Psychology Memory Yr 11 PDF

THE PSYCHOBIOLOGICAL PROCESS OF MEMORY 1 VCAA dot point: synaptic plasticity – resulting from long-term potentiation and long-term depression, which together act to modify connections between neurons (sprouting, rerouting and pruning) – as the fundamental mechanism of memor...

THE PSYCHOBIOLOGICAL PROCESS OF MEMORY 1 VCAA dot point: synaptic plasticity – resulting from long-term potentiation and long-term depression, which together act to modify connections between neurons (sprouting, rerouting and pruning) – as the fundamental mechanism of memory formation that leads to learning 2 3  What is learning? Learning is a relatively permanent change in behaviour (skill) or acquisition of knowledge that results from experience. In order to learn from experience we must remember it (memory). In order to remember it our brains must literally change its physical structure. This change can happen rapidly. 4  Neurons can change Neurons can change in size, shape and function. They can easily change their connections to other neurons forming different networks or different patterns of activation. These changes in neural structure happen in part due to genetics but also due to our experiences. Our experiences physically alter our brain. Our brain’s ability to alter its structure is known as neural plasticity Synaptic plasticity = the ability of the synapse to change in response to experience (thinking about it more at a cellular level) Brain does not change its overall shape but the neural networks alter in response to experiences. 5 6 Synapse Site where the terminal button of a pre-synaptic neuron communicates with the receptor site of a post synaptic dendrite (end of the dendritic spine) Neurotransmitter is released from synaptic vesicles, move across the synaptic gap and bind with post synaptic receptor sites Transmission is CHEMICAL not electrical If post synaptic neuron is stimulated, then subsequent transmission becomes electrical WITHIN the post synaptic neuron or post synaptic cell (eg a muscle cell) 7 Neurotransmitters Chemical substances produced by a neuron that carries a neural message across a synaptic gap to another neuron, muscle or organ/gland cell. Chemical structure (shape) enables it to bind with a specific, tiny receptor site on the post synaptic neuron (dendrite) Excitatory neurotransmitters make activation of the post synaptic neuron more likely Inhibitory neurotransmitters make activation of the post synaptic neuron less likely 8 9 10 Neural Transmission Neurochemicals bind to receptor sites and have an effect on the postsynaptic neuron (chemical Neurochemicals bind to receptor sites and have an effect on the postsynaptic neuron. The postsynaptic neuron becomes either more or less likely to fire an action potential. The firing of an action potential triggers the release of neurochemicals from the axon terminals of this neuron, which is now the presynaptic neuron, into the synaptic gap (chemical transmission). This electrochemical transmission continues along the neural pathway 11  Synaptic Plasticity · Synaptic plasticity involves specific changes that occur within the synapse, between neurons. · There are two important processes involved in synaptic plasticity: long-term potentiation (LTP) and long-term depression (LTD): o LTP is the relatively permanent strengthening of synaptic connections as a result of repeated activation of a neural pathway. o LTD is the relatively permanent weakening of synaptic connections as a result of repeated low level activation. 12  Long term potentiation (LTP) LTP = long lasting strengthening of synaptic connections due to frequent stimulation. Results in more efficient neural transmission between a pre and post synaptic neuron. The more the synapse is strengthened, the more likely it becomes for the post synaptic neuron to activate (makes it more ‘trigger happy’). Therefore, rote learning helps us to learn our times tables! 13  Long term depression (LTD) LTD = long lasting decrease in the strength of a synaptic connection from lack of (or reduced) stimulation. The post-synaptic neuron becomes less likely to activate from an infrequent pre- synaptic signal. LTD helps prune unwanted neural connections. Use it or lose it! 14 15  LONG TERM POTENTIATION LONG TERM DEPRESSION LTP Long lasting change (strengthening) of neural connection due to frequent use Post-synaptic neuron becomes more excitable to glutamate neurotransmitters (excitatory) Increases efficiency in transferring information along pathway Decreases likelihood of forgetting what has been learnt LTD Long lasting change (weakening) of neural connection due to reduced (lack of) use Post-synaptic neuron becomes less excitable to glutamate neurotransmitters (excitatory) Weakening or elimination of unused synapses; pruning unwanted or unimportant connections Allows correction to behaviour or mental processes 16 QueQzzzz Do Question 1- 4 Question Booklet 17  DOT POINT 1 VCAA dot point: the explanatory power of the Atkinson-Shiffrin multi-store model of memory in the encoding, storage and retrieval of stored information in sensory, short- term and long-term memory stores 18 19  MEMORY PROVIDES MEANING TO OUR LIVES Memory provides meaning to our lives by integrating the past and the present (our sense of personal history with our current awareness) Memory enables us to imagine our futures (humans. more than animals have this as a highly developed skill) Memory is not a single thing – it results from interactions of different brain regions with specific functions – we do not have ‘a memory’ – instead we have multiple memory systems Memories are believed to be stored throughout the brain (different regions store different components of the memory – eg sounds, feelings, smells, sights 20 etc.)  