Peak–end rule end. The effects of the duration of an experience upon retrospective evaluation are extremely slight. Fredrickson and Kahneman labeled this phenomenon "duration neglect". The peak–end rule is applicable only when an experience has definite beginning and end periods. A 1993 study titled "When More Pain Is Preferred to Less: Adding a Better End" by Kahneman, Fredrickson, Charles Schreiber, and Donald Redelmeier provided groundbreaking evidence for the peak–end rule. Participants were subjected to two different versions of a single unpleasant experience. The first trial had subjects submerge a hand in 14 °C water for 60 seconds. The second trial had subjects
Phonological rule most general way possible. Thus, the intervocalic alveolar flapping described above can be formalized as The rule given above for intervocalic alveolar flapping describes what sound is changed, what the sound changes to, and where the change happens (in other words, what the "environment" is that triggers the change). The illustration below presents the same rule, with each of its parts labelled and described. Taken together and read from left to right, this notation of the rule for intervocalic alveolar flapping states that any alveolar stop consonant (/t/ or /d/) becomes a tap ([ɾ]) in the environment where it is