Intelligence Enhancement Through Neurotechnical Means? Perspectives on the Debate Between Psychology and Philosophy

Human intelligence is one of the scientifically best understood psychological constructs. 100 years of research have produced a large body of evidence regarding the definition, measurement. ontogenetic development, structure, predictive validity, elementary-cognitive, genetic, and neurobiological underpinnings. Recent intelligence research has focused on the possibilities of intelligence enhancement, a research topic that has now strongly gained relevance in current philosophical debates within the transhumanist movement. This movement focuses on substantially enhancing intelligence and other human qualities and postulates that sociocultural progress - and thus in the end the survival of the human race - depends on the development of neurotechnical and pharmacological methods to substantially enhance human abilities. However, these debates are largely dominated by an unfounded optimism regarding the present and future possibilities of enhancing intelligence and other human qualities. At the same time, however, it neglects potentially negative side effects for the individual as well as society as a whole and humankind in general. This article reviews the pertinent research on the potential of current behavioral, neuroelectrical, and pharmacological methods regarding the enhancement of individual general cognitive ability - intelligence. Based on available experimental studies as well as meta-analyses, we conclude that currently no single method provides any perspective of a substantial enhancement of individual intelligence. Even if such methods should become available in the future, we consider it is essential to critically analyze the potential negative side effects for individuals and for humankind, some of which we outline in the discussion.