Without even realizing, human beings perform extraordinary feats on a daily basis. We navigate an increasingly complicated and demanding world by using our sophisticated ability to override... Show moreWithout even realizing, human beings perform extraordinary feats on a daily basis. We navigate an increasingly complicated and demanding world by using our sophisticated ability to override habitual tendencies. Furthermore, we can meticulously plan, carry out and adapt actions in order to achieve goals that we set for ourselves. This capacity for goal-directed behavior—often considered a hallmark of human excellence over other animals—is commonly referred to as ‘cognitive control’ or ‘executive function’. These are rather vague, typically synonymous concepts that serve more as an umbrella term for many different processes rather than referring to a single, unitary function. Decades of neuropsychological research have been devoted to understanding cognitive control and its component processes, the way it is implemented in the brain, and how we can alter—and possibly improve—its efficacy. These issues have driven the work included in this dissertation. In particular, the research presented in this dissertation concerns itself with the overarching questions of how chemical processes in the brain (dopamine, glutamate, and GABA) enable and affect cognitive control, and how we might non-invasively measure and manipulate these biological underpinnings of goal-directed behavior. Show less
Cognitive enhancement reflects the use of any (legitimate) means such as for example food supplements to reach one’s personal best, and has gained great interest over the past years. The... Show moreCognitive enhancement reflects the use of any (legitimate) means such as for example food supplements to reach one’s personal best, and has gained great interest over the past years. The increasing costs of the welfare offer one explanation, the second is that both Eastern and Western societies are continuously driven towards more individualism pushing the idea that an individual is the director of his or her own life. In this dissertation, I attempted to explain how and why enhancement techniques such as brain stimulation, videogaming, and food supplements (e.g. tyrosine and tryptophan) are promising and inexpensive ways to enhance cognition. That is, clear ideas about the underlying mechanisms of these effects are needed before these techniques can be applied outside the field of science. Our findings have important societal and economic implications and go hand-in-hand with the ideological individualistic trend in society. More research is needed in order to gain better insights into the underlying mechanisms and the role of individual differences in modulating the observed effects. However, the discussed techniques do have promising potential, not only in possibly delaying cognitive decline in elderly, but also enhancing (social) cognitive functioning and mental well-being in healthy humans. Show less