MEMORY IS NOT PERFECT Our brain has the ability to store, in theory, limitless volume of memory in Long Term Memory – but this is not our lived experience of memory Memories can be selective, at times difficult to retrieve, prone to error and exaggeration Some memories seem to fade quickly while others seem to last a lifetime Some can be highly accurate while other memories are very inaccurate Memories are stored physiologically as neural representations (networks and patterns of neuron activation) – this means every time we form a new memory we structurally alter our brain 21  MODEL OF MEMORY AS 3-STAGE PROCESS This process does not happen in one single area of the brain. Memories involve many areas of the brain, most crucially the hippocampus (formation and retrieval) and the neocortex (for LTM 22 storage).  3 STAGE MEMORY PROCESS Stage 1 Encoding changing raw incoming sensory information into a form that can be stored by our brain. Obviously, we cannot store information in its original form. Our brain is not like a USB stick storing information digitally. Sights and sounds cannot be directly recorded in our brain, instead they must be converted into neural representations – this process is called encoding 23 Stage 2 Storage Encoded information is stored in an organised way in Long Term Memory Memories are stored all over the brain. There is no single location where our memories are located. Most are stored in the neocortex. Different components of a single memory are stored in different brain locations are reassembled when we recall. 24 Stage 3 Retrieval Retrieval is the process of getting information back from our memory system when it is required and becoming consciously aware of it. Relies on memory cues (retrieval cues). Retrieval cues can be sounds, sights, words, anything that can act as triggers activating neural pathways that enable us to recall certain information. 25 QueQzzzz Do Question 5- Booklet 26  ATKINSON-SHIFFRIN’S MULTI-STORE MODEL OF HUMAN MEMORY (1968) The A-S model of memory says there are three storage components that each function differently in the way they process and store information. The 3 stores are called : SENSORY, SHORT TERM and LONG TERM. All 3 stores operate simultaneously and interact enabling us to deal in real time with our sensory world (incoming information and our own thinking) Incoming sensory information enters through our sensory memory is then stored by our short term memory briefly (if we pay attention to it) and then may enter long term memory if it is encoded. 27 ATKINSON-SHIFFRIN 1968 MULTI-STORE MODEL OF MEMORY 28  SENSORY MEMORY First stage of memory – when sensory information is received. Stored in sensory registers Information is RAW = unencoded. Information can last from a less than a second (iconic) up to several seconds (auditory). Sensory information will not enter our awareness unless we pay attention to it. Fades quickly (called decay) unless we focus on it. Unlimited capacity! Iconic = visual and lasts about 0.4 seconds. 29 Acoustic =auditory and lasts about 4 seconds.  SHORT TERM MEMORY (STM) STM stores information longer than sensory memory but much shorter than Long Term Memory. If we pay attention to sensory information it gets transferred into STM STM retains information long enough to enable mental manipulations including combining information back from LTM with new incoming information. STM receives information from both sensory and LTM. Can hold 7± 2 items (5 – 9 items with mean = 7) Lasts about 12 – 30 seconds (Average max duration is 18 seconds). Information in STM can be manipulated acoustically and visually. 30 31  SHORT TERM MEMORY (STM) Information in STM can be lost in two different ways: Loss due to DISPLACEMENT - If STM capacity is reached, new information will displace older information already in there. This happens due to its small capacity. Loss due to DECAY – if information is not continually rehearsed it will fade and be lost due to DECAY. 32  INCREASE STM CAPACITY USING CHUNKING Chunking can be used to increase capacity of STM. Involves grouping items together to form ‘unit’ so that more items can be stored in STM as a single unit. Each chunk only occupies one location in STM (7 chunks total). Eg. A phone number like 0353347564 could be chunked into 3 units: 035 334 7564. The more meaningful the chunks, the more effective is this process. 33  INCREASING DURATION OF STM USING MAINTAINENCE REHEARSAL STM duration is significantly less than LTM (which is theoretically lifelong). Can only hold material up to 30 seconds UNLESS the material is rehearsed (repeated over and over) then it can be maintained indefinitely Maintenance rehearsal does not involve elaboration, just repetition (like saying a phone number over and over to hold it in your mind whilst dialling) If our concentration is lost during the rehearsal and we focus on other material, we will most likely lose the initial information due to displacement. 