Individual differences in memory were examined from the levels of processing perspective. The hypothesis that retarded persons process at a more superficial level was not supported. A "Spread of encoding" deficit in retarded persons is favored to explain the recall differences obtained in this experiment. (Author/LMO)

Speed of information processing was examined in relation to fluid and crystallized intelligence in sixth graders. Reaction time parameters (except slope) were negatively correlated with scores on intelligence tasks. Partial correlations failed to support any causal relationship between fluid and crystallized intelligence in either direction.…

Subjects judged whether aerial views would be seen by an observer oriented in various ways. For practiced subjects, time to answer was an approximately linear function of number of abstract spatial dimensions on which aerial view and observer's orientation were consistent. Ability correlated with linearity of response-time. (Author/RD)

First and fifth graders in two IQ groupings reconstructed pictures which were variations on a prototypic picture. In subsequent recognition, children gave confidence ratings on the "oldness" of the pictures. Prototypes were recognized with most confidence. Younger and lower IQ children were less sure about noncases being "new".…

Mildly retarded young adults were given simple and choice reaction time (RT) tests. Subjects' RTs increased with stimulus complexity. RTs of retarded subjects were slower and evidenced more intraindividual variability than those of nonretarded subjects. Several RT parameters were related to measures of intelligence. (Author/RD)

The generality of ability factor structure in adulthood and old age was investigated. Data were analyzed for 198 young individuals (15-32 years), 156 younger old individuals (53-68 years), and 156 older old individuals (69-91). Variables were nine tests marking three ability factors. (Author/CTM)

Results of a study involving 15 mentally retarded and 15 nonretarded control subjects matched for mental age suggest that some low-level aspects of person-related (and probably object-related) perception may not involve the same high-level symbolic functions typically employed in intelligence-quotient related functions. (SLD)

The relationship between speed of information processing (SIP) and psychometric intelligence was investigated by giving 60 college students (22 males and 38 females) 2 choice reaction time (RT) tests (modified Hick paradigm) and Raven's Advanced Progressive Matrices. Results support an association between intelligence and SIP. (SLD)

The possibility that the ability measure activation savings is related to practiced skill, not because of cognitive overlap, but because of the proximity of savings' measurement to measurement of practiced skill was assessed with 404 military trainees. Implications for individual difference research of test-proximity effects are discussed. (SLD)

This paper describes the development and empirical investigation of two new paper-and-pencil measures of elementary cognitive tasks (PP ECTs). In three empirical studies involving 333 adults, the PP ECTs proved reliable. They were substantially correlated with other measures of psychometric intelligence and they displayed convergent validity with…

Administered 2 elementary cognitive task (ECT) tests and 2 psychometric intelligence tests to 169 monozygotic and 131 dizygotic pairs of twins in Germany. Reaction times correlated negatively with psychometric intelligence, and habitability estimates were substantial for both psychometric intelligence and reaction times on the ECTs. Multivariate…

Recent psychometric results [Mem. Cogn. 29 (2001) 745] have supported a distinction between mental abilities that require a spatial transformation of a perceived object (e.g., mental rotation) and those that involve imagining how a scene looks like from different viewpoints (e.g., perspective taking). Two experiments provide further evidence for…

The contrasting approaches of differential psychology and cognitive psychology to the same individual differences data are outlined. Using data from the Clark and Chase sentence-picture verification task, four loci of conflict between these two disciplines are identified: (1) theory versus measurement; (2) meaningfulness versus reliability; (3)…

The goal of this unified theory of human reasoning is to specify what constitutes reasoning and to characterize the psychological distinction between inductive and deductive reasoning. The theory views reasoning as the controlled and mediated application of three processes (encoding, comparison and selective combination) to inferential rules. (JAZ)

Two groups of reading-disabled (RD) children were compared with controls (age- and IQ-matched competent readers), on a serial running memory task. RD children performed reliably worse than their controls due to an inability to encode serial items in the form of serial phonological patterns. (Author/RD)