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SUMMARY.A re-analysis is presented of some data purporting to show that stable children differ from labile ones with respect to the structure of their intellectual abilities. The hypothesis is supported, and additional data are presented tending to show that theories of linear independence between cognitive and non-cognitive areas may have to be supplemented by theories stressing non-linear dependence.It is usually maintained that intelligence is statistically independent of temperamental factors such as neuroticism and extraversion and the evidence does, indeed, show little cause to doubt lack of correlation between the cognitive and the conative-affective sides of personality. (Cf. Cattell, 1963, for a recent study and discussion). However, it would be unwise to equate statistical independence with lack of interaction ; most studies reported in the literature have used statistical methods based on product-moment correlations, thus setting orthogonality equal to linear independence, and failing to allow for the possibility of curvilinear regression. This failure to take into account more complex modes of causation may have arisen from the fact that psychometric procedures have been developed very much in isolation, and without connection with the large body of experimental psychology. Eysenck (1957) has argued that the study of temperament and of intelligence can be enriched tremendously by regarding the performance of personality and intelligence tests from the point of view of experimental psychology, considering it as subject to the well known laws of learning theory, and making predictions from these. The usefulness of this approach to the study of personality variables, such as neuroticism and extraversion, has been demonstrated in several publications (Eysenck, 1960(Eysenck, , 1964. In this paper, we shall be concerned with a consideration of a similar approach to intelligence test problem solution.It has been argued (Eysenck, 1957) that the performance of a typical intelligence test may be regarded as an instance of massed practice, in which very similar tasks are attempted repeatedly without the interposition of a programmed rest pause TJnder these conditions, we would expect reactive inhibition to build up and interfere with the proper execution of the tasks. We would also expect that extraverted subjects, liable as they are to greater accumulation of inhibition, would show work curves different from those produced by introverted subjects, an expectation shown to be verified by two experimental studies a t a high level of significance (Eysenck, 1957, pp. 132-133). In another study, Eysenck (1959) predicted that " in the process of solving the sixty problems of the Morrisby Compound Series Test . . . extraverts would show greater reactive inhibition, and consequently falling off in performance during the last quarter of the test as compared with the first three-quarters." The results showed " that extraverts show greater work decrement . . . by taking longer to obtain correct solutjons toward the end of...

Although the fa/fa Zucker rat shows many of the features of type II diabetes, the absence of consistent cardiovascular complications in this model may be due to the absence of significant hyperglycaemia. We studied the consequences of streptozotocin (STZ)-induced insulin deficiency and hyperglycaemia on vascular reactivity in the fa/fa Zucker rat. Hyperinsulinaemic obese Zucker rats were rendered diabetic by injection of STZ (50-60 mg/kg intraperitoneally, i.p.), and vascular tissue was removed for study 10-12 weeks later. In isolated aorta, there was no difference in the phenylephrine (PE) concentration-response relation between lean and obese control animals, but the concentration-response curve was shifted to the left in diabetic animals, (pD2 7.56 +/- 0.04 in STZ diabetic animals, n = 8; 7.4 +/- 0.04 in obese control, n = 9, p < 0.05). The maximum response was also enhanced in both aorta and perfused mesentery of STZ-treated animals. In contrast, the potency of serotonin (5-HT) in inducing contractions of isolated aorta were enhanced in tissues from obese as compared with lean animals (pD2 6.63 +/- 0.06, n = 9; 6.17 +/- 0.07, n = 7 respectively; p < 0.01) and was attenuated in animals with STZ-induced diabetes (pD2 6.31 +/- 0.09, n = 8, p = 0.05). The differential effects of hyperglycaemia on PE-and 5-HT-induced vasoconstriction suggest that the long-lasting modulation of vasoconstrictor responses induced by increases in blood glucose level may be specific for some agonists.