Memory


Sensation and Perception

Sensation - a physiological response involving the detection of stimulus energy by the sense organs and converting it into electrochemical energy which is then transmitted to the brain.

Occurs in three stages:

  1. Reception - the detection of sensory info by the sensory receptors in sense organs.

  2. Transduction - the transformation of stimulus energy into electrochemical energy that the brain can process.

  3. Transmission - movement of electrochemical energy from sensory receptors to specific areas of the brain for interpreting.

Perception - when electrochemical energy reaches the brain, the information is selected, organised and interpreted.

  1. Selection - process where the brain focuses important sensory info for further processing while filtering out irrelevant details.

  2. Organisation - arranging and grouping sensory info into a meaningful pattern or whole.

  3. Interpretation - assigning meaning to the organised patterns or whole.


Measures of Retention

Retrieval cue - any stimulus aiding in the retrieval of memories.

Retrieval - process of moving info from LTM into conscious awareness.

Recall, recognition, and relearning are measures of retention (methods used to assess how much information has been stored/retained in memory).

Recall - the process of retrieving information from LTM with limited or no retrieval cues.

  • Free recall - retrieval of as much info as possible about a topic in any order and without retrieval cues.

  • Serial recall - retrieval of info in a specific sequence without retrieval cues.

  • Cued recall - retrieval of info with the aid of retrieval cues.

Recognition - the ability to identify previously stored info by matching current stimuli with stored memories (recognition tasks generally lead to more successful retrieval of info than recall tasks because they provide retrieval cues).

Relearning - reacquiring knowledge or skills that were previously learned but have since been partially forgotten (helps identify info that was not successfully remembered and allows it to be re-encoded into LTM through elaborative rehearsal - rehearsal technique that helps encode info into LTM by linking it to existing knowledge.



Levels of Processing Model of Memory (Craik and Lockhart, 1972)

Provides an explanation for why elaborative rehearsal (rehearsal technique that helps encode info into LTM by linking it to existing knowledge) more successfully transfers info from STM store to LTM store than maintenance rehearsal (rehearsal technique where info is repeated to keep it in STM for a longer period).

  • Proposed that the level or ‘depth’ at which we process information during learning determines how well it is stored in LTM.

  • Suggest memories are best encoded, organised and stored in LTM semantically (meaning). If meaning is processed in learning, then LTM will be better.

  • Suggests levels of processing: shallow and deep processing.

Information encoded semantically results in better recognition than information encoded acoustically or visually. Semantic encoding results in deep processing, while acoustic and visual encoding results in shallow processing.

Shallow Processing

  • Structural encoding - encoding sensory information based on its physical features or appearance.

  • Phonemic encoding - encoding sensory information based on its sound or.

Maintenance rehearsal used in shallow processing to hold info in short term memory for longer than the usual 15-30 seconds, requires minimal effort but difficult to retrieve.

Deep Processing

Elaborative rehearsal used in deep processing as information is encoded semantically.

  • Semantic encoding - encoding of sensory information based on its meaning, and/or linking it to previously stored memories in the LTM.

More easily retrieved and longer lasting.



Depth of Processing and the Retention of Words in Episodic Memory (Craik and Tulving, 1975)

Aim - Investigate how depth of processing affects memory retention

Participants - 24 male and female students from the university of Toronto (volunteer sampling /convenience?).

Method:

  • Participants told study was investigating perception and reaction speed (deception used).

  • Participants were presented with 60 words and asked questions about their properties to prompt different levels of processing (structural - capital letters, phonemic - rhyme, or semantic - if fit in sentence).

  • They were later given a surprise recognition/retention test where they were given a list of 180 words containing the original 60 and were asked to identify which words they recognised from the previous task.

Results - Words processed semantically (deeply) were better remembered/recognised most, and structural least.

Implications - The study supported the levels of processing model, showing that deeper, more meaningful processing leads to better memory retention.

Applications - These findings have significant implications for educational strategies and memory improvement techniques, emphasizing the importance of meaningful engagement with information.


Rehearsal

Rehearsal involves the repetition of info to retain it in memory for longer.

Rehearsal techniques:

Maintenance rehearsal - info is repeated to keep it in STM for a longer period.

Elaborative rehearsal - helps encode info into LTM by attaching meaning to it. Involves deeper processing. Methods include mind mapping, mnemonics, chunking.


Role of Repetition in Ebbinghaus’ Forgetting Curve (1885)

Ebbinghaus conducted the first scientific study on forgetting, using nonsense syllables to measure memory decay overtime.

  • Method - Memorised lists of 13 three-letter nonsense syllables (maintenance rehearsal) and tested recall at various intervals, from 20 minutes to 31 days post-learning.

  • Key-findings - Discovered rapid initial forgetting followed by a slower rate of memory loss. After 20 minutes, 58% recalled, after 1 day, only 34%, after 1 week, 21%.


Establishes the ‘forgetting curve’ and lays the foundation for modern memory research in cognitive psychology.

Rapid initial decline - Forgetting is fastest right after learning, so information should be reviewed quickly.

Exponential decay - Forgetting slows overtime, but some information might stay longer.

  • Individual variations - Things like prior knowledge and interest affect how fast you forget. Implications for learning


Implications for learning:

Use spaced repetition and active recall to minimise forgetting.

Info should be reviewed quickly.


Types of Forgetting

Forgetting is the inability to retrieve memories.

Retrieval failure - the inability to consciously recall info stored in the LTM due to the absence of retrieval cues.

Interference - when info in LTM cannot be retrieved due to disruption by similar information.

  • Proactive interference - previously stored info disrupts retrieval of newly learned info.

  • Retroactive interference - newly learned info disrupts retrieval of previously stored info.

Motivated forgetting - the intentional or unintentional suppression of memories or thoughts from conscious awareness to minimise emotional distress.

  • Repression - involuntary and subconscious process.

  • Suppression - deliberate and conscious effort to push certain thoughts and memories out of awareness.

Decay theory - forgetting theory that describes memories as being composed of traces in the brain that fade away over time. Memory traces are established when info is transferred from the sensory register to STM, which gradually fades unless the info is actively rehearsed. Predominantly effects short-term memories.


Causes and Effects of Memory Loss

Chronic Traumatic Encephalopathy (CTE)

  • Cause - repeated traumatic head injuries (concussions).

  • Behavioural impacts - impulsive behaviour, slurred speech, aggressive behaviour, agitation.

  • Emotional impacts - emotional instability (intense mood swings), outburst of anger, symptoms of depression.


Alzheimer’s Disease

  • Cause:

Degeneration of neurons (neuron loss) in brain regions responsible for cognitive skills and memory formation/retrieval.

Neurofibrillary tangles - abnormal accumulations of tau protein causing the breakdown of microtubules that support the axon of a neuron, disrupting the electrical nerve impulses that travel through the axon.

Amyloid plaques - accumulations of clusters of beta-amyloid protein and scar tissue from deteriorated neurons. They gather between neurons and interfere with their ability to function effectively.

  • Behavioural impacts - becoming lost/disorientated, changes in usual habits/routines, social inhibition (more outgoing), easily agitated, aggressive behaviour.

  • Emotional impacts - abrupt mood changes for no obvious reason, feelings of fear/suspicion, anxiety, irritability.


Wernicke-Korsakoff Syndrome (WKS)

  • Cause - drug induced deficiency of thiamine (vitamin B1).

  • Behavioural impacts - confabulation, agitation, repeating same questions or stories, involuntary rapid and repetitive eye movements, slurred speech, poor coordination of muscle movement, reduced balance (ataxia).

  • Emotional impacts - frustration due to memory deficits, anxiety.