actually deeply embodied, such that semantic memory representations are directly mediated by perceptual systems. Barsalou, in particular, has contributed much research to the field of grounded cognition. According to Barsalou (2008), grounded cognition refers to the belief that simulations within specific sensory systems, bodily states, and situated action mediate all cognitive processing. Citing evidence from psycholinguistic, action planning, and social cognition research, Barsalou has suggested that grounded cognition is well positioned to facilitate the development of testable models within cognitive psychology. He has gone on to use a grounded approach to diverse areas within cognitive psychology, including conceptual representations, attitudes, emotion, prejudice, mindfulness, and eating behaviors. Perceptual symbol systems theory Barsalou’s most notable contribution to grounded cognition is the development of perceptual symbol systems theory. According to perceptual symbol systems theory, bottom-up patterns of activation within sensory-motor areas become associated during perception, and thus become perceptually-based symbols. Barsalou suggests that attentional mechanisms then bind these diverse perceptual components into stable networks of associations, termed simulators, which are then stored in long-term memory. Then, during normal conceptual activation, top-down cognitive processes reactivate the simulators associated with these perceptual symbols, such that representation is directly the result of simulated sensory experiences. While this may account for item-level simulations, perceptual symbol systems theory can also account for category-based cognitive processing. The theory states that after repeatedly experiencing members of a category over time, the associated sensorimotor activation develops into a stable simulator that is used to represent the category as a whole. These simulators are thus able to integrate multimodal information from both within and across experiences with category members. Moreover, these simulators are not limited to specific types of entities, but can be used to represent objects, events, actions, introspections, and relational properties. Perceptual Symbol Systems theory has also been used to account for both prediction and the simulation of novel events. Barsalou (2009) states that when we encounter a familiar situation, sensorimotor based representations of the situation are activated. Given that this form of simulation is essentially indexing a specific pattern of sensorimotor activation, this form of grounded representation may then serve as a rich source for prediction through pattern completion mechanisms. In addition, novel events may be simulated by combinatorially and recursively combining discrete aspects of simulation from known concepts. Barsalou also suggests that such processes underlie the experiences of proprioception and introspection. Specifically, Barsalou (1999) notes that the experience