34  Elaborative rehearsal Elaborative rehearsal involves meaningfully linking new information to information already stored in longterm memory. For example, you could remember the name of a new student by relating their name to somebody else you know, such as a family member. Therefore, when you see them again, you may be easily able to retrieve their name because of this connection. 35  STM AS WORKING MEMORY STM enables us to maintain information in our conscious awareness – our moment by moment sense of reality This enables us to undertake our day to tasks – everything from riding a bike, buying goods from a shop, holding a conversation, learning at school, planning a project etc. STM temporally holds information from SM and LTM long enough to complete required mental tasks – when the information is no longer needed, it is eith transferred into LTM or discarded. 36  LONG TERM MEMORY (LTM) LTM is considered to have limitless capacity and possibly life-long duration. Information is stored in LTM after encoding it from STM. LT memories can last for our lifetime due to structural changes to neurons and their connections. Information moves between STM and LTM in both directions INFORMATION in LTM is LOST THROUGH DECAY not displacement. (remember, in STM information can be lost through either!) 37 QueQzzzz Do Question 6-9 Booklet Watch Limitless- Clickview Chris Hemworth 38 DIFFERENT TYPES OF LTM 39  EXPLICIT LTM = WITH CONSCIOUS AWARENESS Can be consciously retrieved and stated (that is why also known as ‘declarative’ memories) Includes our general knowledge and information about our personal experiences 40  SUB TYPES OF EXPLICIT LTM - SEMANTIC & EPISODIC Explicit LTM can be consciously recalled & stated (recallable ‘facts or events’) Semantic memory: Episodic memory: Facts & knowledge A LTM record of personally experienced events Everyday facts Often includes what, when, where information Meanings of words & symbols Always includes self as initiator or recipient of action – Rules directly involved in the experience Concepts Areas of expertise (note – not to confused with ‘Autobiographical memory’ that can contain both semantic and episodic components) 41  IMPLICIT LTM = WITHOUT CONSCIOUS AWARENESS Implicit LTM does not require conscious or intentional recall Often we are not aware we are remembering when implicit LTM is involved Involved in skills, procedures AND also conditioned emotional responses Can be our ‘how to memory’ eg. being able to balance a bike when riding Involved in well rehearsed cognitive and motor skills such as reading, writing, using a computer, playing sport etc. 42  SUB TYPES OF IMPLICIT LTM - PROCEDURAL & CLASSICALLY CONDITIONED MEMORY Implicit LTM does not involve conscious awareness in recall Procedural memory Classically conditioned memory memory for motor skills of ‘how to learned emotional responses to stimuli that have been do’ something classically conditioned through previous exposure Based on practice and demonstrated Typically involve fear and anxiety responses through performance The emotional response is retrieved with no conscious Typically require no conscious effort effort but is stored in LTM to retrieve Eg: feeling of nausea at the sight of fish from a previous Eg: how to balance a bike while you experience of eating undercooked fish and becoming ride it seriously ill. What we remember is automatically Can involve simple conditioned reflexes we have translated into action conditioned over time. Eg: putting our hand out when we fall over. 43 QueQzzzz Do Question 10-12 Question Booklet 44  DOT POINT 2 the roles of the hippocampus, amygdala, neocortex, basal ganglia and cerebellum in long-term implicit and explicit memories 45  BRAIN AREAS INVOLVED IN LONG-TERM IMPLICIT AND EXPLICIT MEMORIES LTM Memories are formed & stored throughout the brain. Different brain structures are critical to formation & storage of different types of long term memories There are 5 structures you need to learn about for the VCE course: 1. Hippocampus 2. Amygdala 3. Neocortex 4. Basal ganglia 46 5. Cerebellum  HIPPOCAMPUS Part of the temporal lobe and closely linked to the amygdala Crucial for forming all new declarative (EXPLICIT) memories Facilitates the formation of new semantic and episodic memories but is NOT the site of storage. Transfers the memory information to the neocortex for permanent storage Enables you to remember explicit biographical information like – where, when, who you were with at the time The hippocampus is DOES NOT encode IMPLICIT PROCEDURAL TYPE MEMORIES not involved in like how to balance a bike etc. storage of implicit Crucial in consolidating short term memories into long term procedural memories – learn memory - BUT NOT for implicit procedural memories! this important 47 point!  