1. Types of Memory Flashcards
1
Q
What is memory
A
Human memory can most broadly be defined as the process by which we retain information about events that have happened in the past
2
Q
3 types of memory
A
- Sensory register
- Short-term memory (STM)
- Long-term memory (LTM)
3
Q
Types of memory: Sensory register
A
- Temporarily stores info from our senses (sight, sound, touch, taste & smell) - it is the initial contact for stimuli & is constantly receiving info from around us
- Unless we pay attention to it, it disappears quickly through spontaneous decay - the trace just fades
- The sensory register has a limited capacity, & a very limited duration (we can remember a little info for a very short time)
- Information is coded depending on the sense that has picked it up (eg. visual, auditory or tactile)
4
Q
Types of memory: Short-term memory (STM)
A
- The information we are currently aware of or thinking about. The information found in STM comes from paying attention to sensory memories
- Has a limited capacity & a limited duration (we can remember a little info for a short time)
- Coding is usually acoustic (sound)
5
Q
Types of memory: Long-term memory (LTM)
A
- Has a pretty much unlimited capacity & is theoretically permanent (it can hold lots of info forever)
- Coding is usually semantic (the meaning of the info)
- Continual storage of info which is largely outside of our awareness, but can be called into working memory to be used when needed
There are 3 different types of LTM:
1. Episodic memory
2. Semantic memory
3. Procedural memory
6
Q
Long-term memory: Episodic memory
A
- Stores info about events that you’ve actually experienced (sa. a concert or visit to restaurant).
- It can contain info about time & place, emotions you felt, & the details of what happened.
- These memories are declarative - this means they can be consciously recalled.
7
Q
Long-term memory: Semantic memory
A
- Stores facts & knowledge that we have learnt & can consciously recall (sa. capital cities & word meanings).
- It doesn’t contain details of the time or place where you learnt the info - it’s simply the knowledge.
- Linked to episodic as new knowledge is linked to experience.
8
Q
Long-term memory: Procedural memory
A
- Stores the knowledge of how to do things (motor skills) (sa. walking, swimming or playing piano) without conscious effort.
- Difficult to explain in words.
- This info cant be consciously recalled.
9
Q
Duration of memory
A
- How long (in time) a memory lasts before it is no longer accessible
- STM & LTM differ in duration
10
Q
Duration of Short-term memory (STM)
A
- STM lasts for a very short period of time, unless they are rehearsed or paid attention to
- Therefore STM is limited in duration
- You can think of STM like a notepad where we scribble things down we need to remember for a short while
- Unfortunately, the notepad cant holy much info & the ink fades away - limited
11
Q
Duration of Long-term memory (LTM)
A
- Long term memories can last anywhere from 2mins to 100yrs.
- LTM has an unlimited duration
12
Q
Studies looking at the duration of memory
A
- Sperling (1960)
- Peterson & Peterson (1959)
- Bahrick et al (1975)
13
Q
What did Sperling (1960) do
A
Investigated the sensory register using very brief displays
14
Q
Method of Sperling (1960)
A
In a laboratory experiment, participants were shown a grid with 3 rows of 4 letters for 50 milliseconds (0.05 secs).
They then had to immediately recall either the whole grid, or a randomly chosen row indicated by a tone (high, medium or low) played straight after the grid was shown
15
Q
Results of Sperling (1960)
A
- When participants had to recall the whole grid, they only managed to recall 4 or 5 letters on average.
- When a participant row was indicated, participants could recall an average of 3 items, no matter which row had been selected
16
Q
Conclusion of Sperling (1960)
A
The participants didn’t known which row was going to be selected, so it could be concluded that they would have been able to recall 3 items from any row, therefore almost the whole grid was held in their sensory register. They couldn’t report the whole grid bc the trace faded before they could finish recall.
