High qualitative scoring (Q scores) indicate intellectual dullness. High Q scores also relate to verbal and performance intelligence. In social contexts, high Q scores are associated with truancy and delinquency. When the Q scores of delinquent and normal groups are compared, the differences are reliable and highly significant. Participants who are less inhibited, obstinate and perseverative had difficulty with each new presentation of the maze test. They often repeated their original, incorrect route, often saying they knew that the particular route was incorrect. Administered regardless of native language, disability status and to literacy. In most cases their scores were low. Subjects unused to tests required additional training in the test-taking procedure. Later studies established the validity of the test as a sensitive tool. Many early comparisons with other intelligence tests found moderate to high correlation coefficients. As a nonverbal test it was not expected to have a high correlation with verbal tests, but the correlation is at least moderately positive. To assess the validity of Q scores, O' Keefe compared the performance of high and low impulse groups. This found no difference in Q scores based on ratings in institutionalized, delinquent, non-delinquent and extreme groups. Riddle and Roberts argued that the test is a reliable and valid measure of foresight, impulsivity, judgment, planning ability and ability to delay gratification. They reported that the test showed acceptable psychometric properties and interrupter reliability. They found that Q score distinguished recidivist from non-recidivist delinquent grouse and found the score the most sensitive to differences in social adjustment. Porteus claimed that the reliability of his test was .96. The original Porteus Maze test was introduced in August 1914 during a session held by the Education Section of the British Association for the Advancement of Science. The original test lacked explanation for practice effects in retesting. The test was revised each year, becoming progressively more difficult. This revision consists of 12 mazes for subjects 3 through 12, 14 and Adult. The purpose of this revision was to standardize the test, account for sex differences in performance, achieve correlations with the Binet-Simon scale and the US Army test and estimate social capability and industrial aptitude. An extension of the original test was devised to reduce practice learning as a result of the re-administration of the same test. Use of the extension was expected to improve test-retest reliability. This series was published by the Centre de Psychologie Appliquée in 1958. The extension contains eight mazes created as a measure for ages 7–12, 14 and adults.