Although psychopharmacology relies heavily upon precise, objective measurement of drug effects, the latter remain phenomenological unless they are relatable to clinically relevant disorders. Consequently, ideal drug testing procedures should not only be based upon understandable physiological principles, but also afford accurate, unequivocal measurement of parameters in models which are available in both animals and humans. In recent years the study of information processing via the peripheral visual system has emerged as a promising model having at least some of the aforementioned features. Much is known about the physiological characteristics of animal visual pathways. It is a unique property of the visual system, that the neurophysiological measures in animals find their analogue in the psychophysical measurements which can be carried out with great precision in humans. This relationship may be used to compare effects of drugs in neurophysiological studies of animals with their influence on perceptive phenomena in humans. However, whereas the animal peripheral visual system has been used to assess drug effects on information processing, there is a paucity of such studies in humans.