Special issue to commemorate the intellectual contributions of Allan R. Wagner

This is an introduction to the special issue "Wagner Tribute." Allan R. Wagner was the first editor in chief of this journal. It is difficult to quantitatively measure the impact that a single individual has on an entire discipline, but a brief consideration of Wagner's research output provides some insight into both the breadth of his interests and depth of his influence. Furthermore, in one way or another the many contributions to this special issue will highlight the powerful role that Wagner's empirical and theoretical work has played and continues to play in driving research into the nature of simple associative learning processes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).