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short non-fiction · the mind

The bicycle ride without a yesterday

Patient H.M. showed that acquiring a skill can be separated from forming conscious episodic memories.

After surgery for severe epilepsy in 1953, Henry Molaison could hold a conversation but usually could not carry its new events into lasting conscious memory. Researcher Brenda Milner asked him to trace a star while watching his hand in a mirror. Across sessions he improved, yet each time the task itself seemed new to him.

Suzanne Corkin’s decades-long account of H.M. helped replace the idea of memory as one faculty with several systems: skill learning could survive while new episodic memory was profoundly impaired. A single, unusual case cannot map every memory mechanism, and the operation’s damage was complex. Its historic force came from the dissociation—the hands could reveal learning that the narrating person could not recall.

Based on the work of

Suzanne Corkin

· 2013

The lead researcher’s detailed history of H.M. and the experiments that divided memory into distinct systems.

What to keep in view

H.M. was one extensively studied patient with complex lesions; conclusions rely on converging cases and experiments, not his case alone.