History
Types
There are two main approaches to coding information: the physiological approach, and the mental approach. The physiological approach looks at how a stimulus is represented by neurons firing in the brain, while the mental approach looks at how the stimulus is represented in the mind. There are many types of mental encoding that are used, such as visual, elaborative, organizational, acoustic, and semantic. However, this is not an extensive listVisual encoding
Visual encoding is the process of converting images and visual sensory information to memory stored in the brain. This means that people can convert the new information that they stored into mental pictures (Harrison, C., Semin, A.,(2009). Psychology. New York p. 222) Visual sensory information is temporarily stored within ourElaborative encoding
Elaborative encoding is the process of actively relating new information to knowledge that is already in memory. Memories are a combination of old and new information, so the nature of any particular memory depends as much on the old information already in our memories as it does on the new information coming in through our senses. In other words, how we remember something depends on how we think about it at the time. Many studies have shown that long-term retention is greatly enhanced by elaborative encoding.Semantic encoding
Semantic encoding is the processing and encoding of sensory input that has particular meaning or can be applied to a context. Various strategies can be applied such as chunking andAcoustic encoding
Acoustic encoding is the encoding of auditory impulses. According to Baddeley, processing of auditory information is aided by the concept of the phonological loop, which allows input within our echoic memory to be sub vocally rehearsed in order to facilitate remembering. When we hear any word, we do so by hearing individual sounds, one at a time. Hence the memory of the beginning of a new word is stored in our echoic memory until the whole sound has been perceived and recognized as a word. Studies indicate that lexical, semantic and phonological factors interact in verbal working memory. The phonological similarity effect (PSE), is modified by word concreteness. This emphasizes that verbal working memory performance cannot exclusively be attributed to phonological or acoustic representation but also includes an interaction of linguistic representation.Acheson, D.J., MacDonald, M.C., & Postle, B.R. (2010). The Interaction of Concreteness and Phonological Similarity in Verbal Working Memory. Journal of Experimental Psychogy: Learning, Memory and Cognition; 36:1, 17-36. What remains to be seen is whether linguistic representation is expressed at the time of recall or whether the representational methods used (such as recordings, videos, symbols, etc.) participate in a more fundamental role in encoding and preservation of information in memory. The brain relies primarily on acoustic (aka phonological) encoding for use in short-term storage and primarily semantic encoding for use in long-term storage.Other senses
Tactile encoding is the processing and encoding of how something feels, normally through touch. Neurons in the primary somatosensory cortex (S1) react to vibrotactile stimuli by activating in synchronization with each series of vibrations.Crawley, AP., Davis, KD., Mikulis. DJ. & Kwan, CL. (1998). Function MRI study of thalamic and cortical activation evoked by cutaneous heat, cold, and tactile stimuli. Journal of Neurophysiology: 80 (3): 1533–46 Odors and tastes may also lead to encode. Organizational encoding is the course of classifying information permitting to the associations amid a sequence of terms.Long-Term Potentiation
Mapping Activity
Positron emission tomography (PET) demonstrates a consistent functional anatomical blueprint of hippocampal activation during episodic encoding and retrieval. Activation in the hippocampal region associated with episodic memory encoding has been shown to occur in the rostral portion of the region whereas activation associated with episodic memory retrieval occurs in the caudal portions.Lepage, M., Habib, R. & Tulving. E. (1998). Hippocampal PET activations of memory encoding and retrieval: The HIPER model. Hippocampus, 8:4: 313-322 This is referred to as the Hippocampal memory encoding and retrieval model or HIPER model. One study used PET to measure cerebral blood flow during encoding and recognition of faces in both young and older participants. Young people displayed increased cerebral blood flow in the right hippocampus and the left prefrontal and temporal cortices during encoding and in the right prefrontal and parietal cortex during recognition.Grady, CL., Horwitz, B., Haxby, JV., Maisog, JM., McIntosh, AR., Mentis, MJ., Pietrini, P., Schapiro, MB., & Underleider, LG. (1995) Age-related reductions in human recognition memory due to inpaired encoding. Science, 269:5221, 218-221. Elderly people showed no significant activation in areas activated in young people during encoding, however they did show right prefrontal activation during recognition. Thus it may be concluded that as we grow old, failing memories may be the consequence of a failure to adequately encode stimuli as demonstrated in the lack of cortical and hippocampal activation during the encoding process. Recent findings in studies focusing on patients with post traumatic stress disorder demonstrate that amino acid transmitters, glutamate and GABA, are intimately implicated in the process of factual memory registration, and suggest that amine neurotransmitters, norepinephrine-epinephrine and serotonin, are involved in encoding emotional memory.Birmes, P., Escande, M., Schmitt, L. & Senard, JM. (2002). Biological Factors of PTSD: neurotransmitters and neuromodulators. Encephale, 28: 241-247.Molecular Perspective
