Behavior Research Methods

, Volume 46, Issue 2, pp 472–487 | Cite as

The Leuven Perceptual Organization Screening Test (L-POST), an online test to assess mid-level visual perception

  • Katrien Torfs
  • Kathleen Vancleef
  • Christophe Lafosse
  • Johan Wagemans
  • Lee de-WitEmail author


Neuropsychological diagnostic tests of visual perception mostly assess high-level processes like object recognition. Object recognition, however, relies on distinct mid-level processes of perceptual organization that are only implicitly tested in classical tests. The Leuven Perceptual Organization Screening Test (L-POST) fills a gap with respect to clinically oriented tests of mid-level visual function. In 15 online subtests, a range of mid-level processes are covered, such as figure–ground segmentation, local and global processing, and shape perception. We also test the sensitivity to a wide variety of perceptual grouping cues, like common fate, collinearity, proximity, and closure. To reduce cognitive load, a matching-to-sample task is used for all subtests. Our online test can be administered in 20–45 min and is freely available at The online implementation enables us to offer a separate interface for researchers and clinicians to have immediate access to the raw and summary results for each patient and to keep a record of their patient’s entire data. Also, each patient’s results can be flexibly compared with a range of age-matched norm samples. In conclusion, the L-POST is a valuable screening test for perceptual organization. The test allows clinicians to screen for deficits in visual perception and enables researchers to get a broader overview of mid-level visual processes that are preserved or disrupted in a given patient.


Perceptual organization Screening test Neuropsychology Brain damage Mid-level vision Shape perception 



We wish to thank the neuropsychologists and the patients from Revarte Rehabilitation Hospital (Edegem) for their kind cooperation and feedback in the development of this test. We would also like to thank Niko Troje, Naoki Kogo, Maarten Demeyer, and three master students, Tim Stekelinck, Sofie Vanthienen, and Ellen Olbrechts, for assistance with the construction of some of the subtest stimuli, Rudy Dekeerschieter for the technical implementation of the L-POST, and Elia Acke and Glyn Humphreys for their help in testing the two case studies reported here. This work was supported by a Methusalem Grant (Meth/08/02) awarded to Johan Wagemans from the Flemish Government. Lee de-Wit was supported by a postdoctoral fellowship from the Research Foundation–Flanders (FWO). Katrien Torfs and Kathleen Vancleef contributed equally to this work.


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Copyright information

© Psychonomic Society, Inc. 2013

Authors and Affiliations

  • Katrien Torfs
    • 1
    • 2
  • Kathleen Vancleef
    • 1
  • Christophe Lafosse
    • 1
    • 3
  • Johan Wagemans
    • 1
  • Lee de-Wit
    • 1
    Email author
  1. 1.Laboratory of Experimental PsychologyUniversity of LeuvenLeuvenBelgium
  2. 2.Psychological Sciences Research Institute and Institute of NeuroscienceUniversity of LouvainLouvain-la-NeuveBelgium
  3. 3.Rehabilitation Hospital RevArteEdegemBelgium

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