Harlow (1848) Case Study
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Case study of Phineas Gage, a railway worker who survived the passing of an iron rod through his head
Due to an explosion the iron tamping rod entered below his left cheek and exited out the top of his head
He was conscious after the accident, and brought to the town doctor, Harlow
Dr. Harlow did not have antibiotics, but kept the wound clean to avoid infection
Gage did not suffer paralysis or speech impairments and seemed to be cured
After his recovery, changes in his personality were noted by Dr. Harlow; he became aggressive, impatient,
profane, and indulgent
Described as a child in his intellectual capacity, but with the animal passion of a strong man
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Findings
 Many years later when Damasio, et al. (1994). Recreated the injury using modern technology it was found
that Gage’s frontal lobes were damaged in the left pre-frontal region
Conclusions and applications
 Study supports that the pre-frontal regions disrupts a person's ability to synthesize these systems and
produce organized social behavior
Evaluation
 Case study is beneficial for studying localization in humans
 Ethical
 Findings have been supported by other research
 Information was acquired from Dr. Harlow’s journals and therefore can we subjected to researcher bias
 Case studies give detailed information
 Not easily replicable
Bouchard (1990) Meta Analysis/ longitudinal study
Aim
Investigate the relative role of genes in IQ
Procedure
 Conducted a meta-analysis that compared MZAs (identical twins raised apart) to MZTs (identical twins
raised together)
 Relied on TV reports to acquire MZAs as participants
 Each twin completed approximately 50 hours of interviews and testing
Findings
 MZTs had a concordance rate of IQ of 86%
 MZAs had a concordance rate of IQ of 76%
 This shows a link between genes and intelligence, but it doesn’t rule out the role of the environment
Evaluation
 Strengths
 Uses participants from all over the world, so it has cross-cultural validity
 Provides insight on how genetics affects intelligence
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Weaknesses
 Cause and effect relationship not established with correlational data
 Findings from this self-selected sample make it difficult to generalize findings
Conclusions and Applications
 Genetic inheritance has large influences on human behavior
 Correlational data does not show a cause and effect relationship
Learning Outcome
Discuss how and why particular research methods are used at the biological level of analysis.
Definitions
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Three main research methods
 Lab experiments: used to establish cause and effect relationship between variables
 Case studies: detailed consideration given to development of a unique person, group, or situation over time
 Correlational studies: determines whether or not two variables are correlated; no causation determined however
Lab Experiments
Strengths
Control of variables allows cause and effect relationship to be discovered, generates numerical data
Weaknesses
Lab setting has low ecological validity, many lab experiments at the BLOA use animals, so there are generalization problems
Case Studies
Strengths
Provides rich, qualitative data, permits investigation of otherwise impractical or unethical situations
Limitations
Difficult to generalize findings to the wider population, difficult to replicate
Correlational Studies
Strengths
Allows for the investigation of naturally occurring variables that may be impractical or unethical to test experimentally, allows researcher
to easily see the relationship between two variables
Weaknesses
Cause and effect cannot be determined, does not allow us to go beyond the collected the data (why and how)
SAQ Thesis
Lab experiments, case studies, and correlational studies are used at the biological of analysis. This can be demonstrated in Rosenzweig
(1972), Harlow (1848), and Bouchard (1990).
LAQ Thesis
This paper will discuss how and why Lab experiments, case studies, and correlational studies are used at the biological level of analysis
demonstrated in Rosenzweig (1972), Harlow (1848), and Bouchard (1990).
Rosenweig, Bennett and Diamond (1972) Lab Experiment
Aim
Investigate whether environmental factors such as a rich or impoverished environment affect development of neurons in the cerebral
cortex.
Procedure
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Rats were either placed in enriched environment (EC), or impoverished condition (IC)
EC had toys to play with, IC had no toys
In EC, 10-12 rats in a cage provided with different stimulus objects to play with; they also received maze training
In IC, each rat was isolated, with no stimulus
Rats typically spent 30-60 days in their environment before they were killed
Changes in brain anatomy were studied
Findings:
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Anatomy of brain of rats was different for those in EC and IC
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Brains of rat in EC had increased thickness and higher weight of cortex; they also had developed more acetylcholine receptors
in the cerebral cortex
Evaluation
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Strengths
 Cause and effect relationship established due to controlled factors of lab experiment
 Provides insight on how the brain can change and adapt to new situations
 Challenged the belief that brain weight cannot change
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Weaknesses
 Use of animals makes it difficult for results to be generalized to humans
 Ethical issues with animals sacrifice
Conclusions and Applications
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A stimulating environment can change increase thickness and weight of the brain and can help develop receptors in the brain
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Lab experiments are useful when a highly controlled setting is required and in order to establish a cause and effect relationship