Memory

Memory

1. Coding Capacity and Duration of Memory

   • Research on coding: Baddeley- Acoustic in STM, semantic in LTM.
     • Evaluation: Artificial stimuli- Word lists had no personal significance.
   • Research on Capacity: Digit span- Jacobs (Digit Span) 9.3 digits 7.3 letters. Span of memory and chunking- Miller 7+/-2 span, putting items together extends STM capacity.
     • Evaluation: Lacking Validity- Could be extraneous variables such as distractions. Not so many chunks- Cowan estimated STM as about four chunks.
   • Research on Duration: STM- Peterson and Peterson up to 18 seconds without rehearsal. LTM- Bahrick et al (yearbooks) recognition of faces 90% after 15 years, recall 60%. Recognition dropped to 70% after 48 years.
     • Evaluation: Meaningless stimuli- Used consonant syllables. Higher external validity- Meaningful real-life memories, showed greater recall than LTM studies with meaningless material (Shephard). Evaluation Extra- Peterson and Peterson may be displacement not decay.

2. The Multi-store model of memory

   • Sensory register: Iconic and echoic stores with very brief duration, high capacity. Transfer by attention.
   • STM: Limited capacity and duration store. Mainly acoustic coding. Transfer to LTM by rehearsal.
   • LTM: Unlimited capacity and duration, permanent store. Mainly semantic. Created through maintenance rehearsal.
   • Evaluation
     • Supporting research evidence: Studies in coding, capacity and duration demonstrate differences between STM and LTM.
     • There is more than one type of STM: Studies of amnesia (e.g. K.F) show different STM for visual and auditory material.
     • There is more than one type of rehearsal: Elaborative rehearsal necessary for transfer to LTM, not maintenance rehearsal.
     • Evaluation Extra: Artificial materials. There is more than one type of LTM.

3. Types of Long-Term Memory

   • Episodic memory: Memory for events in our life (similar to a diary)
   • Semantic memory: Memory for knowledge of the world, like an encyclopaedia and dictionary. Includes language.
   • Procedural memory: Memory for automatic and often skilled behaviours.
   • Evaluation
     • Clinical evidence: Clive Wearing and HM had damaged episodic memories but semantic and procedural memories were fine.
     • Neuroimaging evidence: Episodic and procedural memories recalled from different parts of the prefrontal cortex.
     • Real-life applications: Training programme for adults with mild cognitive impairments.
     • Evaluation Extra: Problems with clinical evidence. Three types of LTM or two?

4. The Working Memory model

   • Central executive (CE): Co-ordinated slave systems and allocates resources, very limited storage.
   • Phonological loop (PL): Auditory information- phonological store and articulatory process (maintenance rehearsal)
   • Visuo-spatial sketchpad (VSS): Visual information- visual cache (store) and inner scribe (spatial arrangement)
   • Episodic Buffer: Integrates processing of slave systems and records the order of events. Linked to LTM.
   • Evaluation
     • Clinical evidence: KF had very poor auditory memory but good visual memory. Damaged PL but fine VSS.
     • Dual-task performance: Difficult to do two tasks at the same time, but one visual and one verbal is ok (Baddeley et al)
     • Lack of clarity over the CE: Not yet fully explained, probably has different components.
     • Evaluation Extra: Studies of the word length effect support the PL. Brain scanning studies support the WMM.

5. Explanations for forgetting: Interference

   • Types of interference: Proactive- old memories disrupt new ones. Retroactive- new memories disrupt old ones.
   • Effects of similarity: McGeoch and McDonald- similar words created more interference.
   • Evaluation
     • Evidence from lab studies: Well-controlled studies show interference effects.
     • Artificial materials: Lists of words are not like everyday memory, may overemphasise interference as an explanation.
     • Real-life studies: Baddeley and Hitch (rugby players) supported interference.
     • Evaluation Extra: Time between learning. Interference effects may be overcome by using cues.

6. Explanations for forgetting: Retrieval failure.

   • Encoding specificity principle: Tulving- cues most effective if present at coding and at retrieval. May be a meaningful link.
   • Context-dependent forgetting: Godden and Baddeley (deep sea divers): recall better when external contexts matched.
   • State-dependent forgetting: Carter and Cassaday (anti-histamine)- recall better when internal states matched.
   • Evaluation
     • Supporting evidence: Wide range of support. Eysenck claims retrieval failure is most important reason for LTM forgetting.
     • Questioning context effects: No forgetting unless contexts are very different, e.g. on land versus underwater (Baddeley)
     • Recall versus recognition: Absence of cues affects recall but not recognition.
     • Evaluation Extra: Problems with encoding specificity principle. Real-life applications.

7. Factors affecting eyewitness testimony: Misleading information.

   • Leading questions: Loftus and Palmer (Car speed) estimates affected by leading questions (Smashed versus contracted)
   • Why do leading questions affect EWT?: Response bias-no change to memory. Substitution explanation supported by Loftus and Palmer and report of presence of glass.
   • Post-event discussion (PED): Discussions with others contaminates eyewitnesses' memories. Gabbert et al demonstrated effect, calling it memory conformity- ISI and NSI involved.
   • Evaluation
     • Useful real-life applications: Could help prevent miscarriages of justice and change police interviewing.
     • Tasks are artificial: Watching film clips ignores the stress and anxiety associated with a real accident or crime.
     • Individual differences: Older people may be less accurate because of own-age bias.
     • Evaluation extra: Demand characteristics. Consequences of EWT.

8. Factors effecting EWT: Anxiety

   • Anxiety has a negative effect on recall: Johnson and Scott (Weapon focus) high-anxiety knife condition led to less good recall. Tunnel theory of memory.
   • Anxiety has a positive effect on recall: Yuille and Cutshall (shooting) high anxiety associated with better recall when witnessing a real crime.
   • Explaining the contradictory findings: Yerkes-Dodson law suggests both low and high anxiety lead to poor recall (Deffenbacher)
   • Evaluation
     • Weapon focus effect may not be relevant: Pickel (raw chicken) showed that it may be surprise and therefore tells us nothing about effects of anxiety.
     • Field studies sometimes lack control: Researchers cannot control what the witnesses do between the crime and the interview.
     • There are ethical issues: Creating anxiety in lab studies may cause psychological harm
     • Evaluation Extra: The inverted-U explanation is too simplistic. Demand characteristics operate in lab studies of anxiety.

9. Improving the accuracy of eye witness testimony: Cognitive interview.

   • Report everything: Include even unimportant details.
   • Reinstate the context: Picture the scene and recall how you felt. Context-dependent forgetting.
   • Reverse the order: Recall from the end and work backwards. Disrupts expectations.
   • Change perspective: Put yourself in the shoes of someone else present. Disrupts schema.
   • The enhanced cognitive interview (ECI): Adds social dynamics, e.g. establishing eye contact.
   • Evaluation
     • CI is time-consuming: Takes longer and needs special training.
     • Some elements may be more valuable than others: Report everything and reinstate the context used together produced best recall.
     • Support for the effectiveness of the ECI: ECI consistently produces more accurate recall than standard interviews.
     • Evaluation Extra: Variations of the CI are used. CI creates an increase in inaccurate information.