Chapter 5: Short Term Memory

Memory

The process involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present

• Comes in many different forms

True

True or false: Memory is ACTIVE any time some past experience has an impact on how you think or behave now or in the future

Modal Model of Memory

• Atkinson and Shiffrin model

Memory Types:

• Sensory memory, short-term memory, and long-term memory

Control processes:

• Rehearsal, strategies used to make a stimulus more memorable, and strategies of attention that help you focus on specific stimuli

Sensory Memory

Initial stage that holds all incoming information for seconds or fractions of a second, a brief persistence of the image

Short-term Memory

Holds 5-7 items for about 15-20 seconds

Long-term Memory

Can hold a large amount of information for years or even decades

Control Processes

Active processes that can be controlled by the person

• Rehearsal

• Strategies used to make a stimulus more memorable

• Strategies of attention that help you focus on specific stimuli

What are the different types of control processes?

1. Looking up the phone number: All information on screen enters the sensory memory, then focus on the actual phone number enters the short-term memory

2. Calling the pizza shop: Rehearsing the number to keep it in short-term memory while making the phone call since the number was not in front of her

3. Memorizing the number: Store number stored in long-term memory for storage

4. A few days later, retrieving the number from long term memory to order pizza again: Retrieve number from long-term memory. It goes back to short-term memory and is remembered

What is the process of memory for ordering a pizza on the phone?

• Retention for brief periods of time, of the effects of sensory stimulation

• Information DECAYS very quickly

• Persistence of vision: retention of the perception of light; EX; trail of light from a moving sparkler or frames in film

What are the characteristics of sensory memory?

Question: What is the capacity and the duration of sensory memory?

Method:

• Array of letters flashed quickly on a screen

• Participants asked to report as many as possible

Whole report method: participants asked to report as many letters as could be seen

Partial report tone (Tone immediate and delayed): Participants heard tone that told them which row of letters to report

What was the method of experiment for sensory memory?

Results:

• Whole report: Average 4.5/12 letters (37.5%)

• Partial report (tone immediate): Average 3.3/4 letters (82%)

• Partial report (tone delayed): Presentation of tone delayed for a fraction of a second after the letters were extinguished; performance DECREASED rapidly

What were the results from the experiment for sensory memory (duration)?

Iconic memory

Brief sensory memory of the things we see; responsible for persistence of vision

Echoic memory

Brief sensory memory of the things that we "hear"; responsible for persistence of sound

• Stores small amounts of information for a brief duration

• Includes both new information received from the sensory memory and information recalled from long-term memory

What are the characteristics of short-term memory?

Question: What is the duration of short-term memory?

Method:

• Read 3 letters (BHM) and then a 3 digit number (403)

• Begin to count backwards by 3s (403, 400, 397, 394)

• After a set time "recall" the 3 letters

What was the method of experiment for short-term memory?

• After 3 seconds of counting, participants performed at 80%

• After 18 seconds of counting, participants performed at 10% (shows the quick decay)

What were the results from the experiment for short-term memory?

Decay

How can we explain the severe reduction in performance for short term memory between 3 and 18 seconds?

Decay

The vanishing of a memory trace due to the passage of time and exposure to competing stimuli

15-20 seconds or less

What is the duration of short-term memory?

Question: What is the capacity of short-term memory?

Method:

• Digit span: how many digits a person can remember?

• OR change detection: remembering the colors of spread out squares; the larger number of squares the less correct if the 2 pictures were the same or not

What was the method for the experiment for short-term memory (capacity)?

5-8 items

What is the typical capacity of short-term memory?

True; more complex items had a higher capacity in short-term memory

True or false: The number of items you can hold in your short-term memory depends on stimuli?

Question: What is an item?

Method:

• Trained a college student with average memory ability to use chunking

Student had an initial digit span of 7

After 230 1 hour training sessions, students could remember up to 79 items

• Chunking them into meaningful units

What was the method for the experiment for short-term memory in deciding what an item was?

Working Memory

-Limited capacity system for temporary storage and manipulation of information for complex tasks such as comprehension, learning, and reasoning

• Set up to process different types of information simultaneously

• Has trouble when similar types of information are presented at the same time

-Involves an interplay between a number of areas of the brain

• Short term memory holds information for a brief period of time

• Working memory is concerned with the storage, processing , and manipulation of information, and is active during complex cognition

What is the difference between short-term memory and working memory?

Baddeley's Working memory model

3 parts

• Phonological loop

• Visuospatial sketchpad

• Central Executive

Phonological Loop

Verbal and auditory information

1. Phonological similarity effect

2. Word length effect

3. Articulatory suppression

What are the 3 phenomena that support the idea of a system specialized for verbal information or language

Phonological similarity effect

Letters or words that sound similar are confused

EX: If you try to memorize the letters B, D, G, P, T, V, you'll likely mix them up more easily because they sound alike.

But if you try to memorize K, L, R, S, Y, F, recall is typically better since the sounds are more distinct.

Word length effect

Memory for lists of words is better for short words than for long words

EX: List 1: Beast, brone, wife, gold, inn, limp, dirt, star

List 2: Alcohol, property, amplifier, officer, gallery, mosquito, orchestra, bricklayer

It takes longer to rehearse long words and to produce them during recall

Articulatory Suppression

Speaking prevents one from rehearsing items to be remembered

• Reduces memory span

• Eliminates work length effect

• Reduces phonological similarity effect for reading words

EX: saying "the, the, the" out loud

Visuospatial Sketchpad

Handles visual and spatial information and is therefore involved in the process of visual imagery

• Creation of visual images in the mind in the absence of a physical visual stimulus

EX: Mental rotation tasks; tasks that called for greater rotations took longer

People took longer to say that they were the same shape

Central Executive

• Acts as the attention controller

• Focus, divide, switch attention

• Controls suppression of irrelevant information

• "Cognitive control" - shifting, updating, inhibition

• Perseveration

Perseveration

Repeatedly performing the same action or thought even if it is not achieving the desired goal

Episodic Buffer

-Backup store that communicates with long-term and working memory components

• Holds information longer and has greater capacity than phonological loop or visuospatial sketchpad

• Still a work in progress

Prefrontal Cortex

Responsible for holding information for brief periods of time

Suffered a traumatic brain injury which severely affected his prefrontal cortex; he became a different person with low impulse control, poor planning, poor social skills, etc.

What happened to Phineas Gage?

Holding information in working memory

What do monkeys without a prefrontal cortex have difficulty with?