The process of encoding is not yet well understood, however key advances have shed light on the nature of these mechanisms. Encoding begins with any novel situation, as theSynaptic Plasticity
The Encoding Process
A significant short-term biochemical change is the covalent modification of pre-existing proteins in order to modify synaptic connections that are already active. This allows data to be conveyed in the short term, without consolidating anything for permanent storage. From here a memory or an association may be chosen to become a long-term memory, or forgotten as the synaptic connections eventually weaken. The switch from short to long-term is the same concerning bothEncoding and Genetics
Human memory, including the process of encoding, is known to be a heritable trait that is controlled by more than one gene. In fact, twin studies suggest that genetic differences are responsible for as much as 50% of the variance seen in memory tasks. Proteins identified in animal studies have been linked directly to a molecular cascade of reactions leading to memory formation, and a sizable number of these proteins are encoded by genes that are expressed in humans as well. In fact, variations within these genes appear to be associated with memory capacity and have been identified in recent human genetic studies.Complementary Processes
The idea that the brain is separated into two complementary processing networks ( task positive and task negative) has recently become an area of increasing interest. The task positive network deals with externally oriented processing whereas the task negative network deals with internally oriented processing. Research indicates that these networks are not exclusive and some tasks overlap in their activation. A study done in 2009 shows encoding success and novelty detection activity within the task-positive network have significant overlap and have thus been concluded to reflect common association of externally oriented processing.Cabeza, R., Daselaar, S.M., & Hongkeun, K. (2009). Overlapping brain activity between episodic memory encoding and retrieval: Roles of the task-positive and task-negative networks. Neuroimage;49: 1145–1154. It also demonstrates how encoding failure and retrieval success share significant overlap within the task negative network indicating common association of internally oriented processing. Finally, a low level of overlap between encoding success and retrieval success activity and between encoding failure and novelty detection activity respectively indicate opposing modes or processing. In sum task positive and task negative networks can have common associations during the performance of different tasks.Depth of Processing
Different levels of processing influence how well information is remembered. This idea was first introduced by Craik and Lockhart (1972). They claimed that the level of processing information was dependent upon the depth at which the information was being processed; mainly, shallow processing and deep processing. According to Craik and Lockhart, the encoding of sensory information would be considered shallow processing, as it is highly automatic and requires very little focus. Deeper level processing requires more attention being given to the stimulus and engages more cognitive systems to encode the information. An exception to deep processing is if the individual has been exposed to the stimulus frequently and it has become common in the individual’s life, such as the person’s name. These levels of processing can be illustrated by maintenance and elaborate rehearsal.Maintenance and Elaborative Rehearsal
''Maintenance rehearsal'' is a shallow form of processing information which involves focusing on an object without thought to its meaning or its association with other objects. For example, the repetition of a series of numbers is a form of maintenance rehearsal. In contrast, ''elaborative or relational rehearsal'' is a process in which you relate new material to information already stored in Long-term memory. It's a deep form of processing information and involves thought of the object's meaning as well as making connections between the object, past experiences and the other objects of focus. Using the example of numbers, one might associate them with dates that are personally significant such as your parents' birthdays (past experiences) or perhaps you might see a pattern in the numbers that helps you to remember them.Craik, F. I. M., & Watkins, M. J. (1973). The role of rehearsal in short-term memory. ''Journal of Verbal Learning and Verbal Behavior'', 12 (6), 599–607.Intention to Learn
Studies have shown that the intention to learn has no direct effect on memory encoding. Instead, memory encoding is dependent on how deeply each item is encoded, which could be affected by intention to learn, but not exclusively. That is, intention to learn can lead to more effective learning strategies, and consequently, better memory encoding, but if you learn something incidentally (i.e. without intention to learn) but still process and learn the information effectively, it will get encoded just as well as something learnt with intention. 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.Optimal Encoding
Organization
