question: Why do repeating things over and over help us remember them?
comment: Every time you perform a voluntary act, a chemical pathway forms in your brain to help you remember what you did. If you only do an act once, the pathway becomes unused and eventually disintegrates. But if you repeat it again and again, the pathway becomes virtually permanent and easy to recall.
passages: Section::::Neural correlates.:Repetition enhancement.
  
  Although repetition priming is most often associated with neural attenuation for repeated presentation of stimuli, increases in neural responses have also been measured in a number of experimental contexts. For example, when performing mathematical calculations, when repeated stimuli are degraded, in studies involving a backward masking paradigm and when stimuli have no pre-existing associations or meaning.
   The effects of elaborative rehearsal or deep processing can be attributed to the number of connections made while encoding that increase the number of pathways available for retrieval.
  
  Section::::Optimal encoding.
  
  Organization can be seen as the key to better memory. As demonstrated in the above section on levels of processing the connections that are made between the to-be-remembered item, other to-be-remembered items, previous experiences and context generate retrieval paths for the to-be-remembered item. These connections impose organization on the to-be-remembered item, making it more memorable.
  
  Section::::Optimal encoding.:Mnemonics.
   The well-known role of repetition in the common process of memorization of course plays a role in the more complex techniques of the art of memory. The earliest of the references to the art of memory, the "Dialexis", mentioned above, makes this clear: "repeat again what you hear; for by often hearing and saying the same things, what you have learned comes complete into your memory." Similar advice is a commonplace in later works on the art of memory.
  
  Section::::Techniques.
   Section::::Theories and models.:"Reduced prediction error/stimulus expectation".
  
  When a stimulus is repeated top-down feedback modulates the neural response of earlier processing regions, with reduced neural activation and improved behavioural responses reflecting fulfilled expectations. The idea for this comes from predictive coding theories and Bayesian statistics and has some support in fMRI studies manipulating stimulus expectation. However, the results may also reflect the involvement of attention, which seems to have a modulatory effect on the extent of priming elicited.
  
  Section::::Theories and models.:"Neural synchrony".
   Section::::Neural correlates.
  
  Section::::Neural correlates.:Repetition suppression.
   One suggested reason for the primacy effect is that the initial items presented are most effectively stored in dormant memory because of the greater amount of processing devoted to them. (The first list item can be rehearsed by itself; the second must be rehearsed along with the first, the third along with the first and second, and so on.) The primacy effect is reduced when items are presented quickly and is enhanced when presented slowly (factors that reduce and enhance processing of each item and thus permanent storage). Longer presentation lists have been found to reduce the primacy effect.
   Section::::Theories and models.
  
  Numerous models have been put forward to explain behavioural efficiencies that are gained with repeated presentations of the same or similar stimuli. These are outlined below.
  
  Section::::Theories and models.:"Fatigue".
   There are different theories proposed to explain the increased performance of isolated items. The total-time hypothesis suggests that isolated items are rehearsed for a longer time in working memory compared to non-isolated items. Another approach offers that subjects could consider the isolated items to be in their own special category in a free-recall task, making them easier to recollect. A separate explanation is based upon the analysis of the deep processing of similarities and differences among the items. 
   This contrasts with a study from surveys of medical students that approximately only 20% frequently used mnemonic acronyms.
  
  In humans, the process of aging particularly affects the medial temporal lobe and hippocampus, in which the episodic memory is synthesized. The episodic memory stores information about items, objects, or features with spatiotemporal contexts. Since mnemonics aid better in remembering spatial or physical information rather than more abstract forms, its effect may vary according to a subject's age and how well the subject's medial temporal lobe and hippocampus function.
   Section::::Spreading activation.
  
  In the brain, memory stores information in a network of nodes that are linked together. When a memory is retrieved, activation spreads on the links until it intersects or enough time has passed. If there is one association, the activation only has to spread to a single link whereas multiple associations would divide the activation to many links. Because there are so many connections, it causes the brain to take a longer time to identify the concepts and retrieve the memory.
  
  Section::::Plausible theories.
   One of the classic experiments is by Ebbinghaus, who found the serial position effect where information from the beginning and end of list of random words were better recalled than those in the center. This primacy and recency effect varies in intensity based on list length. Its typical U-shaped curve can be disrupted by an attention-grabbing word; this is known as the Von Restorff effect.
   This theory suggests that repetition priming is a result of binding the initial stimulus directly to the response while bypassing the intervening layers of computation. The mechanism mediating this direct binding has not been clarified but several hypotheses have been put forward. One theory explains it as a race between automatic activation of a previous stimulus-response route and the reengagement of the "algorithmic" route and another theory suggests the operation of an "action-trigger" where repeated stimuli trigger the previous response through perceptual or conceptual associations with the original stimulus. In support of this theory is evidence of a response congruency effect, which would be expected from these stimulus-response bindings. The increased synchrony between regions discussed above could be a neural correlate of stimulus-response binding.
   Repetition priming refers to improvements in a behavioural response when stimuli are repeatedly presented. The improvements can be measured in terms of "accuracy" or "reaction time", and can occur when the repeated stimuli are either identical or similar to previous stimuli. These improvements have been shown to be cumulative, so as the number of repetitions increases the responses get continually faster up to a maximum of around seven repetitions. These improvements are also found when the repeated items are changed slightly in terms of orientation, size and position. The size of the effect is also modulated by the length of time the item is presented for and the length time between the first and subsequent presentations of the repeated items.
   Section::::Structure of mnemonic skills.:Acceleration.
  
