Memory

Outline research on coding of memory

Outline research on coding of memory

Baddely (1966) found participants who recalled immediately struggled the most with an acoustically similar word list while the group that recalled later on struggled with semantically similar words.

Suggests STM is encoded acoustically and LTM is encoded semantically, hence the struggle to differentiate the similarly encoded words during recall.

Outline research into the capacity of memory

Jacobs (1887) measured digit span; asked ppts repeat back a series of numbers or letters of increasing length. He found the mean span for numbers was 9.3 and for letters, it was 5.3.

Miller (1956) proposed the capacity to be 7+-2, and amount of information could be increased through chunking units together.

Outline research into the duration of memory

Peterson and Peterson (1959) tested STM through nonsense trigrams - three number/digit combinations that ppts had to recall after a varying length of time spent doing another unrelated task to prevent rehearsal. They found these trigrams could be recalled a maximum of 18-30 seconds after hearing them.

Bahrick (1975) yearbook study: Ohio graduates were asked to recall the names of fellow students based on photos, or simply from memory (free recall).
Those who graduated less than 15 years ago were 90% accurate in face recognition, those who graduated 48+ years ago were 70% accurate. Demonstrates potentially unlimited longevity of LTM.

Evaluate these studies of memory

• used artificial tasks, not reflective of everyday memory processes

• high control due to lab setting

Outline the MSM

Environmental stimuli reach the sensory register, information is transferred to the STM through attention. The STM encodes info acoustically, has a capacity of 5-9 items and has a duration of 18-30 seconds. Information will be lost from the STM due to the displacement of more info. Information can be kept in the STM through the maintenance rehearsal. Prolonged rehearsal transfers the information to the LTM, where it will stay indefinitely, some lost to decay. The LTM has an unlimited capacity and encodes its information semantically. Information can be brought back to the STM through retrieval.

Evaluate the MSM

• STM not unitary, KF (Shallice and Warrington), visual STM recall higher than auditory…

  • other models are more comprehensive, WMM shows STM to be a more active process

• research support for encoding, capacity, duration…

  • flawed studies, very artificial

• LTM may not be unitary, - Clive Wearing

• separate LTMs supported by Tulving’s PET scans

• there is more than one type of rehearsal, not just maintenance, elaborative needed to transfer to LTM

What are the three types of LTM?

Semantic - our knowledge of the world, non-declarative, conscious recall

Episodic - our memory of past events and experiences, declarative, conscious recall

Procedural - our memory for how to perform certain actions e.g. tying shoelaces, non-declarative, unconscious recall

Outline the working memory model.

A diagrammatic representation of the processes in STM.

Central executive assigns stimuli to be processed by the slave systems

Phonological loop - auditory information
Articulatory process (inner voice) and Phonological store (inner ear).

Visuospatial sketchpad - visual information
Inner scribe (records arrangement of objects in visual field) and visual cache (stores the info).

Episodic buffer - a temporary information store of info, capacity of 4 chunks, maintains a sense of time-sequencing.

Evaluate the WMM

• dual-task performance, can combine visual and auditory task but not two of the same, supports idea of separate slave systems for processing

• case study of KF, poor auditory STM, good verbal

  • not generalisable etc…

• vague concept of the central executive, cannot test location in brain as role is abstract, understanding of element is limited, WMM not fully explained model

• Baddely found remembering a list of long words is more difficult than remembering a list of short words, due to the limited space of the articulatory process

Explain interference as an explanation for forgetting

Interference occurs when two stimuli become mixed up during retrieval as their encoding is too similar.

Retroactive - new info interferes with the recall of old

Proactive - old info interferes with the recall of new

Outline McGeoch and McDonald’s research on the effects of similarity.

Ppts learnt a list of ten words. Ppts were then given a second list. The second list varied: synonyms for the previous words, antonyms, unrelated words, three-digit numbers or no list at all.

Recall of the original list was tested. Recall was most accurate in ppts who were given no second list, while those given synonyms had the worst.

The more similar the second list, the worse the recall. This supports the idea of interference.

Outline further research support for interference by Baddeley and Hitch (1977)

Studied memories of rugby players, asked them to recall the names of the teams they played last season, found that accurate recall was not dependent on time since the matches, but the number of matches played, supports idea of this similar team-name information interfering, means the explanation can be applied to everyday situations.

