Memory Memory is the ability to store and
Memory Memory is the ability to store and retrieve information over time. Researchers are discovering differences in the structure of several brain regions known to be involved in memory in individuals who possess superior autobiographical memory, such as Jill Price (La. Porte et al. , 2012). Encoding is the process of transforming what we perceive, think, or feel into an enduring memory. Storage is the process of maintaining information in memory over time. Retrieval is the process of bringing to mind information that has been previously encoded and stored. Memories are made by combining information we already have in our brains with new information that comes in through our senses. Memories are dynamically constructed, not recorded.
Semantic Encoding Craik and Tulving (1975) presented participants with a series of words and asked them to make one of three types of judgments: (1) semantic [meaning]; (20 rhyme [sound]; (3) visual [appearance]. The participants who made semantic judgments had much better memory for the words than did participants who thought about how the word sounded or looked. Semantic encoding is uniquely associated with increased activity in the lower left part of the frontal lobe and the inner left part of the temporal lobe. The amount of activity in each of these regions during encoding is directly related to whether people later remember an item. The more activity there is in these areas, the more likely the person will remember the information. Brain Activity during Different Types of Judgments (Fig. 6. 2) will be on the next exam. Visual imagery encoding on the other hand is the process of storing new information by converting it into mental pictures. Snoor and Atkinson, 1969, have shown that visual imagery encoding can substantially improve memory recall. Creating a visual image relates incoming information to knowledge already in memory; two placeholders-visual and verbal– are better than one, visual activates occipital lobe processing regions.
Organizational & Survival Encoding Organizational encoding is the process of categorizing information according to the relationships among a series of items. People can improve recall of individual items by organizing them into multiple-level categories, called hierarchies. Organizational encoding activates the upper surface of the left frontal lobe; different types of encoding strategies appear to rely on different areas of brain activation. Encoding by survival-related information is based on evolutionary psychology; the features of an organism that help it to survive and reproduce are more likely than other features to be passed on to subsequent generations. Our memory systems should be built n a way that allows us to remember especially well encoded information that is relevant to our survival. Naime, Thompson & Pandeirada, 2007 showed that experimental participants recalled more words after a survival-encoding task than after moving or pleasantness tasks. In later studies, survival encoding resulted in higher levels of recall than several other non-survival-encoding tasks involving semantic encoding, imagery encoding, or organizational encoding. Superior recall is also observed for scenarios that involve planning but not survival. At issue here, is how much brain 'real-estate' is being used to store the information, and how it is emotionally-gated through the amygdala. More on that later.
Iconic & Echoic Memory Sensory memory holds sensory information for a few seconds or less. This is much the same as a 'screen refresh' on a computer screen. (Get stuck on a busy webpage, and try to leave, and watch how many dialog boxes come up. ) Sperling, 1960: Iconic Memory Test. He used Pavlovian conditioning (high, medium, low tones) that allowed participants to correctly identify a row of 3 letters. Since they did not know what the tone would be, it meant that for a brief time, all the letters were stored in memory. If the tone was substantially delayed, participants could not perform the task, because the information had slipped away (been'refreshed' in modern language). Iconic memory is the fast-decaying (1 second) store of visual information. Echoic memory is the fast-decaying (5 seconds) store of auditory information. The details of the iconic memory test will be used for the next exam.
Working Memory Short-term memory hold non-sensory information for more than a few seconds (15 -20) but less than a minute. Preston & Peterson, 1959, the Decline of Short. Term Memory. Rehearsal is the process of keeping information in short-term memory by mentally repeating it. Each repetition re-enters the information into short-term memory. Remember micro-sub-vocalizations; your larnyx is actually forming the words, even if mouth is shut, and lips don't move. https: //en. wikipedia. org/wiki/Subvocalization Chunking involves combining small pieces of information into larger clusters that are more easily held in short-term memory. Miller, 1956, reports that short-term memory can hold seven meaningful items at once. Working memory (Baddeley & Hitch, 1974) refers to active maintenance of information in short-term storage. It is the central executive for both visual images and verbal information. The working memory model acknowledges both the limited nature of short-term memory storage and the activities that are commonly associated with it. Individuals with neurological damage to the verbal subsystem of working memory have problems holding onto strings of digits and letters for a few seconds, and difficulty learning new words. (Baddeley, 2001).
