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)