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Public Domain · 1915

Yerkes-Bridges Point Scale for Measuring Mental Ability: Yerkes's Binet alternative

Robert Yerkes's pre-WWI revision of the Binet scale. Instead of age-graded items, Yerkes assigned point values to each item - a more flexible scoring approach that anticipated modern test design. This was the immediate predecessor to Yerkes's Army Alpha work.

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About the Yerkes-Bridges Point Scale for Measuring Mental Ability

Robert Yerkes was the most prominent American psychologist working on intelligence measurement in the years immediately before the United States entered World War I. He found the Binet scale's age-graded structure clinically useful but methodologically frustrating: two children could pass the same number of items overall but receive different mental ages depending on which items they happened to pass. He wanted something cleaner.

The Point Scale assigned a fixed number of points to each item, ranging from 1 point for the easiest items to 6 or more points for the hardest. A subject's score was simply the total points accumulated. The test contained 20 items in its original 1915 form, drawn from the Binet scale, the Healy completion test, the Knox cube test, and a few original additions. Items spanned vocabulary, comprehension, memory, motor sequencing, and abstract reasoning.

The Point Scale was widely used in American psychological clinics through the late 1910s and 1920s. It was particularly influential at the Vineland Training School (where Henry Goddard had also done his work) and at the various state-school psychological services that arose after the WWI testing program created public interest in intelligence measurement. By the early 1930s it had been superseded by the 1916 and 1937 Stanford-Binet revisions, but its point-based scoring idea persisted: every modern IQ test uses points, not age levels.

About this interactive version: The Point Scale was administered individually by a trained examiner with physical materials (form board, picture cards, blocks, watch). Many items cannot be administered in a browser. The interactive subset below covers the verbal and reasoning items only.

The 15 subtests

#1
Vocabulary Examiner asks the subject to define a series of words of graded difficulty.
Interactive
#2
Counting Subject counts backwards from 20 to 1.
Audio
#3
Comprehension 'What's the thing for you to do when...' situational questions.
Interactive
#4
Memory for Digits Examiner reads digits; subject repeats them.
Audio
#5
Healy Pictorial Completion Pictures with missing parts; subject identifies what is missing.
Visual
#6
Knox Cube Test Examiner taps a sequence on 4 cubes; subject reproduces the sequence.
Visual + Motor
#7
Drawing from Memory Examiner shows a geometric design briefly; subject draws it.
Drawing
#8
Repeating Sentences Verbatim repetition of sentences of increasing length.
Audio
#9
Time Orientation Subject states the day of week, month, year.
Interactive
#10
Differences What is the difference between A and B? E.g. president vs king.
Interactive
#11
Definitions of Abstract Terms Define justice, charity, etc.
Interactive
#12
Reversal of Clock Hands At a quarter to three, if the hour and minute hands were swapped, what time would the clock show?
Interactive
#13
Problems of Fact A man saw something in the woods and ran to a policeman. What did he probably see? Tests inferential reasoning.
Interactive
#14
Arithmetic Reasoning Word problems of graded difficulty.
Interactive
#15
Paper Folding (Cube) How many cubes can be made from a folded paper pattern?
Visual

Take the interactive subset

Sample items from the Yerkes-Bridges 1915 Point Scale, focused on the verbal and reasoning subtests.

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Source

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

Yerkes, R. M., Bridges, J. W. & Hardwick, R. S. (1915). A Point Scale for Measuring Mental Ability. Baltimore: Warwick & York. 218 pp.

Public domain in the United States (published before 1929). Yerkes was already a senior figure at Harvard when this volume appeared; two years later he would chair the committee that designed the Army Alpha. The Point Scale represents Yerkes's reaction against the rigid age-graded structure of Binet's scale: he wanted a method that could distinguish more finely between subjects who passed similar numbers of items. Read it on Internet Archive: https://archive.org/details/00550050R.nlm.nih.gov.

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