Human Memory Encoding and Storage - Cognitive Processes - Lecture Slides, Slides of Brain and Cognitive Science

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Human Memory:

Encoding and

Storage

Ebbinghaus

 First rigorous investigation of human memory – 1885.

 Taught himself nonsense syllables  DAX, BUP, LOC

 Savings – the amount of time needed to relearn a list after it has already been learned and forgotten.

 Forgetting function – most forgetting takes place right away.

The Three-Stage Model

Environment Sensory store^ (working) memoryShort-term Long-term memory

Responses

Executive control processes

Sensation/perception Attention

encoding

retrieval

Retention Times

Environment Sensory store^ (working) memoryShort-term Long-term memory

encoding

retrieval

1-3 seconds 15-25 seconds 1 sec to a lifetime

Sperling’s Partial Report

A medium tone signals the subject to report the letters in this row

Sperling’s Results

Delay

Short Term Memory

 The original idea is that when info in sensory memory is paid attention to, it moves into short term memory.

 With rehearsal, it then moves into long term memory.

 STM has limited capacity, called memory span.  Miller’s magic number (7 ± 2)  New info pushes out older info (Shepard)

Shepard’s Results

Number of intervening items

Probability of recalling the target item

Depth of Processing

 Craik & Lockhart – proposed that it is not how long material is rehearsed but the depth of processing that matters.

 Levels of processing demo.

Working Memory

 Baddeley – in working memory speed of rehearsal determines memory span. Articulatory loop – stores whatever can be processed in a given amount of time.  Word length effect: 4.5 one-syllable words remembered compared to 2.6 long ones.  1.5 to 2 seconds material can be kept.  Visuopatial sketchpad – rehearses images.  Central executive – controls other systems.

Delayed Matching Task

 Delayed Matching to Sample – monkey must recall where food was placed.  Monkeys with lesion to frontal cortex cannot remember food location.  Human infants can’t do it until 1 year old.

 Regions of frontal cortex fire only during the delay – keeping location in mind.  Different prefrontal regions are used to remember different kinds of information.

Delayed Matching to Sample

Activation

 Activation – how available

information is to memory:

 Probability of access – how likely you are to remember something.  Rate of access – how fast something can be remembered.

 From moment to moment, items

differ in their degree of activation in

memory.

Anderson’s ACT Model

 ACT – Adaptive Control of Thought

 Moses Effect -- subjects shown the words Bible, animal and flood should recall Noah but recall Moses instead.  When given the word flood they think of Mississippi or Johnstown but not Noah.

 Why? Recall is based on both baseline and activation from associated concepts.  Moses and Jesus have higher baselines.