HIPPOCAMPUS Connected to the amygdala – hippocampus critical in storing the explicit components of emotional episodic events When we have an emotionally traumatic experience the hippocampus and the amygdala encode different aspects of the emotionally arousing event. The hippocampus encodes the EXPLICIT details of where, when and who you were with etc. whereas the amygdala will encode the emotional components (feelings) including activation of the sympathetic NS. 48 THE CURIOUS CASE OF HENRY MOLAISON AND HOW WE LEARNED THE CRITICAL ROLE OF THE HIPPOCAMPUS AND LTM 49 Much of what we understand about the role of the hippocampus and the temporal lobe in terms of new memory formation comes from the in depth case study of Henry Molaison (HM) an American, who in 1957 had his hippocampus removed to treat severe epilepsy. His epilepsy was cured but his memory ability was left severely diminished. The medial temporal lobe is the inner portion of the temporal lobes (towards the centre of the brain) and it consists of two structures called the hippocampus and the amygdala. See diagrams below: 50  AMYGDALA Located towards the end of the hippocampus (left and right) The Amygdala is part of the limbic system (emotional regulation system) that activates in times of arousal, especially when it involves fear, anger or rage Is essential for encoding the emotional reactions (IMPLICIT memory) to an event Enables us to detect danger and therefore fear things from prior learning People & animals without an amygdala cannot learn to fear things that signal danger 51  AMYGDALA Damage to the amygdala can result in loss of memory of previously learned fears. People without an amygdala will still encode explicit details of a frightening situation but will be unable to encode implicit information relating to their fear (emotion). Our amygdala enables us to react immediately in times of danger (we consciously evaluate it later) Increased amounts of noradrenaline in the amygdala in times of heightened emotion increases encoding of emotion and also signals the hippocampus to encode explicit information into LTM. 52 53  NEOCORTEXX The largest and most evolved 90% of the cerebral cortex is referred to as the neocortex. It is divided into 4 lobes – Frontal, Parietal, Temporal and Occipital. Is connected to all other parts of the brain enabling higher order thinking, planning, problem solving, imagined futures, complex feelings etc. The highly developed nature of our neocortex is what makes us distinctly human (when compared to A memory is all other animal brains) RECONSTRUCTED when it is recalled from LTM using information from different parts of the cortex 54  NEOCORTEX & ROLE IN MEMORY Interacts with the hippocampus in the formation and consolidation of explicit LTM Is the site of storage of explicit LTM Overtime, LTM stored in the neocortex become independent of the hippocampus and the amygdala LTM is widely distributed throughout the neocortex BUT relevant types of memory information are stored in cortices that match where the information was first processed (eg. Sights processed and stored in the occipital lobe, sounds in the temporal lobes, thoughts in the frontal lobe, locations in the parietal lobe) When retrieval happens, different information from specific lobes is retrieved to RECONSTRUCT an LTM (like a jigsaw puzzle) – this can explain memory 55 errors.  BASAL GANGLIA Contains an area called the substantia nigra that contains the brain’s dopamine producing neurons (dopamine is part of our brain’s reward system – helps us to experience pleasure) Plays the MOST critical role in forming implicit procedural memories – especially those involving motor movements. important for initiating sequences of movement Helps the brain associate reward (dopamine) with motor actions – leading to formation of habits 56  BASAL GANGLIA The basal ganglia activates every time we move our body in response to a cue It not only helps our brain initiate a voluntary muscle movement but it also helps the brain associate perception of pleasure when a satisfying action is performed. Communicates with other parts of the brain to acquire motor and cognitive skills gradually through repeated practice – leads to improved performance due to pleasure of improved actions. Is part of a habit forming feedback loop - the basal ganglia is critical for supporting learning that is driven by feedback and is motivated by rewards. 57  CEREBELLUM Located at the base of the brain and contains more neurons than the rest of the brain. Coordinates fine muscle movements (smoother actions) Regulates control of posture (standing, balancing, walking etc.) by modulating commands to motor neurons to compensate for shifts in body position or changes in load upon muscles. Enables execution of smooth and precise fine motor movements – especially when well rehearsed – such as playing piano, writing, touch typing etc. Does not initiate motor actions like picking up a cup of coffee but regulates the actions of dozens of muscles to ensure the action is smooth and fluent. 58  CEREBELLUM - ROLE IN MEMORY Temporally stores IMPLICIT PROCEEDURAL MEMORIES for motor skills but is not the site of long term storage (that happens in the neocortex). Enables learning of classically conditioned reflexes to conditioned stimuli and stores the learned associations (eg blinking to a beep instead of a puff). Assists with our sense of timing in movements (eg. tapping a finger to a beat of music) If the cerebellum is removed, animals are unable to learn new conditioned reflexes. 