PSYA01_STUDY_NOTES_Chapter_6.docx.pdf

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Department
Environmental Science
Course Code
EESA10H3
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Jovan Stefanovic

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PSYA01 STUDY NOTES CHAPTER 6 6.1 – Encoding: Transforming Perceptions Into Memories Memory is the ability to store and retrieve information over time. Memories are made by combining information we already have in our brains with new information that comes in through our senses. Encoding, the process by which we transform what we perceive, think, or feel into an enduring memory. Memories are constructed and encoding is the process by which we transform what we perceive, think, or feel into an enduring memory. Encoding is the process by which we transform into a lasting memory the information our senses take in. Most instances of spectacular memory performance reflect the skillful use of encoding strategies rather than so-called photographic memory. Memory is influenced by the type of encoding we perform regardless of whether we consciously intend to remember an event or a fact. Encoding information with respect to its survival value is a particularly effective method for increasing subsequent recall, perhaps because our memory systems have evolved in a way that allows us to remember especially well information that is relevant to our survival. Storage, the process of maintaining information in memory over time. Retrieval, the process of bringing to mind information that has been previously encoded and stored. Most people can repeat a list of numbers as long as it is shorter than seven items. Elaborative Encoding Elaborative encoding, visual imagery encoding, and organizational encoding all increase memory, but they use different parts of the brain to accomplish that. Researchers presented participants with a series of words and asked them to make one of three types of judgments. Semantic judgments required the participants to think about the meaning of the words (“Is hat a type of clothing?”) Rhyme judgments required the participants to think about the sound of the words (“Does hat rhyme with cat?”) Visual judgments required the participants to think about the appearance of the words (“Is HAT written uppercase or lowercase?”). Elaborative encoding, which is the process of actively relating new information to knowledge that is already in memory. Increased activity in the lower left part of the frontal lobe and the inner part of the left temporal lobe. Visual Imagery Encoding Visual imagery encoding, the process of storing new information by converting it into mental pictures. Can substantially improve memory. Visual imagery encoding does some of the same things that elaborative encoding does: When you create a visual image, you relate incoming information to knowledge already in memory. When you use visual imagery to encode words and other verbal information, you end up with two different mental “placeholders” for the items—a visual one and a verbal one—which gives you more ways to remember them than just a verbal placeholder alone Organizational Encoding Organizational encoding, the process of categorizing information according to the relationships among a series of items. Activates the upper surface of the left frontal lobe. 6.2 – Storage: Maintaining Memories over Time Storage is the process of maintaining information in memory over time. Sensory Storage Sensory memory holds sensory information for a few seconds or less. Either people simply couldn’t encode all the letters in such a brief period of time, or they had encoded the letters but forgotten them while trying to recall everything they had seen. Often a “sensory trace” or the stimulus remains after the stimulus is gone. Iconic memory is a fast-decaying store of visual information. Decay in about a second or less Echoic memory is a fast-decaying store of auditory information. Decay in about five seconds. Short-Term Storage and Working Memory Short-term memory, which holds nonsensory information for more than a few seconds but less than a minute. Information can be held in the short-term memory store about 15 to 20 seconds. Hold about seven meaningful items at once. Rehearsal is the process of keeping information in short-term memory by mentally repeating it. Each time you repeat the number, you are “reentering” it into short-term memory, giving it another 15 to 20 seconds of shelf life. Chunking involves combining small pieces of information into larger clusters or chunks. Working memory refers to active maintenance of information in short-term storage. Working memory includes subsystems that store and manipulate visual images or verbal information, as well as a central executive that coordinates the subsystems. Long-Term Storage Long-term memory holds information for hours, days, weeks, or years. No capacity limit. The Role of the Hippocampus as Index Studies of HM and others have shown that the hippocampal region of the brain is critical for putting new information into the long-term store. Anterograde amnesia, which is the inability to transfer new information from the short-term store into the long-term store. Retrograde amnesia, which is the inability to retrieve information that was acquired before a particular date, usually the date of an injury or operation. Different aspects of a single memory—its sights, sounds, smells, emotional content—are stored in different places in the cortex. Hippocampus links together all separate pieces so that we remember them as one memory. Memory Consolidation Consolidation, a process by which memories become stable in the brain. Shortly after encoding, memories exist in a fragile state in which they can be easily disrupted; once consolidation has occurred, they are more resistant to disruption. One type of consolidation operates over seconds or minutes. For example, when someone experiences a head injury in a car crash and later cannot recall what happened during the few seconds or minutes before the crash—but can recall other events normally—the head injury probably prevented consolidation of short-term memory into