This volume on Visual Psychophysics documents the current status of
research aimed toward understanding the intricacies of the visual
mechanism and its laws of operation in intact human perceivers. As can
be seen from the list of contributors, the problems of vision engage the
interest and experimental ingenuity of investi- gators from a variety of
disciplines. Thus we find authors affiliated with depart- ments of
biology, medical and physiological physics, ophthalmology, physics,
physiology and anatomy, psychology, laboratories of neurophysiology,
medical clinics, schools of optometry, visual and othcr types of
research institutes. A continuing interplay between psychophysical
studies and physiological work is everywhere evident. As more
information about the physiological basis of vision accumulates, and new
studies and analyses of receptor photochemistry and the neurophysiology
of retina and brain appear, psychophysical studies of the intact
organism become more sharply focused, sometimes more complex, and often
more specialized. Technological advances have increased the variety and
precision of the stimulus controls, and advances in measurement
techniques have reopened old problems and stimulated the investigation
of new ones. In some cases, new concepts are being drawn in to help
further our under- standing of the laws by which the visual mechanism
operates; in other cases, ideas enunciated long ago have been
reevaluated, developed more fully, and reified in terms of converging
evidence from both psychophysical experiments and unit recordings from
visual cells.