Kohs Block-Design Test (1923) - Foundational Non-Verbal IQ Test

Kohs Block-Design Test: Foundational block-design IQ test

Non-verbal performance test using colored wooden blocks. Subject must reproduce printed designs by arranging the blocks. S.C. Kohs published the standardized version in 1923; the test is the direct ancestor of the Wechsler Block Design subtest (1939, still in active use in WAIS-IV and WISC-V).

About the Kohs Block-Design Test

S.C. Kohs spent the early 1920s developing a standardized non-verbal performance test using 16 colored wooden cubes (each face a different color or color-divided design). The subject was shown a printed pattern card and had to arrange the cubes to reproduce the pattern. Items ranged in difficulty from a simple 4-block 2x2 pattern to a complex 16-block 4x4 design with diagonal elements.

Kohs's test was published in 1923 in his book Intelligence Measurement, which provided complete administration procedures, scoring rules, and standardization data. The test measured visuospatial analysis, planning, and motor coordination - it loaded heavily on what Wechsler later called 'Performance IQ'.

David Wechsler adopted the Kohs Block Design Test essentially unchanged as a core subtest of the Wechsler-Bellevue Intelligence Scale (1939). It has remained a core subtest in every subsequent Wechsler battery: WAIS, WAIS-R, WAIS-III, WAIS-IV (current), WISC, WISC-R, WISC-III, WISC-IV, WISC-V. The Kohs Block Design is one of the most administered cognitive measures in clinical practice; tens of millions of administrations have occurred since 1923.

About this interactive version: The Kohs Block Design Test requires 16 physical wooden cubes with specific color patterns on their faces. The original test cannot be administered in a browser. The current Wechsler version is essentially identical to the Kohs original.

The 1 subtests

Block Design (17 graded items) Each item shows a printed pattern; subject reproduces it using the colored cubes. Items range from 4-block 2x2 patterns (easy) to 16-block 4x4 diagonal patterns (very hard). Scored on accuracy + time bonus.

Blocks Required

Source

All test materials and historical content on this page are transcribed from:

Kohs, S. C. (1923). Intelligence Measurement: A Psychological and Statistical Study Based upon the Block-Design Tests. New York: Macmillan.

Public domain (US, pre-1929). Samuel Calmin Kohs was at the Portland (Oregon) school district and later at the Vineland Training School. The Block-Design Test became one of the most-used non-verbal cognitive measures of the 20th century. Read it on Internet Archive: https://archive.org/details/00530970R.nlm.nih.gov.

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