Traditionally, we define “emotions” as feelings and “feelings” as conscious experiences. Conscious experiences are not readily studied in animals. However, animal research is essential to understanding the brain mechanisms underlying psychological function. So how can we make study mechanisms related to emotion in animals? I argue that our approach to this topic has been flawed and propose a way out of the dilemma: to separate processes that control so-called emotional behavior from the processes that give rise to conscious feelings (these are often assumed to be products of the same brain system). I will use research on fear to explain the way that I and many others have studied fear in the laboratory, and then turn to the deep roots of what is typically called fear behavior (but is more appropriately called defensive behavior). I will illustrate how the processes that control defensive behavior do not necessarily result in conscious feelings in people. I conclude that brain mechanisms that detect and respond to threats non-consciously contribute to, but are not the same as, mechanisms that give rise to conscious feelings of fear. This distinction has important implications for fear and anxiety disorders, since symptoms based on non-conscious and conscious processes may be vulnerable to different factors and subject to different forms of treatment.

This content is only available as a PDF.
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which permits copying and redistributing the material in any medium or format for noncommercial purposes only. For a full description of the license, please visit