Affect has historically been conceptualized in one of two dominant ways. The first perspective, which has its roots in psychology and neuroscience, tends to view affect as an elemental state. This tradition is reflected in Silvan S. Tomkins’s theory of primary affects and Antonio Damasio’s theory of basic emotions. Recent extensions of this tradition include the work of Eve Kosofsky Sedgwick, Lisa Cartwright, and Teresa Brennan. The second perspective, which is typically associated with developments in philosophy and the humanities, treats affect as an intensive force. This tradition, whose most famous proponent is Gilles Deleuze, is evident in Brian Massumi’s theory of autonomous affect and Nigel Thrift’s non-representational theory. Recent extensions of this tradition tend to emphasize the importance of materiality, or what Jane Bennett has called “thing-power.” A number of scholars working in communication and cultural studies have created a third, hybrid tradition that attempts to bridge or mediate the two dominant historical accounts. This third perspective includes Lawrence Grossberg’s notion of affective investments, Christian Lundberg’s Lacanian-inspired view of affect, Sara Ahmed’s work on the sociality of emotion, and Gernot Böhme’s theory of atmospheres.