Memory

• Coding: The format in which information is stored in the various memory stores.

• Capacity: The amount of information that can be held in a memory store.

• Duration: The length of time that information can be held in memory.

• Short term memory: The short-term, limited capacity store of memories.
  • Coding is mainly acoustic, capacity is between 5-9 items on average and duration is about 15-30 seconds.

• Long term memory: Permanent memory store with unlimited capacity.
  • Coding is mainly semantic, unlimited capacity and can store memories for a lifetime.

Baddeley 1966

• STM recall was worse with acoustically similar words, suggesting that STM codes acoustically.
• LTM recall was worse with semantically similar words, suggesting that LTM codes semantically.
• Strengths: Representative (72 volunteers); reliable due to standardised procedure.
• Limitations: Low mundane realism due to artificial stimuli; low ecological validity; confounding variables ignored.

Jacobs 1887:

• The mean number of digits recalled was 9.3 and the mean number of letters was 7.3. This suggests that the STM holds around 8 items.
• Strengths: Research support (Miller 1956); useful for knowing cognitive limitations; reliable due to standardised procedure; representative (443 participants).
• Limitations: Gender bias; low ecological validity due to artificial stimuli; confounding variables ignored.

Miller 1956:

• The capacity of STM is 7+/- 2.
• Strengths: Research support (Jacobs 1887); reliable due to standardised procedure.
• Limitations: Research suggests overestimation (Cowan 2001- Capacity of STM is 4 chunks or 5 items); reductionist as memory improving with age isn't acounted for.

Peterson and Peterson 1959:

• Results suggest that STM has a short duration and LTM is only effective when repetition and rehearsal take place. This can only be done if there is more than one ongoing influence.
• Strengths: Reliable; easy to replicate; high internal validity.
• Limitations: Low external validity; low ecological validity; may be unrepresentative due to small sample.

Bahrick et al. 1975:

• Even after 48 years, recall was 70% with photos and 30% without, showing that LTM has a very long duration.
• Strengths: High ecological validity; high external validity; representative.
• Limitations: Limited explanation (deterioration due to age or duration?); confounding variable of people keeping in touch reduces validity.

• Atkinson and Shiffrin’s 1968 MSM consists of 3 stores.
• The sensory register takes in information from the environment through the five senses, (sight, hearing etc) and has very brief capacity and duration. A lot of decay occurs from this store.
• If attention is paid to information, it is passed to short-term memory store (STM). The STM has limited duration of approximately 30 seconds without maintenance rehearsal and limited capacity 7 items give or take 2. In STM information is encoded acoustically.
• Prolonged rehearsal leads to encoding information semantically (for meaning/understanding) which can be stored in Long-term memory (LTM). This store has unlimited capacity and duration (a lifetime). There is quite a lot of decay from STM but not from LTM. Information sometimes suffers from interference in the LTM rather than decay. 

Environmental stimuli → Sensory register → Short term memory store → prolonged rehearsal → Long term memory store

Retrieval from LTM → Short term memory → Recall 

https://www.simplypsychology.org/Multi-Store-Model%20.jpg

• Strengths: Research support (Baddeley 1966 suggests separate stores as LTM codes semantically and STM codes acoustically); useful; scientific; reliable to an extent as STM and LTM can be tested (Bahrick et al. 1975 and Baddeley 1966)

• Limitations: K.F case study suggests separate STM stores as his STM for verbal information and digits became poor, but his STM for visual information was still strong; incomprehensive as it only accounts for one type of rehearsal (Craik and Watkin's 1973 research pointed to the importance of elaborative rehearsal in memory); low ecological validity of supporting studies; reductionist due to unitary assumption (doubt cast by HM case study).

