Cognition and Memory

Atkinson and Shiffrin's (1968) Model of Memory

• Overview: This model, also known as the multi-store model (MSM), proposes that memory consists of three separate stores: sensory register, short-term memory (STM), and long-term memory (LTM).

• Information Flow: Information flows linearly through these stores. Sensory input is briefly stored in the sensory memory (iconic and echoic), then selected information enters STM through attention, and finally, through rehearsal, it can be encoded into LTM.

Structure, Including the Stores

• Sensory Register: Initial stage for incoming sensory information.

• Short-Term Memory (STM): A temporary store with limited capacity.

• Long-Term Memory (LTM): A more permanent store with potentially unlimited capacity.

Iconic and Echoic Memory

• Iconic Memory: Brief retention of visual information, lasting less than a second.

  • Sperling's (1960) experiments demonstrated iconic memory. Participants could recall letters from a briefly presented grid when cued shortly after stimulus offset.

• Echoic Memory: Brief retention of auditory information, lasting up to 2–4 seconds.

  • Darwin, Turvey, and Crowder’s (1972) study showed that auditory information persisted briefly, improving recall when spatial cues were used.

Short-Term Store (Miller, 1956)

• Limited Capacity: George Miller's (1956) research suggests that STM has a limited capacity of approximately 7 \pm 2 items.

• Research: used digital span tasks to show people can remember about 7 chunks of information at once

• Chunking: Strategy to enhance STM capacity by grouping individual elements into larger, meaningful units.

Strengths and Weaknesses of the Model

• Strengths:

  • Intuitive and systematic framework.

  • Supported by empirical evidence like the serial position effect, where items at the beginning (primacy) and end (recency) of a list are recalled more easily, attributed to LTM and STM, respectively.

• Weaknesses:

  • Oversimplification of memory processes.

  • Fails to explain depth of processing (Craik and Lockhart, 1972), where semantic processing leads to better memory than structural processing, regardless of rehearsal.

  • Case studies of brain-damaged patients like KF (impaired STM but intact LTM) challenge the model's strict linearity.

Working Memory Model of Baddeley & Hitch (1974)

Central Executive

• Function: Supervisory component that coordinates attention and integrates information from other components.

• Role: Task switching and cognitive control.

• Neural Basis: Linked to basal ganglia and prefrontal cortex activation (Dang et al., 2021).

Phonological Loop

• Function: Temporarily stores and manipulates verbal and auditory information.

• Components:

  • Phonological store (inner ear).

  • Articulatory rehearsal process (inner voice).

• Evidence:

  • Word length effect: Participants remember short words better than long ones (Baddeley, Thomson, and Buchanan, 1975).

  • Damage to Broca’s area is linked to phonological loop dysfunction.

Episodic Buffer

• Function: Integrates information across modalities and interfaces with LTM.

• Role: Temporary storage of integrated episodes.

• Neural Basis: Research into the frontal pole (Tsujimoto et al., 2021) suggests that regions like the left frontal pole support high-capacity integration.

Visuospatial Sketchpad

• Function: Processes visual and spatial data.

• Role: Mental rotation and navigation.

• Neural Basis: Activation in the parietal lobes, especially the right hemisphere.

• Impairments: Damage to these areas can result in impairments in spatial working memory.

Strengths and Weaknesses of the Model

• Strengths:

  • Flexibility and ability to account for dual-task performance.

  • Supported by neuropsychological studies involving patients with specific brain lesions.

• Weaknesses:

  • The central executive is ill-defined, often described as a homunculus.

  • Neuroscience suggests a more dynamic and distributed process than the model proposes (McNab & Klingberg, 2008).

Eyewitness Testimonies

What They Are & Are They Reliable?

• Definition: Individuals recounting what they witnessed during an event, often a crime.

• Reliability Issues: Research shows they are fallible due to factors like stress, memory decay, leading questions, and biases.

Confirmation Bias

• Definition: Eyewitnesses focus on information aligning with their expectations.

• Example: Misidentifying someone based on stereotypes.

• Study example: Swedish participants were more likely to misidentify immigrant suspects in a robbery video.

Misinformation Effect

• Definition: Misleading post-event information affects memory accuracy.

• Loftus and Palmer (1974): Participants estimated car speeds as higher when the word “smashed” was used instead of “hit,” and were more likely to report seeing broken glass.

Weapon Focus Effect

• Definition: Witnesses focus on a weapon, reducing their ability to recall other details.

• Impact: Compromises peripheral memory accuracy and contributes to unreliable identifications.

Own-Age Bias

• Definition: Witnesses are more accurate in identifying people of their own age group.

Unconscious Transference

• Definition: A person seen in one context is mistakenly identified as someone seen in another.

• Example: Confusing a bystander with the actual perpetrator.

Other-Race Effect

• Definition: Poorer memory for individuals of races different from the witness’s own.

