Chapter 6

What is the formal definition of memory?

Any cognitive process that involves encoding, storage, and retrieval

Encoding

The initial processing of information by the nervous system

If something is not encoded then it cannot be remembered

What can be a form of short-term transduction of a physical stimulus into a neural code; or a structural change in the brain that processes a fact or event about the world?

Encoding

Storage

Refers to the retention of encoded information; this information remains encoded in some form for a longer duration; can be for both short- and longer-term durations

Retrieval

the brain’s ability to access this stored information for some cognitive purpose

Capacity

Measure of how much information a memory system can hold; some types of memory have a higher capacity than others

Duration

Measure of how long information can be held in memory; some types of memory can be quickly lost or last for a lifetime

What did William James do?

Found that there are two types of memory systems; one for information related to the current task or environment and one for longer-term storage

Modal Model

Atkinson and Shiffrin’s multi-sttore/modal model; created a new era for computer science

Also called “information processing model”

There are three distinct memory stores: sensory, STM, and LTM

Sensory memory can hold sensory input for how long?

1 second

Process of Modal Model/ Information Processing Model

Sensory memory

first stage in modal model of memory, holding information before it can be processed; HAS A HIGH CAPACITY AND SHORT DURATION

STM

Short-term memory is the second stage that served to hold processed information for rehearsal or to produce a behavior

Capable of producing a behavioral output, such as repeating a phone number

Maintenance rehearsal

The mental repetition of information in STM that allows information for retrieval into STM

Only a small fraction of STM is encoded as LTM

LTM

Long-term memory is the final stage that served as cold storage of information for retrieval into STM

Only a small fraction of STM is encoded as LTM

Persistence of Vision

Retention of an image of an object or event for a brief period after it is no longer present (fast moving lights produce a spaced out pattern)

Iconic Memory

The visual form of sensory memory in which much of the visual input can be stored for a short period

HIGH CAPACITY SHORT DURATION (1 second)

Echoic memory

An auditory form of sensory memory in which much of the auditory input can be stored

How much information can STM hold?

STM can hold 7 items in the auditory domain; and 4 items in the visual domain

Chunk

combination of letters, numbers, or sounds that constitutes a meaningful while; proposed unit for measuring capacity in STM

7 chunks is the avg.

What is the item capacity for visual STM?

3-5 items

Chase and Simmons (1973)

Demonstrated that attaching meaning to the information facilitates the storage of information

Maintenance rehearsal

The mental repetition of information in STM that allows information to be regenerated in order to prolong its duration

How long can information last in STM in the absence of maintenance rehearsal?

15 seconds

Proactive interference

Information encoded in the future negatively affects what is recalled from the past

Retroactive interference

Information encoded before negatively affects what is encoded in the future

Peterson and Peterson

Found that decay caused the forgetfulness of information as participants only learned letters in each trial; but it still showed proactive interference

So both decay and interference plays a role in STM

Baddeley’s Working Memory model

STM is an active workspace where information could be mentally manipulated based on the current task (such as a conversation)

includes 3 connected sub-units: visuo-spatial sketchpad, phonological loop, and central executive

Visuo-spatial sketchpad

the visual component of WM; unlike the original conception of VSTM, the visuo-spatial sketchpad can be used to analyze and manipulate visual information such as mentally rotating a remembered object

Phonological Loop

The auditory component of WM, this allows auditory information to be repeated so that it may be used or analyzed

Central executive

A component that is completely novel to the WM model; it is the gatekeeper that determines what information makes it into WM and interacts between the visual and auditory memory stores

Frontal lobes are typically associated with executive functions

Acoustic confusions

difficulty memorizing a list of letters that sound familiar

Episodic Buffer

A component proposed as a revision to the original WM model that can combine information from across different sources including the phonological loop and the VSS as well as LTM

Using fMRI, what did scientists find in brain activity?

Increased activity in the prefrontal cortex during the delay phase of the Delayed-Match-to-Sample task

Recurrent Neural Networks

Class of neural network models applied to sequential data that contain recurrent nosed that loop their output back into themselves as inputs, allowing them to process past and current inputs as the same time (RNNs)

Elaborative rehearsal

Meaning is added to information

Modality-specific region

WM takes place all over the brain