59 60 QueQzzzz Do Question 13- 15- Question Booklet 61  DOTPOINT 4 THE USE OF MNEMONICS (ACRONYMS, ACROSTICS AND THE METHOD OF LOCI) BY WRITTEN CULTURES TO INCREASE THE ENCODING, STORAGE AND RETRIEVAL OF INFORMATION AS COMPARED WITH THE USE OF MNEMONICS SUCH AS SUNG NARRATIVE USED BY ORAL CULTURES, INCLUDING ABORIGINAL PEOPLES’ USE OF SONGLINES 62  USE OF MNEMONICS TO INCREASE MEMORY Any technique used to assist memory is known as a mnemonic. Mnemonics work by using information already stored in LTM to link with new information. This linking process makes encoding and storage of new information easier and more efficient because it takes advantage of existing neural networks/links. Mnemonics organise information into a cohesive ‘whole’ so retrieval of part of the information acts as a retrieval cue for the rest of the information. This makes retrieval more likely and more efficient! 63  MNEMONICS OF WRITTEN CULTURES Western cultures have largely developed based on written cultures. This means information and knowledge including shared collective memory such as concepts around science, the arts etc. is passed down through generations through writing. Several mnemonic techniques have been commonly used over the centuries of written culture to help orators and speakers remember information. These include: Example of ancient Method of Loci Greek method of loci Acronyms Acrostics 64  METHOD OF LOCI Items to be remembered are converted into mental images and are visualized or associated with specific positions or locations in a building or location that is already well encoded (for example it could be walking through your own home). 65  ACRONYMS Study hint ‘nym’almost sounds like ‘name’ Acronyms are pronounceable words formed from the first letters of a group of words. The acronym is most often not a real word. The abbreviation (letters) act as retrieval cues for each of the words to be remembered. Eg: Qantas = Queensland and Northern Territory Aerial Service Ltd. NASA = National Aeronautics and Space Administration WWW = World Wide Web 66  ACROSTICS An acrostic is a sentence that contains words in a particular sequence that helps to remember items/concepts in a particular order. Acrostics involve verbal associations between the words in the sentence and the items to be recalled. This is often, but not always, based on the fisrt letter of the words. Eg: Every Good Boy Desreves Fruit stands for the musical notes E, G, B , D, F in the treble scale Eg: My Very Excellent Mom Just Served Us Noodles stands for the order of the planets in our solar system – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. 67  MNENOMICS IN ORAL TRADITIONS Unlike written cultures, oral cultures had to rely on word of mouth to pass on learned information and cultural traditions. Stories, poetry and songs were often used to help retains and pass down collective knowledge through different generations. This is the system employed by Australian Aborigines. Accuracy of the information was maintained by insisting that stories or songs were performed in highly ritualistic ways – so that things said and done were kept precise. Aboriginal dance 68 ceremony - Photo from 1898  USE OF SONGLINES IN ABORIGINAL CULTURE Aboriginal songlines have been used as a mnemonic for over 40,000 – 60,000 years They are linked to geographical locations but can cross through different groups. Each nation or group had its own established stories and songlines that code for information relating to: customs and law, personal rights, land use, astronomical and navigational information, environmental knowledge including seasonal indicators, edible plants, building materials for weaponry as well as medicines and sources of food and prey. 69  SONGLINES AS A MNEMONIC DEVICE Songlines link information with physical locations Encoding, storage and retrieval of information at each location is enhanced through story telling and dance / song at different locations on country The stories contain highly memorable characters and plots that can be scary or even vulgar A songline told at one location might contain valuable information about animal behaviour that needs to be known when hunting or plants that can be sourced for medicine or food etc. Some locations were reserved for ceremonies of death/marriage only 70  MORE ON SONGLINES FROM VCAA Songlines can be multi-layered – with different levels of depth of knowledge. As aboriginal people grow in age and understanding they are trusted with deeper and more complex levels of knowledge. The vast quantity of information memorised by Aboriginal Elders is evidence of the effectiveness of songlines as a memory technique. Indigenous knowledge systems around the world are mostly performance based. One of the mnemonic advantages of this is that performances evoke enhanced emotions, which in turn increase the memorability (deeper encoding) When a person deliberately makes spatial associations, new information and the location will become linked in the neural pathways. So when a story has been told at a particular sacred location in a songline, thinking of one will trigger memory of the other. The more vivid, unusual, grotesque or vulgar the story, the more active the brain’s neurons and the more likely the memory will be encoded and stored. Mundane information simply does not excite the brain. 71 QueQzzzz Do Question 14 and 15 - Question Booklet 72