Written in 1965. Rings painfully true today.

Defense arousal prevents the listener from concentrating upon the message. Not only do defensive communicators send off multiple value, motive and affect cues, but also defensive recipients distort what they receive. As a person becomes more and more defensive, he or she becomes less and less able to perceive accurately the motives, the values and the emotions of the sender. The writer’s analysis of tape recorded discussions revealed that increases in defensive behavior were correlated positively with losses in efficiency in communication.