In the excerpt, the dashes are an example of a literary device as its purpose is to achieve a particular artistic effect in the piece of writing. There are three types of dashes, and each of them has different functions: The hyphen, the En dash, and the EM dash. The one used here is the Em dash, the longest dash of them all, which takes up the spacing of a capital M in print, and can be written as double hyphens "--" or like this "—." The purpose of this dash is to introduce new ideas into a sentence, to create heightened drama, or to put emphasis on a phrase or part of a sentence, such as it is used in the excerpt.