Quantified sleep. Self-tracking technologies and the reshaping of 21st-century subjectivity

>> Quantified Sleep: Self-Tracking-Technologien und die Neuordnung der Subjektivitatim 21. Jahrhundert <<. Taking sleep-tracking as its case study, this article seeks to theorise the understandings of the self that are at stake in the Quantified Self (QS) movement and everyday self-tracking practices by bringing together a cultural theorist's and a philosopher's perspectives. We situate the rise of sleep-tracking practices within the sleep crisis discourse, namely, the sense that in today's society sleep disorders are on the rise and sleep deprivation is rife. Through analyses of self-trackers' blogs about sleep, sleep-tracking technologies' marketing information, and the functionalities of these devices and apps, we argue that the drive to self-improve at the heart of self-and sleep-tracking props up an understanding of the self that is cen-tred around achievement. This understanding ends up devaluing sleep and risks contributing to the sleep crisis. We show how these paradoxes can be further understood from an epistemological perspective. Self-and sleep -tracking are arguably practices that seek to obtain knowledge by trading ref-erential expert knowledge for self-referential nonexpert knowledge and that strive for self-optimisation by self-sabotaging achievement subjectivity. We conclude that the use of self-tracking technologies magnifies what is essen-tially a crisis of subjectivity.