The same label, different processes: What lies behind the term “mental simulation” in the embodied cognition literature?

Over recent decades, cognitive science has increasingly focused on the theory of "Embodied Cognition", an "umbrella" term that encompasses several often non-converging approaches. A main construct underlying these approaches is the notion of "Mental Simulation". This paper argues that mental simulation is far from being a unitary construct and proposes a taxonomy in which different types of mental simulations are placed on a continuum, making it possible to disentangle the complex nature of mental simulation. To support this taxonomy empirically, a series of studies are reviewed showing that mental simulation is a fundamental cognitive process, underlying several abilities (e.g., action observation, language comprehension, mental imagery). Although the same label is used in different domains, the literature review supports the necessity to distinguish mental simulations on at least two dimensions, namely the process and the result of this process. The process can be automatic or voluntary, fast or slow; the outcome can range from a mental representation to motor resonance. Our analysis underscores the importance of a nuanced understanding of the cognitive, phenomenological and neural aspects of mental simulation. This helps clarify the state of knowledge in this domain while the taxonomy provides future research with a solid conceptual ground.