Models of memory

what is memory

what is memory

the mental processes involved in receiving, storing and recovering information

what is the capacity of STM and LTM
+ relevant research

STM - 9-5 items on average = jacobs + miller

LTM- Unlimited - Ramscar

what is the duration of STM and LTM
+ relevant research

STM- 18-30 secs = peterson and peterson

LTM - Up to a lifetime = Bahrick

what is the coding of STM and LTM
+ relevant research

STM - mainly acoustic

LTM - mainly semantic

both baddeley

What are the 3 of memory stores

STM, LTM and the sensory register

What is the sensory register

This store temporarily stores information from our senses - constantly receiving information from around us. Unless we pay attention to it, it disappears quickly - due to spontaneous decay

It has unlimited capacity but a very short duration 50 milliseconds

What was the procedure for Jacobs research into the capacity of STM

participants were given a string of digits for example 4 numbers in a row. The ps have to repeat the list of numbers out loud in the correct order. The list of numbers increases until the p cannot recall them in the correct order.

What were the findings for Jacobs research into the capacity of STM

the mean span of recalled digits was 9.3 items. the mean span for letters was 7.3

What were the conclusions for Jacobs research into the capacity of STM

The capacity of the STM in limited

limited to around 7-9 items

What was the aim for Millers study on the capacity of STM

To investigate the capacity of STM and to see whether chunking assists memory in the short term.

What was the procedure for Millers study on the capacity of STM

Ps were read strings of numbers which they had to recall immediately.

Gradually the length was increased until the ps could only recall the lists correctly on 50% of the trials

Miller also included trials whereby he chunked the numbers into small groups to see if it aided memory

What were the findings for Millers study on the capacity of STM

Miller found that typically people remember 7± 2 items of information e.g letters, numbers or chunks

he also noted that many things come in sevens e.g 7 days of the week, or musical notes in 7s

What were the conclusions for Millers study on the capacity of STM

The capacity of the STM is limited to 7± 2

it is the number of chunks that limit memory, but it does not matter how much goes into each chunk

AO3 + Research into Capacity of STM

• millers research has useful real life applications - people use chunking to remember phone numbers

• Jacobs research is supported by miller who also found on average people short term memory could remember between 5-9 things. These consistent findings mean the conclusions on the capacity of the STM is reliable

AO3 - Research into Capacity of STM

• Millers conclusion that it doesnt matter how much is in each chunk has been criticised. Simon found that it did matter how many items were in the chunk. Ps in his study had a shorter memory span for larger chunks than smaller ones

• A problem with the study was that it was carried out in a lab environment. The ps may have concentrated more than they would in everday life. Due to demand characteristics - therefore the results may lack ecological validity. This means the research findings are more difficult to generalise to real life memory settings.

Research on the Capacity of LTM

Capacity of LTM is thought to be unlimited, depending on individual differences. However decay, interference and illness may result in a loss of information. Ramscar (2014) trained computers to mimic elderly people’s brains. he found that as computers aged by aquiring more and more information, they slowed down. The research suggests that human rains slow down because they are filling with information.

What was the aim of Peterson & Peterson research on the duration of STM

To find out how long items would remain in the STM rehearsal

What was the procedure of Peterson & Peterson research on the duration of STM

Presented ps with consonant trigrams e.g CDX

ps were asked to count backwards on 3s from a specified number. - this was to prevent rehearsal

After intervals of 13-18 seconds Ps were asked to stop counting and recall the triagram

What were the findings of Peterson & Peterson research on the duration of STM

Ps were able to recall about 80% if the trigrams correctly after an interval of 3s, but recall became progressively worse as the time intervals increased.

after 18seconds they would recall less than 10% corrrectly.

What were the conclusions of Peterson & Peterson research on the duration of STM

Information disappears/decays very rapidly in the STM when rehearsal is prevented. STM duration is about 18sec

AO3 + Research into Duration of STM

One strength of the research is that it was conducted under highly controlled laboratory conditions. This allowed them to use control procedures such as counterbalancing which reduces order effects. Reduced extraneous variables increases the internal validity of the study

Another strength is that a repeated measures design was used this limits the individual differences in memory performance which allows us to see cause and effect between IV seconds without rehearsal and DV ability to recall trigram.

AO3 - Research into Duration of STM

A main criticism of the research is that the trigram task is highly artificial, it is not a realistic task that people have to carry out in their daily lives. This means this study may lack ecological validity making it harder to generalise to real life situations.

Trigrams from earlier trials may have caused confusion interfering with the memory on later on trials this could have led to poor recall rather than the limited duration of the STM,

What is reliability in terms of schizophrenia diagnosis

How consistent diagnoses are among specialists

What is validity in terms of schizophrenia diagnosis

• Internal validity - does the ICD/Psychologists accurately give schizophrenia diagnoses

What are the 3 diagnostic criteria for schizophrenia from the DSM

1. Characteristic symptoms - two or more of the following : Delusions, Hallucinations. disorganised speech, negative symptoms. The only 1st rank symptoms are bizarre delusions and auditory hallucinations.

2. Social or occupational dsyfunction

3. significant duration - 6 months

What was the aim of Rosenhan’s experiment

To test the reliabilty and validity of psychiatric diagnosis.

What was the procedure of Rosenhan’s experiment

Sent 8 health individuals to try and gain hospital admission. 12 hospitals were used, in 5 different states. The pseudopatients faked auditory hallucinations, saying they could hear a voice saying “empty”, “hollow” and “thud”. Once admitted they stopped all symptoms, acted normally and said they felt well and asked to be released.

What were the findings of Rosenhan’s experiment

All the participants were diagnosed as insane and admitted into the hospital. 7/8 participants were diagnosed with schizophrenia, and 1/8 with bipolar. It took participants between 7 to 52 days to be released as “in remission” not normal.

What were the conclusions of Rosenhan’s experiment

Psychiatrists are not reliably diagnosing schizophrenia as different clinicians diagnosised the patient differently despite the same symptoms

psychiatrists are not validly diagnosing schizophrenia as they may not distinguish between real and pseudopatients.

AO1 Reliability of schizophrenia diagnosis

An important measure of reliability is inter-rater reliability, the extent to which different mental health professionals agree on the same diagnosis for a patient, a problem for relability is that there a two slightlty different classification systems used the DSM and ICD-10.

One difference is that the DSM only includes bizarre delusions and auditory hallucinations as first rank symptoms, whereas under the ICD though echo is considered a first rank symptom. This means diagnosis is not consistent.