Biological Approach Part 2

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  • Created by: Beth
  • Created on: 10-04-14 15:40

Methodology - Evaluation of Animal Studies (rats)

When and why?

  • trial drugs
  • high control over factors
  • easy and cheap to keep
  • similar evolutionary past to humans
  • test hypothesis not ethical on humans (brain lesions, sex hormones

Credibility?

  • trustworthy? believe? likelihood?
  • yes - hormones same effect on humans and rats
  • no - baby development different - humans more complex 
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Methodology - Evaluation of Animal Studies (rats)

Generalisability?

  • low 
  • different cognitively and emotionally
  • brains different - humans larger prefrontal cortex
  • different behaviour - shaped by different social norms

Pratical reasons?

  •  genetic engineering - unethical in humans
  • allow 'minimal' pain and distress - not in humans
  • size - small and easily kept
  • short pregnancy - study generations of genes quickly
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Methodology - Evaluation of Animal Studies (rats)

BPS guidelines and ethics;

  • legislation to protect
  • suitable species choice
  • number limited - no wastage
  • procdures - minimalise pain
  • procurement - reputable supplier
  • suitable housing and care
  • another purpose - breeding or experiment

Bateson's cube;

  • animal suffering
  • medical benifit
  • quality of research - not guaranteed untl after
  • only proceed if missing block 
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Practical - Spatial Awareness - description

Aim: To see if there is a difference between males and females when solving a mental shape rotation task, which represents a spatial awareness task, with males solving it quicker than females

Method:

  • lab experiment
  • oppurtunity sampling
  • 20 participants (10 male, 10 female)
  • independent measures
  • IV = gender   DV= time to complete spatial awareness task
  • alternative hypothesis (directional) = males perform quicker at s.a. task than females
  • null hypothesis = no difference males at time taken to complete s.a. task
  • non directional hypothesis = no difference
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Practical - Spatial Awareness - description

Procedure:

  • P. chosen and fully informed, not spoil test
  • P. taken seperate room to do test individually
  • Researcher reads instruction to p. and ask if agree, before do test on computer. DV = time taken
  • P. debriefed check if can use data
  • Researcher only records gender and time, prove to p.

Equipment:

  • data sheet
  • standardised instructions
  • mental shape rotation task on computer, providing average time in sec.
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Practical - Spatial Awareness - description

Results:

  • male mean score = 2.74
  • female mean score  = 4.12
  • observed value U=34

Conclusion:

Observed value of U=34 is above critical value of 27 and so result is not significant, therefore I must accept null hypothesis " there will be no difference between males and females, with time taken to complete spatial awareness task"

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Practical - Spatial Awareness - evaluation

Generalisability:

  • oppurtunity sampling - not representative of target population - based on gender, not account for age or ability

Reliablilty:

  • lab environment - high control of extraneous variables - more replicable
  • standardised procedure - reliable

Application:

  • careers - but sexism

Validity:

  • low ecological - lab experiment - artificial environment
  • computer test - artifical task - not real life scenario
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Practical - Spatial Awareness - evaluation

Ethics:

  • all BPS guidelines followed - no issues
  • brief, debrief, informed consent, confidentiality

Objectivity:

  • measurement of time - free from bias - no opinion

 

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Statistics

Inferential stats = how much due to chance?

descriptive stats = measurements of central tendency = mean, median, mode

Levels of measurements:

  • interval = real measurements
  • ordinal = ranks
  • nominal = categories

Experiment (difference) = indpendent measures = interval = Mann Whitney U = or nominal = Chi squared

Correlation (2 measures) = ordinal = Spearman's

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Statistics (Mann Whitney U)

  • Observed value = result you found
  • Critical value = table of significance
  • significance = below critical value
  • o.v less c.v accept alternative hypothesis
  • o.v higher c.v accept null hypothesis

 

 p <= 0.05

 

p              probability of results due to chance

< =            less than or equal to

0.05      5% (chance)

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Detail study - Money - David Reimer (Ablatio Penis

Aim:

  • encourage the Reimer's to let their twins (Bruce & Brian) be part of experiment
  •  Bruce brought up as female after circumcision accident, left no penis, easier for reconstruction surgery
  • prove nurture overide nature

Case description:

  • Mother and twins visited Money often for 9 years to report on developments
  • mother most because put most effort unto Bruce becoming Brenda

Case analysis by Money (results) :