long- term memory. Another type of consolidation occurs over much longer periods of time—days, weeks, months, and years—and likely involves transfer of information from the hippocampus to more permanent storage sites in the cortex. The act of recalling a memory, thinking about it, and talking about it with others probably contributes to consolidation. Sleep plays an important role in memory consolidation. Reconsolidation, memories can become vulnerable to disruption when they are recalled, requiring them to become consolidated again. If information is stored in memory in an organized way, and especially if it is linked to potential retrieval cues in some systematic manner … then it can be much easier to find that information better Memories, Neurons, and Synapses Memories are in the spaces between neurons. This long-term storage involves the growth of new synaptic connections between neurons. Long-term potentiation a process where communication across the synapse between neurons strengthens the connection, making further communication easier. The primary agent is a neural receptor site called NMDA, known more formally as N-methyl-D-aspartate. The NMDA receptor influences the flow of information between neurons by controlling the initiation of LTP in most hippocampal pathways. The hippocampus contains an abundance of NMDA receptors, more so than in other areas of the brain. This is not surprising because the hippocampus is intimately involved in the formation of long-term memories. But for these NMDA receptors to become activated, two things must happen at roughly the same time. First, the presynaptic, or “sending,” neuron releases a neurotransmitter called glutamate (a major excitatory neurotransmitter in the brain), which attaches to the NMDA receptor site on the postsynaptic, or “receiving,” neuron. Second, excitation takes place in the postsynaptic neuron. Together, these two events initiate LTP, which in turn increases synaptic connections by allowing neurons that fire together to wire together There are several different types of memory storage  Sensory memory holds information for a second or two.  Short-term or working memory retains information for about 15 to 20 seconds.  Long-term memory stores information for anywhere from minutes to years or decades. The hippocampus and nearby structures play an important role in long-term memory storage, as shown by the severe amnesia of patients such as HM. The hippocampus also is important for memory consolidation, the process that makes memories increasingly resistant to disruption over time. Sleep contributes importantly to memory consolidation. Memory storage depends on changes in synapses, and long-term potentiation (LTP) increases synaptic connections. 6.3 – Retrieval: Bringing Memories to Mind One of the best ways to retrieve information from inside your head is to encounter information outside your head that is somehow connected to it. Retrieval cue, external information that helps bring stored information to mind. State-dependent retrieval, the tendency for information to be better recalled when the person is in the same state during encoding and retrieval. Information is sometimes available in memory even when it is momentarily inaccessible and that retrieval cues help us bring inaccessible information to mind. Encoding specificity principle, the idea that a retrieval cue can serve as an effective reminder when it helps re-create the specific way in which information was initially encoded. Transfer-appropriate processing, the idea that memory is likely to transfer from one situation to another when the encoding context of the situations match. Repair Can Improve Subsequent Memory Repeating an item usually improves memory for that item, so the act of retrieval might boost subsequent memory simply because the information is repeated, resulting in the same benefit you would receive from studying the information twice instead once. Repair Can Impair Subsequent Memory Retrieval-induced forgetting, a process by which retrieving an item from long-term memory impairs subsequent recall of related items. Separating the Components of Retrieval Regions in the left frontal lobe show heightened activity when people try to retrieve information that was presented to them earlier. Recall of previously heard sounds is accompanied by activity in the auditory cortex (the upper part of the temporal lobe), whereas recall of previously seen pictures is accompanied by activity in the visual cortex (in the occipital lobe) Recent fMRI evidence indicates that during the retrieval practice phase of a retrieval-induced forgetting paradigm, regions within the frontal lobe that are involved in retrieval effort play a role in suppressing competitors, whereas the hippocampal region is associated with successful recall. However, when hippocampal activity during retrieval practice signals successful recall of an unwanted competitor, frontal lobe mechanisms are recruited that help to suppress the competitor. Though this process results in retrieval-induced forgetting, there’s also a benefit: Once the competitor is suppressed, the frontal lobe no longer has to work as hard at controlling retrieval, ultimately making it easier to recall the target item Whether we remember a past experience depends on whether retrieval cues are available to trigger recall. Retrieval cues are effective when they help reinstate how we encoded an experience. Moods and inner states can serve as retrieval cues. Retrieving information from memory has consequences for later remembering. Retrieval improves subsequent memory of the retrieved information, as exemplified by the beneficial effect of testing on later recall. However, retrieval can impair subsequent remembering of related information that is not retrieved. Retrieval can be separated into the effort we make while trying to remember what happened in the past and the successful recovery of stored information. Neuroimaging studies suggest that trying to remember activates the left frontal lobe, whereas successful recovery of stored information activates the hippocampus and reg
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