The two-level theory of mental abilities posits two broad classes of ability: level I (learning and memory) and level II (the "g" factor of intelligence tests, reasoning, abstraction, and problem solving). Levels I and II are hypothesized to interact with SES and/or race such that: (l) SES differences are greater for level II than for I,…

The purpose of this study was to attempt to determine if score gains obtained upon repeated testing with an intelligence test result from a practice effect, from students remembering specific items, or from a combination of both. The verbal and nonverbal batteries of an I.Q. test were administered to 860 sixth graders on three occasions with…

The long-term stability of verbal and nonverbal IQ scores was studied for 146 Spanish-surname students. About 30-50% of Spanish students do no speak English when they begin school. The California Test of Mental Maturity or the Lorge-Thorndike Intelligence Tests were administered in grades 1,2,4,7,9, and 11. The stability of IQ scores for…

The relationship of the Progressive Matrices Test (PM) to the Lorge-Thorndike Intelligence Test (LTIQ) and the Wechsler Intelligence Scale for Children (WISC) is examined. Predictive power of these measures with respect to a number of achievement measures was also investigated. The initial sample consisted of 242 first graders and 281 second…