Intelligence and neural efficiency II

Based on the preceding FWF-project ("Intelligence and neural efficiency") which aimed at a comprehensive inquiry into the physiological bases of human intelligence differences, especially into the concept of "neural efficiency" (which suggests a more efficient use of the cortex or even the brain in brighter as compared to less intelligent individuals), we intend here to explore the neural efficiency phenomenon more deeply in order to establish possible cornerstones for a comprehensive physiological theory of human intelligence differences. For this purpose we need a deeper understanding of the physiological basis of some key concepts in human intelligence research, namely the distinction between fluid and crystallized intelligence and between verbal vs. visuospatial processes, the role of knowledge or expertise in special domains, and finally the roles of two biological key variables probably influencing the functioning of the brain: sex and age. Thus, in the proposed project the following questions should be addressed: (1) How do individuals of lower vs. higher fluid cognitive ability differ in their usage of the brain especially when they perform tasks employing the central basic component of intelligence, namely working memory tasks? Moreover, do the spatio-temporal patterns of cortical activation differ depending on the age of the tested individuals (e.g., are there signs of dedifferentiation with age and does dedifferentiation interact with the level of cognitive ability)? (2) What are the relationships between cortical activation patterns and more crystallized intellectual abilities like expertise or knowledge? How do experts in a specific domain differ in their brain usage when contrasted with novices when performing an expertise task vs. a rather novel task and how do these patterns interact with the fluid intelligence level? (3) Can cognitive performance be enhanced through the use of training of a central basic component of cognitive ability, namely the working memory? Are such improvements reflected physiologically, e.g., in the development of neurally efficient cortical activation patterns? Do special trainings aiming at an improvement of separate working memory subcomponents (i.e., central executive, phonological loop, visuospatial sketchpad) - which might be responsible for successful performance on a variety of cognitive tasks - show rather "specific" effects (behaviorally and physiologically) or do they generalize also to the other task components? Finally, how do younger and elderly individuals profit from such training programs (behaviorally and physiologically)?

In the FWF research project "intelligence and neural efficiency II" (P16393) we continued our research on possible brain correlates of individual differences in human intelligence (follow up project of FWF-project P13461). To this end, we measured brain activity by means of the electroencephalogram while individuals where engaged in different cognitive tasks. Usually, brighter individuals appear to solve such tasks more efficiently (less brain activation) than less intelligent individuals who display stronger brain activation when confronted with cognitively demanding tasks (i.e., neural efficiency hypothesis). In a first study of this research project we could replicate and at the same time extend the finding of the preceding research project that neural efficiency interacts with participants` sex and task material. The neural efficiency pattern (less overall cortical activation in less bright individuals) emerged for males predominantly in the figural-spatial task condition, while for females only in the verbal task the expected differences between the IQ groups were found. The strength of this brain activation-IQ relationship also varies with the intelligence component: In males the highest correlations were observed for the figural-spatial IQ, in females for verbal IQ. In study II the neural efficiency phenomenon was studied in the domain of chess. In analyzing brain activity of tournament chess players while engaged in cognitive task performance we found evidence that superior cognitive performance is not only a function of domain-specific knowledge or expertise but also a function of the general efficiency of the information processing system. Study III dealt with another exciting research question within the intelligence or cognitive ability domain, i.e., the neurophysiology of scholastic achievement or underachievement, respectively. Findings of study III suggest that underachieving persons, i.e., persons who fail to achieve the scholastic level of which he or she is capable of, considerably differ in brain activation from those who might be characterized by a high level of scholastic achievement. In light of recent advances in the field of cognitive sciences and the neurosciences we have expanded our primary research question on neural efficiency to another cognitive domain that has recently attracted great attention in this field of research, viz. divergent or creative thinking, respectively. Unlike convergent tasks (or intelligence test tasks, respectively), which require the single correct answer to a given problem, divergent thinking tasks allow for a broad range of different associations to a given stimulus. In study IV of the research project we analyzed brain activity while individuals were confronted with different divergent thinking tasks. Analyses revealed that creative thinking was generally accompanied by lower levels of cortical activation, as suggested by relatively strong increases (relative to rest) in alpha power immediately prior to the production of a creative idea. In study V we could demonstrate that creative thinking can be enhanced through training. Most interestingly, this training effect was also reflected in changes in brain activity as a result of the training: Analyses revealed that the training group who received a computerized creativity training over a time period of 2 weeks displayed higher increases in frontal alpha activity (relative to rest) than the untrained participants who received no training.