Psychonomic Bulletin & Review

, Volume 22, Issue 1, pp 251–257 | Cite as

Two visual targets for the price of one? Pupil dilation shows reduced mental effort through temporal integration

  • Michael J. Wolff
  • Sabine Scholz
  • Elkan G. Akyürek
  • Hedderik van Rijn
Brief Report


In dynamic sensory environments, successive stimuli may be combined perceptually and represented as a single, comprehensive event by means of temporal integration. Such perceptual segmentation across time is intuitively plausible. However, the possible costs and benefits of temporal integration in perception remain underspecified. In the present study pupil dilation was analyzed as a measure of mental effort. Observers viewed either one or two successive targets amidst distractors in rapid serial visual presentation, which they were asked to identify. Pupil dilation was examined dependent on participants’ report: dilation associated with the report of a single target, of two targets, and of an integrated percept consisting of the features of both targets. There was a clear distinction between dilation observed for single-target reports and integrations on the one side, and two-target reports on the other. Regardless of report order, two-target reports produced increased pupil dilation, reflecting increased mental effort. The results thus suggested that temporal integration reduces mental effort and may thereby facilitate perceptual processing.


Temporal integration Mental effort Attention Working memory Pupil dilation Rapid serial visual presentation 



The authors thank Sarah Maass and Johanna Kuhr for assistance with data acquisition and Udo Böhm for discussions.


