Chapter 4 endnote 36, from Lisa Feldman Barrett.
Some context is:
Affect is the general sense of feeling that you experience throughout each day. It is not emotion but a much simpler feeling with two features. The first is how pleasant or unpleasant you feel, which scientists call valence.
The word “valence” can have meanings other than pleasant/unpleasant, which is more specifically called hedonic valence. In other fields such as philosophy, valence can also mean morally desirable/undesirable. This is distinguished from socially desirable / undesirable, which refers to whether something is viewed favorably by others. In this book, “valence” always refers to hedonic valence.