Memory

Memory

Coding capacity and Duration
1. Coding: the format in which the information is stored in the memory stores
  1. Research: Alan Baddeley gave different lists of words to four groups of ppts. Semantically similar,semantically dissimilar,acoustically similar and acoustically dissimilar. They were asked to recall the words in the correct order. When carrying out the task immediately (STM) ppts did worse with the acoustically similar words whereas with LTM ppts did worse with semantically similar words. This suggests info is coded semantically in LTM
2. Capacity: the amount of information that can be held in the memory store
  1. Research: Joseph Jacobs, Digit span. Ppts given 4 digits and asked to recall them in correct order aloud. If correct they are asked to recall 5 digits and so on until they can no longer recall correctly. The mean span was 9.3 items and 7.3 letters.
  2. Research: George Miller made observations of everyday practice and found things come in 7. This suggests span is about 7 items +-2. But also people can recall 5 words as well as letters by chunking.
3. Duration: the length of time information can be held in the memory
  1. STM Research: Peterson and Peterson tested 24 undergraduate students. 8 trials, each trial given a trigram to learn and a 3 digit number. Had to count back from the 3 digit number and then told to recall the trigram at different points. Each trial was a different stop time. Found duration in STM is very small unless rehearsed.
  2. LTM research: Bahrick studied 392 ppts from Ohio. Age range was 17-74. High school yearbooks used to measure recall. 1)photo recognition task, 2)free recall task. Ppts tested within 15 yrs of graduation did well on photo recognition whereas at 48 years recall declined 20%. The free recall was worse. However, both showed duration can last a very long time.
Multi-store model
1. Definition: A model to show how memory works in terms of three stores.
  1. Sensory register
    1. Stimulus from environment enters the sensory register. Inside are many stores, the two main ones include the iconic(visually coded) and the echoic(acoustically coded). The duration is less than a second but it has high capacity.
  2. STM
    1. Limited capacity store, on average between 5-9 items but closer to 5 than 9. Info is coded acoustically and lasts about 30 seconds unless rehearsed.
  3. LTM
    1. Potentially permanent store for info that has been rehearsed for prolonged period. Capacity is unlimited and lasts many years (as seen in Bahricks study) Tend to be coded semantically.
Types of LTM
1. Episodic
  1. Similar to a diary it is a memory store for personal events. It includes memories of when events occurred any many of the things involved within it. eg. when first pet died
2. Semantic
  1. Memory store for knowledge of the world. Facts and what words and concepts mean. Usually need to be recalled with effort and consciously. eg. Paris is capital city of France
3. Procedural
  1. Memory for actions, or skills. Can be recalled without conscious effort. eg. riding a bike
The working memory model
1. Definition: A representation of STM. Suggests that STM is a dynamic processor of different types of info using sub-units coordinated by central decision making system.
  1. Central executive
    1. Makes decisions and allocates slave systems tasks. Has very limited capacity.
  2. Phonological loop
    1. Deals with auditory info(coded acoustically). Divided into two: Phonological store-stores the words you hear, and the articulatory process-allows maintenance rehearsal
  3. Visio-spatial sketchpad
    1. Stores visual and spatial information with a limited capacity. Divided into two areas: visual cache-stores visual data and inner scribe-records arrangement of objects in visual field.
  4. Episodic Buffer
    1. Added to the model. Temporary store for information, storage component of central executive and has limited capacity of four chunks.
Explanations for forgetting
1. Interference
  1. Two pieces of information conflict with each other. Two types: Proactive interference- where an older memory interferes with a newer one, or retroactive interference- where a newer memory interferes with an older one.
    1. Research: Effects of similarity. Mcgeoch and Mcdonald studied retroactive interference by changing extent of similarity between materials. Ppts learned a list of words until they could 100% recall them. They then learned a new list. 6 groups learned different types of lists. when ppts recalled original list of words their performance depended on second list. Most similar material produced worst recall. Interference is therefore strongest when material is similar.
2. Retrieval failure
  1. Occurs when we don't have the necessary cues to access the memory. Encoding specificity principle (ESP)- states that the cue has to be present at encoding and retrieval in order to help recall. If cues available at encoding and retrieval are different forgetting will take place.
    1. Context dependent forgetting- Godden and Baddely research into sea divers. Ppts learned a list of words either underwater or on land. Then asked to recall them either underwater or on land. Creating four conditions learn on land recall on land, learn on land recall in water,learn in water recall on land,learn in water recall in water. Accurate recall was 40% lower in non-matching conditions.
    2. State-dependent forgetting- Carter and Cassaday gave anti-histamine drugs which contained a mild sedative to ppts, making them drowsy. Creates an internal physiological state. Given list of words which they had to recall. Creating four conditions: learn on drug-recall on drug, learn on drug-recall not on drug, learn not on drug-recall not on drug, learn not on drug-recall on drug. More forgetting when physiological state was different.
Eye witness testimony
1. Misleading information
  1. Leading questions: Loftus and Palmer got ppts to watch film clips of car accidents and then gave them questions about the accident. The critical question ppts asked how fast the cars were travelling when they 'hit' 'smashed' 'collided' 'bumped' 'contacted' eachother. Mean speed calculated for each group. Verb contacted 31.8mph whereas smashed 40.5mph.
  2. Post-event discussion- when witnesses to a crime discuss it with each other their testimonies may become contaminated. Research: Gabbert studied ppts in pairs. Each watched a video of the same crime but from different angles, some could see things that others could not. Both then discussed what they had seen before completing test of recall. 71% of ppts mistakenly recalled aspects of the event they did not see in the video but had picked up in discussion. Control group had 0%.
2. Anxiety
  1. Has a negative effect on recall. Research: Johnson and Scott led ppts to believe they were taking part in a lab study. Whilst seated in waiting room ppts heard loud argument next door, in low-anxiety condition a man walked through waiting area with a pen and grease on his hands. In the high anxiety condition a man walked through carrying a paper knife covered in blood. Ppts later picked out the man from a set of 50 photos. 49% of ppts in the low anxiety condition able to identify, ONLY 33% in other condition.
    1. Tunnel theory- weapon focus effect
  2. Has a positive effect on recall. Fight or flight response increases our awareness. Research: Yuille and Cutshall conducted study of real life shooting in Vancouver gun shop. 13/21 witnesses agreed to take part in the study. Interviews held 4-5 months after compared to original interviews. Also asked to rate level of stress and if they have had any emotional problems since the event. Those who reported higher levels of stress were the most accurate.
    1. Inverted U theory. Yerkes Dodson law
3. Cognitive interview
  1. Four main techniques uses: report everything,reinstate the context(return to original scene in their mind) reverse order(prevent people recalling their expectations) change perspective(from another persons perspective to prevent schema).
    1. Enhanced cognitive interview-focusing on social dynamics of the interaction

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	Creado por Elizabeth Hallam hace alrededor de 7 años