Cognitive Psychology

thumb|300px|right Welcome to our cognitive psychology section, this section compliments Week 4, 5,6 and 7 of our AS Psychology Student Workbook (Redshaw & Redshaw, 2009). Cognitive psychology is a general approach to psychology that is interested in investigating internal mental processes such as how we store and recall information.

Learning Objectives
This section will cover the Multi-Store Model proposed by Atkinson & Shiffrin (1968) and the Working Memory Model proposed by Baddeley and Hitch (1974).

Therefore, on completion of this section you should be familiar with the following.
 * 1) The Multi-Store Model and its strengths and weaknesses.
 * 2) The Working Memory Model and its strengths and weaknesses
 * 3) Research into the differences between STM & LTM in relation to the concepts of encoding, duration and capacity.



The Multi-Store Model and its strengths and weaknesses.
In this model, memory is divided into three stores: sensory memory, the short-term memory and the long-term memory. Atkinson and Shiffrin (1968) claimed that information enters sensory memory and will only last for approximately 200-500 milliseconds before it fades away. However, if attention is paid to it, the information will be transferred into short-term memory (STM). STM has a limited capacity of 7 plus or minus 2 items. This is known as Millers magic number. It also has a short duration of about 18 - 30 seconds and is encoded acoustically. Information is then transferred to LTM through rehearsal and without rehearsal it is forgotten. The more something is rehearsed the stronger the memory trace. Long Term Memory (LTM) is said to have unlimited capacity. A duration of potentially forever and memory is stored by semantic encoding. The Multi Store Model emphasises the storage (the three stores) and process (attention and rehearsal) of memory.

Evaluation of the Multi-Store Model of Memory  

Strengths 
 * 1) As one of the first theories outlining the structure and processes of memory it has had a major influence on our understanding of information processing.
 * 2) Scientific laboratory based research into encoding, capacity, and duration of STM and LTM supports the model’s claim that they are separate stores.
 * 3) The concepts of attention and rehearsal make sense and therefore, have face validity.
 * 4) Case studies provide further support that STM and LTM are separate and distinct stores, as shown in Shallice & Warrington’s (1972) case studies of brain damaged patients. In one case a patient with damage to STM could still recall information from LTM. In another case findings showed that a patient with damage to LTM was able to form new short-term memories but was unable to transfer them to LTM.

Weaknesses 
 * 1) The MSM emphasises that rehearsal is the only way that information can be transferred to LTM. However, research has shown that information can be recalled with minimum or no rehearsal. For example, Hyde and Jenkins’ (1973) study aimed to see if there was a difference between intentional and incidental learning of word lists. Their findings showed that there was no difference in the number of words recalled.
 * 2) Further research has shown that STM is not a single store, but has visual memory as well as auditory memory. Similarly, different memory systems have been identified within LTM, such as declarative memory (facts) and procedural memory (skills). Therefore, the multi-store model is reductionist (oversimplified).
 * 3) The MSM claims that information transfers through STM to LTM in a one-way transfer of information. Further research that led to the development of the Working Memory Model shows memory as an active process, with information going forwards and backwards.

The Working Memory Model and its strengths and weaknesses
This model expands on the multi-store model’s over-simplistic representation of STM as a single passive store. In 1974 Baddeley & Hitch proposed that STM is an active store made up of various components and went on to produce the working memory model. The model consists of a central executive, which acts as a controlling component, supervising and switching attention between the two slave systems. The visuo-spatial sketchpad deals with visual and spatial information and the articulatory phonological loop that deals with auditory information. The articulatory phonological loop is subdivided into the phonological store, that is directly concerned with speech perception and acoustics and an articulatory process that acts as an 'inner voice' and silently repeats words (or other speech elements) on a loop to prevent them from decaying and is also linked to speech production. In 2000 Baddeley added another component to the model, called the 'episodic buffer'. This component has become known as a third slave system, dedicated to linking information across domains to form integrated units of visual, spatial, and verbal information and chronological ordering (e.g., the memory of a story or a movie scene). The episodic buffer is also assumed to have links to long-term memory and semantic meaning.

