Biological exps of phobias
- Created by: Sophie Kelly
- Created on: 11-05-13 23:05
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- Biological explanations of phobias
- Genetics
- View that we inherit genetic predisposition to become anxious
- Research uses family and twin studies to asses what role genetics play
- MZ = identical
- Same genes
- DZ = unidentical
- Only 50% same genes
- FAMILY
- Lautch (1971)
- Fear of dentist runs in family
- Noyes et al (1986)
- High incidence of agoraphobia in 1st degree relatives
- Ost (1992)
- 64% blood/injection phobics had 1st deg relative with phobia too, comapred to 3% rate in general population
- Lautch (1971)
- TWINS
- Torgersen (1983)
- Panic disorder and agoraphobia. 31% concordance in 13 MZ twins
- No concordance in 16 DZ twins
- HOWEVER - Kendler et al (1992) found opposite
- 722 female twins, history of agoraphobia
- MZ twins significantly lower concordance rates than DZ
- 722 female twins, history of agoraphobia
- Torgersen (1983)
- MZ = identical
- Commentary
- Can't just be 100% genetic as concordance is never 100%
- Not clear what exactly is passed on genetically
- Other factors? E.g. shared environment
- Family
- Self report
- Memory lapses
- Distortations
- Impress investigator
- Self report
- Twins
- More reliable but few done
- Adoption studies would be better
- More reliable but few done
- Biochemistry
- Structural or biochemical abnormalities should be detectable in the brains of those with phobic disorders
- GABA = neurotransmitter, main inhibitory chemical in nervous system
- Reduces stress and anxiety
- Phobia could be caused by reduction of GABA
- Reduces stress and anxiety
- Amygdala = part of brain that is activated in response to threat
- Applegate et al (1982)
- Studies show that when you pair aversive stimulus with neutral stimulus, neurons fire in amygdala
- Kemble et al (1990)
- When amygdala is deliberatley damaged in animal studies, they show a reduction in innate fears
- Applegate
- Conditioned fears also
- Applegate
- When amygdala is deliberatley damaged in animal studies, they show a reduction in innate fears
- Commentary
- :)
- Treatment with drugs successful
- Treatment mimics GABA
- Drug effects are short term
- Treatment with drugs successful
- :(
- Drug effects are short term
- Effects only slightly better than placebo in kids
- Use of animal studies?
- Blood flow abnormalities - Causal factor or result of phobic disorder?
- :)
- Evolutionary
- "Innate biological memory"
- Fact phobias still apparent suggests evolutionary
- If phobias had no purpose, natural selection would have selected them out
- Research
- Rakinson (2000)
- 11 month old girls learned quicker than boys to associate negative facial emotions with snakes and spiders
- No gender diff for fear irrelevant objects
- Suggesting evol theory - 4 times as many females have snake/spider phobia
- They more likely to encounter them while foraging in old times
- Suggesting evol theory - 4 times as many females have snake/spider phobia
- No gender diff for fear irrelevant objects
- 11 month old girls learned quicker than boys to associate negative facial emotions with snakes and spiders
- Cook and Mineka (1989)
- Demo'd to lab raised monkeys fear response to toy snake and rabbit
- They then showed similar fear to snake but not rabbit
- Suggests evol readiness to fear snakes but not rabbits
- They then showed similar fear to snake but not rabbit
- Demo'd to lab raised monkeys fear response to toy snake and rabbit
- Commentary
- :)
- Explains for dangerous stimuli
- Learned helplessness explains why harder to develop fear of dangerous modern day things
- E.g. guns, weren't around before evolution
- Learned helplessness explains why harder to develop fear of dangerous modern day things
- Good explaining how easy can be developed e.g. Ohman
- Explains for dangerous stimuli
- :(
- Some phobias so bizarre and individual
- Best explained as conditioned not evol
- Deterministic, doesn't account for individual/cultural diffs
- Davey (2004)
- Not evol fear of snakes and spiders but evol disgust
- Linked to disease
- Not evol fear of snakes and spiders but evol disgust
- Ohman - were developing phobia or just afraid of shocks?
- Some phobias so bizarre and individual
- :)
- Rakinson (2000)
- Genetics
- Ohman et al (1975)
- Research
- Rakinson (2000)
- 11 month old girls learned quicker than boys to associate negative facial emotions with snakes and spiders
- No gender diff for fear irrelevant objects
- Suggesting evol theory - 4 times as many females have snake/spider phobia
- They more likely to encounter them while foraging in old times
- Suggesting evol theory - 4 times as many females have snake/spider phobia
- No gender diff for fear irrelevant objects
- 11 month old girls learned quicker than boys to associate negative facial emotions with snakes and spiders
- Cook and Mineka (1989)
- Demo'd to lab raised monkeys fear response to toy snake and rabbit
- They then showed similar fear to snake but not rabbit
- Suggests evol readiness to fear snakes but not rabbits
- They then showed similar fear to snake but not rabbit
- Demo'd to lab raised monkeys fear response to toy snake and rabbit
- Commentary
- :)
- Explains for dangerous stimuli
- Learned helplessness explains why harder to develop fear of dangerous modern day things
- E.g. guns, weren't around before evolution
- Learned helplessness explains why harder to develop fear of dangerous modern day things
- Good explaining how easy can be developed e.g. Ohman
- Explains for dangerous stimuli
- :(
- Some phobias so bizarre and individual
- Best explained as conditioned not evol
- Deterministic, doesn't account for individual/cultural diffs
- Davey (2004)
- Not evol fear of snakes and spiders but evol disgust
- Linked to disease
- Not evol fear of snakes and spiders but evol disgust
- Ohman - were developing phobia or just afraid of shocks?
- Some phobias so bizarre and individual
- :)
- Rakinson (2000)
- Paired pics with electric shocks, either harmful or not
- 5 times longer for people to show fear response to harmless pics
- Research
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