Howard Knox’s Cube Imitation Test
John T.E. RICHARDSON
The Cube Imitation Test (CIT) was devised by Knox (1913) as a nonverbal test of intelligence. Variants of the original apparatus and procedure have been used over the last 90 years in experimental, clinical, neuropsychological, educational, and cross-cultural research.
Performance on the CIT shows moderate correlations with mental age and IQ, but the association with Verbal IQ may be as strong as the association with Performance IQ. The CIT makes only modest contributions to measures of general intelligence, but it shows moderate correlations with other tests involving the retention of sequential information, including digit span. Performance increases between the ages of 3 and 10 and declines after the age of 50. Unlike many other tests of verbal or spatial thinking, the CIT shows no consistent difference in performance between male and female participants or between patients with damage to the left hemisphere and those with damage to the right hemisphere. People who are dyslexic are impaired on the test, but people who are deaf show no consistent impairment.
The CIT was a highly imaginative development of the notion of memory span. Later researchers were able to build on Knox’s conception using the technology of mental testing. Nevertheless, it is now clear that the CIT is primarily a tool for measuring rote memory and only indirectly a measure of intelligence. Moreover, it is very much a “hybrid” instrument. According both to participants’ introspective reports and to the objective impact of concurrent tasks, it relies upon verbal coding as much as upon visuospatial memory. However, the main contribution of Knox’s work lies in the fact that we nowadays take it for granted that any adequate measures of intelligence must incorporate both verbal tests and performance tests, and the CIT was central to this development in our thinking.
Tenth Annual Meeting of the International Society for the
History of the Neurosciences (ISHN) and
St. Andrews, Scotland, 2005