FIGURAL TESTS OF REASONING IN AFRICA

L'A présente les résultats d'un certain nombre d'expéricnces qui ont été réalisées avec les Progressive Matrices de Raven en Afrique et en Grande-Bretagne. II a utilisé des méthodes d'analyse factorielle pour comparer la difficulté des items d'une culture à L'autre et pour décrire les différentes stratégies individuelles des répondants. Les principales conclusions sont les suivantes : 1. Les tests qui utilisent des dessins et des figures sont des instruments complexes qui entraînent des biais caractéristiques dans les réponses. 2. Ces biais jettent un certain doute sur L'idée qu'il peut exister des tests libres de toute influence culturelle ou même dans lesquels les facteurs culturels seraient réduits. 3. Les résultats sont mis en liaison avec une théorie de L'intelligence qui met L'accent sur le rôle du système de valeurs en vigueur dans une société donnée; le système de valeurs dètermine en partie la nature des capacités humaines et leurs rclations.     

Color discrimination and luminance

This experiment studied the relation between luminance level and color discrimination at 570 millimicrons. A variety ofstimuli whose luminances varied from .1 to 100 ft-L were viewed against a variety of surrounds. 1t was found that color discrimination ability was a joint function of the luminance level of the stimulus and the ratio of the luminance of the stimulus to that of the surround.     

A note on luminance control in tachistoscopes

Procedures are described for measuring tachistoscopic luminance levels for brief light flashes and over longer intervals. Stability of luminance levels is discussed for both conditions.     

The cognitive basis of the comprehension and production of relational terminology

The comprehension of big, little, and same number and the productio of relational terminology was assessed in 168 preschool children. Stimuli were used which varied the relationships of length, number, and density. Language comprehension and production were related to the complexity of cognitive operations required by the task. Specifically, comprehension was easier in the situations in which length and number were positively correlated than when length provided no cue to number. Comprehension was most difficult when length and number were negatively correlated. There was asymmetry in language comprehension such that the positive term big, was comprehended earlier than little in some tasks; there was also asymmetry in production in that the child was more likely to use language related to the positive pole than to the negative pole. These data were interpreted as providing support for theories of the cognitive basis of language acquisition.     

Sex differences in retention of verbal and spatial characteristics of stimuli

Males and females from Grades 3, 6, and college viewed sets of five or seven letters in a 4 × 4 matrix, and remembered either (a) names of the letters, (b) positions of the letters within the matrix, or (c) both letters and positions. At all grade levels females remembered letters more accurately than positions, while males remembered letters and positions equally well. However, there was also evidence that verbal and spatial information was processed independently by both males and females. Results are discussed in terms of neurological development and sex differences in specific abilities.     

Developmental changes in the semantic processing of pictures and words

Second- and fifth-graders' semantic decision times for pictures and words were analyzed relative to the predictions derived from unitary- and dual-memory models. At both grade levels, word-word response latencies were greater than picture-word latencies which, in turn, were greater than picture-picture latencies. An interaction between Grade and Condition indicated that verbal access times decreased more than pictorial access times. The data fit the predictions of a memory model postulating category storage in a single memory system as opposed to simultaneous representation in verbal and nonverbal memory systems. It was concluded that with increasing experience verbal access to this single semantic system is more rapid.     

Absolute identification of notes and intervals by musicians

Speech sounds are judged reliably and absolutely, while the judgment of nonspeech stimuli, such as tones, is thought to be unreliable and dependent on contextual cues. Here we demonstrated that the judgment of tonal stimuli may also be reliable and absolute, provided that the subjects are trained musicians. In Experiment 1, musicians with relative pitch identified 21 tonal intervals ranging from unison to major third, and the resulting identification functions were similar to those that have been previously obtained for speech. In Experiment 3, the judgment of intervals by musicians was shown to be free of context effects, since the best subjects gave virtually identical judgments to the same intervals in two stimulus contexts. Similar results were obtained in Experiments 2 and 4 for the judgment of single tones by possessors of absolute pitch. Performance with both notes and intervals by nonmusicians, however, was unreliable and greatly influenced by context. These findings suggest that musicians acquire categories for pitch that are functionally similar to phonemic categories for speech