Investigating the Declarative and Procedural Memory Processes Underlying Acquisition of Tool-Related Knowledge and Skills

It has been proposed that the acquisition of tool-related knowledge and skills (e.g., attributes of a tool, how it is used, how it is grasped) relies on a complex set of memory processes. However, the precise memory representations of different aspects of tool knowledge are still unclear. It has also been argued that some aspects may require an interaction between the declarative and procedural memory systems. However, the nature of this interaction between both memory systems in relation to tool-related knowledge is not well understood. A series of three experiments was carried out in the current dissertation to systematically investigate the role of declarative and procedural memory in mediating complex tool knowledge and skills. In Experiment 1 participants with Parkinson’s disease (PD) showed unimpaired memory for tool attributes and tool grasping relative to controls. In addition, participants with PD showed intact motor skill learning and skilled tool use within sessions, but failed to retain proficiency of these skills after a 3-week delay. In Experiment 2, declarative encoding processes were interrupted in healthy adults by dividing attention during training. Findings showed that dividing attention during training was detrimental for subsequent memory for tool attributes as well as accurate demonstration of tool use and tool grasping. However, dividing attention did not interfere with motor skill learning. In Experiment 3, motor procedural learning among healthy adults was disrupted by limiting access to performance-based feedback during training. Results showed that recall of tool attributes and tool grasping were intact, but limited feedback was detrimental for motor skill learning and skilled tool use. Taken together, the results suggest that memory for tool attributes and tool grasping primarily relies on declarative memory which is associated with the medial temporal lobes. In contrast, findings suggest that motor skill acquisition related to complex tools is primarily supported by striatal-dependent procedural memory. Thus, these results represent a dissociation between declarative and procedural aspects of tool knowledge and skills. Findings from the current studies also provide new insights into the interaction between declarative and procedural memory. The results suggest that skilled tool use requires a cooperative interaction of both systems. The evidence also suggests that the pattern of interaction between memory systems may vary, depending on the learning context.