Which of the following is NOT a type of retrieval cue?

Retrieval cues are stimuli that can help access information stored in memory, thus aiding the process of recall. State-dependent cues refer to the idea that memory retrieval is more effective when an individual is in the same state of consciousness or mood as when the information was encoded. Contextual cues also play a role, as they involve the external environment or context in which the memory was formed, enhancing retrieval when an individual is in that same context.

Mnemonic devices, on the other hand, are memory aids designed to improve encoding and retrieval of information by associating new information with familiar patterns or structures, such as acronyms or rhymes.

Retrieval failure theory, however, is a concept rather than a cue. It explains why memory recall can fail — it addresses situations where the needed cues to retrieve information are absent or ineffective. Therefore, it does not fit the definition of a retrieval cue. This distinction is what makes recovery failure theory the correct answer to the question.