Two Key Studies of a Biological Explanation of Phobias (DP IB Psychology)

Key study one: Ohman et al. (1975)

Aim: 

• To investigate Biological Preparedness linked to snake phobia (ophidiophobia)

• To investigate whether snake phobia be more easily conditioned than phobia for stimuli which pose no immediate threat e.g. houses, faces

Participants: 

• 64 participants (38 female; 26 male, aged 20-30 years) from the University of Uppsala in Sweden

• All of the participants were Psychology students who comprised a self-selecting sample

• The participants were paid to take part in the experiment

Procedure: 

• Each participant was wired up  to a machine that measured skin conductance 

• The participants were given a trial electric shock to determine the level which they found uncomfortable but not painful

• Participants were told that they would be viewing a series of images and that after some of the images they would receive a shock

• There were three conditions of the independent variable:

  • Half of the participants received shocks after viewing images of snakes

  • A quarter of the participants received shocks after viewing images of houses

  • A quarter of the participants received shocks after viewing images of faces

• Each image was shown for 8 seconds

Results:

• Participants in the ‘snakes’ condition responded with 0.062 skin conductance but only 0.048 when they viewed the houses or the faces (after which they were not given a shock)

• Participants in the ‘snakes’ condition sweated more than participants in the other two conditions which is evidence of an increased physiological response (e.g. fear)

• Participants in the ‘houses’ and ‘faces’ conditions showed a lower skin conductance rate of 0.037 

Conclusion:

• Viewing images of snakes in the presence of an electric shock may increase the fear response to snakes in general

• The results support Biological Preparedness as an explanation for phobias i.e. that humans may have evolved a mechanism to avoid dangerous stimuli such as snakes

• Participants should have shown similar levels of fear to all the stimuli as they were all paired with the shocks: the fact that, over time, the 'snakes’ condition still showed higher fear than the others suggests there is an underlying biological/evolutionary cause

Evaluation of Ohman et al. (1975)

Strengths

• This was a well-designed lab experiment using distinct, operationalised variables within a standardised procedure which means that it is replicable and can thus be checked for reliability

• The use of the biological measure of skin conductance is almost impossible to fake which reduces the possibility of demand characteristics influencing the findings

Weaknesses

• There are some issues with the ethical validity of this study: showing fear-inducing images and issuing electric shocks to participants brings with it real concerns for the participants’ psychological and physical wellbeing

• The researchers inferred that the higher skin conductance in the ‘snakes’ condition was due to viewing the snakes in the presence of a shock but the results could be due to other factors e.g. nervousness, anxiety about the procedure, rather than a fear of snakes

Can measuring skin conductance provide evidence for Biological Preparedness?

Key study two: Ahs et al. (2018)

Aim: To investigate Biological Preparedness as a valid explanation of phobias.

Procedure: 

• The researchers conducted a review of existing literature (published, peer reviewed research) which had investigated fear-conditioning experiments

• A total of 23 studies were used in the review which included 32 experiments, giving a combined total sample size of 1887 participants

• The studies in the review had been published between 1975 and 2018

• Each study in the review had used procedures which aimed to decondition fear of spiders (arachnophobia) and fear of snakes which involved showing participants a series of images designed to lead to extinction of the conditioned phobia

• If the participants showed resistance to deconditioning of their snake/spider phobia then this would act as evidence that such phobias are innate and are a result of Biological Preparedness

Results:

• 22 of the 32 studies in the review reported that participants with snake/spider phobia had been successfully deconditioned i.e. their phobia had disappeared

• Only 10 of the 31 studies reported an increased resistance to snake/spider phobia extinction

Conclusion: 

• Biological Preparedness may not be a 100% valid theory to explain phobias

• Biological Preparedness cannot successfully explain the origin of specific phobias

Evaluation of Ahs et al. (2018)

Strengths

• A review of the literature on a specific topic allows researchers to access a high number of studies incorporating much data and a large total sample size which increases the reliability of the findings

• The researchers who conducted this study are unlikely to have succumbed to researcher bias in their analysis of the studies reviewed as they used other people’s work over which they had no influence

Weaknesses

• The researchers had no way of knowing how the original studies in the review had been conducted which could be an issue in terms of consistency and reliability

• The researchers may have succumbed to selection bias in choosing research for the review which would decrease the validity of their conclusions