Working Memory Studies Brain imaging studies indicate that the central executive component of working memory depends on regions within the frontal lobe that are important for controlling and manipulating information on a wide range of cognitive tasks. Children who score low on working memory tasks have difficulty learning new information and performing well in the classroom. (Alloway et al. , 2009) In typical studies, participants are first given extensive practice performing working memory tasks that require the maintenance and manipulation of visual or verbal information. They are then tested on new working memory tasks that have not been specifically taught, as well as reading comprehension or sustained attention. There is a problem here in the experimental design, with respect to external validity. Control groups did not perform any kind of training, or performed less challenging training tasks. Redick et. Al, used a control condition that involved active processing (a visual search task). Working memory improved on the task that was trained, but not on other cognitive tasks.
Long-Term Storage Long-term memory holds information for long periods of time, even years. Babrick, 2000 reported that even 50 years after graduation from high school, people could accurately recognize about 90% of their classmates from yearbook photographs. Consider how rarely this information had been accessed. Scoville & Miller's case study of Henry Molaison will be on the next exam. In a desperate attempt to stop epileptic seizures, parts of his temporal lobes, including the hippocampus and some surrounding regions were removed. H. M. Then exhibited anterograde amnesia, the inability to transfer new information from the short-term store into the long-term store. Note that his disability was based in verbal or numeric information, not visual information. http: //www. sciencedirect. com/science/article/pii/0028393281900907 And this takes us to Leonard Shelby, who could drive if he had directions and landmarks. http: //mrgregoryonline. com/Studies/Maguire. pdf Contrast this to the more common retrograde amnesia the inability to retrieve information that was acquired before a particular date, usually the result of injury or surgery. H. M. 's condition indicated that the hippocampus is not the site of long-term storage. The hippocampal region index is critical when a memory is first formed, but not so much later.
Memory Consolidation Consolidation is the process whereby memories become stable in the brain. Shortly after encoding, memories exist in a fragile state in which they can be easily disrupted. A head injury or car crash will make it difficult for the subject to later recall the events immediately previous to the incident. Another type of consolidation involves transfer of information from the hippocampus to more permanent storage in the cerebral cortex. Mounting evidence suggests that sleep plays an important role in memory consolidation. Jenkins & Dallenbach 1924: recall of recently learned information is greater immediately after sleeping than after the same time spent awake. Diekelmann & Born, 2010 report that sleep plays an active role in memory consolidation, more than simple protecting against waking interference. Payne et al, . 2009 report that sleep selectively enhances the consolidation of memories that reflect the meaning of an experience as well emotionally important memories.
Reconsolidation Memories can become vulnerable to disruption when they are recalled, requiring them to become consolidated again. When rats are cued to retrieve a new memory that was acquired a day earlier, giving the animal a drug that prevents initial consolidation will cause forgetting. If the animal is not actively retrieving that memory the same drug will have no effect when given a day after initial encoding. Each time memories are retrieved, they become vulnerable to disruption and have to be reconsolidated. Can painful memories be eliminated by disrupting reconsolidation? Brunet et al. , 2011 reported that when a traumatic event was reactivated after administration of a drug that reduces anxiety, there was a subsequent reduction in traumatic symptoms. Agren et al. , 2012 reported that disrupting reconsolidation can seemingly eliminate a conditioned fear memory in the amygdala, a brain region that plays a key role in emotional memory.
Synaptic Memory The act of sending a neurotransmitters across a synaptic gap changes the synapse, making it easier to send the next batch. This is where the comparison between brains and computers falls apart. Computer circuits don't change. Eric Kandel won the Nobel Prize in 2000 for his work with the sea snail Aplysia, a relatively uncomplicated animal with an extremely simple nervous system of only 20, 000 neurons. If the experimenter shocks Aplysia over and over, it will develop an enduring memory caused by the growth of new synaptic connections between neurons. Learning is based on changes involving the synapses for both short-term storage (enhanced neurotransmitter release) and long-term storage (growth of new synapses). Experience that results in memory produces physical changes. A similar process occurs in the human hippocampus, called long-term potentiation, a process whereby communication across the synapse between neurons strengthens the connection, making further communication easier. LTP occurs in several pathways within the hippocampus, it can be induced rapidly and it can last for a long time. Drugs can block LTP. https: //www. youtube. com/watch? v=4 Hm 08 ks. Pt. Mo
Retrieval Retrieval cue: external information that is associated with stored information and helps bring it to mind. Tulving & Pearlstone, 1966 reported that information is sometimes available in memory even when it is momentarily inaccessible. Encoding specificity principle: a retrieval cue can serve as an effective reminder when it helps recreate the specific way in which the information was encoded. External contexts often make powerful retrieval cues. Recovering alcoholics often experience a renewed urge to drink when visiting places in which they once drank. Compare to Web Article Three. State-dependent retrieval: the tendency for information to be better recalled when the person is in the same (usually emotional) state during encoding and retrieval. Being in a good mood affects patterns of electrical activity in parts of the brain responsible for semantic processing, suggesting mood has a direct influence on semantic encoding. (Kiefer et al. , 2007). Transfer-appropriate processing: memory is likely to transfer from one situation to another when the encoding and retrieval contexts of the situation match. Note: retrieval does not merely provide a readout of what is in memory, it also changes the state of the memory system important ways.