  The final step in skilled memory theory is acceleration. With practice, time necessary for encoding and retrieval operations can be dramatically reduced. As a result, storage of information can then be performed within a few seconds. Indeed, one confounding factor in the study of memory is that the subjects often improve from day-to-day as they are tested over and over.
  
  Section::::Learned skill or innate ability.
  
  The innateness of expert performance in the memory field has been studied thoroughly by many scientists; it is a matter which has still not been definitively resolved.
   In the study of human memory, the contiguity effect has been found in studies of free recall. Analyses of free recall data indicates that there tends to be the greatest number of +/- 1 transitions between words, suggesting that a person is more likely to recall words together that are closer together in a list. This is shown in a graph of conditional response probability as a function of lag as originated by Dr. Michael Kahana. The probability of recall (y-axis) is plotted against the lag, or separation between subsequently recalled words. For example, if two items A and B are learned together, when cued with B, A is retrieved and vice versa due to their temporal contiguity, although there will be a stronger forward association (when cued with A, B is recalled).
   Beyond examining the relative probability of particular items being recalled, one can examine the order in which items are retrieved during the recall period. When a participant is asked to recall a set of random words, there is a marked tendency for items from neighboring positions in the study set to also be recalled successively also known as the contiguity effect, characterized by Michael J. Kahana though others have shown that this "law of contiguity" applies only locally and not globally to the full list of items 
  
  Section::::Subjective organization.
   The characteristic behaviour of the system is shown to create and reinforce patterns. The current set of patterns in the system determine how new experiences are integrated. Attention tends to flow along well-worn paths and patterns have large catchment areas. Novel experiences are often lost as attention flows down old paths that are in some way similar to the new experience. Sometimes starting at a different point in an established pattern can lead to a jump out of that pattern to a new one.
   For example, if a person examines a shopping list with one item highlighted in bright green, he or she will be more likely to remember the highlighted item than any of the others. Additionally, in the following list of words – desk, chair, bed, table, chipmunk, dresser, stool, couch – chipmunk will be remembered the most as it stands out against the other words in its meaning.
  
  Section::::Explanation.
   Maintenance rehearsal has the potential to assist in long-term memory in certain situations. In a previous study, researchers looked at the difference in recall for a set of words between participants who knew they were going to be asked to recall the words, in which they repeated the words multiple times and the participants who did not know they were going to recall the words, in which they only repeated the words once. The group that were told they would have to recall the words at a later date, did significantly better than those who were not told they would have to recall (Baddeley, 2009). There is also a positive correlation between the meaningfulness of words and how much an individual will remember them (Baddeley, 2009). The more meaning an individual associates with a certain word or a list of words, the more likely and easier it will be for them to remember them if asked to repeat them at a later date.
   Section::::Theories and models.:"Stimulus-response binding".
   In short-term memory tasks, participants are given a set of items (e.g. letters, digits) one at a time and then, after varying periods of delay, are asked for recall of the items. As well, participants could be asked whether a specific target item was present in their original set. The serial order of items and the relationships between them can have varying effects on the item's speed and accuracy of recall.
  
  Section::::Overview.
   Yet another explanation offered by the authors is the fact that in the case of frequency, people often come across them multiple times and have a sequential input, compared to a probability value, which is given in one time. From John Medina’s Brain Rules, sequential input can lead to a stronger memory than a onetime input. This can be a primary reason why humans choose frequency encounters over probability.
  
  Section::::Supporting arguments.:Easier storage.
   Overt rehearsal was a technique that was meant to test participants' rehearsal patterns. In an experiment using this technique, participants were asked to recite out loud the items that come to mind. In this way, the experimenter was able to see that participants would repeat earlier items more than items in the middle of the list, thus rehearsing them more frequently and having a better recall of the prime items than the middle items later on.
   Section::::Description.
  
  Repetition priming can occur without a person being aware of either the repeats or the improvements in his/her response, so it is generally thought to involve implicit memory processes that are dissociable from explicit memory processes. This idea has support from findings that amnesic patients with damage to limbic and/or diencephalic structures show measurable repetition priming effects but have deficits on explicit measures of memory. However, some researchers suggest that implicit and explicit memory systems are not in fact separate. Repetition priming has also been associated with attentional processes, stimulus expectation and episodic memory.
   Repetition compulsion
  
  Repetition compulsion is a psychological phenomenon in which a person repeats an event or its circumstances over and over again. This includes reenacting the event or putting oneself in situations where the event is likely to happen again. This "re-living" can also take the form of dreams in which memories and feelings of what happened are repeated, and even hallucinated.
  