Which memory sin can lead to a firmly held false memory when exposed to repeated suggestions?

The correct answer is suggestibility because it refers to the phenomenon where a person's memory can be influenced by external information or repeated suggestions, leading to the formation of false memories. When individuals are exposed to misleading information, either through direct suggestion or through the influence of others recounting events, their recollection can become distorted. This process can result in the incorporation of inaccuracies into the memory, solidifying a false version of events that the individual may sincerely believe to be true.

In this context, suggestibility highlights how memories are not static but can be malleable and affected by context, conversation, or even leading questions. This aspect of memory can be particularly pronounced in traumatic events or when people are asked to recount experiences under suggestive circumstances.

The other concepts—bias, blocking, and transience—are related to memory but do not capture the specific process of forming false memories through suggestion. Bias refers to the influence of present beliefs or feelings on the recollection of past events, blocking is the inability to access information that is stored in memory, and transience involves the gradual forgetting of information over time. These do not specifically address the impact of repeated suggestions on memory formation, making suggestibility the most appropriate choice in this scenario.