Six-Pointed Brass Star Psychological Testing Apparatus
New York University Psychology Department: c. 1920s
Six-Pointed Brass Star Psychological Testing Apparatus
Six-Pointed Brass Star Psychological Testing Apparatus Six-Pointed Brass Star Psychological Testing Apparatus
Six-Pointed Star Mirror Drawing Psychological Testing Apparatus
New York: c. 1920s
Sheet brass
12 x 12 inches, cut out square outer plate
10 x 10 inches, star-form inner plate
Provenance: New York University Psychology Department

A six-pointed star apparatus from the period known informally as the “brass instruments era” of psychological testing.  It was used by the New York University Psychology Department.  The device consists of a square sheet, burnished with a repeating circular pattern and having a separate inset cutout six-pointed star.  There are numerous threaded holes in each sheet fitted with small bolts; the screw heads of the bolts and washers are currently on the underside of the device.  Hence it appears that small posts are sticking through the front of the device (the ends of the bolts).  Originally the device probably also had glass panes and other fittings that related to these.

This instrument was used in experimental psychology, a field that achieved its greatest popularity in the first half of the 20th century. According to Gregory, various brass instruments were used “to measure sensory thresholds and reaction times” since those were thought to indicate “the heart of intelligence.”  The star device in particular was employed to investigate the process of learning a visual-spatial skill through trial and error.  To use the device, the testing subject was given the task of tracing the outline of the star against the apparatus with a metal stylus or pencil on a sheet of white paper fed under it while looking at it in a mirror.  Niches were cut along the borders of the brass star to eliminate the tendency of the subject to rest the stylus against the edge of the brass plate. The process was scored for speed and accuracy and was repeated several times to measure the degree of improvement through repetition. 

A similar device is described and illustrated in a psychology monograph published in 1920 (see References below).  Mirror drawing tests involving a star form were deemed useful for such experiments because they presented a situation unfamiliar to the subject, yet relatively quick to complete and open to accurate objective measurement.  A recent article observes that such tests are not completely obsolete:

"The task has also been used as a classic experimental activity designed to illustrate the effects of learning in many undergraduate laboratories for decades. More recently Goldstein, Hopkins and Strube (1994) used the task to demonstrate observer bias.  Although this activity is designed to provide students with an experience that will allow for comparison of the left and right hand, this activity may also be used to illustrate the effects of distributive practice effects and observer bias" (McCarthy).

The outer plate is incised lower right "New York University/ Dept. of Psychology/ W.S.C." W.S.C. refers to "Washington Square College," which was a division of the university from 1913 to 1973 and is now known as the College of Arts and Science.

Condition: Generally very good with the usual overall wear and oxidation.  Apparently originally finished with a so-called microscope brass lacquer, now partly abraded.  The device has the main elements, but originally probably had glass and other components.


"About CAS." NYU College of Arts & Science. (15 May 2013).

Gregory, Robert J. Psychological Testing: History, Principles and Applications (4th Edition). Allyn & Bacon, 2003. p. 5. Online at Allyn & Bacon Partners in Psychology: (17 May 2013).

McCarthy, Maureen, ed. "Mirror Drawing." Online Psychology Laboratory, American Psychological Association Education Directorate. (15 May 2013).

Snoddy, George S. "An Experimental Analysis of a Case of Trial and Error Learning in the Human Subject." Psychological Monographs: General and Applied, Vol. 28, No. 2. Princeton, NJ: Psychological Review Company, 1920. pp. 1-5. Online at Google Books: (15 May 2013).