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When discussing memory, recall is the act of retrieving from long term memory a specific incident, fact or other item. A temporary failure to retrieve information from memory is known as the tip of the tongue phenomenon. Various means, including metacognitive strategies, priming, and measures of retention may be employed to improve later recall of a memory.

[edit] Types of recollection

Recollection often requires prompting (as in stimulus or clues) to assist the mind in retrieving the information sought. There are three types of recall:

• Free recall: when no clues are given to assist retrieval
• Serial recall: when items are recalled in a particular order
• Cued recall: when some clues are given to assist retrieval

[edit] Recognition

The ability to recognize what is known is usually superior to the ability to recall it. Examples abound:

• We know a person's face, but his name eludes us.
• People are more likely to recognize a suspect in a police line-up (or a book of mug shots) than to provide an accurate description from recall memory.
• It is easier to answer multiple-choice questions than essay questions because the correct answer may be recognized.

For possible exceptions, see Tulving's work on episodic memory.

[edit] Relearning

Another means of remembering is through relearning. Relearned information may return quickly, even if it hasn't been used for many years. For example:

• Relearning a language not spoken since schooldays.
• Riding a bike after not using one since childhood.

The number of successive trials a learner takes to reach a specified level of proficiency may be compared with the number of trials needed later to attain the same level. This yields a measure of retention. Relearning may be the most efficient way of remembering information ( Ebbinghaus, 1885).

[edit] Relative sensitivity of measures of retention

Sensitivity refers to the ability to assess the amount of information that has been stored in memory. Research suggests that recall is the least sensitive measure of retention, relearning is the most sensitive and recognition is in between (Nelson, 1978).

[edit] Plato and Socrates on recollection

Plato can be said to have believed that humans learn entirely through recollection. He thought that humans already possessed knowledge, and that they only had to be led to discover what they already knew. In the Meno, Plato used the character of Socrates to ask a slave boy questions in an excellent demonstration of the Socratic method until the slave boy came to understand a square root without Socrates providing him with any information.

After witnessing the example with the slave boy, Meno tells Socrates that he thinks that Socrates is correct in his theory of recollection, to which Socrates replies, “I think I am. I shouldn’t like to take my oath on the whole story, but one thing I am ready to fight for as long as I can, in word and act—that is, that we shall be better, braver, and more active men if we believe it right to look for what we don’t know...” (Meno, 86b).