MemoryLi, Kristoffer Daniel

Lee, Seoui

What is Memory?

An active system that receives information from the senses, puts that information into

usable form, organises it as it stores it away, and then retrieves the information from storage (adapted from Baddely, 1996,

2003)

Three Processes of Memory

Encoding Storage

Retrieval

Encoding

The set of mental operations that people perform on sensory information to convert

that information into a form that is usable in the brain’s storage system.

Storage

Holding on to some information for a period of time.

Retrieval

Getting information that is in storage into a form that can be used

Models of Memory

Information-Processing Model

Parallel Distributed Processing (PDP) Model

Levels of Processing Model

Information-Processing Model

Model of memory that assumes the processing of information for memory

storage is similar to the way a computer processes memory in a

series of three stages.

Parallel Distributed Processing Model

A model of memory in which memory processes are proposed to take place at the same time

over a large network of neural connections.

Levels of Processing Model

Information processed according to its meaning, rather than

sound or physical characteristics of the word, will be remembered

more efficiently and for a longer period of time.

The Information-Processing Model:

Three Memory Systems

Sensory Memory: How does it work?

the very first stage of memory, the point at which information enters the nervous system through the

sensory systems.

Iconic Sensory Memory

Visual sensory memory,lasting only a fraction of a second.

Capacity of Iconic Sensory Memory

The capacity of iconic memory is everything that can be seen at

one time.

Duration of Iconic Memory

In real life, information that has just entered iconic memory will be pushed out very quickly by new information, a

process called masking (Cowan, 1988). Research suggests that after only a quarter of a second, old information is replaced by new

information.

Although it is rare, some people do

have what is properly called

eidetic imagery, or the ability to access

a visual sensory memory over a long

period of time.

Echoic Sensory Memory

echoic memory is the brief memory of

something a person has just heard. It is

limited to any can be heard at any one

moment and lasts about 2-4 seconds.

Short-Term Memory

the memory system in which information is held for brief periods of time while

being used. This is possible through the process of selective attention, the ability

to focus ononly one stimulus from among all sensory

input

Selective AttentionFirst Stage: incoming stimuli in sensory memory are filtered on the basis of simple physical characteristics.

Second Stage: the processing of only the stimuli that meet a certain threshold of importance.

Working Memory

an active system that processes the

information in short-term memory.

Techniques to Remember

Chunking

Maintenance Rehearsal

Long Term Memory

the system of memory into which all the information is placed to be kept

more or less permanently.

Elaborative Rehearsal

method of transferring information from STM into LTM by making

that information meaningful in some way.

Types of Long-Term Information

Procedural (Nondeclarative)

LTM• Implicit Memory

Declarative LTM

• Semantic Memory

• Episodic Memory

Procedural LTM

Includes memory for skills, procedures, habits and conditioned responses. These

memories are not conscious but are implied to exist because they affect behaviour; also

Implicit Memory.

Declarative LTM

Contains information that is conscious and known; also, explicit memory.

Semantic Memory

Type of declarative memory containing general knowledge.

Episodic Memory

Type of declarative memory containing personal information that are not

readily available to others.

LTM Organisation: Semantic Network Model

Retrieval of Long Term Memories

Encoding Specificity

The tendency for memory of information to be improved if related information that is

available when the memory is first formed is also available when the memory is being

retrieved.

Recall vs Recognition

The Serial Position Effect

Tendency of information at the beginning (Primacy Effect) and end (Recency Effect) of a body of information to be remembered more accurately

than information in the middle.

False Positive

Error of recognition in which people think they recognise some stimulus that is not

actually in memory.

Automatic Encoding

Tendency of certain kinds of information to enter LTM with little or no effortful

encoding.

Flashbulb Memories

Type of automatic encoding that occurs because an unexpected event has strong emotional associations for the person

remembering it.

The Reconstructive Nature of Long-Term

Memory RetrievalHow Reliable Are Memories?

Constructive Processing of

Memories• Memories are rarely completely accurate and

become less accurate over time.• Loftus and others have suggested that memory

retrieval is a constructive process; memories are “built” at the time of retrieval.

• Hindsight bias – “knew-it-all-along”

Memory Retrieval Problems

• The Misinformation Effect o Misleading information can become part of the actual

memory, affecting its accuracy.

Reliability of Memory Retrieval

• False memory syndromeo Creation of inaccurate or false memories through the

suggestion of others, often while the person in under hypnosis

1. The event must be made to seem as plausible as possible.

2. Individuals are given information that helps them believe that the event could have happened to them personally.

Forgetting

Mnemonist

The Forgetting Curve

• Distributed practiceo Produces far better retrieval than massed practice

(cramming)• Encoding failure

o Nonattended information is not encoded into memory

• Memory trace decayo Over time, if not used, neuronal connection can weaken

or decay• Interference

o Other information interferes with accurate retrievalo Proactive: previously learnedo Retroactive: newly acquired

Neuroscience of Memory

Different brain areas are associated with

different types of memory

• Procedural memories: cerebellum• Short-term memories: prefrontal cortex and

temporal lobes• Semantic and episodic long-term memories:

frontal and temporal lobes

Consolidation• Several physical change in brain are associated

with memory formationo Changes at receptor

• Long-term potentiation – changes in the sensitivity of the synapse through repeated stimulation

o Changes in dendrites• 4E-BP2

H.M.

Hippocampus• Plays a vial role in the formation of new

declarative long-term memory.

Organic Amnesia• Caused by problems in brain function associated

with brain trauma, disease or aging.• Retrograde

o Loss of memory from the point of injury backwards• Anterograde

o Loss of memory from the point of injury forwards

Infantile Amnesia• Memories before age 3 are likely implicit, not

explicit.• Social relationships

o Children develop autobiographical memory.