  1. Akyürek, E. G., Eshuis, S. A. H., Nieuwenstein, M. R., Saija, J. D., Başkent, D., & Hommel, B. (2012). Temporal target integration underlies performance at Lag 1 in the attentional blink. Journal of Experimental Psychology. Human Perception and Performance, 38, 1448–1464.PubMedCrossRefGoogle Scholar
  2. Akyürek, E. G., & Meijerink, S. K. (2012). The deployment of visual attention during temporal integration: An electrophysiological investigation. Psychophysiology, 49, 885–898.PubMedCrossRefGoogle Scholar
  3. Akyürek, E. G., Schubö, A., & Hommel, B. (2010). Fast temporal event integration in the visual domain demonstrated by event-related potentials. Psychophysiology, 47, 512–522.PubMedCrossRefGoogle Scholar
  4. Akyürek, E. G., Toffanin, P., & Hommel, B. (2008). Adaptive control of event integration. Journal of Experimental Psychology. Human Perception and Performance, 34, 569–577.PubMedCrossRefGoogle Scholar
  5. Allport, D. A. (1968). Phenomenal simultaneity and the perceptual moment hypothesis. British Journal of Psychology, 59, 395–406.PubMedCrossRefGoogle Scholar
  6. Bates, D., Maechler, M., Bolker, B., & Walker, S. (2013). lme4: Linear mixed-effects models using Eigen and S4. (R package version 1.0-5) [Computer Software]. Retrieved from
  7. Beatty, J. (1982). Task-evoked pupillary responses, processing load, and the structure of processing resources. Psychological Bulletin, 91, 276–292.PubMedCrossRefGoogle Scholar
  8. Broadbent, D. E., & Broadbent, M. H. (1987). From detection to identification: Response to multiple targets in rapid serial visual presentation. Perception and Psychophysics, 42, 105–113.PubMedCrossRefGoogle Scholar
  9. Di Lollo, V., & Dixon, P. (1988). Two forms of persistence in visual information processing. Journal of Experimental Psychology. Human Perception and Performance, 14, 671–681.PubMedCrossRefGoogle Scholar
  10. Di Lollo, V., & Hogben, J. H. (1987). Suppression of visible persistence as a function of spatial separation between inducing stimuli. Perception and Psychophysics, 41, 345–354.PubMedCrossRefGoogle Scholar
  11. Dux, P. E., Wyble, B., Jolicœur, P., & Dell’Acqua, R. (2014). On the costs of lag-1 sparing. Journal of Experimental Psychology. Human Perception and Performance, 40, 416–428.PubMedCrossRefGoogle Scholar
  12. Efron, R. (1967). The duration of the present. Annals of the New York Academy of Sciences, 138, 713–729.CrossRefGoogle Scholar
  13. Eimer, M. (1996). The N2pc component as an indicator of attentional selectivity. Electroencephalography and Clinical Neurophysiology, 99, 225–234.PubMedCrossRefGoogle Scholar
  14. Eriksen, C. W., & Collins, J. F. (1967). Some temporal characteristics of visual pattern perception. Journal of Experimental Psychology, 74, 476–484.PubMedCrossRefGoogle Scholar
  15. Forget, J., Buiatti, M., & Dehaene, S. (2010). Temporal integration in visual word recognition. Journal of Cognitive Neuroscience, 22, 1054–1068.PubMedCrossRefGoogle Scholar
  16. Geerligs, L., & Akyürek, E. G. (2012). Temporal integration depends on increased prestimulus beta band power. Psychophysiology, 49, 1464–1467.PubMedCrossRefGoogle Scholar
  17. Hecht, S., & Verrijp, C. D. (1933). Intermittent stimulation by light: III. The relation between intensity and critical fusion frequency for different retinal locations. The Journal of General Physiology, 17, 251–268.PubMedCentralPubMedCrossRefGoogle Scholar
  18. Hess, E. H., & Polt, J. M. (1964). Pupil size in relation to mental activity during simple problem-solving. Science, 143, 1190–1192.PubMedCrossRefGoogle Scholar
  19. Hogben, J. H., & Di Lollo, V. (1974). Perceptual integration and perceptual segregation of brief visual stimuli. Vision Research, 14, 1059–1069.PubMedCrossRefGoogle Scholar
  20. Hommel, B., & Akyürek, E. G. (2005). Lag 1 sparing in the attentional blink: Benefits and costs of integrating two events into a single episode. Quarterly Journal of Experimental Psychology, 58A, 1415–1433.CrossRefGoogle Scholar
  21. Kiss, M., van Velzen, J., & Eimer, M. (2008). The N2pc component and its links to attention shifts and spatially selective visual processing. Psychophysiology, 45, 240–249.PubMedCentralPubMedCrossRefGoogle Scholar
  22. Long, G. M., & Beaton, R. J. (1982). The case for peripheral persistence: Effects of target and background luminance on a partial-report task. Journal of Experimental Psychology. Human Perception and Performance, 8, 383–391.PubMedCrossRefGoogle Scholar
  23. Miller, G. A. (1956). The magical number 7, plus or minus 2 – some limits on our capacity for processing information. Psychological Review, 63, 81–97.PubMedCrossRefGoogle Scholar
  24. Morey, R. D., & Rouder, J. N. (2013). Package BayesFactor, version 0.9.5.
  25. Olivers, C. N. L., Hilkenmeier, F., & Scharlau, I. (2011). Prior entry explains order reversals in the attentional blink. Attention, Perception, & Psychophysics, 73, 53–67.CrossRefGoogle Scholar
  26. Porter, G., Troscianko, T., & Gilchrist, I. (2007). Effort during visual search and counting: Insights from pupillometry. Quarterly Journal of Experimental Psychology, 60, 211–229.CrossRefGoogle Scholar
  27. Potter, M. C., Chun, M. M., Banks, B. S., & Muckenhoupt, M. (1998). Two attentional deficits in serial target search: The visual attentional blink and an amodal task-switch deficit. Journal of Experimental Psychology: Learning, Memory, and Cognition, 24, 979–992.PubMedGoogle Scholar
  28. Potter, M. C., Staub, A., & O’Connor, D. H. (2002). The time course of competition for attention: Attention is initially labile. Journal of Experimental Psychology. Human Perception and Performance, 28, 1149–1162.PubMedCrossRefGoogle Scholar
  29. Privitera, C. M., Renninger, L. W., Carney, T., Klein, S., & Aguilar, M. (2010). Pupil dilation during visual target detection. Journal of Vision, 10, 1–14.CrossRefGoogle Scholar
  30. Raymond, J. E., Shapiro, K. L., & Arnell, K. M. (1992). Temporary suppression of visual processing in an RSVP task: An attentional blink? Journal of Experimental Psychology. Human Perception and Performance, 18, 849–860.PubMedCrossRefGoogle Scholar
  31. Rouder, J. N., Morey, R. D., Speckman, P. L., & Province, J. M. (2012). Default Bayes factors for ANOVA designs. Journal of Mathematical Psychology, 56, 357–374.CrossRefGoogle Scholar
  32. Rousselet, G. A., Macé, M. J. M., & Fabre-Thorpe, M. (2003). Is it an animal? Is it a human face? Fast processing in upright and inverted natural scenes. Journal of Vision, 3, 440–455.PubMedCrossRefGoogle Scholar
  33. Saija, J. D., Andringa, T. C., Başkent, D., & Akyürek, E. G. (2014). Temporal integration of consecutive tones into synthetic vowels demonstrates perceptual assembly in audition. Journal of Experimental Psychology. Human Perception and Performance, 40, 857–869.PubMedCrossRefGoogle Scholar
  34. Tervaniemi, M., Saarinen, J., Paavilainen, P., Danilova, N., & Näätänen, R. (1994). Temporal integration of auditory information in sensory memory as reflected by the mismatch negativity. Biological Psychology, 38, 157–167.PubMedCrossRefGoogle Scholar
  35. Van Rijn, H., Dalenberg, J. R., Borst, J. P., & Sprenger, S. A. (2012). Pupil Dilation Co-Varies with Memory Strength of Individual Traces in a Delayed Response Paired-Associate Task. PLoS One, 7(12), e51134.PubMedCentralPubMedCrossRefGoogle Scholar
  36. VanRullen, R., & Thorpe, S. J. (2001). Is it a bird? Is it a plane? Ultra-rapid visual categorization of natural and artifactual objects. Perception, 30, 655–668.PubMedCrossRefGoogle Scholar
  37. Visser, T. A. W., Bischof, W. F., & Di Lollo, V. (1999). Attentional switching in spatial and non-spatial domains: Evidence from the attentional blink. Psychological Bulletin, 125, 458–469.CrossRefGoogle Scholar
  38. Visser, T. A. W., & Enns, J. T. (2001). The role of attention in temporal integration. Perception, 30, 135–145.PubMedCrossRefGoogle Scholar
  39. Wierda, S. M., Van Rijn, H., Taatgen, N. A., & Martens, S. (2012). Pupil dilation deconvolution reveals the dynamics of attention at high temporal resolution. Proceedings of the National Academy of Sciences U.S.A, 109, 8456–8460.CrossRefGoogle Scholar
  40. Zylberberg, A., Olivia, M., & Sigman, M. (2012). Pupil dilation: A fingerprint of temporal selection during the “Attentional Blink”. Frontiers in Psychology, 3, 1–6.CrossRefGoogle Scholar

Copyright information

© Psychonomic Society, Inc. 2014

Authors and Affiliations

  • Michael J. Wolff
    • 1
  • Sabine Scholz
    • 1
  • Elkan G. Akyürek
    • 1
  • Hedderik van Rijn
    • 1
  1. 1.Department of Psychology, Experimental PsychologyUniversity of GroningenGroningenThe Netherlands

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