Internal Simulation as a Key Mechanism for Cognitive Function in Humans, Animals and Robots
Germund Hesslow, Lund University
Abstract:
The lecture will outline a hypothetical mechanism by which the brain can simulate interaction with the external world. Three assumptions underlie this simulation theory. Firstly, we can simulate an action in the sense that we can activate motor structures, as during a normal overt action, but suppress its execution. Secondly, we can simulate perception by internal activation of sensory cortex in a way that resembles its normal activation during perception of external stimuli. The third assumption ('anticipation') is that both overt and simulated actions can elicit perceptual simulation of their most probable consequences. Evidence, mainly from neuroimaging studies, that supports these assumptions, is reviewed briefly. The theory is ontologically parsimonious and does not rely on standard cognitivist constructs such as internal models or representations. It is argued that the simulation approach can explain the relations between motor, sensory and cognitive functions and the appearance of an inner world. It also unifies and explains important features of a wide variety of cognitive phenomena such as memory, goals and cognitive maps. Novel findings from recent developments in memory research on the similarity of imaging and memory and on the role of both prefrontal cortex and sensory cortex in declarative memory and working memory are predicted by the theory and provide striking support for it. Some attempts to implement the simulation mechanism in artificial neural networks and robots is reviewed.