Bruner outlines the historical perspectives in physics, psychology, and neurophysiology that have restricted and shaped theoretical attempts to define perceptual and cognitive processes. Individuals develop 'strategic evaluative techniques' through early sensory experience. Though no experimental data show us why, it is clear that sensory deprivation early in life seriously and probably permanently impairs later perceptive-cognitive-adaptive processes. Wide variations in individual response to experimental isolation suggest that capacity to adapt to environments of differing mode and intensity of stimulus results from learned 'strategies of evaluation'. The individual totals of such strategies and their adaptive concomitants necessarily correlate with personality.