鏡映描写の運動学習

Explicit or declarative memory encompasses factual information like birthdates or what you ate for lunch. Implicit or procedural memory includes knowledge you cannot easily put into words, such as how to skate or navigate home without knowing street names. Motor memories fall within implicit memory and require motor learning to develop.

Mirror drawing measures motor learning by having participants trace a star shape while viewing only the mirror reflection. Researchers count the number of times participants cross the borderlines in each session, then graph errors against session number. Improvement over time and faster learning after breaks indicate motor skill acquisition and retention.

A mirror drawing experiment requires a pencil, a mirror approximately 12 inches by 8 inches that stands independently, and an occluder made of wood, foam, or cardboard. Position the mirror about 12 inches from the table edge and the occluder about 6 inches from the edge to block direct viewing. The stimulus is a large star with a smaller star inside for participants to trace.

The savings effect occurs when participants make fewer errors in the session following a long break compared to their first session of the day. This demonstrates retention of previously learned motor skills. Combined with steeper improvement slopes after breaks, the savings effect provides evidence that motor learning has occurred and persists over time.

Research using mirror drawing shows that participants who napped between sessions made fewer errors than those without sleep breaks. This indicates sleep promotes retention of recently learned motor skills and increases the rate of improvement. Sleep appears to consolidate motor memories, allowing faster learning on subsequent testing days.

Patient H.M. had his hippocampus removed to prevent seizures, resulting in severe anterograde amnesia preventing new explicit memories. However, H.M. performed normally on mirror drawing tasks, showing retention and rapid improvement. This famous case demonstrated a distinction between explicit and implicit memory systems, supported by different brain regions.

Motor skill acquisition involves implicit or procedural memory, which develops through practice and becomes automatic over time. Initially, learning new skills like driving requires conscious effort and explicit attention. Eventually, the skill becomes second nature through repeated practice, allowing faster performance with less conscious deliberation.