task interference: Integration, automatization, or just stage-shortening?

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Abstract

The present study assessed three hypotheses of how practice reduces dual-task interference: Practice teaches participants to efficiently integrate performance of a task pair; practice promotes automatization of individual tasks, allowing the central bottleneck to be bypassed; practice leaves the bottleneck intact but shorter in duration. These hypotheses were tested in two transfer-of-training experiments. Participants received one of three training types (Task 1 only, or Task 2 only, or dual-task), followed by dual-task test sessions. Practice effects in Experiment 1 (Task 1: auditory–vocal; Task 2: visual–manual) were fully explained by the intact bottleneck hypothesis, without task integration or automatization. This hypothesis also accounted well for the majority of participants when the task order was reversed (Experiment 2). In this case, however, there were multiple indicators that several participants had succeeded in eliminating the bottleneck by automatizing one or both tasks. Neither experiment provided any evidence that practice promotes efficient task integration.

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Notes

  1. Stage-shortening is an inevitable consequence of task practice. It plays a critical role in the intact bottleneck hypothesis—in fact, it is the sole cause of PRP reduction. Although the task integration and task automatization hypotheses also allow for stage-shortening, it is not assumed to be the principle cause of PRP reduction (e.g., if the bottleneck is bypassed, then interference will be small regardless of stage durations).

  2. A chi-squared test revealed that this difference is statistically significant, χ2(1) = 5.581, p < .05. The difference between experiments is also significant using Fisher’s exact test (p = .0497, two-tailed), which is more appropriate given cell frequencies less than 5.

  3. One complication for the hypothesis that Task 2 automatization was the key to bypassing the bottleneck is that one of the bypassers had not practiced Task 2 during the training phase. Nevertheless, this individual did respond very quickly to Task 2 at the long SOA (M = 376 ms) but not to Task 1 (M = 527 ms). It is possible that this person was naturally skilled at Task 2 and was able to achieve automatization relatively quickly (e.g., during the practice session).

References

  • Allport, D. A., Antonis, B., & Reynolds, P. (1972). On the division of attention: A disproof of the single channel hypothesis. Quarterly Journal of Experimental Psychology, 24, 225–235.

    CAS  PubMed  Google Scholar 

  • Bertelson, P., & Tisseyre, F. (1969). Refractory period of c-reactions. Journal of Experimental Psychology, 79, 122–128.

    Google Scholar 

  • Davis, R. (1956). The limits of the “Psychological Refractory Period.” Quarterly Journal of Experimental Psychology, 8, 24–38.

    Google Scholar 

  • Davis, R. (1957). The human operator as a single channel information system. Quarterly Journal of Experimental Psychology, 9, 119–129.

    Google Scholar 

  • De Jong, R. (1993). Multiple bottlenecks in overlapping task performance. Journal of Experimental Psychology: Human Perception and Performance, 19, 965–980.

    Article  PubMed  Google Scholar 

  • De Jong, R. (1995). The role of preparation in overlapping-task performance. Quarterly Journal of Experimental Psychology, 48, 2–25.

    PubMed  Google Scholar 

  • Dutta, A., & Walker, B. N. (1995, November). Persistence of the PRP effect: Evaluating the response-selection bottleneck. Poster presented at the 36th Annual Meeting of the Psychonomic Society, Los Angeles.

  • Fletcher, B. C., & Rabbitt, P. M. A. (1978). The changing pattern of perceptual analytic strategies and response selection with practice in a two-choice reaction time task. Quarterly Journal of Experimental Psychology, 30, 417–427.

    CAS  PubMed  Google Scholar 

  • Greenwald, A., & Shulman, H. G. (1973). On doing two things at once. II. Elimination of the psychological refractory period effect. Journal of Experimental Psychology, 101, 70–76.

    CAS  PubMed  Google Scholar 

  • Greenwald, A. G. (1972). On doing two things at once. I. Time-sharing as a function of ideomotor compatibility. Journal of Experimental Psychology, 94, 52–57.

    CAS  PubMed  Google Scholar 

  • Greenwald, A. G. (2003). On doing two things at once. III. Confirmation of perfect timesharing when simultaneous tasks are ideomotor compatible. Journal of Experimental Psychology: Human Perception and Performance, 29, 859–868.

    Article  PubMed  Google Scholar 

  • Hazeltine, E., Teague, D., & Ivry, R. B. (2002). Simultaneous dual-task performance reveals parallel response selection. Journal of Experimental Psychology: Human Perception and Performance, 28, 527–545.

