PSYCh 258 Case Studies / Experiments

Baddeley and Hitch Model (1974)

1. Central Executive

2. Episodic Buffer

3. Phonological Loop

4. Visuospatial Sketchpad

Funahashi et. al., 1989 (PFC neurons in healthy monkeys)

PFC holds info active in WM (recorded neurons in healthy monkeys, neurons in PFC kept firing when for was flashed and during the delay too)

Vogel et. al,. 2005 (Why is working memory better in some ppl than others?)

Individual differences in working memory are partly explained by how well the central executive filters out irrelevant info. Better filtering = higher WM capacity. High and Low WM capacity people were shown either simple or complex stimuli (w or w/o distractions), measured by ERP, high capacity ppl showed less response to distractors. 

Wickens et. al., (semantic coding + proactive interference)

Participants remembered words from different categories. Condition 1: same category repeated (eg. fruit), performance was worse and proactive interference built up. Condition 2: category switches )eg. professions, fruit), performance improved, release from proactive interference, showed semantic coding involved). Interference disappears because old similar meanings are no longer blocking new one like in C1, this is evidence that stem and ltm use semantic coding, because if they only coded visually or auditory, then switching categories wouldn’t help.

Murdoch 1962 (serial position curve, recall)

U-Shaped

1. Primacy effect → early words get more rehearsal, less interference from other words, transfer to LTM, stick around after delays

2. Recency effect → last words still active in STM/WM, fresh in mental buffer, easy to recall immediately but with a delay added, effect disappears bc STM “emptied out’”

important bc it shows strong evidence that STM and LTM are separate memory systems, supporting Baddeley and Hitch’s model

Shepard and Metzler (1971) (shape rotating, visual imagery work)

People were shown pairs of 3D shapes, some were the same or mirrored copies, but they were rotated at different angles. The task was to figure out whether the shapes were the same or not. When they were slightly rotated, decisions were fast, when they were rotated a lot, decisions were slower. This is because people were mentally rotating the shapes in their mind, proof that the Brian is doing visual imagery work. 

HM and KF double dissociation

HM had surgery for epilepsy (also wearing who had encephalitis), they had impaired LTM but intact STM. KF had traumatic brain injury form motorcycle accident, had impaired STM but intact LTM. This proves that STM and LTM are separate functions ran by separate systems. 

KC and LP double dissociation (episodic and semantic memory)

KC had damaged hippocampus: no episodic memory, cannot relive any events of this past, but semantic memory was intact, and he can remember general info about the past.

LP had impaired semantic memory, episodic memory for past events was preserved. 

Patrician et. al., 2010

as people get older their memories of past experiences tend to change in a way that places an emphasis on facts (semantic).

Graf et. al., 1985 (implicit and explicit memory)

Tested ALC patients, amnesic patients, and healthy controls. First asked participants to rate how much they liked a series of words (facilitating incidental processing, participants were not attempting to memorize the list). They were then tested 2 ways: explicit (recall memory), implicit (word stem completion). Amnesic patients showed severe deficit in explicit memory but performed normally in implicit ones, demonstrating that memory is made up of different systems which may be independent. 

Bransford & Johnson, 1972 (context before info improves recalling)

• Participants were given a difficult-to-understand passage. Some participants saw a title or context cue before reading, while others did not. Later, participants were tested on how much they could recall from the passage. Participants who received the contextual title beforehand remembered significantly more than those who did not. Without context, the passage was confusing and poorly understood, leading to lower recall. Based on differences in what groups were able to recall about the story, the authors argued this could be taken as evidence for the beneficial effect that organization can play in encoding.

Brunnet et al., 2008; Mitchell et al., 2023

Studies that reported benefits for patients with post-traumatic stress disorder (PTSD) after pharmaceutical manipulations in the form of either propranolol or MDMA (Brunnet et al., 2008; Mitchell et al., 2023). One of the potentially relevant mechanisms that could be hypothesized to underlie such benefits include reconsolidation of traumatic memories. (brain is in more vulnerable state were memories can be revisited, softened, altered)

Stanny & Johnson, 2000 (how stress affects memory of witnesses)

Simulated a high-stress shooting scenario. When a shooting occurred, witnesses recalled fewer details overall, and notably, they remembered the weapon better than the perpetrator. The study highlights how acute stress (especially involving a weapon) can impair memory for peripheral details, supporting the weapon‑focus effect. Weapon focus: the firing of a weapon impaired memory for the people involved with the event.

Rosch et al., 1976 (basic level of categorization)

Results indicated that people have a bias towards using the basic level of categories (in other words, they might argue that 'this (category) is the best')

retroactive vs. proactive interference

1. Retroactive (eg. misinformation effect) → new info/memories interferes with remembering old ones

2. Proactive → old info/memories interfere with encoding/learning new ones

exemplars vs. prototypes

Exemplars are specific instances of a category, while prototypes are the most typical or average representation of that category. Both concepts are used to understand how we categorize objects and experiences.

