| Cognitive Performance |
| 1. Intelligence Tests |
| The Army Alpha examination (forms A and B) is a combination of the five forms of Alpha used in the United States Army during World War I. The questions best for general use were selected by order-of-merit method. Items addressed specifically to male recruits were excluded and military terms modified (Bregman, 1925, 1947). |
| Form A of this paper-and-pencil examination, consisting of eight subtests, has been administered to all subjects since 1960. Form B is administered on visit 5 (six to eight years later), and Form A is repeated on visit 9; the two forms are given alternately on all subsequent visits. When the subject reaches age 70 and is tested every year, the form of the test given on the last previous visit is repeated. A speed score is obtained for each subtest by stopping the subject after the time specified, while a power score is obtained by permitting the subject to spend as much time as he likes in completing each test. |
| The Vocabulary Test (WAIS). This subtest from the Wechsler Adult Intelligence Scale (Wechsler, 1955) has been administered at six-year intervals since 1960. The task is to define 40 words. |
| Southern California Tests of Mental Ability. From 1959 to 1978 this battery of tests (Christensen et al., 1958; Christensen and Guilford, 1959) was administered twice, at a six-year interval. First-time testing was discontinued in 1972; by 1978, all participants who had taken the earlier test had completed it a second time, and the test was discontinued. The five timed tests (Associational Fluency, Expressional Fluency, Ideational Fluency, Word Fluency, and Consequences) were designed to measure several aspects of creative thinking. For example, in Expressional Fluency the task is to write meaningful four-word sentences in which the initial letter of each word has been specified; in Ideational Fluency, the subject lists items that meet such specific criteria as "fluids that burn." |
| 2. Learning, Memory, and Decision Tasks |
| Verbal learning. Data collection began in 1960 for two studies of verbal learning. In serial learning, a list of familiar words is presented repeatedly in the same order. The task is to respond to each word with the next word in the list. In paired-associate learning, items that consist of a stimulus (two consonants) and a response component (a familiar adjective) are presented repeatedly in different orders. The task is to say the word that is paired with the two consonants. For both tasks, each subject was assigned to one of three pace conditions determined by the amount of time permitted for each response. Total errors and trials to criterion are the measures (Arenberg, 1967b; Arenberg and Robertson-Tchabo, 1977). These tasks are repeated at six-year intervals with different sets of words and consonants. |
| Benton Visual Retention Test. This non-verbal memory test (Benton, 1963) has been administered at six-year intervals since 1960. Form C is used for the first administration, Form E for the second, Form D for the third, and Form C again for the fourth. Each form is made up of ten designs with one or more figures; the task is to reproduce each design from memory after inspecting it for ten seconds. The primary measure is the number of errors in all ten reproductions (Arenberg, 1978). |
| Memory and decision tasks. In 1978 the following set of memory and decision tasks was introduced: |
- Single-trial, immediate free recall (IMFR). Each of four lists consists of 12 familiar nouns. After the words are shown paced, the task is to report as many words as possible.
- Forward digit memory. The task is to recall, in order, lists of three to nine digits presented auditorily.
- Delayed memory. After each IMFR list and an interpolated task (forward digit memory), one of two delayed memory procedures is administered. In delayed free recall, the task is to report as many of the words as possible from the previous IMFR list. In delayed recognition, the 12 words from the previous IMFR list and 12 distractor words are shown one at a time, and the task is to decide whether the word has already been presented.
- Dichotic listening. The task is to identify two digits presented simultaneously, one to each ear. Each set consists of 28 pairs.
- Decision tasks. These tasks require response to the visual presentation of designated digits under five different conditions. With the exception of the first task, the display is paced at a rate of one digit per second. The first task is to respond to the onset of a zero. The second is to respond to a specified digit. The third is to respond to any even or odd digit. The fourth is to respond to an even-odd or odd-even sequence of digits, and the fifth to respond to any two consecutive even or consecutive odd digits. Decision time and accuracy are the measures.
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| The same set of tasks, with different word lists, is to be repeated six years after the first administration. |
| 3. Problem Solving |
| Logical problem solving. An experimental procedure was designed to measure effectiveness of reasoning. The apparatus consists of a display with six numbered and three lettered lights, each of which has an adjacent push-button, and a central light (G) that has no button. Each problem contains a set of logical relations indicated by arrows between lights. The ultimate task in each problem is to arrive at the outcome, G, via a sequence of inputs. The number of uninformative inputs is the primary measure. A set of logically identical problems is administered at least six years later. From 1962 to 1966, each problem was presented as a single task (Arenberg, 1974). From 1966 to 1974, for subjects who were administered these problems for the first time, each problem was presented in two parts to obtain independent measures of performance in analysis and synthesis. |
| Concept identification. The ability to identify concepts in the context of a problem-solving task is also evaluated. Each of 12 concept problems requires the identification of one or two "poisoned" foods. The subject selects "meals" consisting of four of the foods on a list, and the experimenter indicates whether that "meal" is fatal. The task is to identify the "poisoned" foods with as few "meals" as possible. The two primary performance measures are correctness of the identification and effectiveness in reaching a solution as indicated by the number of "meal" selections. Concept problem solving, initiated in 1967, is administered at six-year intervals. |