Outline retrieval failure as an explanation for forgetting.

The encoding specificity principle argues one must have the same cues present at recall as at learning in order to accurately retrieve info. These cues may be related to in internal or external environment…

Context-dependent forgetting - Godden and Baddeley, deep sea divers, recall of list was best when both learnt and recalled underwater or on land, not a mixture.

State-dependent forgetting - Carter and Cassady, gave ppts antihistamine drugs to make them drowsy, those who then recalled the list in the same drowsy state had better recall than those in a different state at retrieval

Evaluate retrieval failure as an explanation for forgetting

• good range of supporting evidence

• difference in context must be dramatic to yield effect

• Baddeley recreated the study but tested recognition, found no difference between conditions

How do leading questions affect eye witness testimony? Outline key research.

Loftus and Palmer (1974)

Ppts watched a clip of a car crash and were asked ‘how fast were the cars going when they [blank] into each other’. Each group were given a different verb to fill the space: hit, bumped, contacted, smashed, collided.

Those with the leading verb of ‘contacted’ reported an average speed of 31.8mph, while those who heard ‘smashed’ had a mean of 40.5mph.

This occurs due to response bias - the verb encourages them to give a certain answer.

Or the substitution explanation - the verb actually alters their memory. This is supported by the high impact verb groups reporting seeing smashed glass when there wasn’t any.

How does Post-event Discussion affect eye witness testimony? Outline key research.

Gabbert et al (2013)

A pair watched a clip of the same scenario, but watched from a different perspective. One could see elements of the situation that the other couldn’t e.g. the title of a book

They discussed what they had seen before filling in a recall test.

71% recalled an element of the clip that they had picked up from their pair, that they had not seen themselves.

This is due to a desire for social approval or because they believe they were wrong and the other participant was right i.e. memory conformity.

Evaluate leading questions/post-event discussions as factors affecting EWT

• based on artificial tasks, no repercussions for altering response, not reflective of deeper processing in EWT situations

• application to EWT, evidence of leading questions led to reform in police interviews, improved legal system

• demand characteristics of the participants

• other factors, such as age, explanations are not comprehensive

Anxiety: a positive effect on memory

Yuille and Cutshall (1986)

Studied a real-life shooting, 13 witnesses took part, recorded their level of anxiety at the time of the event, interviewed witnesses 4-5 months post-event, compared accuracy to their original interviews, found high anxiety to be correlated with more accurate recall

Anxiety: a negative effect on memory

Johnson and Scott (1976)

Deceived ppts into thinking it was a lab study. In the ‘waiting room’, they overhear an argument, then a man walks through either holding a greasy pen or a bloody knife. Memory is assessed through picking out the man from 50 pictures.

49% of the low-anxiety condition picked him out, only 33% of the high-anxiety condition did so.

This occurs due to tunnel vision.

How does the Yerkes-Dodson law explain these contradictory findings?

As anxiety increases, recall accuracy also increases. However, it reaches a threshold of optimum anxiety for aiding memory. Past the threshold, accuracy of recall decreases.

How does Pickel’s research contrast with Johnson and Scott?

Found that it was the unusualness of the object that causes poor recall, not the anxiety. Recall of a man walking through a hairdresser was just as poor when he was carrying a handgun (unusual, high anxiety) as when carrying a raw chicken (unusual, low anxiety). Weapon focus is not due to the anxiety, but the surprise at seeing it and therefore tells us little about the effects of anxiety.

Outline the Cognitive Interview

Recall everything - interviewee should include all the details of the science, regardless of their presumed relevance, they may trigger other memories

Reinstate the context - returning to the original scene in their mind, related to context-dependent forgetting

Reverse the order - recall events in non-chronological order, reduces dishonesty

Recall from a different perspective - reduces influence of schemas and expectations.

Enhanced includes:
Low anxiety, no leading questions, minimising distractions, effective eye-contact.

Evaluate the effectiveness of the Cognitive Interview of improving EWT

• Milne and Bull (2002) found some combinations of elements to be more effective than others

• Kohnken (1999) that volume of incorrect info increased as well as that of correct info, no net benefit?

• not appropriate for young people, unable to perform ‘alter the perspective’ due to egotistical nature

• time-consuming to train and conduct

  • reluctance to do it thoroughly may account for negative findings