Karn, H. W., & Weitz, J. (1955). The scientific analysis of behavior. In H. W. Karn & J. Weitz, An introduction to psychology (pp. 1-17). Hoboken, NJ, US: John Wiley & Sons Inc.
http://dx.doi.org/10.1037/13196-001
How often have you heard someone say—"Use psychology on him?" You will probably agree that this statement is frequently made, and if you stop to analyze its implications you conclude that what the person really meant was—"trick him." Thus the high-pressure salesman is alleged to use psychology in selling an article to some unthinking person who really does not need it; or the politician, through the "use" of psychology, gets people to vote for him when he actually has no intention of keeping his campaign promises. Psychology in this sense appears to be a system of tricks for the charlatan. Such a concept is basically unsound and, of course, not very flattering to the psychologist. It carries the erroneous implication that astrologers and fortune tellers are psychologists. Though such individuals may gain their ends through a superficial understanding of some aspects of human nature, they no more "use psychology" than the boy "uses physics" when he kicks the football into a tree. Actually, psychology is a term applied to a systematized body of knowledge just as physics, chemistry, or biology are names applied to groups of data so arranged as to show the operation of certain natural laws. Each of these specialized branches of knowledge is called a science. There is more to be said about the nature of science, but about one main point you should be certain at the outset: dealing with human beings is not psychology unless it is done through the well-ordered principles of scientific methodology. (PsycINFO Database Record (c) 2016 APA, all rights reserved)