¹⁴To explicitly apply the definition fo reward loss, we would need to define the “expected reward”. Clearly, here the expectation is something different from Chapter 5, where it was essentially a prediction (but see footnote 14 in that chapter on discussion of different definitions of the expectation). Here, the expectation is something defined by evolution or the programmer. In fact, the situation is very simple if the internal reward system gives a negative reward when a threat appears: the expected reward can be defined as always zero, so any negative reward leads to reward loss. The same logic applies to the self-evaluation system if it operates with similar negative rewards, as discussed next in the text.