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Types of experiments - Coggle Diagram
Types of experiments
- lab exp conducted in highly controlled env
- not necessarily always in a lab - could be a classroom where conditions can be well controlled
:check: high control over EV = research can ensure any effect of the DV is likely a result of manipulation of the IV = we can be more sure about demonstrating cause & effect = high internal validity
:check: replication is easier than in other types of exp because high levels of control. this ensure new EV are not introduced when repeating and exp. replication = vital to check result of any study & see if finding is valid & nor just a one off
:green_cross: may lack generalisability. lab env may = artificial & not like everyday life. in unfamiliar context ppts may behave in unusual ways so their behaviour can't always be generalised beyond the research setting ( low external validity)
:green_cross: ppts are usually aware they are being tested in lab exp & this may also give rise to 'unnatural' behaviour
:green_cross: tasks ppt are asked to carry out in lab exp may not represent real-life experience, e.g. recalling unconnected lists of words as part of memory exp (= low mundane realism)
- in field exp, IV is manipulated in natural, more everyday setting (in the field, not necessarily in a field)
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:check: may produce behaviour that's more valid & authentic, especially because fact ppts may be unaware they are being studied (high external validity)
:green_cross: price to pay for increased realism due to loss of control of EV. means cause & effect between IV and DV in field studies may be more difficult to establish & precise replication is often not possible
:green_cross: also important ethical issues. if ppts are unware they are being studied they cannot consent to being studied & such research may constitute an invasion of privacy
- natural exp is when research takes advantage of pre-existing IV.
- called natural because variable would've changed even if experimenter was not interested
- it's the IV that is natural not necessarily the setting - ppts may be tested in a lab. in a field exp, the setting is natural
:check: natural exp provide opportunities for research which may not otherwise be undertaken for practical/ethical reasons, e.g. studies of institutionalised romanian orphans
:check: often have high external validity because they involve the study of real-life issues & problems as they happen, e.g. effects of a natural disorder on stress levels
:green_cross: naturally occurring event may only happen very rarely, reducing opportunities for research. may also limit scope for generalising findings to other similar situations
:green_cross: ppts may not be randomly allocated to experimental conditions (only happens when there's an independent group design)
- means researcher may be less sure whether the IV affected the DV, e.g. study of romanian orphans the IV was whether children were adopted early or late but there were lots of other difference between these groups such as those who were adopted late may have been less attractive children who noone wanted to adopt
- quasi-exp have an IV based on an existing difference between people (e.g. age/gender)
- no one has manipulated this variable, it simply exists, e.g. if anxiety levels of a phobic and non-phobic patients were compared, the IV of 'having a phobia' would not have come about through any experimental manipulation
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:green_cross: like natural exp, it's not possible to randomly allocate ppts to conditions & therefore there may be confounding variables