PET imaging was approved by the Ethics Committee of Heinrich-Heine-University Düsseldorf (Application 868). PET was used to obtain regional cerebral bloodflow (rCBF) data in 13 right-handed participants, mean age 26 (range 21 to 34). For the spatial and verbal tasks, overall mean scores (number correct in 4 min) were as follows: high- g spatial, 12 (range 4 to 18) low- g spatial, 198 (range 162 to 225) high- g verbal, 7 (range 1 to 17) low- g verbal, 41 (range 16 to 75). In this study, the measure of g was Cattell's Culture Fair, Scale 2 Form A, with one section omitted because of overlap with other tasks in the study (mean score in our sample 24/34 items correct, range 12 to 31). Further data on the two verbal tasks, again completed with a range of other tasks, were obtained in a second study of 46 participants, mean age 42 (range 35 to 51). To obtain an overall measure of g for each participant, scores on the latter pair of tasks were standardized and averaged. 1B) and two standard measures of g, Cattell's Culture Fair, Scale 2 Form B (17) (mean score in our sample 34/46 items correct, range 24 to 43), and the verbal scale of the AH4 (18) (mean score in our sample 43/65 items correct, range 27 to 58). In three test sessions, participants completed a range of tasks, including high- and low- g spatial ( Fig. In the first study, 60 participants were tested, mean age 42 (range 29 to 51). Studies were designed to measure correlations between a range of candidate tasks for PET and standard measures of g. The results suggest that “general intelligence” derives from a specific frontal system important in the control of diverse forms of behavior. Many previous experiments have shown these same frontal regions to be recruited by a broad range of different cognitive demands.
Despite very different task content in the three high- g–low- g contrasts, lateral frontal recruitment is markedly similar in each case. Instead they are associated with selective recruitment of lateral frontal cortex in one or both hemispheres. In contrast to the common view that g reflects a broad sample of major cognitive functions, high- g tasks do not show diffuse recruitment of multiple brain regions. Spatial, verbal, and perceptuo-motor tasks with high- g involvement are compared with matched low- g control tasks. Here the neural basis for g is investigated by means of positron emission tomography. Universal positive correlations between different cognitive tests motivate the concept of “general intelligence” or Spearman's g.
0 kommentar(er)
