Biological Preparedness

• What is it?• How does it explain phobias?

Key Points

• Evolutionarily relevant (adaptive)• Automatic• Can’t be cognitively controlled (at

least not easily)• Separate from learned associations

in the brain• Originates in the amygdala

Background• Evolutionary Psychology suggests

phobias are once adaptive behaviours which helped our ancestors to survive

• If we are extremely fearful of an animal and we try to get away from the animal, we are unlikely to get hurt by it.

• If the fearfulness becomes inherited by an individual’s offspring - ie: naturally selected - then that genetic line is more likely to survive than another genetic line that didn’t inherit that trait.

Aim

• To see if phobias of snakes could be more easily conditioned than phobias of faces or houses (which would indicate a biological preparedness for phobias of certain stimuli)

Method• Lab exp• Machine• Pics• Deliver shocks after some of them• GSR

• Independent deisgn• 1/3 conidtions

• Snakes houses or face• 64 paid volunteers -20-30 yr• 38 females 26 males• Psychology students university of Upsalla

• Wired to machine• Measured skin conductance• Shock – uncomfortable not painful• Pics presented on coloured slides 8

seconds• If shock it was immediate• Seated comfortably and told they would

experience shocks and see 3 types of pics

• Order of pics randomised – why?• 32 pps received shocks after snakes• 16 after pics of houses• 16 picks after human faces

Findings

• All participants had a similar measure of skin conductance prior to stimulus and shocks

• Snakes: av 0.062 conductance to snakes• 0.048 to houses and faces• Higher the conductance = more sweat• Physiological response to fear

• Control group: 0.037 to conditioned stimulus• 0.03 to neutral (no shocks)

• Micro mhos

Conclusions

• Pps more likely to show fear reactions to snakes

• Biological preparedness to stimuli that may cause us danger e.g. snakes

• Easier to use classical conditioning to treat phobias of non-evolutionarily relevant stimuli

Role Play

In groups of 4, role play the procedure

section.

If you finish this quickly, you can add

in findings/conclusions.

Evaluation

You are all adept at evaluating studies.

You will have had a go at your own evaluation, I’d like you to now pair up and share your ideas.

Evaluation• G – relatively balanced gender wise• Swedish – ethnocentric?• Psychology students – issues with this?

• R – good controls, therefore easily replicable• Bennet-Levy & Marteu• Mineka et al showed how wild monkeys displayed fear of real, model and toy snakes,

whereas laboratory-reared monkeys showed only a mild response to model and toy snakes, showing lab monkeys had an innate preparedness to fear certain characteristics of the snakes, e.g. their movement. If the ‘snakes’ were moving the lab monkeys showed fear.

• A – helps us to understand the bio basis for phobias and also suggests that conditioning may be an effective treatment

• Provides evidence for both nature (predisposition) and nurture (conditioned responses and treatments)

• V – Good controls • Shows response, but doesn’t explain why to us (no qual. responses)• Lab: low ecological validity

• E – unethical to expose people to potentially distressing stimulus and to condition fear responses?

• Shocks uncomfortable but not painful

Extension/additional information

• Bennet-Levy and Marteau• Overview, but you may research this in more

detail if you wish

• Characteristics not the animal itself that leads to fear – what kind mind they be?

• Asked to rate animals on how they’d feel about certain things e.g. level of avoidance

• Ugliness, speediness, sliminess and suddenness of movement rated also

• Correlation between avoidance and how much of the above they were!

• Most significant relationships were found between nearness and ugliness and nearness and sliminess.

Homework

1.APRCE Watson and Rayner’s Study

Use the booklet + internet + text books at school. For weds