Psych Case Studies

milner 1966, Longitudinal case study

HM. - Brain Localisation
• Aim: To investigate the role of the hippocampus in memory formation following surgical removal of the medial temporal lobes.

• Procedure: A longitudinal case study using method triangulation, including psychometric IQ testing, direct observation, interviews, and cognitive tasks like reverse mirror drawing.

• Findings:

    ◦ Anterograde Amnesia: H.M. could not form new episodic (events) or semantic (facts) memories.

    ◦ Intact Functions: His working memory (capacity for rehearsal) and procedural memory (learning new motor skills) remained functional, though he never remembered learning the skills.

• Conclusion: The hippocampus is critical for transferring information from short-term memory to long-term memory but is not the site of permanent storage.

bartlett 1932

Schema Theory

Aim: To investigate how cultural schemas and prior knowledge lead to the reconstructive distortion of memory.

• Procedure: British participants heard a Native American legend, "The War of the Ghosts," which contained unfamiliar cultural concepts. They recalled it using either repeated reproduction (recalling multiple times over a period) or serial reproduction (retelling it to another person).

• Findings: Both groups distorted the story through three patterns:

    ◦ Assimilation: Changing details to fit British cultural norms.

    ◦ Leveling: Omitting information seen as unimportant, making the story shorter.

    ◦ Sharpening: Changing the order or adding details to make the story more coherent.

• Conclusion: Memory is an active, reconstructive process rather than a passive copy of experiences; we retrieve and change information to fit existing schemas.

strack and mussweiler 1997

Ghandi - Anchoring Bias

• Aim: To investigate the influence of anchoring bias on decision-making, specifically to see if implausible or "outlandish" anchors still affect judgment.

• Procedure: 69 German undergraduates were randomly assigned to a low anchor (did Gandhi die before/after age 9) or a high anchor (before/after age 140). Afterward, they were asked to estimate his actual age at death.

• Findings: The anchors significantly influenced the estimates. The high anchor group gave a mean estimate of 66.7 years, while the low anchor group gave a mean estimate of 50.1 years (the actual age was 78).

• Conclusion: Anchoring bias is a powerful influence on judgment; even when an anchor is recognized as impossible or outlandish, it still pulls the final decision toward that initial piece of information.

Lord et al 1979

Death sentence - confirmation bias

• Aim: To investigate how confirmation bias affects the evaluation of evidence regarding a controversial issue.

• Procedure: 48 Stanford students with strong, opposing views on capital punishment evaluated two fictitious studies: one supporting it as a deterrent and one showing no effect.

• Findings: Participants rated the study that aligned with their pre-existing beliefs as more credible and found the contradictory evidence unconvincing.

• Conclusion: Exposure to contradictory evidence resulted in polarization, where both groups became even more committed to their original positions. This bias serves as a way to protect one's ego and sense of self.

glanzer and cunitz 1966

MSM experiment — Rehearsal and STM—>LTM transfer

• Aim: To investigate the existence of separate short-term (STM) and long-term (LTM) memory stores through the Serial Position Effect.

• Procedure: Participants (Army enlisted men) heard lists of 15 words and were asked to recall them under three conditions: immediate recall, a 10-second delay, or a 30-second delay. During the delay, they performed an interference task (counting backward).

• Findings:

    ◦ Primacy Effect: Participants recalled words from the beginning of the list well in all conditions because they had time to rehearse them into LTM.

    ◦ Recency Effect: Participants recalled words from the end of the list well only during immediate recall. With a 30-second delay, these words were lost from STM.

• Conclusion: Memory consists of separate, sequential stores. STM has a limited duration and is susceptible to interference, while the primacy effect supports the existence of a distinct LTM store.

Landry and bartling 2011

WMM

• Aim: To investigate if articulatory suppression influences the recall of a written list of phonologically dissimilar letters in serial recall.

• Procedure: 34 psychology students were randomly assigned to a control group or an experimental group. The experimental group recalled lists of seven letters while repeatedly saying the numbers '1' and '2' (an articulatory suppression task), while the control group performed the recall without an interference task.

• Findings: The control group recalled 76% of the letters accurately, whereas the experimental group recalled only 45%.

• Conclusion: Articulatory suppression prevents rehearsal in the phonological loop due to overload, supporting the Working Memory Model's idea of separate stores.

• Evaluation: The study has high internal validity, allowing for a cause-and-effect conclusion, but it lacks ecological validity because the task is artificial

tversky and kahneman 1974

Anchoring bias, X primacy effect

• Aim: To investigate the effect of anchoring bias on the estimation of a mathematical product,.

• Procedure: High school students were asked to estimate the product of a sequence of numbers (1 to 8) within five seconds,. One group saw the sequence in ascending order (1x2x3x4x5x6x7x8), while the other saw it in descending order (8x7x6x5x4x3x2x1),.

• Findings: The ascending group (anchor: 1) gave a median estimate of 512, whereas the descending group (anchor: 8) gave a median of 2250,. The actual product is 40,320,.

• Conclusion: The first numbers seen acted as an "anchor," biasing the final estimate. This supports the Dual Process Model, showing that intuitive System 1 thinking is prone to such heuristics,.