Is the feeling of fear instantiated in some brain area or is fear just a word we use to describe a series events distributed across the brain which make us avoid things that are bad? Do other animal experience the same subjective state that we experience when we are afraid? Those are some of the questions that are asked in a recent review paper published by Ralph Adolphs in Current Biology. The text is freely available for download1.
Fear refers to a subjective experience and like any other subjective experience it leads to many debates among biologists, psychologists and philosophers. The problem is as follows: although you can be sure that fear exists because you have already experienced it, you can never really be sure that other animals – or even other people – experience it just like you do. Sure you can analyze their brain and see that some areas seem to respond in some way to things that you think are fearful. But scientific tools do not at the moment – and some argue will never – allow us to understand how an other brain experiences feelings. In philosophy the problem is known as the problem of other minds. It is due to the fact that the only way in which we can conceive of the feelings of others is through their behaviors – we think someone experiences fear because he behaves in a fearful way. But we can never be sure. Someone might have the behaviors without having the feelings associated with it, or might even be displaying behaviors to fool us on certain occasions. Another big question, in my view, is whether or not the conscious experience of fear plays a direct role in modifying behavior or if it has other functions such as driving the expression and communication of the state to others.
The review presents recent findings arguing for fear and disgust activating numerous brain areas. A set of studies however seem to point toward the amygdala as a particularly important center for fear. Adolphs describes three major challenges for future research in the field: 1. Improving the methods to obtain finer understanding of the brain mechanisms that relate to fear, 2. Understanding fear in many different animal species to have a clearer view of how it evolved and 3. Investigate the conscious experience of fear and which brain areas participate in this subjective state.
The article is very accessible so I recommend to anyone with an interest on the subject to read it!
1. Adolphs R. (2013) The Biology of Fear. Current Biology 23:R79-R93.