In
an increasingly complex information society, demands for cognitive
functioning are growing steadily. In recent years, numerous strategies
to augment brain function have been proposed. Evidence for their efficacy
(or lack thereof) and side effects has prompted discussions about
ethical, societal, and medical implications. In the public debate,
cognitive enhancement is often seen as a monolithic phenomenon. On
a closer look, however, cognitive enhancement turns out to be a multifaceted
concept: There is not one cognitive enhancer that augments brain function
per se, but a great variety of interventions that can be clustered
into biochemical, physical, and behavioral enhancement strategies.
These cognitive enhancers differ in their mode of action, the cognitive
domain they target, the time scale they work on, their availability
and side effects, and how they differentially affect different groups
of subjects. Here we disentangle the dimensions of cognitive enhancement,
review prominent examples of cognitive enhancers that differ across
these dimensions, and thereby provide a framework for both theoretical
discussions and empirical research.