Knox Cube Imitation Test: The Ellis Island block-tapping test

About the Knox Cube Imitation Test

The US Public Health Service was responsible for screening arriving immigrants at Ellis Island for various conditions including mental deficiency. With over a million arrivals per year speaking dozens of languages, the standard Binet scale was useless. Howard Knox, the senior PHS surgeon at Ellis Island, developed a battery of non-verbal tests including the cube imitation task that bears his name.

The procedure: four wooden cubes are placed in a row in front of the subject. The examiner taps a sequence on the cubes (e.g., cube 1, then cube 3, then cube 2, then cube 4). The subject must imitate the sequence exactly. Sequences range from 2 taps (easy) to 9 taps (very hard). The score is the longest sequence the subject can reliably reproduce.

The Knox Cube Test was incorporated into the Yerkes-Bridges Point Scale (1915) and into many subsequent batteries. Modern neuropsychology uses essentially the same task under the names Block Tapping (Corsi), Spatial Span (WAIS-IV), and the digital touchscreen version in cognitive testing apps. The Knox Cube remains one of the most direct measurable correlates of visual-spatial working memory in the entire psychometric literature.

The 1 subtests

Source

All test materials and historical content on this page are transcribed from:

Knox, H. A. (1914). A scale, based on the work at Ellis Island, for estimating mental defect. JAMA, 62(10), 741-747.

Public domain - US government work (Knox was a Public Health Service physician). Howard Knox was the Senior Surgeon at the US Public Health Service detail at Ellis Island. He developed the cube test (and several other non-verbal items) specifically for immigrants who spoke no English. The published 1914 paper describes the procedure and the scoring.