    Article  PubMed  Google Scholar 

  • Hazeltine, E., Ruthruff, E., & Remington, R. W. (2004). The pairings of stimulus and responses modalities affect dual-task costs. Manuscript submitted for publication.

  • Hick, W. E. (1948). The discontinuous function of the human operator in pursuit tasks. Quarterly Journal of Experimental Psychology, 1, 36–51.

    Google Scholar 

  • Hirst, W., Spelke, E. S., Reaves, C. C., Caharack, G., & Neisser, U. (1980). Dividing attention without alternation or automaticity. Journal of Experimental Psychology: General, 109, 98–117.

    Google Scholar 

  • Johnston, J. C., & Delgado, D. F. (1993, November). Bypassing the single-channel bottleneck in dual-task performance. Paper presented to the 34th annual meeting of the Psychonomic Society, Washington D.C.

  • Kahneman, D. (1973). Attention and effort. Englewood Cliffs, NJ: Prentice-Hall.

  • Karlin, L., & Kestenbaum, R. (1968). Effects of number of alternatives on the psychological refractory period. Quarterly Journal of Experimental Psychology, 20, 167–178.

    CAS  PubMed  Google Scholar 

  • Keele, S. (1973). Attention and human performance. Pacific Palisades, CA: Goodyear.

  • Levy, J., & Pashler, H. (2001). Is dual-task slowing instruction dependent? Journal of Experimental Psychology: Human Perception and Performance, 27, 862–869.

    Article  CAS  PubMed  Google Scholar 

  • Lien, M.-C., & Proctor, R. W. (2002). Stimulus-response compatibility and psychological refractory period effects: Implications for response selection. Psychonomic Bulletin & Review, 9, 212–238.

    Google Scholar 

  • Lien, M.-C., & Ruthruff, E. (2004). Task switching in a hierarchical task structure: Evidence for the fragility of the task repetition benefit. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30, 697–713.

    Google Scholar 

  • Lien, M.-C., Proctor, R. W., & Allen, P. A. (2002). Ideomotor compatibility in the psychological refractory period effect: 29 years of oversimplification. Journal of Experimental Psychology: Human Perception and Performance, 28, 396–409.

    Article  PubMed  Google Scholar 

  • Lien, M.-C., Proctor, R. W., & Ruthruff, E. (2003). Still no evidence for perfect timesharing with two ideomotor compatible tasks: An observation on Greenwald (2003). Journal of Experimental Psychology: Human Perception and Performance, 29, 1267–1272.

    Article  PubMed  Google Scholar 

  • Lien, M.-C., McCann, R. E., Ruthruff, E., & Proctor, R. W. (in press). Processing limitations in dual-task performance: Can the central bottleneck be bypassed with ideomotor compatible tasks? Journal of Experimental Psychology: Human Perception and Performance.

  • Maquestiaux, F., Hartley, A. A., Bertsch, J. (in press). Can practice overcome age-related differences in the psychological refractory period effect? Psychology and Aging.

  • 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.

    Article  Google Scholar 

  • Meyer, D. E., & Kieras, D. E. (1997a). A computational theory of human multiple-task performance: The EPIC information-processing architecture and strategic response deferment model. Psychological Review, 104, 1–65.

    Google Scholar 

  • Meyer, D. E., & Kieras, D. E. (1997b). A computational theory of human multiple-task performance. II. Accounts of psychological refractory phenomena. Psychological Review, 107, 749–791.

    Google Scholar 

  • Mowbray, G. H., & Rhoades, M. V. (1959). On the reduction of choice reaction times with practice. The Quarterly Journal of Experimental Psychology, 14, 1–36.

    Google Scholar 

  • Pashler, H. (1994). Graded capacity-sharing in dual-task interference? Journal of Experimental Psychology: Human Perception and Performance, 20, 330–342.

    Article  CAS  PubMed  Google Scholar 

  • Pashler, H., & Baylis, G. (1991). Procedural learning. I. Locus of practice effects in speeded choice tasks. Journal of Experimental Psychology: Learning, Memory and Cognition, 17, 20–32.

    Article  Google Scholar 

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

    Google Scholar 

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

  • Pashler, H., Carrier, M., & Hoffman, J. (1993). Saccadic eye movements and dual-task interference. Quarterly Journal of Experimental Psychology, 46A, 51–82.

    Google Scholar 

  • Posner, M. I., Nissen, J. M., & Klein, R. (1976). Visual dominance: An information processing account of its origins and significance. Psychological Review, 83, 157–171.

