chapter 5- memory

• process of memory:

  sensory information → encoding → storage → retrieval
• encoding is the process of converting information into a form that is usable / can be stored in the brain
• storage is the retention of information for a period of time
• retrieval is accessing the information that has been previously stored
• sensory memory enables perceptual continuity for the world around us, by receiving sensory information from our environment
• sensory memory has a potentially unlimited capacity, with a duration of about 0.2-0.4 seconds
• short term memory receives information from sensory memory and transfers information to and from LTM. it maintains information in conscious awareness for immediate use
• short term memory has a capacity of 5-9 items, and a duration of 18-30 seconds (which can be extended if renewed/rehearsed)
• long term memory is the storage of information for re-access and use at a later time
• long term memory has a potentially vast capacity, and a duration that is potentially permanent (however some information may be lost or inaccessible over time)
• types of sensory memory are iconic and echoic memory
• iconic memory is visual sensory memory. each bit of information is stored as a 'still' image (multiple creating a moving image), retained for a 3rd of a second in its original form. without it, there would be darkness between blinks
• echoic memory us auditory sensory memory. each part of auditory information is separate, but is made sense by combining (especially in language). if attended to, it will pass to STM
• storage of iconic memory is typically 0.2-0.4 seconds, whereas storage of echoic memory is typically 3-4 seconds
• to enhance the duration of short-term memory, there are two types of rehearsal:

  • maintenance rehearsal : a way of renewing information through continual repetition losing information can be prevented with sustained attention
  • elaborative rehearsal : linking new information in a meaningful way with information already stored in memory
• information previously stored in short-term memory can be lost due to:

  • decay : information is not renewed (through rehearsal)
  • displacement : information is pushed out by information coming from sensory registers or from LTM
• types of long-term memory include:

  • explicit memory : memory that is consciously retrieved and stated (words, concepts, visual images)
  • implicit memory : memory that does not require conscious effort, such as motor skills and fear
• types of explicit memory include:

  • episodic : memory from personal experience, connects past and present to remember thoughts and feelings from the past
  • semantic : memory of facts and specialised knowledge, so you don’t know when you learnt it, just that you do (mostly school based learning)
• types of implicit memory include:

  • procedural : motor skills / actions learned previously, how to do something (shown through performing them)
  • classically conditioned : simple conditioned reflex responses (blinking)
• the neocortex is used for the storage of all explicit memories, while the hippocampus is used for the encoding of all explicit memories (with the amygdala assisting with the emotional component)
• implicit procedural memories are encoded in the cerebellum and basal ganglia, while their storage occurs in just the cerebellum
• implicit classical conditioned memories are encoded using hippocampus (+ amygdala for emotional components), while their storage occurs in the basal ganglia
• autobiographical episodic memory is the ability to recall personal experiences in a detailed and accurate way. through reconstruction and mental time travel, we combine stored info with other available info, to form a more coherent and accurate memory
• autobiographical semantic memory provides context or framework for constructing and organising episodic future thinking. semantic memory is not time-related so it does not require mental time travel. we can know a lot of things without mental time travel, but you can’t remember events from your past
• alzheimers disease is an irreversible, progressive and fatal neurodegenerative disease that attacks the brain and kills brain cells, causing severe cognitive and behavioural decline. earliest damage occurs in the hippocampus, where both explicit declarative and implicit procedural memories are impaired/impacted
• biological causes of Alzheimers disease

  • decreased cortical area due to neuron death (particularly medial temporal lobe and hippocampus)
  • deposits of ‘plaque’ bound together in blobs and ‘tangles’ of brain fibres – interferes with neuron communication
  • amyloid plaques (sticky, abnormal clusters of betaamyloid fragments that collect on outside of nerve cells, destroying synapses and conduction of neural impulses)
  • neurofibrillary tangles (twisted strands of tau protein found in the centre of dead and dying nerve cells)
• Aphantasia is a phenomenon in which people are unable to visualise imagery. when asked to imagine something, people with Aphantasia cannot form a mental image to accompany knowledge.
• symptoms of Aphantasia

  • struggling to remember or ‘relive’ autobiographical events
  • having difficulty imagining future or hypothetical events
  • having problems with factual memory
  • dreaming less
  • decreased imagery involving other senses like sound or touch
  • trouble with facial recognition
• causes of Aphantasia

  • isn’t clear what causes aphantasia; however, it has been suggested that areas involved in visual imagery, such as the visual cortex, may be underactive.
  • people with aphantasia do experience mental imagery but can’t access the image in their conscious thoughts.
  • Aphantasia can be congenital (present from birth) or can be acquired (due to brain injury or significant psychological event).
• mnemonics are any technique used for improving or enhancing memory

  • add information to organise the material in long-term memory, making it easier to locate and retrieve
  • organise information into a cohesive whole – and connect new information to existing information – so that partial memory retrieval generally assists entire retrieval
  • work best for remembering information that needs to be memorised but is not necessarily understood
• written culture is a culture in which stories and information are shared and preserved through the processes of reading and writing. mnemonics for written cultures include acronyms, acrostics and method of loci
• acronyms are

  • using the first letter of each word to be remembered to create a pronounceable word or name
  • each letter acts as a retrieval cue for the first letter of each word to be recalled
  • useful for remembering lists or sequences
  • for example, EOD = end of day
• acrostics are

  • a phrase (or poem) where the first letter of each word functions as a cue to help with recall
  • the first letter of each word acts as a retrieval cue for the first letter of each word to be recalled
  • for example, every good boy deserves fruit
• method of loci is

  • committing a familiar location or sequence of locations to memory, and visually linking these locations with information to be recalled
  • each location acts as a retrieval cue that make it easier to retrieve the information when needed
  • if the visual association is personal in nature or bizarre, the information will be easier to recall
• oral cultures are a culture that involve people who communicated vital information and spread stories via word of mouth. Aboriginal and Torres Strait Islander languages, cultural practices and spiritual beliefs have survived for many thousands of years without the need for written communication. they use methods like Songlines
• Songlines


  Sung narratives of the landscape that weave across the country and enable every significant place in Aboriginal Dreaming's to be remembered
• Songlines

  • Navigational routes comprising a sequence of locations incorporate significant landscape features and associated stories, songs, dances, or ceremonies
  • Link information with physical locations in a deeply connected manner
  • Act as a retrieval cue for the location of each significant site and the specific rituals that must occur there
  • At the significant site, the rituals act as a retrieval cue for Dreaming's which content a range of information encoded within the stories, songs and dances performed
• Songlines in encoding and retrieval

  • stories with vivid characters enhance encoding, storage and retrieval of knowledge
  • gender and status in the group determine the version of knowledge performed (secret business)
  • Elder’s share knowledge with those who have sufficient knowledge to receive it
• Songlines in location & transmission

  • locations within songlines hold important information
  • eg. hunting tool materials, sacred sites, waterholes, rock art
  • stories provide explanations
  • eg. hunting techniques, medicinal plants, and cultural customs
• Songlines in enhancing transmission

  • relating new information to personal experiences enhances memory
  • spiritual or emotional significance and repetition in ceremonial ways aid encoding
  • Elders carefully guard and transmit songline stories, ensuring their longevity