Home/Historical IQ Tests/Kraepelin 1895
EMIL KRAEPELIN · 1856–1926 · 7 SOURCES

A curve, not a score.

Kraepelin had people add single digits for long stretches, then plotted how much they did minute by minute. The shape of that "work curve" was the result. Kraepelin considered it his chief scientific contribution, ahead of his famous division of psychoses.3

ONE ROW PER MINUTE, TWO HALVES
Illustrative curve. In the Japanese version, a pause separates the two halves, and the second half usually starts higher.

A laboratory method that became a test

Kraepelin only meant to analyse the work process in the laboratory, not to build a personality test. That came later, in Japan.2

1880sLeipzig, with WundtKraepelin begins the experimental work he pursues under Wundt's guidance. The two remain friends for life.1
1886–91TartuAs professor in Tartu he is more interested in psychology than in clinical work he finds unsatisfying.3
1912"The curve of work"Thorndike publishes his own study of continuous addition, part of the contemporary recognition Kraepelin's school received.3
1927Uchida's adaptationIn Japan, Yuzaburo Uchida, then at Matsuzawa Psychiatric Hospital, publishes his version as a personality test. Psychiatrists there had been retesting Kraepelin's method.2
LaterStandardised in EuropeGermany standardises the Arbeitskurve nach Kraepelin with the Pauli test (Mainz revision), and the Czech Republic issues its own edition.5
EXPLORE · KRAEPELIN'S COMPONENTS

Add up the forces behind one curve

Kraepelin treated the curve as the sum of positive effects (the drive to act) and negative ones (fatigue).5 Japanese researchers later tried to verify his proposed work factors: Übung, Gewöhnung, Ermüdung, Antrieb and Anregung.4 Switch them on and off.

Minute 1Output per minute (baseline dashed)Minute 15
A schematic model. The components are Kraepelin's, but their sizes are invented to show direction and timing only.
TAKE IT · TWO HALVES · ABOUT 2½ MINUTES

Add each pair, type the last digit

A compressed version of the Japanese procedure. Figures from 3 to 9 run in rows, you move to a new row at a fixed interval, and a pause separates two halves.2 Here you type only the last digit of each sum, so 7 + 8 gives 5.

0:00Ready
749385639748
Your work curve: correct answers per row
A1A2A3A4pauseB1B2B3B4
Correct0
Errors0
First half → second half—
First row vs last row of half A—

The real test uses 15-minute halves after 2 minutes of practice, a 5-minute pause, and one-minute rows.2,6 Here there are four 15-second rows per half and a 15-second pause, so treat the curve as a demonstration, not a diagnosis. Nothing leaves your browser.

Two national afterlives

JAPANThe Uchida-Kraepelin testCalled the most original personality test developed by Japanese psychologists, it diagnoses temperament from addition work and spread throughout Japan.2
WHAT THE CURVE CARRIESPatterns inside one curveFactor studies found each person's curve is built from several patterns. When one pattern dominates, the curve stays fairly stable over repeated testing.7
EUROPEThe Pauli lineThe Kraepelin work curve was standardised alongside Pauli's version in Germany, and separately in the Czech Republic.5
Kraepelin is remembered as the founder of modern psychiatry. Yet he and his students pioneered four branches of psychology: pharmacopsychology, individual differences, sleep studies and the work curve. Their contemporaries recognised this work, and later generations largely forgot it.3

References

  1. [1]Emil Kraepelin and experimental psychology (book chapter). Springer.link.springer.com
  2. [2]Kuraishi, S., Kato, M., & Tsujioka, B. (1957). Development of the "Uchida-Kraepelin Psychodiagnostic Test" in Japan. Psychologia, 1, 104–109. J-STAGE (PDF).jstage.jst.go.jp
  3. [3]Allik, J. (2016). Why was Emil Kraepelin not recognized as a psychologist? TRAMES, 20(4), 369–391 (PDF).kirj.ee
  4. [4]Factorial studies on the work curve of the Uchida-Kraepelin Psychodiagnostic Test. Japanese Journal of Psychology, 31(2), 103. J-STAGE.jstage.jst.go.jp
  5. [5]Evaluation of the Uchida-Kraepelin psycho-diagnostic test based on addition work from the view of the Big Five. ResearchGate.researchgate.net
  6. [6]Uchida-Kraepelin psychological test: methods. Ice Cream Tutor.icecreamtutor.com
  7. [7]A factorial study of the Uchida-Kraepelin Psychodiagnostic Test. Japanese Journal of Psychology, 43(4), 176. J-STAGE.jstage.jst.go.jp
HOW TO CITE THIS PAGE
What's Your IQ. (2026). Kraepelin Continuous Arithmetic Test (1895). In Historical IQ Tests Archive. Retrieved October 1, 2026, from /en/historical-iq-tests/kraepelin-arithmetic-1895
EDITORIAL RECORD
First published2026
Last reviewed1 October 2026
Sources7: histories of the work curve, Uchida-Kraepelin studies and reviews
Open questionsWhich 1895 publication the archive date refers to; Kraepelin's own session lengths
Canonical URLwhats-your-iq.com/en/historical-iq-tests/kraepelin-arithmetic-1895

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Part of the Historical IQ Tests Archive. Editorial content under CC BY-SA 4.0. Kraepelin's writings are in the public domain; the Uchida-Kraepelin materials are not reproduced.

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