17
Q
Evaluation of Sperling (1960): PROS
A
- Since this was a laboratory experiment, it was highly scientific - so the variables could be controlled & it would be easy to replicate
18
Q
Evaluation of Sperling (1960): CONS
A
- However, the artificial setting of the study means that it lacks ecological validity - ppl dont normally have to recall letters in response to a sound, so results might not represent what would happen in real world
19
Q
What did Peterson & Peterson (1959) do
A
Investigated short-term memory using Trigrams
20
Q
Method of Peterson & Peterson (1959)
A
Participants were shown nonsense trigrams (3 random consonants, eg. CVM) & asked to recall them after either 3, 6, 9, 12, 15 or 18 secs.
During the pause, they were asked to count backwards in threes from a given number. This was an ‘interference task’ to prevent them from repeating the letters internally.
21
Q
Results of Peterson & Peterson (1959)
A
- After 3secs, participants could recall about 80% of trigrams correctly
- After 18secs, only about 10% were recalled correctly
22
Q
Conclusion of Peterson & Peterson (1959)
A
When rehearsal is prevented, very little can stay in short-term memory for longer than about 18secs
Showed that forgetting in STM can occur if information is not rehearsed
23
Q
Evaluation of Peterson & Peterson (1959): PROS
A
- Results are likely to be reliable - it was a **laboratory experiment* where the variables can be tightly controlled, so limited effects of extraneous variables
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Q
Evaluation of Peterson & Peterson (1959): CONS
A
- However, nonsense trigrams are artificial, so study lacks ecological validity
- Artificial stimuli would hold no personal meaning to the participants - lacked mundane realism
- Meaningful or ‘real-life’ memories may last longer in STM
- Only one type of stimulus was used - the duration of STM may depend on the type of stimulus
- Each participant saw many different trigrams - this could have led to confusion, meaning that the first trigram was the only realistic trial
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What did Bahrick et al (1975) do
Investigated **long-term memory** in a Natural setting
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Method of Bahrick et al (1975)
**392 ppl** were asked to list the names of their ex-classmates (this is called a **'free-recall test'**). They were then shown photos & asked to recall the names of the ppl shown (**photo-recognition test**) or given names & asked to match them to a photo of the classmate (**name-recognition test**).
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Results of Bahrick et al (1975)
- Within 15yrs of leaving school, participants could **recognise** about **90%** of names & faces.
- They were about **60%** accurate on **free recall**.
- After 30ys, **free recall** had declined to about **30%** accuracy.
- After 40yrs, **name-recognition** was about **80%** accurate, & **photo-recognition** about **40%** accurate
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Conclusion of Bahrick et al (1975)
The study is evidence of **Very long-term memories (VLTMs)** in a **'real-life'** setting.
Recognition is better than recall, so there may be a huge store of info, but its not always easy to access all of it - you just need help to get to it
29
Evaluation of Bahrick et al (1975): PROS
- This was a **field experiment** so had **high ecological validity**
30
Evaluation of Bahrick et al (1975): CONS
- However, in a 'real-life' study like this, its hard to **control** all the variables, making results **less reliable** - theres no way of knowing exactly **why** information was recalled well.
- It showed better recall than other studies on LTM, but this may be bc **meaningful** info is stored better
- This type of info could be rehearsed (if you're still in touch w classmates, or if you talk to friends about memories of classmates), increasing the rate of recall. This means the results **cant be generalised** to other types of info held in LTM
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Studies looking at the **capacity** of memory
- Jacobs (1887)
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What did Jacobs (1887) do
Looked into the **capacity** of **short-term memory**
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Method of Jacobs (1887)
Participants were presented with a **string of letters or digits**. They had to repeat them back in the **same order**.
The no. of digits or letters **increased** until the participant failed to recall the sequence correctly
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Results of Jacobs (1887)
The majority of the time, participants recalled about **9 digits** & about **7 letters**.
This capacity increased with **age** during childhood
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Conclusion of Jacobs (1887)
- Based on the range of results, Jacobs concluded that STM has a **limited storage capacity** of **5-9 items**.
- Individual differences were found, sa STM increasing with age, possibly due to use of memory techniques sa **chunking**.