Paper Folding Test

Psychological assessment of spatial visualization ability, specifically how well someone can mentally manipulate 2D and 3D objects. Participants see a diagram of a piece of paper being folded one or more times with holes punched in it. They must predict what the paper will look like when unfolded.

Reminiscence Bump

The greater number of memories that the average person typically recalls from between adolescence and early adulthood (~10 - 30 years) has been termed the

Articulatory Surpression

The phenomenon where verbal memory is impaired when an individual is required to repeat irrelevant speech or sounds, preventing rehearsal of information.

Visual STM capacity limits

The average person can hold about four objects in WM (or VSTM), though that may depend to some extent on how detailed those objects are.

Types of LTM

1. Explicit (conscious) → Episodic (experiences), Semantic (facts, knowledge)

2. Implicit (unconscious) → Procedural (skills), Priming (prior exposure to stimuli), Conditioning (eg. pairing neutral stimuli with reflexive response)

Classic conditioning

A learning process in which a neutral stimulus becomes associated with a meaningful stimulus, leading to a conditioned response. This is often exemplified by Pavlov's experiments with dogs.

Expert-Induced Amnesia

being so good at a skill that its carried out with such. degree of automacity that the individual performing the action has little to no recollection of what actually happened (driving?)

Load Theory

If you still have unused perceptual activity, then distraction gets processed automatically (think attention bucket)

Martin et al. (1996) - PET Study

• Contrasted brain activity during the silent naming of animals vs. tools.

• Results seemed consistent with the data from Hoffman and Ralph (2013):
  • Animal naming was associated with greater activation in visual cortex (due
  to a role in processing low-level visual features)
  • Tool naming was associated with greater activation in areas related to
  action generation: posterior middle temporal gyrus (due to a role in
  processing motion) and premotor cortex (due to a role in processing
  movement, and/or mirror neuron activity)

Kosslyn (1973)

• Task: Memorize picture → mentally “search” for a part
  Finding things farther away takes longer
  → imagery has spatial properties

• Criticism – Lea (1975) → Longer distance = more distractions
  → maybe slower due to complexity, not spatial travel

• Kosslyn et al. (1978) – Island study

• Participants imagine an island w/ 7 locations

• Scan between points

• Longer physical distance = longer mental time

• Disproves distraction theory → supports true spatial imagery

Bottom line:
🧠 Mental images = spatial maps, not just vague ideas.

Conceptual-Peg Hypothesis (Pavio’s)

Concrete nouns act like mental hooks that other info can attach to. Eg. boat-hat → imagine a hat on a boat → easier recall

Mental Chronometry

Uses reaction time to infer mental steps

Pylyshyn’s argument

• Mental images aren’t “picture-like” → they’re propositional (stored like language/symbols).

• The “picture feeling” = epiphenomenon (feels real but isn’t the actual mechanism).

• People might use tacit knowledge = they expect longer distances → slower times.

Kosslyn’s argument

• Mental imagery IS spatial (like a mental map).

• Scanning farther → longer RT → just like real perception.

➡ The debate is basically:
“Do we picture things or just use logic?”

Semantic Distance

• Bigger conceptual distances also slow RT.

• Could explain results without “mental pictures.

Perky (1910)

• People confused a faint real image with their imagination.
  → Shows imagery feels real AF.

• BUT expectations might have influenced this.

Farah (1985) – Letter priming

• Imagining a letter makes you faster to detect it.
  → Imagery behaves like perception (priming effect).

Ganis et al. (2004)

• Strong overlap in the front of the brain during imagery & perception.

• Less overlap in the back (occipital).
  → Some shared systems, some different.

Amedi et al. (2005)

During imagery:

• visual areas = activate

• other senses (hearing/touch) = turn down
  → Your brain reduces distractions so the mental image doesn’t break.

MVPA (Multivoxel Pattern Analysis) - Johnson and Johnson

You can “decode” what someone is imagining based on their brain pattern.
→ Shows imagery creates stable, perception-like patterns.

Object / Spatial Imagery Trade-off

• Object imagery: details, colors, textures

• Spatial imagery: layouts, shapes, rotating objects

• High spatial imagers often have low object imagery and vice versa.

tacit-knowledge explanation

ppl unconsciously use real-world knowledge to simulate what “should” happen, which mimics spatial imagery

Farah letter-priming

Imagining a letter makes u detect that same letter fast when flashed, imagery = priming

Is communication language

No, because language is a system of communication using sounds/symbols to express thoughts, feelings, ideas. Not all communication = language (bees doing lil’ dances, animals changing colour, etc.)

Features of human language

1. Hierarchical (levels of units, letters to words to sentences)

2. Rule-based (grammar + syntax(

3. Dynamic (always evolving, eg. rizz)

4. Creative (infinite new sentences)

Pollack and Picket (1964)

Showed participants were unable to identify words they had said themselves when recorded and presented out of context (as individual words, not entire sentences

Word Superiority Effect

letters are easier to identify when part of a word than alone or in a jumble.

phonemic restoration

brain fills in missing sounds using context.