Organization is key to memory encoding. Researchers have discovered that our minds naturally organize information if the information received is not organized. One natural way information can be organized is through hierarchies. For example, the grouping mammals, reptiles, and amphibians is a hierarchy of the animal kingdom. Depth of processing is also related to the organization of information. For example, 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 and can act as retrieval cues. These connections create organization on the to-be-remembered item, making it more memorable.Visual Images
Another method used to enhance encoding is to associate images with words. Gordon Bower and David Winzenz (1970) demonstrated the use of imagery and encoding in their research while using paired-associate learning. Researchers gave participants a list of 15-word-pairs, showing each participant the word pair for 5 seconds for each pair. One group was told to create a mental image of the two words in each pair in which the two items were interacting. The other group was told to use maintenance rehearsal to remember the information. When participants were later tested and asked to recall the second word in each word pairing, researchers found that those who had created visual images of the items interacting remembered over twice as many of the word pairings than those who used maintenance rehearsal.Mnemonics
Chunking
Chunking is a memory strategy used to maximize the amount of information stored in short term memory in order to combine it into small, meaningful sections. By organizing objects into meaningful sections, these sections are then remembered as a unit rather than separate objects. As larger sections are analyzed and connections are made, information is weaved into meaningful associations and combined into fewer, but larger and more significant pieces of information. By doing so, the ability to hold more information in short-term memory increases. To be more specific, the use of chunking would increase recall from 5 to 8 items to 20 items or more as associations are made between these items. Words are an example of chunking, where instead of simply perceiving letters we perceive and remember their meaningful wholes: words. The use of chunking increases the number of items we are able to remember by creating meaningful "packets" in which many related items are stored as one. The use of chunking is also seen in numbers. One of the most common forms of chunking seen on a daily basis is that of phone numbers. Generally speaking, phone numbers are separated into sections. An example of this would be 909 200 5890, in which numbers are grouped together to make up one whole. Grouping numbers in this manner, allows them to be recalled with more facility because of their comprehensible acquaintanceship.State-Dependent Learning
For optimal encoding, connections are not only formed between the items themselves and past experiences, but also between the internal state or mood of the encoder and the situation they are in. The connections that are formed between the encoders internal state or the situation and the items to be remembered are State-dependent. In a 1975 study by Godden and Baddeley the effects of State-dependent learning were shown. They asked deep sea divers to learn various materials while either under water or on the side of the pool. They found that those who were tested in the same condition that they had learned the information in were better able to recall that information, i.e. those who learned the material under water did better when tested on that material under water than when tested on land. Context had become associated with the material they were trying to recall and therefore was serving as a retrieval cue. Results similar to these have also been found when certain smells are present at encoding. However, although the external environment is important at the time of encoding in creating multiple pathways for retrieval, other studies have shown that simply creating the same internal state that was present at the time of encoding is sufficient to serve as a retrieval cue. Therefore, being in the same mindset as in at the time of encoding will help with recalling in the same way that being in the same situation helps recall. This effect called context reinstatement was demonstrated by Fisher and Craik 1977 when they matched retrieval cues with the way information was memorized.Transfer-Appropriate Processing
Transfer-appropriate processing is a strategy for encoding that leads to successful retrieval. An experiment conducted by Morris and coworkers in 1977 proved that successful retrieval was a result of matching the type of processing used during encoding. During their experiment, their main findings were that an individual's ability to retrieve information was heavily influenced on whether the task at encoding matched the task during retrieval. In the first task, which consisted of the rhyming group, subjects were given a target word and then asked to review a different set of words. During this process, they were asked whether the new words rhymed with the target word. They were solely focusing on the rhyming rather than the actual meaning of the words. In the second task, individuals were also given a target word, followed by a series of new words. Rather than identify the ones that rhymed, the individual was to focus more on the meaning. As it turns out, the rhyming group, who identified the words that rhymed, was able to recall more words than those in the meaning group, who focused solely on their meaning. This study suggests that those who were focusing on rhyming in the first part of the task and on the second, were able to encode more efficiently. In transfer-appropriate processing, encoding occurs in two different stages. This helps demonstrate how stimuli were processed. In the first phase, the exposure to stimuli is manipulated in a way that matches the stimuli. The second phase then pulls heavily from what occurred in the first phase and how the stimuli was presented; it will match the task during encoding.Encoding Specificity
