Based on Goldstein Book Chapter and lecture from Jeff Beck

Note on Forms of Memory

Definition pin down can be very tricky!

Definition

• Retaining, retrieving, using information after the original information (stimuli) does not present. (Inner view)
• Any process that some past experience has an effect on the way the subject think and behave in the future. (Outer View)
  • Thus can generalize into even non-animated things! Memory of magnet

Use of Memory

• Longterm Memory
  • Human: Remember things relevant for life. (name, pw, birthday, info about others, address, knowledge)
  • Ecological: cache for food, foraging location.
• Shorterm Memory
  • Continuity of awareness

Different forms

Memory has many forms.

• Sensory memory
• Short-term memory / Working Memory
• Long term memory
  • Episodic memory (experience from past, sensory)
  • Semantic memory (facts in verbal sense, abstract)
  • Procedural memory (how to do something, motor)

Modal Model

Sensory-> Short term -> Long term memory

by Atkinson & Shiffrin (60s)

• Strucutral features: Where / in what form information resides,
• Control processes: How we manipulate information
  • E.g. Encoding, retrieval, rehearsal.

Remark

• Very computer like! Input-Output <-> Short Memory <-> Disk
• STM is too simple! Obsolete in modern research!
  • Doesn’t need to get into STM to be stored in Long term memory
  • ST and LT is too phenomenological no specific mechanism
• Human CogPsych literature is quite different from animal literature, human literature is more dichotomy

Distinction in neural term

• Transient
  • Persistence of firing: Recurrent network firing patterns
  • Short term synaptic / cellular change, can memorize things without firing.
• Permanent
  • Very long term synaptic change

Sensory Memory

Very short term, < 1 sec

• Visual persistence (Iconic memory)
• Auditory persitence (Echoic memory)

Application

• Movie, moving picture
• Sparkling trace!
• Extract information from the persistence

Classic Exp on Capacity and Duration of Sensory Memory

Experiment: Sperling’s visual memory experiment

• Whole report: Baseline, test how much he can report
• Partial report : To test if they have access to the sensory data
  • No limit of capacity!
• Delay partial report : To test how long they have access to the sensory data
  • If cue come later, the memory trace may decay away.

Understanding

• Majorly it’s the persistence of neural activity (time constant is not infinitely short, so it reflects precision of time integration.)
  • Time constant of visual cortices firing determined by some recurrent or biophysics (single cell excitability)
  • Can be after effect
  • Thus, visual features can cause the difference in persistence time!
• Masking can disrupt the sensory persistence
• Pre-categorization (stimuli without name / verbal memory)
• Quite unlimited in capacity

Short-term Memory

• Awareness, window to present

• believed to last 15-30s
• Capacity is limited, in psycho unit (chunk)
• Items are processed in some way. Features matter!

Experiment: Brown Peterson task

Original working memory task, later it is called STM later.

• Exp: Remember 3 words / consonants, then counting down a number to avoid rehearsal
• Result: Observe the recall probability decay through time!

Experiment: Change detection.

• At first, feature / conjunction features (add size shape color …) doesn’t affect the change detection performance !
• But complex objects like character …. are harder at change detection! (maybe encoding problem)

Chunking

Memorizing 3 letter vs words, a word is easier than all letters.

Note:

• The capacity of working memory $7\pm 2$
• Modern estimate is lower!

Note: Champions in memory usually use association & chunking to alleviate the memory load!

Working Memory

Baddeley model:

• Phonological loop
• Visuospatial sketch pad
• Central Executive

( Differentiate between the auditory part and visual part, maybe more! )

Exp can show, the visual and auditory memory doesn,t interfere that much !

Phonological Loop

Word length effect : If a word is faster to reproduce, we can remeber more of them!! Disrupt rehearsal, disrupt this effect

Mind rotation: Operation time correlates with the angle

Event Model and Memory

Change in events / environment / scene may flush the memory cache

Neural Correlates of Working Memory

PFC has persistent activity during working memory retention period.

Hippocampus is also important

Long term Memory

Long term memory has many form.

• Explicit (Declarative)
  • Semantic (knowledge, facts)
  • Episodic (experience, sensory)
  • Autobiographic
• Implicit
  • Procedural memory
  • Priming
  • Conditioning

Classical study

To distinguish longterm from shorterm memory is serial position curve in sequence memory.

Implicit Longterm Memory

Experimentally, implicit memory is hard to be pure!

Procedural Learning

Practise makes perfect.

Common in life, include but not restricted to motor learning.

• Perform an action sequence (violin, piano)

• Novel visual processing,like mirror reading, writing.

• Cog control task learning

Speeding up over time! Automization.

• At first, it’s visual processing, and it become retrival afterward.

Priming

Presenting stimuli affects how it is processed later!

Even if you are not tasked to remember something, exposure to the item will help you.