Strengths
 * 1) The concept of the working memory as an active processor is an advance over the multi-store’s representation of STM as a passive store, making it a less reductionist interpretation of STM than that proposed by the multi-store model.
 * 2) Scientific laboratory based research into dual task performance supports the working memory model’s representation of STM as a multiple system. In these experiments participants are asked to perform two tasks at the same time using the same system. Findings showed that performance on one or both tasks were affected, whereas when tasks involved different systems performance was not affected.
 * 3) Further lab based research by Baddeley and Lewis (1981) supports the role of the articulatory-phonological loop. They found that its main role is to silently repeat the words enabling the reader to remember the meaning and order of the words in a sentence.
 * 4) Shallice & Warrington’s case study in 1974 also provides support for the working memory model’s representation of STM as a multiple system. They found that the patient they had studied two years earlier who had damage to their STM only had problems with verbally presented information and not with visual information; this indicated that the articulatory loop was impaired.
 * 5) It has face validity because it makes sense that different types of information should be processed by different systems and can account for real life activities such as reading and maths.

Weaknesses
 * 1) Whilst the working memory model is a more sophisticated and realistic interpretation of STM it is still too simple and therefore, reductionist to believe that it is controlled by one system (the central executive).
 * 2) The WMM fails to explain how the components work. For example, the functioning of the central executive and the visuo-spatial sketch pad are not fully explained and lack research support. Therefore, the model is descriptive rather than explanatory.
 * 3) It does not explain LTM and therefore, in this respect it is not as good as the MSM.

Research into the differences between STM and LTM in relation to the concepts of encoding, capacity and duration.
DURATION

KEY STUDY: Duration of STM - Peterson & Peterson (1959) thumb|right|260px|Introduction to the differences STM - LTM'''Peterson & Peterson (1959) were interested in finding out the duration of short–term memory (STM). They believed that information is held in the STM for only around 20 seconds, after that it disappears if rehearsal is prevented. '''

Examiner Tip - from the first three weeks of research methods you should be able to write an appropriate aim for the above research, and formulate an experimental hypothesis and state whether your hypothesis is directional or not.

'''Peterson & Peterson carried out a laboratory experiment. Participants were presented with sets of trigrams (nonsense syllables in sets of three, e.g. BCM), which they were then asked to recall in order after a delay of 3, 6, 9, 12, 15 and 18 seconds. Participants were given an interference task of counting backwards in three’s from a random three digit number to prevent rehearsal (known as the Brown-Peterson technique). Recall had to be 100% accurate and in the correct order for it to count as correctly recalled. '''

Examiner Tip - from the procedures of any given senario you should be able to identify the independent variable (IV) and the dependent variable (DV), the experiemntal design used and be able to outline at least one advantage and one disadvantage.



Examiner Tip - From tables and charts you will need to be able to draw conclusions, a conclusion is more than just writing what is shown, you must attempt to contextualise the outcome with the original aim of the investigation.

In conclusion, Peterson & Peterson study clearly shows that the duration of STM is short. We now need to look at the duration of LTM.

KEY STUDY: Duration of LTM - Bahrick et al (1975) 'High School Year book Study

'''Bahrick and his colleagues where interested in investigating the duration of very-long-term memory (VLTM). They wanted to demonstrate that memories could endure in order to support the assumption that the duration of the LTM is infinite.'''

The procedures of the research involved a field experiment, in which 392 American ex-high school students where used as participants and asked to recall in one of two conditions:


 * 1) A photo recognition test where they were asked to identify former classmates in a set of 50 photos without being given a list of possible names (recall group).
 * 2) A name and photo matching test, where they were given a list of names and they were asked to match the names to the photos (recognition group).

T'''his was designed to test VLTM as time since departing high school varied, for some it was as long as 48 years. It was assessed by comparing their responses with high school year books, which contained all of the names and photos of the students in that year.'''

