Milner et al (1957) - Case study of HMSevere & frequent epilepsy. Seizures based in a brain structure called the hippocampus. Doctors surgically removed the part of the brain.
Operation reduced his epilepsy, but led him to suffer memory loss. He couldnt recall events that had already happened.
HM's episodic memory (for past events) and semantic memory (for knowledge) was affected more than procedural memoty.
Gardener & Gardner (1969) - teaching ASL to a chimp.
Washoe was raised like a human being and taught american sign language.
Washoe had learnt 34 signs by the end of the 22nd months.
Washoe learnt language at similar rates to children of the same age. Additionally, language ecquisition seemed to require interaction with caregivers and communication in everyday situations. Washoe did not learn grammar.
Ethical considerations, in that Washoe ws taken from the wild. Diprived of other chimps. External validity as well, is not possible to accureately generalise results from a chimp to human children.
Peterson & Peterson (1959) investigated the duration of STM.
Participants were shown nonsense trigrams, and asked to recall them after either 3,6,9,12,15 or 18 seconds. During the pause they were asked to count backwards in threes from a given number. This was an 'interference task' - it prevented them from repeating the letters to themselves.
After 3 seconds participants could recall abotu 80% of trigrams correctly. After 18 seconds, only about 10% were recalled correctly
When rehearsal is prevented, very little can stay in the STM. for longer than about 18 seconds.
The results are likely to be reliable - it's a laboratory experiment where the variables can be tightly controlled. The nonsence trigrams are artifical so the study lacks ecological validity. Meaningful or real life memories may last longer in STM.
Atkinson & Shiffrin (1968) created the multistore model, demonstrates how memory works, where you store and keep something - different compartments/stores.
- memory consists of 3 different stores.
- sensory store
- short term store
- long term store
Sensory memory.- information from our environment (e.g. visual/auditory) intially goes into sensory memory. But we dont really take much notice of this stuff. However, if we pay attention to it, or think about it, the information will be encoded.
Short term memory - STM has a finite capacity and duration. but if information is processed further (rehursed) then it can be transferred to long-term memory.
Long term memory - The information can remain there forever, unless you really really need to remember it, in which case it'll probably stay there untill something more inteeresting comes along.
Several studies have been carried out that show memory is made up of Seperate stores.
- The primacy effect - e.g/ recal first tiem off a list
- The regency effect - remember the last few items on the list
- People with Korsakoffs syndrome - nothing wrong with their STM but their LTM doesnt work, which measn that different memories are in seperate stores.
Working memory model.
Baddeley & Hitch (1974) developed the working memeory model.
The central executive is the key component and can be described as attention. It has a limited capacity:
- The articulatory-phonological loop holds speech-based information. It contains a phonological loop (the inner ear) and an aticulatory process (the inner voice)
- The visuo-spatial sketchpad deals with the temporary storage of visual and spatial information.
Baddley & Hitch based their model on results from studies that used 'interferance tasks'
- If participants are asked to perfrom two taks simultaneously that use the same system, their performance will be affected -e.g saying "the the the" while silently reading something is very difficult.
- Accoring to the working memory model, both these tasks use the articualtory phonological loop. This has limited capacity so it can't cope with both tasks. Performance on one, or both tasks, will be affected.
However, if the two tasks involve different systems, performance isnt affected on either task (e.g. saying "the the the" whilst tracking a moving object).
Loftus & Palmer (1974) studied the eyewitness testimony.
Participants were shown a film of a miltiple car crash. They were then asked a series of questions including 'How fast do you think the cars were going when they hit?' In different conditions, the word 'hit' was replaced with 'smashed', 'colided', 'bumped' or 'contacted'.
It was seen that participants given the word 'smashed' estimated the highest speed (an average of 41mph), and those given the word 'contacted' gave the lowest estimate (an average of 32 mph).
The participants were split into three groups. One group was given the verb 'smashed', another 'hit' and the third, control group wasnt given any indication of the vehicles speed. A week later, the participants were asked 'Did you see any broken glass?'
Although there was no broken glass in the film , participants were more likely to say that they'd seen broken glass in the 'smashed' condition than any other.
Leading questions can affect the accuracy of people's memories of an event.
This has implications for questions in police interviews. However, this was an artificial experiment - watching a video is not as emotionally arousing as a real life event, which potentially affects recall.
Harlow (1959) showed the need for 'contact comfort'
He aimed to find out whether baby monkeys would prefer a source of food or a source of comfort and protection as an attachment figure. In lab experiments rhesus monkeys were raised in iscolation. They had two surrugate mothers. One was made of wire mesh and contained a feeding bottle, the other was made of cloth but didn't contain a feeding bottle.
The monkeys spent most of their time clinging on to the cloth surrogate and only used the wire surrogate to feed. The cloth surrogate seemed to give them comfort in new situations. When monkeys grew up they showed signs of social and emotionsal disturbance. The females were bad mothers who were often violent towards their offspring.
Infant monkeys made more of an attachement with a figure thatprovided comfort and protection. Growng up in iscolation affected their development.
Conformity & obedience
MILGRAM (1963) Findings were revolutionary
1)- Before the study Milgram asked different experts on human behaviour (e.g. psychiatrists) to predict the results. They thought the maxumum average shock that participants would go up to was 130V and that only someone with a psychopathic personality disorder would administer a 450V shock.
2)- He actually found that 65% of participants went up to 450V even when they clearly didnt want to.
Milgrams study completely changed what people thought about obedience and its had a huge impact ever since.
Zimbardo - Looked at the effect of Deindividuation.
Deindividuation is when people lose their personal identity (stop feeling like individuals), and identify with a group.
1)- Zimbardo replicated Milgrams experiment and examined the effect of different conditions.
2)- He compared participants who wore ther own clothes and were treated as individuals, to ones who wore hood covering their faces and were spoken to as a group.
3)- He found that an average level of electric shock doubles when the participants were wearing a hood.
When the participants were deindividuated they became more obedient and more antisocial. Zimbardo later demonstrated this in Stanord Prison Experiment (1973). This prison guards wore unifoms and sunglasses and they quickly became aggressive towards the prisoners. It seems that they stopped taking personal responsibilty for their actions, and changed their behaviour to fit into their social role.