AS ocr psychological investigations

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  • Created by: Emma
  • Created on: 24-05-11 11:51

Likert scales:

strengths: quantitative data, which is easy to stastically analyse. also gives us an idea of how strongly or unstrongly a particpant feels - more detail than a yes or no answer.  

weaknesses: quantitative data is not indepth, particpants may lean towards the middle of the scale. there's a chance of social desirability bias.

self report:

strengths: allow particpants to describe their own expierences rather than inferring from observations. can gain large samples, which increase representiveness and generalisability. can ask people about real life situations and examine a large number of variables.

weaknesses: particpants may not respond truthfully, because of social desirability bias. questions may not be clear to particpant which decreases validity. questions can often be leading, increases chance of demand characteristics.

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Observation: the independent variable is not manipluated. so its not an expieremental method. A undisclosed/covert observation - where the particpants do not they are being observed.

strengths: high in ecological validity, you get to see how particpants actually behave rather than them just telling you. less ethical issues involved in naturalistic observations. can be useful for a starting point in research or creating a hypothesis.

weaknesses: diffcult to repeat. you cannot tell what particpants are thinking or feeling. little control over extraneous variables. observer bias.

a way of checking reliabilty in observations is inter-rater reliabilty. Validity could be improved by keeping the observer unaware of the aim of study, and not telling the particpants they are being observed. Ethics: privacy, informed consent, debreifing.

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lab, quasi (natural) and field.

Lab: because they involve the delibrate manipluation of the independent variable, you can establish cause and effect. the experiments can be replicated because the procedures are standardised.

these type of experiments are conducted in strange and contrived environments. the artifical situation together with the unatural tasks may produce distorted behaviour. << lacking ecological validity. A problem with Lab is demand characteristics and Ethics.

Field: high in ecological validity because particpants are usually unaware they are taking part in an expierment. may avoid demand characterisitcs. much harder to control extraneous variables because conducted in a real life situation. you cant gain informed consent and debreif.

Quasi:  high in ecological valdity, particpants are often unaware they are taking part in an expierment. <<< no demand characteristics + ethical problems... also useful when it would be impossible or unethical to manipluate the independent variable. hard to establish realtionships because the independent variable is not being directly manipulated. hard to replicate.

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Order Effects: acts as a confuding variable. but can be reduced by counterbalancing (rearranging task order)

Hypothesis: one tailed hypothesis: predicting the expected direction of results. two tailed hypothesis: does not predict the expected direction but does state that there will be a difference. the hypothesis that states the expected results is called the alternate hypothesis. The null hypothesis:  is a statement of no difference

reliabilty could be tested by using the ''spilt half method'' - this is splitting a test into two, and having the same particpant do both halves, if both produce similar results this would suggest internal reliabilty. Also ambigous questions could be clarified.

Validity could improved by avoiding leading questions , open questions could be added always to allow particpants to expand on thier replies. confidentiality could be reinforced to allow more truthful responses.

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