Memory Studies Flashcards
Capacity
Short term memory can be assessed using digit span in one of the earlier studies in psychology Jacobs assessed short-term memory and found average span for digits was 9.3 items and 7.3 for letters. Jacob suggested that it was easier to remember digits over letters because there are only nine digits where is there are 26 letters.
Miller believe that the capacity for short-term memory was 7+/-2.
The capacity for long-term memory is potentially infinite.
Duration
The duration for long-term memory is potentially infinite again.
Bahrick et al tested this using yearbook photos.
This short term memory Peterson and Peterson studied this using 24 students each participant was tested over eight trials. On each trial a participant was given a consonant syllable and a three digit number they were asked to recall this after a retention interval of 3 to 18 seconds. During the retention interval they had to count backwards from there three digit number. Ppts on average were 90% correct for three seconds however after 18 seconds were only 2% correct.
Coding
Long-term memory is encoded semantically. Short-term memory is encoded acoustically. Baddeley tested this.
The multi store model
Designed by Atkinson and Shiffrin in 1968.
It is called multi store because it consists of three memory stores linked to each other by the processes that enable transfer of information from one store to the next.
1) The sensory register. This is where information is held at each of the senses.
2) Attention. If a person’s attention is focused on one of the sensory stores then the data is transferred to STM.
3) STM. Information is held in STM so it can be used for immediate tasks. STM has a limited duration so it needs to be rehearsed.
4) maintenance rehearsal. Repetition keep information in STM but eventually such repetition will create a LTM. A and S proposed a direct relationship between rehearsal in STM and the strength of the LTM.
5) LTM. Potentially unlimited duration + capacity.
6) Retrieval. The process of getting information from LTM involves the information passing back through STM.
The working memory model
Baddeley and Hitch 1974.
1) Central executive. The function of the CE is to direct attention to particular task determining any time how the brains resources are allocated to tasks. The brains resources are the slave systems below.
2) Phonological loop. Deals with auditory information. Subdivides into:
- Phonological store. Which holds the words you hear.
- Articulatory process. Used for words you see and hear and are silently repeated as a form of maintenance rehearsal.
3) Visuo-spatial sketchpad. Used for spatial tasks. Subdivides into:
- Visual cache. Stores information about visual items.
- Inner scribe. Stores the arrangement of objects in the visual field.
4) Episodic buffer. Added in 2000 because he realised the model needed a general store. The episodic buffer is an extra storage system but has limited capacity. It integrates information from the CE, PL and VSS. It also maintains a sense of time sequencing.
Types of long term memory.
Episodic.
Personal memories of events such as what you did yesterday. This kind of memory includes contextual details plus emotional tone and specific details.
Semantic.
Shared memories for facts and knowledge. These memories may be concrete, such as knowing that ice is made of water, or abstract, such as mathematical knowledge.
Procedural
This is memory for how to do things, for example riding a bicycle or learning how to read. Such memories are automatic as the result of repeated practice.
Explanations for forgetting: interference.
Retroactive interference.
Current attempts to learn something interfering with past learning.
Muller et al were the 1st to identify retroactive interference affects. They gave participants nonsense syllables to learn for six minutes and then after a retention interval they asked the ppts to recall the list. Performance was worse if the ppts had been given an intervening task. This is because it interfered with what had previously been learnt.
Proactive learning.
Underwood showed proactive interference could be equally significant. Underwood found that if ppts memorised 10 or more less then after 24 hours they remembered about 20% of what they learnt. If they only learnt one list recall was over 70%.
Real world study: Baddeley rugby.
Explanations for forgetting: retrieval failure
The encoding specificity principle: Tulving and Thomson propose that memory is most effective if information that was present at encoding is also available at the time of retrieval. It further states that cues don’t have to be exactly right but the closer the cue is to the original item, the more useful it will be.
Context dependant forgetting.
Godden and Baddeley - scuba diving.
State dependant forgetting.
Goodwin et al. Word lists drunk or sober.
Misleading info. EWT.
Leading questions. Loftus and palmer. 1974. 45 students. Smashed, collided, bumped, hit, contacted. Experiment 2: smashed glass.
Post event discussion.
Gabbert et al.
71% reported seeing something they hadn’t seen.
Conformity effect
Also possible through repeat interviewing - especially for children.
Anxiety. EWT.
Negative effect.
Johnson and Scott.
1976.
Greasy pen or bloody knife. Asked to identify man from a set of photographs.
Findings: supported idea of weapon focus effect.
49% in greasy pen
33% in knife condition.
Loftus et al showed anxiety does focus attention of central features of crime e.g. the weapon. They tracked eyewitnesses eye movements and found they were drawn towards the weapon and away from the persons face.
Positive effect
Evolutionary advantage?
Christianson + Hubinette found evidence of enhanced recall when they interviewed 58 real witnesses to bank robberies in Sweden. They were either victims (high anxiety) or bystanders (low anxiety). Found that those that had been the most anxious had the best recall.
Christianson in a review of research concluded that memory for negative emotional events is better than neutral events.
Resolving the conflict.
Yerkes-Dodson effect. The observation that arousal has a negative effect on performance when it is very low or very high, but moderate levels are actually beneficial.
Cognitive interview. EWT.
The cognitive interview is a police technique for interviewing witnesses to a crime, which encourages them to recreate the original context of the crime.
1) Mental reinstatement of original context.
Encourages the interviewee to mentally recreate both the physical and psychological environment of the original incident. The aim is to make memories more accessible.
2) Report everything.
Encourages reporting every single detail of the event without editing anything out, even if it seems irrelevant. This may lead to one memory being a cue for another memory.
3) Change order.
The interviewer may try alternate ways through the timeline of an event. This prevents schema influencing memory of events.
4) Change perspective.
The interviewee is asked to recall the incident from multiple perspectives. This is again to disrupt the effect that schema have on recall.
