CAPACITY

WHY FORGET

HOW ENCODED

RECALL THAT EBBINGAUS FOUND RAPID FORGETTING, WHICH LEVELED OFF AS TIME WENT BY

WHY DO WE FORGET

IN THE YEARS FOLLOWING EBBINGAUS TWO THEORIES COMPETED

DECAY THEORY=FORGETTTNG IS TIME-DEPENDENT IN AS MUCH AS MEMORIES BECOME WEAKER AND WEAKER OVER TIME

INTERFERENCE THEORIES FORGETTING IS EVENT-DEPENDENT IN AS MUCH AS OTHER EVENTS STORED IN MEMORY CAUSE THE PROBLEM

BASIC PARADIGMS

RETROACTIVE INTERFERENCE (RI)
 

	TIME 1	DELAY	TIME 2
E C	STUDY X STUDY X	STUDY Y	RECALL X RECALL X

PROACTIVE INTERFERENCE (PI)
 

E C

STUDY Y

STUDY X STUDY X

RECALL X RECALL X

- distinguished between PRIMARY MEMORY

• limited capacity
• actively maintained
• in consciousness
• worked on

• large capacity
• maintained for long periods of time
• not conscious of, until it is used

consider the immediate memory span;
how many, on average do people remember in order?

Find the same number in task after task

so people have a limited capacity to process

how do we overcome this

chunking:

mnmiabrktyaesletaz

mynameisalbertkatz

example of expertise in chess

task:

many many trials
each trial has the same format:

1. present a trigram (a 3 letter swing) or three words
2. Present a digit (eg., 974) and ask the person to count backwards by 1, 3s or 7s
manipulate the time required to count
3. Ask for recall of the presented items

example; ghost justice lettuce

number 573 by 7's

what did they find?

IS IT DECAY?

EVIDENCE OF INTERFERENCE

BUILD UP OF P1 OVER TRIALS
CONSIDER THE FOLLOWING TRIALS TN TUE BROWN-PETERSONS TASK (COUNT BACKWARDS FOR 30 SEC)

eg.
Trial 1 COW DOG HORSE
Trial 2 GOAT PIG SHEEP
Trial 3 CAT RACOON MONKEY
Trial 4 ZEBRA CAMEL GIRAFFE

%RECALL=GETS POORER WITH EACH TRIAL

but note WHAT HAPPENS IF ON TRIAL 5 WE HAVE
Trial 5 ROSE DAFFODIL CARNATION

RELEASE FROM P1

task: PRESENT A LIST OF 16 DIGITS
        FOLLOWED BY A PROBE DIGIT
SUBJECT IS ASKED TO NAME THE DIGIT THAT FOLLOWED THE PROBE

example 5 8 2 4 9 7 2 5 3 7 1 9 6 4 3 5
probe=6
manipulated: 1. NUMBER OF INTERVENING ITEMS
        2. SPEED OF PRESENTATION

found;

STM AND SOUND BASED CODING

-ON AN AUDITORY PERCEPTUAL TASK (SUCH AS RECOGNIZING WHAT IS SAID WHEN THE SOUND IS COVERED WITH STATIC) ONE FINDS THAT ITEMS THAT SOUND ALIKE ARE CONFUSED WITH ONE ANOTHER (EG., SAY "P", PERSON HEARS "C")

CAN SHOW VIA AN ERROR MATRIX
 

	Hear A B C D ......
present A B C D etc.

note: correct perception in diagonal, errors off-diagonal

WHAT HAPPENS IF THE SAME ITEMS ARE PRESENTED VISUALLY IN A STM TASK... SUCH AS PRESENTING A LIST OF LETTERS AND, AFTER COUNTING BACKWARDS FOR SEVERAL SECONDS,
ASKING FOR RECALL

CAN ALSO GET AN ERROR MATRIX FOR STM!
 

	Remember A  B  C
present A B C

with words this means if present a word, such as LAD (visually) that, when tested for the STM memory of that word, IF an error is made it tends to be to a word that sounds like the presented word (eg CAD)

when the same items are tested in LTM task (such as after 24 hours delay)

one finds different results
Namely, errors, when they do occur, are now to word that are similar in MEANING (e.g, LAD IS NOW REMEMBERED AS BOY)

in the modal model: SUGGESTED THAT ITEMS ARE ENCODED IN A SOUND-BASED FASHION

BUT: NOTE PROBLEM WITH THIS
-EG., RELEASE FROM PI (INDICATING SEMANTIC ENCODING IN STM)
.EG., IMAGERY-BASED STUFF: (INDICATING A VISUAL COMPONENT)

DISTINCTION BETWEEN MAINTENANCE AND ELABORATIVE REHEARSAL

MAINTENANCE: KEEPING MATERIAL FRESH OR ACTIVE IN STM, WITHOUT CHANGING IT (EG., REPEATING WORDS OVER AND OVER)

ELABORATIVE REHEARSAL: CHANGING THE INFORMATION IN STM, BY EXTRACTING MEANING, AND RELATING TO OTHER KNOWLEDGE)

EXAMPLE: ARE NONSENSE SYLLABLES NONSENSICAL

remember how: (did you use Natural Language Mediators) ie change the items to be real words, such as LOVE, TRIM, BITE???); if so, you have just demonstrated elaborative rehearsal

BY THE EARLY 1970'S MANY WERE ARGUING THAT WHAT WAS IMPORTANT FOR ENCODING IN LTM WAS NOT HOW OFTEN SOMETHING WAS REHEARSED (MAINTENANCE-WISE) BUT WHAT YOU DID WITH THE MATERIAL TO BE REMEMBERED (ELABORATIVELY)

WE WILL GET BACK TO THIS THEME WHEN WE TALK ABOUT ABOUT LEVELS OF PROCESSING THEORY