Generation Effect
Another principle that may have the potential to aid encoding is the generation effect. The generation effect implies that learning is enhanced when individuals generate information or items themselves rather than reading the content. The key to properly apply the generation effect is to generate information, rather than passively selecting from information already available like in selecting an answer from a multiple-choice question In 1978, researchers Slameka and Graf conducted an experiment to better understand this effect. In this experiment, the participants were assigned to one of two groups, the ''read group'' or the ''generate group''. The participants assigned to the ''read'' ''group'' were asked to simply read a list of paired words that were related, for example, horse-saddle. The participants assigned to the ''generate'' ''group'' were asked to fill in the blank letters of one of the related words in the pair. In other words, if the participant was given the word ''horse,'' they would need to fill in the last four letters of the word ''saddle''.The researchers discovered that the group that was asked to fill in the blanks had better recall for these word pairs than the group that was asked to simply remember the word pairs.Self-Reference Effect
Research illustrates that the self-reference effect aids encoding. The self-reference effect is the idea that individuals will encode information more effectively if they can personally relate to the information. For example, some people may claim that some birth dates of family members and friends are easier to remember than others. Some researchers claim this may be due to the self-reference effect. For example, some birth dates are easier for individuals to recall if the date is close to their own birth date or any other dates they deem important, such as anniversary dates. Research has shown that after being encoded, self-reference effect is more effective when it comes to recalling memory than semantic encoding. Researchers have found that the self-reference effect goes more hand and hand with elaborative rehearsal. Elaborative rehearsal is more often than not, found to have a positive correlation with the improvement of retrieving information from memories. Self-reference effect has shown to be more effective when retrieving information after it has been encoded when being compared to other methods such as semantic encoding. Also, it is important to know that studies have concluded that self-reference effect can be used to encode information among all ages. However, they have determined that older adults are more limited in their use of the self-reference effect when being tested with younger adults.Salience
When an item or idea is considered "salient", it means the item or idea appears to noticeably stand out. When information is salient, it may be encoded in memory more efficiently than if the information did not stand out to the learner. In reference to encoding, any event involving survival may be considered salient. Research has shown that survival may be related to the self-reference effect due to evolutionary mechanisms. Researchers have discovered that even words that are high in survival value are encoded better than words that are ranked lower in survival value. Some research supports evolution, claiming that the human species remembers content associated with survival. Some researchers wanted to see for themselves whether or not the findings of other research was accurate. The researchers decided to replicate an experiment with results that supported the idea that survival content is encoded better than other content. The findings of the experiment further suggested that survival content has a higher advantage of being encoded than other content.Retrieval Practice
Studies have shown that an effective tool to increase encoding during the process of learning is to create and take practice tests. Using retrieval in order to enhance performance is called the testing effect, as it actively involves creating and recreating the material that one is intending to learn and increases one’s exposure to it. It is also a useful tool in connecting new information to information already stored in memory, as there is a close association between encoding and retrieval. Thus, creating practice tests allows the individual to process the information at a deeper level than simply reading over the material again or using a pre-made test. The benefits of using retrieval practice have been demonstrated in a study done where college students were asked to read a passage for seven minutes and were then given a two-minute break, during which they completed math problems. One group of participants was given seven minutes to write down as much of the passage as they could remember while the other group was given another seven minutes to reread the material. Later all participants were given a recall test at various increments (five minutes, 2 days, and one week) after the initial learning had taken place. The results of these tests showed that those who had been assigned to the group that had been given a recall test during their first day of the experiment were more likely to retain more information than those that had simply reread the text. This demonstrates that retrieval practice is a useful tool in encoding information into long term memory.Computational Models of Memory Encoding
