Cognitive Case Studies and Experiments

Glanzer and Cunitz (Aim)

The effect of a 30 second distraction task on the likelihood of remembering words dependent upon their position in a list

Glanzer and Cunitz (Method)

• IV: presence of a 30 second distraction task

  1. Condition 1: No Distraction Task

  2. Condition 2: 30 Second Distraction Task

• DV: % likelihood of word remembered based on position in serial list (serial position effect)

• P: 

  1. Free recall task using a set of 15 words (nouns) 

  2. Free recall task using 15 words however with a distraction

Glanzer and Cunitz (Results)

30-s Distraction task eliminated recency effect (higher percentage for words at the end of the list)

Baddeley (Aim)

to determine whether word length, defined by the number of syllables, affects an individual's accuracy in recall

Baddeley (Method)

Independent Variable (IV):

• Word Length: This refers to the length of the words presented to participants during the memory tasks. Words were categorized into short (one syllable) and long (multiple syllables) groups.

Dependent Variable (DV):

• Memory Performance: The main DV was the participants' ability to recall the words presented to them accurately. This was typically measured by the number of words correctly recalled or the accuracy of recall in each condition (short vs. long word length).

Baddeley (Results)

• Participants had better recall for short words compared to long words.

• The difference in recall between short and long words was more pronounced when participants were asked to recall the words in the correct serial order.

• When participants were allowed to recall the words in any order (free recall), the difference in recall between short and long words was less significant.These results suggest that the phonological loop, a component of Baddeley's model of working memory, is involved in the rehearsal of verbal information, and longer words may overload this loop, leading to poorer recall.

These results suggest that the phonological loop, a component of Baddeley's model of working memory, is involved in the rehearsal of verbal information, and longer words may overload this loop, leading to poorer recall.

KF

• Patient KF, who had suffered brain damage as a result of a motorcycle accident.  KF's LTM was intact, but he showed impairment of his short-term memory.

• Appeared to have problems recalling lists of words and numbers, he was able to learn new episodic memories

• He was clearly moving information from STM to LTM.

• He quickly forgot numbers and words when they were presented to him orally, he was able to remember these words or numbers when presented to him visually. KF's impairment was mainly for verbal information - his memory for visual information was largely unaffected.

Bartlett (Aim)

See how memory of a story is affected by previous knowledge (i.e. schema)

Bartlett (Prodecure)

• Told participants a Native American legend (The War of Ghosts)

• Participants in the study were british and the story was filled with unknown names and concepts and how the story developed was foreign.

• Condition 1:

  • Repeated reproduction - participants heard the story and were told to reproduce it after a short time and then to do so again repeatedly over a period of days, weeks, months, or years.

• Condition 2:

  • Serial reproduction - participants were told to recall the story and repeat it to another person

Bartlett (Results)

• No significant difference between the way that the groups recalled the story, participants in both conditions changed the story as they tried to remember it

  • Distortion

• Assimilation = the story became more consistent with the participants’ own cultural expectations. Details were unconsciously changed to dit the norms of their culture.

• Leveling = the story also became shorter with each retelling as participants omitted information which was seen as not important.

• Sharpening = participants tended to change the order to the story make sense of it using terms more familiar to their culture. Also added details and/or emotions.

Remembering is an active process, which shows 'effort-after meaning' we make sense of the information first based on previous 'schemas' and then recall an altered, personalised version of events

Westcott (Aim)

• To investigate the effect of robbery scripts (event schema) on eyewitness memory recall

Westcott (Procedure)

M: 144 participants (19 years old)

Study 1: Questionnaire for robbery script creation.  Count frequency of ideas.

Study 2: Lab experiment.  Slides showing photos from a (staged) convenience store robbery 

IV 1: Omission of either central or peripheral actions of robbery from the slide show

IV 2: Recall interval: (5 minutes vs. 1 week) between seeing the ‘robbery’ and Qs.

DV: 18 action verbal recognition Qs (“Did you see…” y/n) including 6 critical questions (about the 3 central, 3 peripheral that were removed from the slides)

Westcott (Results)

False recognition of event details was:

•  ↑ false memories for the missing central script details than peripheral

•  ↑ false memories recalled after a longer recall interval.