New Experiment to Test Confirmation Bias in Eyewitness Testimony

• Title: The Influence of Suspect Expectations on Memory Recall: A Test of Confirmation Bias in Eyewitness Identification

• Objective: To explore how pre-existing beliefs or suggestions about a suspect’s guilt affect the accuracy and reliability of eyewitness memory.

• Participants: 100 adult participants aged 18–40.

• Conditions:

  • Neutral Expectation (control).

  • Biased Expectation (experimental).

• Procedure:

  1. Watch a 60-second video depicting a bookstore theft.

  2. Complete a free recall task.

  3. Answer leading and specific questions.

  4. Identify the suspect from a photo lineup.

  5. Rate confidence in their selection.

• Expected Results: Participants in the biased condition will falsely recall or inflate details about the man in the blue jacket and more frequently misidentify him as the thief.

• Reliability of Eyewitness Memory: Eyewitness memory is not consistently reliable, especially when influenced by suggestion or preconceptions.

New Experiment to Test the Misinformation Effect in Eyewitness Testimony

• Title: The Influence of Post-Event Information on Memory Accuracy: A Test of the Misinformation Effect

• Objective: To investigate how exposure to misleading information after witnessing an event can distort memory recall.

• Participants: 120 university students (aged 18–30).

• Conditions:

  • Control Group (no post-event narrative).

  • Neutral Information Group (accurate summary).

  • Misinformation Group (misleading narrative).

• Procedure:

  1. Watch a 90-second video showing a theft in a café.

  2. Complete a distractor task.

  3. Receive post-event narrative (or none).

  4. Complete a recognition task, free recall task, and rate confidence.

• Expected Results: The misinformation group is expected to perform worse on accuracy measures.

• Reliability of Eyewitness Memory: Eyewitness memory is not inherently reliable, particularly when witnesses are exposed to misleading post-event information.

New Experiment to Test the Weapon Focus Effect

• Title: The Impact of Weapon Presence on Eyewitness Memory for Peripheral Details

• Objective: To investigate the weapon focus effect, where the presence of a weapon impairs memory for peripheral features.

• Participants: 150 adult participants.

• Conditions:

  • Weapon Condition (man holds a handgun).

  • Neutral Object Condition (man holds a mobile phone or wallet).

  • No-Object Control Condition (man is empty-handed).

• Procedure:

  1. View a 2-minute video of a staged interaction in a convenience store.

  2. Complete a filler task.

  3. Complete a free recall task and recognition task.

  4. Eye-tracking data may be collected.

• Expected Results: Participants in the Weapon Condition will recall fewer accurate details about the perpetrator and the environment.

• Reliability of Eyewitness Memory: Eyewitness memory is not entirely reliable, especially when a weapon is present.

New Experiment to Test the Own-Age Bias

• Title: Age Congruency and Eyewitness Identification Accuracy: Testing the Own-Age Bias in Face Recognition

• Objective: To investigate the own-age bias, where individuals demonstrate better recognition memory for faces of their own age group.

• Participants: 120 participants (60 younger, 60 older).

• Design: 2x2 between-subjects factorial design with age group and face age as independent variables.

• Procedure:

  1. View a short video of a man entering a post office.

  2. Complete a distraction task.

  3. Complete a recognition test with a photo lineup.

• Expected Results: Participants will show greater accuracy when identifying faces from their own age group.

• Reliability of Eyewitness Memory: Memory is systematically biased such that individuals are more accurate in recognizing own-age individuals.

Experiment to Test Unconscious Transference

• Title: Mistaken Identity in Familiar Contexts: An Experimental Test of Unconscious Transference in Eyewitness Testimony

• Objective: To investigate the conditions under which unconscious transference occurs and to measure its frequency and impact on eyewitness accuracy.

• Participants: 90 adult participants.

• Conditions:

  • Control group.

  • Incidental exposure group.

  • Transference-prone group.

• Procedure:

  1. View a filler video.

  2. Transference-prone group sees a man walking down a hallway before watching the theft video.

  3. All participants are shown a simultaneous photo lineup that includes the innocent bystander from the hallway scene, but not the actual thief.

  4. Participants will be asked to identify the perpetrator.

• Expected Results: The transference-prone group will show significantly higher rates of false identification of the innocent bystander.

• Reliability of Eyewitness Testimony: Eyewitness testimony is not always reliable, particularly when unconscious transference is likely.

Experiment to Test the Other-Race Effect

• Title: Cross-Race Facial Recognition and Memory Accuracy in Simulated Crime Identification

• Objective: To explore the magnitude and reliability of the ORE in a controlled setting.

• Participants: 120 participants equally divided into two racial groups.

• Design: Mixed factorial design with race and condition (own-race or other-race) as variables.

• Procedure:

  1. Watch a short video of a mock theft.

  2. Complete a distractor task.

  3. View a photo lineup and identify the perpetrator.

• Expected Results: Participants will demonstrate significantly higher identification accuracy in the own-race condition compared to the other-race condition.