Computational models of memory encoding have been developed in order to better understand and simulate the mostly expected, yet sometimes wildly unpredictable, behaviors of human memory. Different models have been developed for different memory tasks, which include item recognition, cued recall, free recall, and sequence memory, in an attempt to accurately explain experimentally observed behaviors.Item recognition
In item recognition, one is asked whether or not a given probe item has been seen before. It is important to note that the recognition of an item can include context. That is, one can be asked whether an item has been seen in a study list. So even though one may have seen the word "apple" sometime during their life, if it was not on the study list, it should not be recalled. Item recognition can be modeled usingCued Recall
In cued recall, an individual is presented with a stimulus, such as a list of words and then asked to remember as many of those words as possible. They are then given cues, such as categories, to help them remember what the stimuli were. An example of this would be to give a subject words such as meteor, star, space ship, and alien to memorize. Then providing them with the cue of "outer space" to remind them of the list of words given. Giving the subject cues, even when never originally mentioned, helped them recall the stimulus much better. These cues help guide the subjects to recall the stimuli they could not remember for themselves prior to being given a cue. Cues can essentially be anything that will help a memory that is deemed forgotten to resurface. An experiment conducted by Tulvig suggests that when subjects were given cues, they were able to recall the previously presented stimuli. Cued recall can be explained by extending the attribute-similarity model used for item recognition. Because in cued recall, a wrong response can be given for a probe item, the model has to be extended accordingly to account for that. This can be achieved by adding noise to the item vectors when they are stored in the memory matrix. Furthermore, cued recall can be modeled in a probabilistic manner such that for every item stored in the memory matrix, the more similar it is to the probe item, the more likely it is to be recalled. Because the items in the memory matrix contain noise in their values, this model can account for incorrect recalls, such as mistakenly calling a person by the wrong name.Free Recall
In free recall, one is allowed to recall items that were learned in any order. For example, you could be asked to name as many countries in Europe as you can. Free recall can be modeled using SAM (Search of Associative Memory) which is based on the dual-store model, first proposed by Atkinson and Shiffrin in 1968. SAM consists of two main components: short-term store (STS) and long-term store (LTS). In brief, when an item is seen, it is pushed into STS where it resides with other items also in STS, until it displaced and put into LTS. The longer the item has been in STS, the more likely it is to be displaced by a new item. When items co-reside in STS, the links between those items are strengthened. Furthermore, SAM assumes that items in STS are always available for immediate recall. SAM explains both primacy and recency effects. Probabilistically, items at the beginning of the list are more likely to remain in STS, and thus have more opportunities to strengthen their links to other items. As a result, items at the beginning of the list are made more likely to be recalled in a free-recall task (primacy effect). Because of the assumption that items in STS are always available for immediate recall, given that there were no significant distractors between learning and recall, items at the end of the list can be recalled excellently (recency effect). Studies have shown that free recall is one of the most effective methods of studying and transferring information from short term memory to long term memory compared to item recognition and cued recall as greater relational processing is involved. Incidentally, the idea of STS and LTS was motivated by the architecture of computers, which contain short-term and long-term storage.Sequence Memory
Sequence memory is responsible for how we remember lists of things, in which ordering matters. For example, telephone numbers are an ordered list of one digit numbers. There are currently two main computational memory models that can be applied to sequence encoding: associative chaining and positional coding. Associative chaining theory states that every item in a list is linked to its forward and backward neighbors, with forward links being stronger than backward links, and links to closer neighbors being stronger than links to farther neighbors. For example, associative chaining predicts the tendencies of transposition errors, which occur most often with items in nearby positions. An example of a transposition error would be recalling the sequence "apple, orange, banana" instead of "apple, banana, orange." PositionalReferences
{{DEFAULTSORT:Encoding (Memory) Memory