• Activation of a relevant script (robbery) increased false recognition: guided what to expect, what to encode, and what to recall

• Gap-filling errors were made with schema-consistent information 

Loftus and Palmer (Aim)

• To investigate the effect of language and schematic associations on estimates of speed in a car crash 

Loftus and Palmer (Procedure)

M: lab experiment with car crash video

IV: action verb used in memory recall question

DV:

• Experiment 1: estimation of speed (mph) (recall interval: 5 minutes)

• Experiment 2: did you see broken glass (yes/no)

  • (recall interval: 1 week later)

Loftus and Palmer (Results)

Tversky and Kahneman (Aim)

• To investigate the cognitive biases and heuristics that individuals use when making judgments under uncertainty.

Tversky and Kahneman (Procedure)

Participants= two groups of HS students

• One group estimates: 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 = 

• The other estimates: 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 

Tversky and Kahneman (Results)

Median estimate for:

• 1x2x3… condition = 512.

• 8x7x6...condition = 2,250

Conclusion: 

• Judgements were affected by the first, anchoring, numbers

• Adjustment

Englich and Mussweiler (Aim)

Whether or not the simple request for a certain length of prison sentence would unduly influence the decision made by a judge 

Englich and Mussweiler (Procedure)

• 19 young trial judges (15m 4f), around 29 years old, average of 9 months of experience

• 24 senior law students

  • Participants given material and told to form an opinion on the case 

  • Condition 1: 2mos (low anchor)

  • Condition 2:  34 mos. (high anchor)

  • Then asked a questionnaire.

  • Asked whether the sentence was too low or high

Englich and Mussweiler (Results)

• Average rating for realistic nature of case wa 7.17, (scale of 1-9)

• Judges certainty was lower, at an average rating of 4.53

• Low anchor: averaged 18.78 months, STDEV: 1.3

• High anchor: averaged 28.70 months, STDEV: 6.53

• The anchoring bias influences the length of sentencing

  • Experience does not have a relevant influence on h

Shaw and Porter (Aim)

To investigate false memories of committed crimes & emotional events

Shaw and Porter (Procedure)

M:  Experiment with 60 college age participants

• Phase 1: Family informant questionnaire to support criminal story

• Phase 2: 3 Interview sessions using strategies to elicit false memory

• Q’s after study: Self reported- believe it? Confidence? Vividness? 

IV:  Questions about Real v false memory (2 conditions of false memory: crime condition vs. emotional condition e.g. attacked by a dog)

DV: belief in and 10+ details given of  false memory.  Confidence, vividness.

Shaw and Porter (Results)

No false recalls in first interview condition

•  64.95% false recall of crimes* condition & 76% in non-criminal condition (*this has been recalculated from 70% in 2015!)

• Confidence ratings- True memory- 5.3, False memory- 2.9 

• Vividness ratings- True memory- 4.7, False- 2.7  

• False memory had fewer sensory details reported.

Sharot et al (Aim)

Investigate the relationship between proximity, vividness, detail, confidence in a flashbulb memory  and fMRI scans of brain activity

Sharot et al (Procedure)

• 24 Participants from different locations of Manhattan

•  fMRI machine: measuring brain activity

• Words on screen related to 9/11. 

  • “Summer” (Related to holiday)

  • “September” ( Related to 9/11)

• Asked to rate; vividness, detail, confidence, arousal of both 

Sharot et al (Results)

• Memory of 9/11 attacks showed increased amygdala activity and decreased parahippocampal activity compared to everyday memories.

• People who were further from the attacks showed less difference in brain activity between the two types of memory, and they reported less detail about the 9/11 memory compared to those who were closer to the towers.

Talarico & Rubin (Aim)

To investigate the differences between a regular episodic memory and a flashbulb memory (find out about 9/11) in terms of accuracy, consistency, vividness and emotional valence.

Talarico & Rubin (Prodcure)

M:  Repeated measures design

• 54 Students from Duke University

• Initially tested on september 12th (day after)- baseline.  Then interviewed once more each (either after 1 week, after 6 weeks or after 32 weeks)

• IV: Episodic memory vs emotional memory ( 9/11)  

• DV: 

  • open ended questions about the event (qualitative)

rating scales to measure emotional intensity and questions about the characteristics of the memory (e.g. clarity, confidence…) (quantitative)

Talarico & Rubin (Results)

• Consistency in the details given for both episodic and flashbulb memory decreased over time (i.e. their story changed) 

• Flashbulb memories had a greater intensity (vividness)  had more narrative coherence (less fragmented), had a more negative valence than autobiographical memory, and were more detailed.

HM

A patient who, because of damage to his hippocampus, was unable to encode new episodic memories. Retained LTM.

Shows that STM and LTM function somewhat independently of each other (separate stores).