Remember versus know judgements

There is evidence suggesting that different processes are involved in remembering something versus knowing whether it is familiar. It appears that "remembering" and "knowing" represent relatively different characteristics of memory as well as reflect different ways of using memory.

To remember is the conscious recollection of many vivid contextual details, such as "when" and "how" the information was learned. Remembering utilizes episodic memory and requires a deeper level of processing (e.g. undivided attention) than knowing. Errors in recollection may be due to source-monitoring errors that prevent an individual from remembering where exactly a piece of information was received. On the other hand, source monitoring may be very effective in aiding the retrieval of episodic memories. Remembering is a knowledge-based and conceptually-driven form of processing that can be influenced by many things. It is relevant to note that under this view both kinds of judgments are characteristics of individuals and thus any distinctions between the two are correlational, not causal, events.

To know is a feeling (unconscious) of familiarity. It is the sensation that the item has been seen before, but not being able to pin down the reason why. Knowing simply reflects the familiarity of an item without recollection. Knowing utilizes semantic memory that requires perceptually based, data-driven processing. Knowing is the result of shallow maintenance rehearsal that can be influenced by many of the same aspects as semantic memory.

Remember and know responses are quite often differentiated by their functional correlates in specific areas in the brain. For instance, during "remember" situations it is found that there is greater EEG activity than "knowing", specifically, due to an interaction between frontal and posterior regions of the brain. It is also found that the hippocampus is differently activated during recall of "remembered" (vs. familiar) stimuli. On the other hand, items that are only "known", or seem familiar, are associated with activity in the rhinal cortex.

The remember-know paradigm began its journey in 1985 from the mind of Endel Tulving. He suggested that there are only two ways in which an individual can access their past. For instance, we can recall what we did last night by simply traveling back in time through memory and episodically imagining what we did (remember) or we can know something about our past such as a phone number, but have no specific memory of where the specific memory came from (know). Recollection is based on the episodic memory system, and familiarity is based on the semantic memory system. Tulving argued that the remember-know paradigm could be applied to all aspects of recollection.

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Wikipedia