• Proposed by Baddley and Hitch in 1974.
• Explanation of how the STM is organised.
• Comprised of 4 components, responsible for storing short term memories and transferring them to the long term stores.
• Firstly, the central executive is responsible for allocating sensory information to the slave systems.
• One slave system is the phonological loop, which deals with auditory information. It stores things you have heard and repeats them back to you in the same order, and is made up of the phonological store and the articulatory process. Capacity is believed to be about 2 seconds.
• A second slave system is the visuo-spatial sketchpad, which stores visual and spatial information. It contains a visual cache which holds information and an inner scribe which records the arrangement and structure of visual information.
• The third slave system is the episodic buffer. This acts like a memory card and is responsible for time sequencing.

• Strengths: Research support (KF could remember letters and digits but not sound, pointing to different components in stores); dual task performance study support (Baddeley 1975 → easier to multi-task on a visual and verbal task because they are separate); studies of the word length effect support the phonological loop (Baddeley et al. 1975 → harder to remember long lists); research support (Braver et al. 1997 → Brain scan showed C.E worked harder which showed greater prefrontal cortex activity)

• Limitations: Case studies may not be reliable due to unique cases and trauma; lack of clarity regarding the central executive; not comprehensive as only the STM is covered; reductionist as memory improvement isn't accounted for; Lieberman (1980) argued that the VSS is separate as blind people have spatial awareness which limits the usefulness of the WMM.

Proposed by Tulving 1985

• Episodic memory: A long-term memory store for personal events. Here, memories are time-stamped and include people, places and behaviours. Memories from this store have to be retrieved consciously and with effort.

• Semantic memory: A long-term memory store for our knowledge of the world. This includes facts and our knowledge of what words and concepts mean. These memories are not time-stamped and usually have to be recalled deliberately.

• Procedural memory: A long-term memory store for our knowledge of how to do things. This includes our memories of learned skills. We usually recall these memories without making a conscious effort.

• Strengths: Clinical evidence in case studies (HM and Clive Wearing's semantic and procedural memories remained intact); neuroimaging evidence (Tulving et al. 1994 → PET scanner showed the left prefrontal cortex was involved in semantic memory, and the right is episodic); scientific credability; real life application (Belleville et al. 2006 → episodic memory can be improved); reliable due to testability of cognitive neuroscience.

• Limitations: Confounding variables in clinical studies due to subjective nature; Cohen and Squire (1980) proposed that semantic and episodic memories were stored together in the declarative store due to conscious recall; deterministic as this implies that we don't have the free will to decide how we remember things.

• Interference: Forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten.

• Proactive interference: Forgetting occurs when older memories, already stored, disrupt the recall of newer memories. The degree of forgetting is greater when memories are similar.

• Retroactive interference: Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is greater when memories are similar.

The effects of similarity on interference: 

• McGeoch and McDonald 1931: Synonyms produced worse recall, showing that interference is stronger when memories are similar.

• Strengths: Supporting evidence (McGeoch and McDonald 1931, Burke and Skrull 1981-advert recall harder when similar-, Baddeley and Hitch 1977); real life studies show mundane realism (Baddeley and Hitch 1977 → rugby recall depended on the number of games played instead of time).

• Limitations: Artificial stimuli in lab studies create low ecological validity as they make interference more likely in the lab; low ecological validity due to time between learning in lab studies; interference may be overcome with cues (Tulving and Psotka 1971).

• Retrieval failure: Occurs when we don't have the necessary cues to access a memory. The memory is available but not accessible unless a certain cue is provided.
• Encoding Specificity Principle (ESP → Tulving 1983): Cues must be present at encoding and at retrieval in order to help recall. If cues differ or are absent, there will be some forgetting. 
• Context dependent forgetting: External cues (e.g. environment)
• State dependent forgetting: Internal cues (e.g. level of drunkeness)

Context dependent forgetting: 

• Godden and Baddeley 1975 → Recall was 40% lower in non-matching conditions because external cues were different at recall, leading to retrieval failure.

State dependent forgetting:

• Carter and Cassaday 1998 → Mismatching conditions produced worse recall, showing that absent or different cues create forgetting.

• Strengths: Useful in clinical psychology and social care (dementia patients often function better at home); research support (Godden and Baddeley 1975, Carter and Cassaday 1998); real-life application in cognitive interviews (revisiting crime scene).

