"Only a lot of patience"
Bourdon's paper, "Comparative observations on recognition, discrimination and association", ran to 32 pages in the Revue philosophique. Alfred Binet reviewed it the same year in his new journal.1
Binet placed Bourdon among those who thought psychologists should move past sensations to the higher functions of understanding. He also noted that experiments of this kind needed no apparatus, and that Bourdon had chosen letters and words as his material.1
« … n'exigent point d'appareils, mais seulement beaucoup de patience, et quelques personnes de bonne volonté. »
Cross out a, e and r in text you can't read
Bourdon's subjects struck three target letters in text printed in a language they didn't know.
Letter mode uses generated pseudo-words, so nobody can read them. Square mode follows Toulouse and Piéron's idea of squares told apart by the position of an attached stroke.4 Layouts, timing and scoring are our own, and there are no norms. Missed targets are ringed when time runs out.
Letters, then squares, then dots
French psychology calls this the test de barrage: crossing out the same letters or signs in a series, as a measure of concentrated attention.9
References
- [1]Binet, A. (1895). Review of Bourdon, "Observations comparatives sur la reconnaissance, la discrimination et l'association" (Revue philosophique, Aug. 1895, 153–185). L'Année psychologique, 2, 693–697. Persée.persee.fr
- [2]Wikipedia contributors. Benjamin B. Bourdon (accessed 1 Oct 2026).en.wikipedia.org
- [3]Wikipedia contributors. Dot cancellation test (accessed 1 Oct 2026).en.wikipedia.org
- [4]L'examen individuel et la recherche en psychologie de l'enfant: historique du test de barrage. Bulletin de psychologie 13 (1960). Persée.persee.fr
- [5]Repertorios cognoscitivos de atención, percepción y memoria (working paper). ResearchGate.researchgate.net
- [6]Wikipedia contributors. Henri Piéron (accessed 1 Oct 2026).en.wikipedia.org
- [7]Psychologies expérimentales: cultures expérimentales fin de siècle. Mil neuf cent (2006). Cairn.shs.cairn.info
- [8]Wikipedia contributors. Bourdon illusion (accessed 1 Oct 2026).en.wikipedia.org
- [9]Test de barrage. Grand dictionnaire terminologique, Office québécois de la langue française.vitrinelinguistique.oqlf.gouv.qc.ca
Related historical tests
Brickenkamp's d2 keeps Bourdon's basic act of striking targets among distractors. It adds tight time limits per row, which makes errors and speed easier to separate.
Kraepelin measured sustained work with simple additions over long sessions. Like Bourdon's, his test made attention visible as a trace of work over time.
Binet reviewed Bourdon in the same volume where he and Henri set out their programme of individual psychology. Both argued for studying higher functions without apparatus.
Bourdon used unreadable text so that reading couldn't interfere. Stroop made reading interfere on purpose, by printing colour names in clashing inks.
Trail Making also asks for fast visual search across a page. Part B adds a switching demand that plain cancellation tests don't have.