Findings:The percentage recall for the: 

Recall group  'Recognition group
 * 60% accuracy after 7 YEARS 
 * 20% accuracy after 47 YEARS 
 * 90% accuracy after 14 YEARS 
 * 80% accuracy after 25 YEARS
 * 75% accuracy after 34 YEARS
 * 60% accuracy after 47 YEARS

Examiner Tip - These two studies on the duration of memory can be used to support the difference between STM and LTM for example: '''There is a clear difference between STM and LTM in relation to duration. The duration of STM is short lasting about 20 seconds as shown by Peterson & Peterson research. Whereas the duration of LTM can last a lifetime as shown by the findings of the high school year book study.'''

Examiner Tip ''- Furthermore from Week 1-3 you should be able to evaluate the methodology of the above to pieces of research. One is a lab experiment the other a field experiment for the shorter questions you need to know at least one strength and weakness of these experimental methods. Its also good practice for evaluation in the longer 12 mark questions.''

CAPACITY

KEY STUDY: Capacity of STM - Miller (1956) thumb|300px|left|Millers Magic Number 7 +/- 9George Miller was interested in researching the capacity of STM. information which can be remembered in STM is between five and nine items.

In a laboratory experiment participants were presented with a string of letters or digits and were asked to repeat them back in the same order. Initially, there were 3 digits and the condition increased by 1 digit until the participants failed to recall the digits correctly.

Participants on average could only remember 5-9 items. But this number could vary due to individual differences, such as age. Miller also found that if participants combined individual letters or numbers into more meaningful units, for example 2, 0, 0, 7 would make one unit 2007; STM can hold much more information. This has become known as ‘chunking’. However, interestingly further research has found that STM can only hold 5 - 9 ‘chunked’ items of information.

Examiner Tip - ''You need to be able to recognise the experimental design of a study. Note a common mistake is to confuse this with the experimental method, students answer 'a lab experiment' which is wrong this leads to a double rammy because the next question is generally outline one strength (or weakness) of this design.''

The answer is its a repeated measure design, because participants have been asked to repeat the letters or digits which increased by one each time they took part.

The capacity of LTM is believed to be unlimited, this lack resarch evidence because to date no one has been able to design a study to test the capacity of LTM (as far as I am aware).

ENCODING

KEY STUDY: Encoding of both STM & LTM - Baddeley (1966)

Baddeley (1966) was interested in investigating the encoding of information in STM and LTM. Encoding is the way in which information is stored in memory. He predicted that because the preferred method of encoding in the STM is acoustic, people would make more mistakes when trying to recall words that sound alike. In addition because LTM’s preferred method of encoding information is semantic, they would make more mistakes when asked to recall words with a similar meaning.

In a laboratory experiment participants were presented with one of four word lists. Two of the lists were experimental ones; one was acoustically similar (meet/feet/sweet) and the other list was semantically similar (neat/tidy/clean). The other two lists acted as control lists and were acoustically and semantically dissimilar. One group was asked to recall the word list immediately (testing STM) and the other group was asked to recall the list after 20 minutes (testing LTM).

Overall, in the STM the words that sounded similar were remembered least well and in the LTM the words that were remembered least well were the ones with similar meanings.

Examiner Tip - On completion of this sections you should now be able to complete a 12 mark essay question on......Outline and Evaluate the research thats supports the Multi Store Model of Memory (12 marks)  A-Level Psychology Facebook - Discussion

Learning Objectives
This section will cover factors affecting the accuracy of eyewitness testimony (EWT).

Therefore, on completion of this section you should be familiar with the following.
 * 1) The affect of misleading information on the accuracy of eyewitness testimony.
 * 2) The affect of anxiety on the accuracy of eyewitness testimony.
 * 3) The affect of age of witness on the accuracy of eyewitness testimony.

Learning Objectives
This section will cover the cognitive interview as a way of improving the accuracy of eyewitness testimony (EWT) and ways of improving memory.

Therefore, on completion of this section you should be familiar with the following.
 * 1) The use of the cognitive interview
 * 2) Strategies for memory improvement