- Digits may have been easier to recall as there were only 10 different digits to remember, compared to 26 letters
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Evaluation of Jacobs (1887): PROS
no PROS
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Evaluation of Jacobs (1887): CONS
- Research is **artificial** & **lacks ecological validity** - its not smth you'd do irl
- Meaningful info may be recalled better, perhaps showing STM to have an even greater capacity.
- Previous sequences recalled by the participants may have confused them on future trials
38
What did Miller (1956) do
- Reviewed research into the **capacity** of **STM**. He found that ppl can remember about 7 items.
- He argued that the capacity of STM is **7, plus or minus 2** ('Miller's magic number')
- He suggested that we use **chunking** to combine individual letters or numbers into larger, more meaningful units.
(eg. **2,0,0,3,1,9,8,7** is about all the digits STM can hold. Chunked into the meaningful recent years of **2003** & **1987**, its much easier to remember)
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What did Miller suggest about Chunking
- Miller argued that our capacity for remembering information can be increases if we chunk items tg
- If we find links between things & group them together then we will remember more (eg. LOL, NHS)
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What is coding
Coding is about the way information is **stored** in memory
It is stored in different forms:
- Visual
- Acoustic
- Semantic
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What is acoustic coding
About how the information sounds
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What is semantic coding
About the meaning of the information
43
Coding in STM
In **STM**, we sometimes try to keep info active by repeating it to ourselves. This means it generally involves **acoustic** coding
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Coding in LTM
In **LTM**, coding is generally **semantic** - its more useful to code words in terms of their meaning, rather than what they sound or look like (although coding in LTM can also be visual or acoustic)
45
What did Baddeley (1966) do
Investigated coding in STM & LTM
46
Method of Baddeley (1966)
Participants were given **4 sets of words** that were either
**acoustically similar** (eg. man, mad, mat),
**acoustically dissimilar** (eg. pit, cow, bar),
**semantically similar** (eg. big, large, huge)
or **semantically dissimilar** (eg. good, hot, pig).
The experiment used a **independent groups** design - participants were asked to recall the words either immediately or following a 20-min task.
47
Results of Baddeley (1966)
- Participants had problems recalling **acoustically similar** words when recalling the word list immediately (from STM).
- If recalling after an interval (from LTM), they had problems with **semantically similar** words
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Conclusion of Baddeley (1966)
The patterns of confusion between similar words suggest that **LTM** is more likely to rely on **semantic** coding & **STM** on **acoustic** coding
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Evaluation of Baddeley (1966): PROS
no PROS
50
Evaluation of Baddeley (1966): CONS
- Lacks **ecological validity**
- There are **other types** of LTM (eg. episodic, memory, procedural memory) & **other methods of coding** (eg. visual), which this experiment doesnt consider
- The experiment used an **independent groups** design, so there wasn't any control over participant variables
51
Episodic: Parts of the brain involved
- The **prefrontal cortex** in the forward part of the **frontal lobe** is associated with **initial coding of episodic memory**
- Memories of the different parts of an event are located in the different **visual, auditory, olfactory (smell) areas** of the brain, but are connected tg in the **hippocampus** to create a memory of an **episode**
52
Semantic: Parts of the brain involved
- Theres some disagreement over which brain areas are involved in the **semantic memory**, HOWEVER, the **hippocampus** is thought to be involved
- The **left prefrontal cortex** is involved in coding associated with the **frontal & temporal lobes**
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Procedural: Parts of the brain involved
- **Motor cortex** & **Prefrontal cortex** associated with procedural LTM & aid in the memories of how to walk etc.
- **Cerebellum** helps w timing & coordination of movements. Making them smooth & precise. Recent research also suggests a role in higher cognitive e processes.
54
Glanzer & Cunitz (1966)
Showed participants a list of 20 words, presented one at a time & then asked them to recall.
This is called the **serial position effect**:
- When asking ppl to remember a list of words which is greater than the capacity of STM they have a tendency to remember words from the beginning & en of the list
- It is comprised of the **primacy effect**: the tendency for ppl to remember the first 5 or so words from the beginning of the list (STM)
- And the **recency effect**: the tendency for ppl to remember the last 5 or so words from the end of the list (LTM)
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