  • success, Brenda showed gender appropriate beahviour ;dresses, dolls and happy
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Detail study- Money - David Reimer (Ablatio Penis)

Conclusion (Money's):

  • can go against nature
  • nurture stronger with small interventions (surgery)
  • Brenda happier as girl

Real Analysis (results):

  • 13 yrs Brenda masculine and suicidal
  • 15 yrs mother against Money tells of change
  • Brenda becomes David
  • David reconstructive surgery, marry, stepkids and 'male' job
  • 30 yrs depressed, divorced, no job
  • 2002 Brian (twin) drug o.d. - belief over case
  • 2004 David suicides
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Detail study -Money -David Reimer (Ablatio Penis)

Real conclusion:

  • Nature stonger than nurture - felt wrong to be girl - changed back to natural gender
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Detail study-Money -David Reimer (Ablatio Penis)

Generalisability:

  •  low
  • one off study and unique case - not g. other situations

Reliability:

  • unethical if repeat - unkown reliabilty
  • support of Reiner & Gaerhart study - majority females convert back - reliable
  • against of Daphne West - not reliable

Application:

  • childhood transgender ops, only when child decides 
  • nature more determinate of gender than nurture
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Detail study-Money -David Reimer (Ablatio Penis)

Validity:

  • no procedure controls - case study -  no unnatural criticisms- eco. valid

Ethics:

  • no consent 
  • no right to withdraw
  • parental mpermission of brief and informed consent
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Detail study-Raine-Murderers brains PET

Aim:

  • to use PET measure brain acticity in areas associated with violence, in murderers and non-murderers

Procedure:

  • 2 groups - 41 murderers plead not guilty reason insanity - matched control group 41 non-murderers on age, sex and schizophrenia
  • all injected glucose and rodioactive tracer, reveal active areas - absorb glucose
  • p. continuous performance task (CPT) detect signals 32 mins
  • finish task immediate PET scan show levels of activity in areas
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Detail study-Raine- Murderers brains PET

Results:

  • m. less active prefrontal cortex - low control and violence
  • m. less active left angular gyrus and bilateral superior gyrus (parietal cortex) - low verbal ability - poor education and compensation of crime
  • m. less active corpus callosum - low self control - can't control violent impulses
  • m. abnormal limbic system - emotion expression
  • m. less active amygdala and hippocampus (left)
  • m. more active thalamus (right) 
  • =  fearlessness - lack understanding negative efects of violent behaviour

   

Conclusion: violence and agression biological not environmental

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Detail study-Raine-Murderers brains PET

Generalisability:

  • 41 p. each group - large - matched - confident in result of difference
  • no circumstances for murders or others who agressive but not murderers
  • only murderers - no other violent criminals

Reliability:

  • repeat other groups - strengthen results
  • results cannot conclude biolongy only cause (e.g. environmental trigger)
  • compare to Raine's Anti-social Personality Disorder study results - small prefrontal cotex

Application:

  • PET scans evidence in court when plead NGBRI

 

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Detail study-Raine-Murderers brains

Validity:

  • PET results not precise on area or activity
  • not why active
  • not tell which - abnormalities causes violence or violence causes abnormalities

Ethics:

  • no protection - stress of PET scan
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Key Issue - Are transgender ops. ethical? Describ

What are transgender ops?

  • aim of channging the physical sex of person

Why would someone want a transgender op?

  • choice of patient - transsexuals
  • infancy  identity - indiscriminate sex organs - hermaphrotidism

Why are transgender ops a society issue?

  • ethics of changing gender by surgery - especially children, no consent
  • surgery permanent and irreversible - consider carefully
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Key Issue - Are transgender ops. ethical? Evaluate

For:

  • surgery sucess - new parts develop and function need done early infancy
  • reactions of others - ethics of changing child to 'normal' so others accept better than maintain original

Against:

  •  consent - adult informed risks and give consent - child not consent to life altering surgical procedure - parents and Dr decision not fit childs feelings later
  • surgery decisions - choice of gender - driven surgeon - female genitals easier to create and function

 

 

 

 

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Key Issue- Are transgender ops. ethical?

Against:

  • David Reimer case -  raised female and op. as penis construction surgery limited- biology overided and felt more masculine - other reactions caused low self esteem - depression and suicide - ethic problems
  • Reiner & Gaerhart - 16 males born small or no penis but normal testes- 14 raised female but all identiftied some point gender identity issues - most of 14 later chose male identity and lives from teenagers - 2 males raised males always identified as male despite abnormalities
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