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Tuesday, November 9, 2010

How to measure experiments in psychology

How to measure experiments in psychology?
Something that differentiates psychology from other sciences is that the things in which we are interested – mental states and processes – can never be directly observed or measured. You cannot touch or see a mood, a thought, a disposition, a memory or an attitude. You can only observe things that are associated with these phenomena. While this problem does occur in other sciences (such as astronomy), it can often be overcome through technological development (e.g. a better telescope). Psychology has made significant advances too (e.g. measuring skin conductance and brain blood flow), but these techniques still only allow psychologists to study the outcomes of mental activity, or things that are associated with it – never the activity itself. Psychologists have developed three main types of measure to help them examine mental processes and states:
A Behavioural measures These involve observation of particular forms of behaviour in order to make inferences about the psychological phenomena that caused or contributed to them. For example, developmental psychologists (see chapter 9) might observe which toys are approached or avoided by children in a play situation. On the basis of such observations, they might plausibly infer that decisions to approach a toy are determined by the toy’s colourfulness.
B Self-report measures These involve asking people about their thoughts, feelings or reaction to a particular question. Provided that it is possible for the participants to reflect consciously on the relevant thoughts or behaviours, their responses can be used either to supplement other behavioural measures or as data in themselves. So a researcher could ask a six-year-old (but clearly not a six-month-old) ‘Which toys do you like?’ or ‘Did you pick that toy because it was brightly coloured?’
C Physiological measures These involve measuring things that are believed to be associated with particular forms of mental activity. For example, heart rate or galvanic skin response (GSR –a measure of the electrical conductivity of the skin) can serve as measures of anxiety or arousal. In our developmental example, researchers might look at children’s heart rate to see whether they become more excited when particular toys are presented or
taken away.

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