• Limitation: Research support has low mundane realism; questioning contextual effects (Baddeley 1997 said that much disparity between settings needed, showing that setting has little impact on everyday forgetting); only really works for recall (Godden and Baddeley repeated their diver experiment and saw no contextual effect with recognition); ESP cant be tested as there is no way of knowing whether a cue has been encoded.

• Misleading information: Incorrect information given to the eyewitness usually after the event (hence often called post-event information). It can take many forms, such as post-event discussion and leading questions between co-witnesses and/or other people.

Why do leading questions affect EWT?

• Response bias explanation: Wording influences how you decide to answer.
• Substitution information: Wording changes memory (Loftus and Palmer 2nd experiment)

Research into leading questions:

• Loftus and Palmer 1974 → Speeds varied according to the verb used in the critical question, increasing with more violent verbs.

Research into post-event discussion:

• Gabbert et al. 2003 → 71% recalled aspects they didn't see after the discussion, while 0% of the control group (which had no discussion) did.
• Post-event discussion: Witnesses discuss what they have seen with others, which may influence the accuracy of recall.

• Strengths: Useful real-life application to make the police and justice system more careful.

• Limitations: Artificial research lacks mundane realism; reductionist due to age differences not accounted for (Anastasi and Rhodes 2006 → People better at recognising their own age group); demand characteristics reduce usefulness as participants try to be helpful (Zaragosa and McCloskey 1989); EWT only has consequences in the real world so emotion isn't accounted for in research (Foster et al. 1994).

• Anxiety has a negative effect on recall: Anxiety creates physiological arousal in the body which prevents us from paying attention to important cues, so recall is worse.
  • Johnson and Scott (1976) → All participants in the low anxiety condition were able to identify the man, but only 33% of the high anxiety condition were able to do so. The Tunnel Theory argues that narrowed focus to the weapon because it is a source of anxiety.

• Anxiety has a positive effect on recall: The fight-or-flight response is triggered from physiological arousal, which increases our alertness and improves our memory for the event because we become more aware of cues.
  • Yuille and Cutshall (1986) → Participants who reported the highest stress levels were the most accurate, with 88% compared to 75% of the less stressed group.

• The Yerkes-Dodson law explains contradictory findings, with a U-curve diagram to demonstrate this. Optimum recall is achieved with medium anxiety, with high and low levels showing a decrease in performance.

• Strengths: Real-life research is ethical because you aren't inducing anxiety; useful for police and justice system as the Yerkes-Dodson law shows the accuracy of EWT.

• Limitations: Weapon focus may test surprise rather than anxiety (Pichel 1988 showed low EWT accuracy in high unusualness conditions); field studies lack control and have extraneous variables, e.g. post-event discussion masking effects of anxiety; ethical issues through inducing anxiety; inverted-U explanation is reductionist as it only focuses on physiological arousal and ignores other elements of anxiety; demand characteristics in lab studies may invalidate findings.

Proposed by Fisher and Gieselman in 1992

1) Report everything → Trivial info could trigger important memories.

2) Reinstate the context → Relates to context-dependent forgetting.

3) Reverse order → To prevent dishonesty and the reporting of expectations.

4) Change perspective → To disrupt schema and expectations.

The enhanced cognitive interview (ECI): Fisher et al. 1997 created more focus on social dynamics, such as eye contact, reducing eyewitness anxiety, minimising distractions, slow speech and asking open-ended questions to improve the accuracy of cognitive interviews.

• Strengths: Each technique singularly produced more info than a police interview (Milne and Bull 2002); using a combination of report everything and reinstate the context produced the best recall which makes the process easier (Milne and Bull 2002); support for the effectiveness of ECI (Köhnken et al. 1999) in meta-analysis compared with police interviews.

• Limitations: C.I's are time consuming and the police may lack the resources and training for this; can increase the recall of incorrect information (Köhnken et al. 1999 → 81% correct, 61% incorrect).