THE HYPOTHESIS THAT ENVIRONMENTAL CIRCUMSTANCES INFLUENCE THE PROCESS OF KNOWLEDGE ACQUISITION IS DISCUSSED. THE ROLE OF PARTIAL AND FULL SENSORY ISOLATION AND DEPRIVATION AND ITS NEGATIVE EFFECT ON LEARNING IS SHOWN TO BE SUPPORTED BY RESEARCH. THE INSTITUTE FOR DEVELOPMENTAL STUDIES AT NEW YORK UNIVERSITY IS ENGAGED IN RESEARCH DEALING WITH THE AUDITORY MODALITY DISCRIMINATION OF LOWER CLASS CHILDREN. THE AUDITORY MODE OF LEARNING FOR LOWER CLASS CHILDREN SEEMS TO BE LESS EFFICIENT THAN THE VISUAL MODE. REFERENCES ARE INCLUDED. THIS PAPER WAS PRESENTED AT THE INTERNATIONAL READING ASSOCIATION CONFERENCE (SEATTLE, MAY 4-6, 1967). (BK)