Memory retrieval is the process of remembering information stored in long term memory (LTM). Some theorists suggests that there are three stores of memory: (1) working, (2) long term and (3) short term memory. Only data that is processed through short term memory (STM) and encoded into LTM can later be retrieved and used in working memory (Figure 1). Overall, the mechanisms of memory are not completely understood. However, there are many theories concerning memory retrieval.
There are two main types of memory retrieval: recall and recognition. In recall, the information is reproduced from memories. In recognition, the presentation of the information provides a cue that the information has been seen before. Recall may be assisted when retrieval cues are presented which enable the subject to quickly access the information in memory.
Facilitating Memory Retrieval
People tend to recall items or events in the order which they occurred. This is called serial recall and can be used to help cue memories. By thinking about a string of events or even words, it is possible to use a previous memory to cue the next item in the series. Serial recall helps a person to remember the order of events in his or her life in autobiographical memory. These memories appear to exist on a continuum on which more recent events are more easily recalled.
When recalling serial items presented as a list, two types of memory effects tend to occur frequently: the primacy effect and the recency effect.The primacy effect occurs when a participant remembers words from the beginning of a list better than the words from the middle or end. The theory behind this is that the participant has had more time to rehearse these words in working memory. The recency effect occurs when a participant remembers words from the end of a list more easily, possibly since they are still available in short term memory. These effects can often be seen in free recall experiments and are not mutually exclusive. Free recall is the process in which a person is given a list of items to remember and is then asked to recall the items in any order. It is a common method of memory research.
Cues can facilitate recovery of memories that have been "lost". A cue might be an object or scene that reminds a person of something related. In research, a process called cued recall is used to study these effects. Participants are given pairs of words to study. The experimenter then gives the participant one word to cue the recall of the word it was paired with. The stronger the link between the words, the better the participant will recall the pairs.
Interfering with Memory Retrieval
Interference occurs in memory when there is an interaction between the new material being learned and previously learned material. There are two main kinds of interference: proactive and retroactive.
Proactive interference is the forgetting of information due to interference from previous knowledge in LTM. Past memories can inhibit the encoding of new memories. This is particularly true if they are learned in similar contexts and the new information is similar to previous information.
Retroactive interference occurs when newly learned information interferes with the encoding or recall of previously learned information. If a participant was asked to recall a list of words, and was then immediately presented with new information, it could interfere with remembering the initial list. This may be due to the fact that the additional information does not allow the participant to encode the initial information.
Sometimes a person is not able to retrieve a memory that they have previously encoded. This can be due to the process of decay, a natural process that occurs when neural connections decline, like an unused muscle.
Occasionally, a person will experience a specific type of retrieval failure called tip-of-the-tongue phenomenon. This is the failure to retrieve a word from memory combined with partial recall and the feeling that retrieval is imminent. People who experience this can often recall one or more features of the target word such as the first letter, words that sound similar, or words that have a similar meaning. While this process is not completely understood, there are two theories as to why it occurs. The first is the direct-access perspective, which sates that the memory is not strong enough to retrieve but strong enough to trigger the state. The inferential perspective posits that the state occurs when the subject infers knowledge of the target word and tries to piece together different clues about the word that are not accessible in memory.