Retrieval & Subsequent Memory 1 Bjork, 1975: the act of retrieval can strengthen a retrieved memory, make it easier to remember the information at a later time. Retrieving information from memory has different effects than studying the information again. Roediger & Karpicke, 2006: memory testing benefits long-term retention. The study-test condition yields much higher levels of recall than does the study-study condition. This is why Psy 120. 6 has so many tests, and even rewrites. Retrieval-induced forgetting: a process by which retrieving an item from long-term memory impairs subsequent recall of related items. Anderson et al. , 1994: retrieving similar target items caused subsequent forgetting of the related but suppressed items. Storm et al. , 2006: if the target is not successfully retrieved, the act of suppressing the competitors while you attempt to retrieve the target still reduces your ability to retrieve the competitors at a later time. Cuc, Koppel & Hirst, 2007: when a speaker selectively talks about some aspects of memories shared with a listener and does not mention related information, both the listener and the speaker later have a harder time remembering the omitted events.
Retrieval & Subsequent Memory 2 In addition to improving or impairing subsequent memory, the act of retrieval can also change what we remember from an experience. Schacter, 2013: The Museum Tour experiment. Participants sometimes incorrectly remembered that the stop shown in the novel photograph had been part of the tour. Participants who tended to make this mistake also tended to have more vivid recollections during the reactivation session. Reactivating a memory temporarily makes it vulnerable to disruption and change. Schacter, 1996: trying to recall an incident and successfully recalling one are fundamentally different processes that occur in different parts of the brain. Regions in the left frontal lobe show heightened activity when people try to retrieve information that was presented to them earlier. Successful remembering a past experience tends to be accompanied by activity in the hippocampal region. PET Scans of Successful and Unsuccessful Recall will be on the next exam. Successful recall also activates parts of the brain the play a role in processing the sensory features of an experience. Recent f. MRI evidence indicates that during memory retrieval, regions within the frontal lobe that are involved in retrieval effort play a role in suppressing competitors.
Multiple Forms of Memory Explicit memory occurs when we consciously or intentionally retrieve past experiences. Implicit memory occurs when past experiences influence later behaviour and performance, even without effort to remember them or an awareness of the recollection. Procedural memory is the gradual acquisition of skills as a result of practice. People with amnesia can acquire new procedural memories, because they are not processed through the hippocampus. Study the figure Multiple Forms of Memory for the next exam. Priming is the enhanced ability to think of a stimulus such as a word or object, as a result of recent exposure to the stimulus. It is an example of implicit memory. Mitchell (2006) discovered that priming can persist over long periods of time. Amnesic individuals can show substantial priming effects even though they have no explicit memory of learning. Remember Sammy Jenkis! Priming occurs in parts of the occipital lobe involved in visual processing (perceptual) and parts of the frontal lobes (conceptual) involved in word retrieval.
Semantic & Episodic Memory Semantic memory is a network of associated facts and concepts that make up our general knowledge of the world. Episodic memory is the collection of past personal experiences that occurred at a particular time and place. (Brandt et al. , 2009) studied three young adults who suffered damage to the hippocampus during birth as a result of difficult deliveries that interrupted oxygen supply to the brain. All three children learned to read, write and spell, developed normal vocabularies and acquired other kinds of semantic knowledge that allowed them to perform well in school. Thus, the hippocampus is not necessary for new semantic memories. Tulving, 1985 reported that individuals with hippocampal amnesia reveal that some of them have difficulty imagining new experiences. This occurs also in aging. Neuroimaging studies reveal a network of brain regions involved in episodic memory, including the hippocampus, showing increased activity when people remember the past or imagine the future. Study this figure for the next exam. We rely heavily on episodic memory to envision our personal futures, as it is a flexible system that allows us to recombine elements of past experiences in new ways. This flexibility of episode memory might also be responsible for memory errors.
Collaborative Memory Collaborative memory is how people remember in groups. A collaborative group will typically recall more items than a single individual. A nominal group is the combined recall of several individuals recalling memory targets on their own, more than the collaborative group. This was first attributed to social loafing (letting the strong leaders do the work), but the more likely cause is the disruptive effect of others' retrieval strategies on one's own. Collaboration has other benefits. One person will remember something another did not, and later testing will see improved performance. What effect does present-day Google have on our memories? Sparrow et al. , 2011 reported that partipants were using their computers in an efficient way to help remember facts, while relying on their own memories to recall where those facts could be found.
