This is the ability to recognize and understand novel concepts or relationships; it involves the solution of logical problems–to foresee and plan. Thurstone (1949) proposed that persons with good reasoning ability could solve problems, foresee consequences, analyze situations on the basis of past experience, and make and carry out plans according to recognized facts.
PMA Reasoning (R). (Longitudinal marker) The study participant is shown a series of letters (e.g., a b x c d x e f x g h x). The letters in the row form a series based on one or more rules. The study participant is asked to discover the rule(s) and mark the letter that should come next in the series. In this case, the rule is that the normal alphabetical progression is interrupted with an x after every second letter. The solution would therefore be the letter i. There are 30 test items, with a time limit of 6 minutes.
ADEPT Letter Series (LS; Blieszner, Willis, & Baltes, 1981). This is a parallel form to the PMA Reasoning test. It has 20 test items, with a time limit of 4.5 minutes.
Word Series (WS). The study participant is shown a series of words (e.g., January, March, May) and is asked to identify the next word in the series. Positional patterns used in this test are identical to the PMA Reasoning test. There are 30 test items, with a time limit of 6 minutes.
Number Series (NS; T. G. Thurstone, 1962). The study participant is shown a series of numbers (e.g., 6, 11, 15, 18, 20) and is asked to identify the number that would continue the series. There are 20 items with a time limit of 4.5 minutes.
Spatial Orientation
This is the ability to visualize and mentally manipulate spatial configurations in two or three dimensions, to maintain orientation with respect to spatial objects, and to perceive relationships among objects in space. This ability is important in tasks that require deducing one’s physical orientation from a map or visualizing what objects would look like when assembled from pieces.
PMA Space (S). (Longitudinal marker) The study participant is shown an abstract figure and is asked to identify which of six other drawings represents the model in two-dimensional space. There are 20 test items, with a time limit of 5 minutes.
Object Rotation (OR; Quayhagen, 1979; Schaie, 1985). The study participant is shown a line drawing of a meaningful object (e.g., an umbrella) and is asked to identify which of six other drawings represent the model rotated in two-dimensional space. There are 20 test items, with a time limit of 5 minutes.
Alphanumeric Rotation (AR; Willis & Schaie, 1983). The study participant is shown a letter or number and is asked to identify which of six other drawings represents the model rotated in two-dimensional space. There are 20 test items, with a time limit of 5 minutes. Test stimuli in the Object and Alphanumeric rotation tests have the same angle of rotation as the abstract figure in the PMA Space test.
Cube Comparison (CC; Ekstrom et al., 1976). In each item, two drawings of a cube are presented; the study participant is asked to indicate whether the two drawings are of the same cube rotated in three- dimensional space. The Cube Comparison test has two parts, each with 15 items, and a time limit of 3 minutes.
Number Skills
This is the ability to understand numerical relationships, to work with figures, and to solve simple quantitative problems rapidly and accurately.
PMA Number (N). (Longitudinal marker) The study participant checks whether additions of simple sums shown are correct or incorrect. The test contains 60 items, with a time limit of 6 minutes.
Addition (AD; Ekstrom et al., 1976). This is a test of speed and accuracy in adding three single or two-digit numbers. The test has two parts, each with 20 items and a time limit of 3 minutes.
Subtraction and multiplication (SM; Ekstrom et al., 1976). This is a test of speed and accuracy with alternate rows of simple subtraction and multiplication problems. The test has two parts, each with 20 items and a time limit of 3 minutes.
Verbal Ability
This is the ability to understand ideas expressed in words. It indicates the range of a person’s passive vocabulary used in activities where information is obtained by reading or listening.
PMA Verbal Meaning (V). (Longitudinal marker) A four-choice synonym test. This is a highly speeded test with significant loading on Perceptual Speed (Hertzog, 1989; Schaie, Willis, Jay, & Chipuer, 1989). The test has 50 items, with a time limit of 4 minutes.
ETS Vocabulary V-2 (VC; Ekstrom et al., 1976). A five-choice synonym test. The test has two parts, each with 18 items and a time limit of 4 min.
ETS Vocabulary V-4 (AVC; Ekstrom et al., 1976). A more advanced five-choice synonym test consisting mainly of difficult items. This test also has two parts, each with 18 items and a time limit of 4 min. Both ETS vocabulary tests are virtually unspeeded.
Word Fluency
This ability is concerned with the verbal recall involved in writing and talking easily. It differs from verbal ability in that it focuses on the speed and ease with which words are used, rather than on the degree of under standing of verbal concepts.
PMA Word Fluency (W). (Longitudinal marker) The study participant recalls as many words as possible according to a lexical rule in a 5-minute period. No additional markers were included for this ability, because it appears to be factorially more complex than suggested by Thurstone’s original work. The test is retained, however, because of the availability of extensive longitudinal data for this variable. In factor analytic work it has been shown to load on Verbal Memory and Verbal Ability (Schaie, Dutta, & Willis, 1991).
Perceptual Speed
This is the ability to find figures, make comparisons and carry out other simple tasks involving visual perception with speed and accuracy.
Identical Pictures (IP; Ekstrom et al., 1976). (Longitudinal marker beginning in 1975) The study participant identifies which of five numbered shapes or pictures in a row is identical to the model at the left of the row. There are 50 items, with a time limit of 1.5 minutes.
Finding A’s (FA; Ekstrom et al., 1976). (Longitudinal marker beginning in 1975. In each column of 40 words, the study participant must identify the 5 words containing the letter “a”. There are 50 columns of numbers, and a time limit of 1.5 minutes.
Number Comparison (NC; Ekstrom et al., 1976). The study participant inspects pairs of multi-digit numbers and indicates whether the two numbers in each pair are the same or different. There are 40 items, with a time limit of 1.5 minutes.
Verbal Memory
This ability involves the memorization and recall of meaningful language units (Zelinski, Gilewski, & Schaie, 1993).
Immediate Recall (IR). Subjects study a list of 20 words for 3.5 minutes, they are then given an equal period of time to recall the words in any order.
Delayed Recall (DR). Subjects are asked to recall the same list of words as in Immediate Recall after an hour of other activities (other psychometric tests).
Composite indexes
From the original five longitudinal markers, we have consistently derived and reported data on five linear composites. Both indexes were originally suggested by the Thurstones (1949). The first is an Index of Intellectual Ability (IQ), a composite measure likely to approximate a conventional deviation IQ, obtained by summing subtest scores weighted approximately inversely to their standard deviation of each test:
IQ = V + S + 2R + 2N + W
The second composite score is an Index of Educational Aptitude (EQ) suggested by T. G. Thurstone (1958) as the best predictor from the PMA test battery of performance in educational settings:
EQ = 2V + R