    Article  CAS  PubMed  Google Scholar 

  • Ruthruff, E., Miller, J. O., & Lachmann, T. (1995). Does mental rotation require central mechanisms? Journal of Experimental Psychology: Human Perception and Performance, 21, 552–570.

    Article  CAS  PubMed  Google Scholar 

  • Ruthruff, E., Pashler, H. E., & Klaassen, A. (2001). Processing bottlenecks in dual-task performance: Structural limitation or voluntary postponement? Psychonomic Bulletin & Review, 8, 73–80.

    CAS  Google Scholar 

  • Ruthruff, E., Johnston, J. C., & Van Selst, M. (2001). Why practice reduces dual-task interference. Journal of Experimental Psychology: Human Perception and Performance, 27, 3–21.

    Article  CAS  PubMed  Google Scholar 

  • Ruthruff, E., Pashler, H., & Hazeltine, E. (2003). Dual-task interference with equal task emphasis: Graded capacity-sharing or central postponement? Perception and Psychophysics, 65, 801–816.

    PubMed  Google Scholar 

  • Ruthruff, E., Johnston, J. C., Van Selst, M. A., Whitsell, S., & Remington, R. (2003). Vanishing dual-task interference after practice: Has the bottleneck been eliminated or is it merely latent? Journal of Experimental Psychology: Human Perception and Performance, 29, 280–289.

    Article  PubMed  Google Scholar 

  • Schumacher, E. H., Seymour, T. L., Glass, J. M., Fencsik, D., Lauber, E., Kieras, D. E., & Meyer, D. E. (2001). Virtually perfect time sharing in dual-task performance: Uncorking the central attentional bottleneck. Psychological Science, 12, 101–108.

    Article  CAS  PubMed  Google Scholar 

  • Schweickert, R. (1978). A critical path generalization of the additive factor method: Analysis of a Stroop task. Journal of Mathematical Psychology, 18, 105–139.

    Article  Google Scholar 

  • Shaffer, L. H. (1975). Multiple attention in continuous verbal tasks. In P. M. A. Rabbitt & S. Dornic (Eds.) Attention and Performance V (pp.157–167). San Diego, CA: Academic.

  • Spelke, E. S., Hirst, W. C., & Neisser, U. (1976). Skills of divided attention. Cognition, 4, 215–230.

    Article  Google Scholar 

  • Tombu, M., & Jolicoeur, P. (2000, November). Is the PRP effect due to a strategic or structural bottleneck? Paper presented at the 41st annual meeting of the Psychonomic Society, New Orleans, LA.

  • Van Selst, M., & Johnston, J. C. (1997, November). Modality modulates PRP interference. Presented at the 38th annual meeting of the Psychonomic Society, Philadelphia.

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

    Google Scholar 

  • Van Selst, M., & Jolicoeur, P. (1997). Decision and response. Cognitive Psychology, 33, 266–307.

    Article  PubMed  Google Scholar 

  • Van Selst, M., Ruthruff, E., & Johnston, J. C. (1999). Can practice eliminate the Psychological Refractory Period effect? Journal of Experimental Psychology: Human Perception and Performance, 25, 1268–1283.

    Article  PubMed  Google Scholar 

  • Welford, A. T. (1952). The “psychological refractory period” and the timing of high-speed performance—A review and a theory. British Journal of Psychology, 43, 2–19.

    Google Scholar 

  • Welford, A. T. (1976). Skilled performance: Perceptual and motor skills. Glenview, IL: Scott, Foresman.

  • Wickens, C. D., & Liu, Y. (1988). Codes and modalities in multiple resources: A success and a qualification. Human Factors, 30, 599–616.

    CAS  PubMed  Google Scholar 

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Acknowledgements

This research was funded by the Airspace Operations Systems Project of NASA’s Airspace Systems Program. We thank Mei-Ching Lien, Hal Pashler, and Robert Proctor for helpful comments on an earlier draft of the paper.

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Authors and Affiliations

  1. MS 262–4, NASA Ames Research Center, Moffett Field, CA 94035, USA

    Eric Ruthruff, James C. Johnston & Roger Remington

  2. Department of Psychology, San José State University, San José, CA 95192, USA

    Mark Van Selst

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  1. Eric Ruthruff
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Correspondence to Eric Ruthruff.

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Ruthruff, E., Van Selst, M., Johnston, J.C. et al. How does practice reduce dual-task interference: Integration, automatization, or just stage-shortening?. Psychological Research 70, 125–142 (2006). https://doi.org/10.1007/s00426-004-0192-7

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