Memory Failures 1 Transience: forgetting with the passage of time. Transience occurs during the storage phase of memory, after an experience has been encoded and before it is retrieved. Ebbinghaus noted a rapid drop-off in retention during his memory tests, followed by a slower rate on later tests. In all subsequent studies, memories did not fade at a constant rate as time passed; most forgetting happened soon after the event occurred, with increasingly less forgetting as more time passed. Quality the same. Distorted memories can be caused by: retroactive interference, information learned later impairs memory for information acquired earlier; proactive interference, information learned earlier impairs memory for information acquired later. Note: always ask, what does the interference work on? Absent-mindedness is a lapse in attention that results in memory failure. Without proper attention, material is much less likely to be stored properly and recalled later. This is an example of divided attention. Shallice et al. , 1994 reported that less activity in the lower left front lobe when attention was divided between an easy and a difficult task. This lobe was prevented from playing its normal role in semantic encoding. Recent research indicates that divided attention leads to less hippocampal involvement in encoding (necessary for episodic memory).
Memory Failures 2 Prospective memory: remembering to do things in the future. A failure can be averted by having a cue available at the moment you need to remember to carry out an action (deferred request). Memory for a deferred action improves only when the reminder was available at the time needed for retrieval. Blocking: failure to retrieve information that is available in memory even though you are trying to produce it. This occurs especially often for names of people and places, because links to related concepts and knowledge are weaker than for common names. Descriptive names have more semantic encoding (neuronal linkages) than arbitrary names. Name blocking usually results from damage to parts of the left temporal lobe on the surface of the cortex, most often as a result of stroke (also old age). Damasio et al. , 1996 reported that strong activities of regions within the temporal lobe when people recall proper names.
Memory Misattribution Misattribution involves assigning a recollection or an idea to a wrong source. Schacter 1996. Thompson rape case. Try 'Nurse Betty' to see a movie about this. Faulty eyewitness memory was a factor in more than 75% of the first 310 American cases in which individuals were shown to be innocent by DNA evidence after conviction for crimes they did not commit. Source memory: the recall of when, where, and how information was acquired. Source misattribution is correct information, but the wrong source. This could be the cause of deja vu, where a present situation that is similar to a past experience may trigger a general sense of familiarity (mistakenly attributed to having been in the exact situation). Individuals with damage to the frontal lobes are especially prone to memory misattribution errors, due to effortful mental processing. Schacter 1984: M. R. False recognition, a feeling of familarity about something that has not been encountered before (without recall of associated details). Study the figure Hippocampal Activity during True and False Recognition for the next exam. False recognition occurs in part because a new object does not have specific details, but those details need to be retrieved for the old object to correctly indicate that the similar object is new. Feeling versus thinking!
Suggestibility Suggestibility: the tendency to incorporate misleading information from external sources into personal recollections. A suggestive question will lead participants to misattribute information. Loftus, 2003: Not only misleading details, but entire episodes that never occurred can be implanted by suggestion. We do not store all the details of our experiences in memory, making us vulnerable to suggestion. Visual imagery plays an important role in constructing false memories. The Diana Halbrook case (Schacter, 1996). A number of techniques used in psychotherapy to 'recover' childhood memories are clearly suggestive. Specifically, imagining past events under hypnosis can create false memories. (Garry et al. , 1996) Bias: the distorting influence of present knowledge, beliefs, and feelings on recollection of previous experiences. Our current moods can bias our recall of past experiences. Consistency Bias: reconstructing the past to fit the present. See 'Shutter Island'. Change Bias: exaggerates the difference between past and present. Egocentric Bias: change bias that exaggerates our importance & influence (looking good in the presence of others. )
Persistence is the intrusive recollection of memories that we wish we could forget, normally after disturbing or traumatic events. This is the emotional-gating of memory; we remember emotional experiences better than non-emotional ones. Ochsner, 2000: Memory for unpleasant pictures is more accurate then for pleasant ones. Flashbulb memories: detailed recollection of when and where we experience emotionally intense events, elaborated by semantic encoding. The figure The Amygdala's Influence on Memory will be on the next exam. Stress-related hormones, such as adrenaline and cortisol, mobilize the body in face of threat. Individuals with amygdala damage remember mundane and emotionally arousing events equally well. For normals, amygdala levels during arousing events is a good predictor of subsequent memory quality. In conclusion, forgetting are side effects of our brain's usually successful attempt to sort through incoming information, preserving details worthy of attention and recall, and discarding others less worthy.
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