⁴⁰On the other hand, if we expect something unpleasant to happen, and it does not happen, we feel relief which is clearly not suffering; in general, obtaining more reward than expected may be the very definition of pleasure (see footnote 17 in Chapter 5). Perhaps, in that case, the unexpected positivity (of reward) overrides the inherent suffering in prediction error. For research on relief from pain, see Seymour et al. (2005); Leknes et al. (2008).