Short and Long term memory

Question 1

What is memory?

Answer 1

A process in which information is retained about the past.

Question 2

What is long term memory (LTM)?

Answer 2

The memory of events that have happened in the past. Can last between 2 minutes to 100 years. It is potentially unlimited duration and capacity.

Question 3

What is short term memory (STM)?

Answer 3

Your memory of immediate events. STM lasts for a very short time and disappears unless it is rehearsed. It has a limited duration and a limited capacity. STM is also known as WM (working memory).

Question 4

Define capacity.

Answer 4

How much data can be stored.

Question 5

Define duration.

Answer 5

The amount of time the data can be stored for.

Question 6

Define coding.

Answer 6

How information is stored/ recorded.

Question 7

What is the capacity of STM?

Answer 7

7±2

Question 8

What is the digit span technique?

Answer 8

Jacobs (1887) used this technique to assess STM. A participant had to immediately recall a sequence of letters or numbers which increased by one letter or number with each trial. He found the average span for digits was 9.3 items and 7.3 for letters. Jacobs suggested this because there are only 9 digits and 26 letters.

Question 9

What was the study to prove the magic number 7±2?

Answer 9

Miller (1956) suggested people can typically remember between 5-9 items. (7±2). He also found that people can recall 5 words and 5 letters by chunking things together and can remember more.

Question 10

What is the duration for STM?

Answer 10

18-30 seconds

Question 11

What is the study for the duration of LTM?

Answer 11

Bahrick (1975) tested 400 people aged 17-74 on their memory of classmates. A photo recognition test consisted of 50 photos, some from the high school yearbook. In a free recall test, they were asked to recall as many names as they could remember. Participants within 15 years of graduating were about 90% accurate. After 48 years this went to 70%. Free recall was about 60% accurate after 15 years to then 30% after 48 years.

Older participants were less good at free recall but nearly as good as younger participants in the matching task. The conclusion was that the duration of LTM is potentially lifelong.

Question 12

What is the duration for LTM?

Answer 12

Infinite

Question 13

What is the study for duration of STM?

Answer 13

Peterson and Peterson (1959). A group of participants were shown nonsense trigrams of 3 random consonants and asked to recall them after either 3,6,9,12,15 or 18 seconds. On waiting, the participants were asked to count backwards in threes from a random number (interference task to stop them from repeating the letters to themselves). After 3 seconds participants could recall about 80% of trigrams correctly after 18 seconds about 10% of the trigram was recalled successfully. It was concluded that the duration of STM is around 18-30 seconds if rehearsal is prevented.

Question 14

What type of coding is generally for LTM?

Answer 14

Semantic

Question 15

What was the study for acoustic and semantic coding?

Answer 15

Baddeley (1966) gave participants one of four-word lists to learn. The lists contained words that were either acoustically similar (sounded the same, e.g. hat, cat, bat); acoustically dissimilar (sounded different, e.g. hat, stage, ball); semantically similar (had the same meaning, e.g. big, large); or semantically dissimilar (had different meanings, e.g. gate, big). Participants either recalled the list immediately, testing the coding of short-term memory (STM) or after 20 minutes, testing the coding of long-term memory (LTM). Participants did worse with acoustically similar words in STM, suggesting that information in STM is coded according to sound, as similar-sounding information conflicted with each other. For LTM, they did worse with semantically similar words, suggesting that information in LTM is coded according to meaning, as information with similar meanings conflicted with each other.

Question 16

What did they evaluate from the Peterson and Peterson investigation?

Answer 16

+ However, Peterson & Peterson’s study was highly controlled and took place in a laboratory of Indiana University. As a result, Peterson & Peterson had a high degree of control for extraneous variables, which makes their procedure easy to replicate.

• One of the primary weaknesses of the study is its limited external validity. The study used artificial stimuli (trigrams) that do not reflect the types of information that people typically encounter in their daily lives. As a result, the study’s findings may not generalise well to real-world memory tasks.
• Additionally, the study had a relatively small sample size (24 participants), which limits the generalisability of the findings. Furthermore, the study’s design did not allow for the investigation of individual differences in STM capacity and duration.

Question 17

What was the evaluation of Bahrick et al’s experiment?

Answer 17

• A strength of this study is that it used meaningful stimuli. Bahrick et al. tested people’s memories from their own lives by using high school yearbooks. The study has higher external validity when compared to studies using meaningless pictures (where recall rates tend to be lower).
• In addition, this information could have been rehearsed (for example if you are still in touch with classmates or you tell stories of memories about your old classmates), this would increase the rate of recall. This means that the study can’t be generalised to other types of information held in LTM.

Question 18

What was Millers evaluation?

Answer 18

• Lack of clarity on what constitutes a “chunk”: Miller’s definition of a “chunk” is somewhat vague, leading to confusion and inconsistency in subsequent research. It is unclear whether a chunk represents a single letter, a word, a phrase, or some other unit of information.
• Limited external validity: Miller’s study used simple tasks, such as recalling random strings of numbers or letters. It is unclear whether these tasks reflect real-life situations in which STM is used, such as remembering a telephone number or a list of grocery items.

+ Miller’s (1956) classic paper on the capacity of short-term memory (STM) demonstrated a key strength in its clear and concise explanation of a fundamental aspect of human cognitive processing. Specifically, Miller proposed that the capacity of STM is limited to approximately 7±2 items, often referred to as “Miller’s Law”. This finding has been replicated in numerous studies and is widely accepted as a fundamental characteristic of STM.

Question 19

What was Baddeley’s evaluation?

Answer 19

• In the study, STM was tested by asking participants to recall a word list immediately after hearing it. LTM was tested by waiting 20 mins. It’s questionable as to whether this is really testing LTM. This casts doubt on the validity of Baddeley’s research because he wasn’t testing LTM after all.

Question 20

What was Jacobs’s evaluation?

Answer 20

• Cultural bias: The test may be biased towards individuals from certain cultures, as the ability to recall digits in the exact order presented may not be equally valued across all cultures. Thus, we should take an emic approach.

+ One strength of this technique is that it is a reliable and valid measure of working memory capacity, which is an important cognitive construct that is associated with a wide range of cognitive and academic outcomes. Specifically, the Jacobs Digit Span technique has been shown to have good test-retest reliability, meaning that individuals tend to perform similarly on the task when they take it multiple times. It has also been shown to be a valid measure of working memory capacity, as it correlates with other measures of working memory, such as the reading span task, and is associated with a wide range of cognitive and academic outcomes, such as reading comprehension and problem-solving ability.