Wolff, W. (1947). Association. In W. Wolff, What is psychology: A basic survey (pp. 106-122). New York City, NY, US: Grune & Stratton.
http://dx.doi.org/10.1037/14018-006
Mental processes are manifest in associations. The phrase "to associate" means to join or connect intimately. A mental association denotes a union of mental patterns. Our organism never works with one single activity, and even the simplest activity is a union of many factors. Every impression and expression is a compound, and it is impossible to isolate one single idea from related ideas. The following topics are discussed: (1) Historical theories; (2) Types of association; (3) Associations to meaningless material; (4) The system of associations under the concept of machine and organism; and (5) Associations as the frame of reference for thoughts. (PsycINFO Database Record (c) 2016 APA, all rights reserved)