PSYA1 Cognitive Psychology - Memory
The Nature of Memory: STM and LTM
* Baddeley, encoding in short term memory – whether it’s acoustic or semantic in the STM. Acoustically similar words recalled the least suggests that the STM is encoded on an acoustic basis.
* Jacobs, capacity of the STM – he found that people remember nine numbers and seven letters. He did this with the series span technique.
* Miller, capacity of the STM – reviewed all the research available and found that the capacity of the STM was between 5 or 9 items. Chunking or grouping information into meaningful bits allows for more information to be held in the STM.
* Peterson and Peterson, duration of the STM – nonsense trigrams (the Brown-Peterson technique). Recalled without rehearsal. 90% of trigrams recalled after 3 seconds but only 5% after 18 seconds. Thus, STM duration is about 20 to 30 seconds.
* Baddeley, encoding in the LTM - Recall for semantically similar items after 20 minutes was less efficient than for the other lists. Semantic confusion in the LTM, suggests that the LTM is coded semantically.
* Bahrick, duration of the LTM – photo and name recognition task for age group 17 to 74 from highs school, even after 48 years recall was very high for names and faces. This suggests that the duration of the LTM is very long.
The multi-store model of memory
* Glanzer and Kunitz, evidence supporting the MSM – primacy and recency effects. People remember words from the beginning of the list and at the end of the list, but not in the middle. Why? Beginning of the list has been rehearsed and is in the LTM. Most recent words are in the STM.
* Brain scan to support the MSM – take images of active brain and show which region is active when doing a task. The pre-frontal cortex for short- term memories, but the hippocampus active for long term memory.
* HM, support for the MSM – he had his hippocampus removed. No new long term memory possible but short term memory intact.
The working memory model
* Baddeley, support for the WMM and criticism of the MSM – two tasks done at the same time. One acoustic and one visual. Do them both at the same time or separately very well. However, if the same type of task is conducted at the same time, there is conflict, performance is poor in this case.
* Baddeley, evidence for the visuo-spatial sketchpad – given a visual tracking task plus two other tasks. One verbal and another visual. Difficult to carry out two visual tasks but no problem with the verbal and visual. This is evidence of two different slave systems.
* KF, support for the WMM – brain damage meant that short-term memory for sound (auditory information) was much worse than visual. Seems like brain damage was restricted to the phonological loop.
* Bunge, evidence for the central executive – brain scans show that more activation when in dual task condition than in the single task condition, suggesting increased attention demands.
* Loftus and Palmer, leading questions – seven films of traffic accidents. Questions asked, one critical question; how fast were the cars going when they hit/smashed/collided/bumped/contacted each other? The verb smashed produced the highest estimate of speed. Contacted produced the lowest estimate of speed. Leading questions can distort accuracy of recall.
* Loftus and Palmer, post event information – three groups shown a film of a car accident. They are asked question about the speed with the verbs smashed and hit. There was a control group which did not get a question about speed asked at all. They return a week later and they were asked whether they saw any broken glass. There was no broken glass in the film. The participants gave higher speed estimates in the smashed group and they were also more likely to say that they had seen broken glass.
Factors that influence the accuracy of EWT – anxiety and age...
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