CFS MATLAB toolbox: An experiment builder for continuous flash suppression (CFS) task

  • Mikko Nuutinen
  • Terhi Mustonen
  • Jukka Häkkinen


CFS toolbox is an open-source collection of MATLAB functions that utilizes PsychToolbox-3 (PTB-3). It is designed to allow a researcher to create and run continuous flash suppression experiments using a variety of experimental parameters (i.e., stimulus types and locations, noise characteristics, and experiment window settings). In a CFS experiment, one of the eyes at a time is presented with a dynamically changing noise pattern, while the other eye is concurrently presented with a static target stimulus, such as a Gabor patch. Due to the strong interocular suppression created by the dominant noise pattern mask, the target stimulus is rendered invisible for an extended duration. Very little knowledge of MATLAB is required for using the toolbox; experiments are generated by modifying csv files with the required parameters, and result data are output to text files for further analysis. The open-source code is available on the project page under a Creative Commons License ( and


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  1. Brainard, D. H. (1997). The psychophysics toolbox. Spatial Vision, 10 (4), 433–436. Scholar
  2. Gayet, S., Paffen, C. L. E., & Van der Stigchel, S. (2013). Information matching the content of visual working memory is prioritized for conscious access. Psychological Science, 24 (12), 2472–2480. Scholar
  3. Gayet, S., Van der Stigchel, S., & Paffen, C. L. E. (2014). Seeing is believing: Utilization of subliminal symbols requires a visible relevant context. Attention, Perception, & Psychophysics, 76(2), 489–507. Scholar
  4. Gelbard-Sagiv, H., Faivre, N., Mudrik, L., & Koch, C. (2016). Low-level awareness accompanies “unconscious” high-level processing during continuous flash suppression. Journal of Vision, 16(1), 3. Scholar
  5. Hesselmann, G., Darcy, N., Ludwig, K., & Sterzer, P. (2016). Primingin a shape task but not in a category task under continuous flash suppression. Journal of Vision, 16(3), 17. Scholar
  6. Hong, S. W. (2015). Radial bias for orientation and direction of motion modulates access to visual awareness during continuous flash suppression. Journal of Vision, 15(1), 3. Scholar
  7. Jiang, Y., Costello, P., & He, S. (2007). Processing of invisible stimuli: Advantage of upright faces and recognizable words in overcoming interocular suppression. Psychological Science, 18(4), 4 349–355. Scholar
  8. Kleiner, M., Brainard, D., Pelli, D., Ingling, A., Murray, R., & Broussard, C. (2007). What’s new in psychtoolbox-3. Perception, 36(14), 1–16. Scholar
  9. Moors, P., Wagemans, J., & de Wit, L. (2016a). Faces in commonly experienced configurations enter awareness faster due to their curvature relative to fixation. PeerJ, 4, e1565.
  10. Moors, P., Wagemans, J., van Ee, R., & de Wit, L. (2016b). No evidence for surface organization in Kanizsa configurations during continuous flash suppression. Attention, Perception, & Psychophysics, 78(3), 902–914.
  11. Moors, P., Wagemans, J., van Ee, R., & de Wit, L. (2016c). Scene integration without awareness: No conclusive evidence for processing scene congruency during continuous flash suppression. Psychological Science, 27 (7), 45–56.
  12. Peirce, J. (2006). Psychopy—psychophysics software in python. Journal of Neuroscience Methods, 162, 8–13. Scholar
  13. Peirce, J. (2009). Generating stimuli for neuroscience using psychopy. Frontiers in Neuroinformatics, 2, 10. Scholar
  14. Pelli, D. (1997). The Video Toolbox software for visual psychophysics: Transforming numbers into movies. Spatial Vision, 10(4), 437–442. Scholar
  15. Stein, T., Thoma, V., & Sterzer, P. (2015). Priming of object detection under continuous flash suppression depends on attention but not on part-whole configuration. Journal of Vision, 15(3), 15. Scholar
  16. Tsuchiya, N., & Koch, C. (2005). Continuous flash suppression reduces negative afterimages. Nature Neuroscience, 8(8), 1096–1101. Scholar
  17. Tsuchiya, N., Koch, C., Gilroy, L. A., & Blake, R. (2006). Depth of interocular suppression associated with continuous flash suppression,flash suppression, and binocular rivalry. Journal of Vision, 6(10), 6. Scholar
  18. Yang, E., & Blake, R. (2012). Deconstructing continuous flash suppression. Journal of Vision, 12(3), 8. Scholar
  19. Yang, Y. H., & Yeh, S. L. (2011). Accessing the meaning of invisible words. Consciousness and Cognition, 20(2), 223–233. Scholar
  20. Zhu, W., Drewes, J., & Melcher, D. (2016). Time for awareness: The influence of temporal properties of the mask on continuous flash suppression effectiveness. PLoS ONE, 11(7), 1–15. Scholar

Copyright information

© Psychonomic Society, Inc. 2017

Authors and Affiliations

  • Mikko Nuutinen
    • 1
  • Terhi Mustonen
    • 1
  • Jukka Häkkinen
    • 1
  1. 1.Department of Psychology and Logopedics, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland

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