What type of memory is intact in someone who can perform actions like crocheting but has amnesia?

The ability to perform actions such as crocheting despite having amnesia suggests that implicit memory is intact. Implicit memory, often referred to as procedural memory, involves the unconscious retention of skills and tasks that are performed automatically, such as riding a bicycle or playing a musical instrument. This type of memory is not reliant on conscious recall of past experiences or facts, which is characteristic of explicit memory.

In cases of amnesia, especially when it affects explicit memory, individuals may struggle to remember facts or events from their past, but their ability to perform well-learned procedures remains unaffected. Therefore, someone with amnesia who can still crochet demonstrates that their implicit memory system is functioning, allowing them to execute learned skills without the need for conscious thought or recollection of past experiences.

The other types of memory mentioned, such as explicit memory, would generally be impaired in amnesia, as they involve the conscious recall of information. Prospective memory refers to the ability to remember to perform actions in the future, and semantic memory relates to general knowledge and facts independent of personal experience, both of which also would be compromised in someone with significant amnesic conditions.