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Dependant + Independent variables Independent = directly manipulated by the experimenter Dependant = the variable affected by the independent variable.

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Presentation on theme: "Dependant + Independent variables Independent = directly manipulated by the experimenter Dependant = the variable affected by the independent variable."— Presentation transcript:

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3 Dependant + Independent variables Independent = directly manipulated by the experimenter Dependant = the variable affected by the independent variable The DV is something which is assessable and measurable to determine if the IV has had an effect Experimental control All other variables must be kept constant so we can only say that one IV is causing the change in the DV Confounding variables Those not controlled which may get in the way of the link between IV and DV Prevents us from interpreting findings Participants and Settings Reduce bias the main way of allocation is by randomisation Advantages Establish causal relationships IV ∞ DV Doesn’t necessarily establish cause and effect = confounding variables Easily replicable Highlight inconsistent findings = replicability Highly objective therefore less subject to researcher bias and more reliable Establish control therefore high internal validity

4 Disadvantages Artificiality low ecological validity low mundane realism – the use of an artificial situation which closely resembles real life Aware that their participants are being observed Demand characteristics – participants try to work out the hypothesis and act accordingly Evaluation apprehension – people are anxious about being observed and want to do well so behave differently Ethical Issues Right to withdraw Inform participants at the start of the experiment Remind participants if they show any signs of distress

5 Carried out in natural settings Control IV and DV Reasonably controlled = replicable Advantages establish the causal effect in terms of IV ∞ DV experimental control means replicability behaviour of participants is more typical : lab therefore high external validity External Validity – the extent to which the research finding can be applied to other situations Disadvantages Ethical Issues – lack of voluntary informed consent impossible to offer the right to withdraw or debriefing Low internal validity = the control of confounding variables is decreased : lab Internal validity – the validity in terms of the context of the experiment e.g. Lab is all about control

6 Make use of a natural occurring event Don’t qualify as actual experiments as you cannot control the IV and DV Advantages Participants behaviour is more typical therefore findings have high external validity Allows us to research effects of IV that would be unethical for researchers to manipulate Disadvantages Selection bias – unable to randomise participants so unable to determine whether the results were due to the manipulation of the IV or the individual differences Lacks internal validity to the extent that you cant fully establish what part of the IV has caused any effect on behaviour Issues with voluntary informed consent Take into account the sensitiveness of the situation

7 When looking to see if one thing leads to another we would be looking for a correlation/link. Disadvantages impossible to establish cause/effect = cant control confounding variables interpretation of results is difficult Advantages allows study of hypothesis that cannot be examined directly obtain large amounts of data much more rapidly and efficiently Easily establish is their is a link Ethics The public may misinterpret information of correlational studies

8 Three types of observational techniques controlled observation researcher controlling environment observations are made e.g. Strange Situation naturalistic observation observe participants in natural situation with no interaction from observer participant observation the observer is directly involved in the interactions of the participants What to record? Event Sampling – focusing only on events of particular interest Time Sampling – observations at specific times Point Sampling – observe one participant at a time

9 Advantages Used in association with lab experiments therefore has the same positive features Less risk of confounding variables more concise and rich information Disadvantages in association with lab experiments has the same negative features investigator effects – expectations of the experimenter demand characteristics – the participants expectations Advantages no demand characteristics or evaluation apprehension = if participants are unaware of observation high external validity Disadvantages Low internal validity Participants are usually aware of being observed = demand characteristics and evaluation apprehension Hard to replicate Ethical issues Undisclosed Observation – participants don't realise their behaviour is being observed

10 Advantages usually long lasting therefore allot of rich data and detailed info certain research couldn’t be carried out successfully without it Disadvantages Ethical Issues – failure to obtain fully informed consent from group members demand characteristics evaluation apprehension subjectivity researcher bias

11 Techniques Non-directive less structure free discussion interviewer directs interview Semi-structured moderate structure identify issue prior similar Q asked Clinical same initial Q flexibility to assess answers Fully structured standard set of Q only allowed to choose from set answers Advantages unstructured = personal rich info. = able to assess the interview structure = info for comparison Structure = controlled, therefore replicable and reliable Structure = used in lab. = positive effects Disadvantages Demand characteristics and evaluation apprehension Researcher bias of unstructured Accuracy = recording data

12 Techniques Fixed choice items e.g. Yes/no open ended – flexible Advantages large amounts of data efficiently easily comparable Disadvantages social desirability bias poorly constructed – less reliability and consistency not easy to compare open ended Q. Fixed choice items may lead to exaggeration of results

13 Advantages large amounts of rich data implications for further research often used to back up negative effects as suggested by theories Disadvantages Data is ungeneralisable to the rest of the population Making use of several techniques such as Q. May lead to researcher bias/interviewer bias

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15 Aims = the purpose of a research study Hypothesis = a testable statement, which specified the IV and DV Hypothesis – 2 types: Experimental/alternative, null Experimental/alternative hypothesis -written prior to the experiment, involving the IV and DV -directional = predicts the nature of the effect of the independent variable on the dependent variable e.g. The presence of artificial light will decrease the effects of sleep deprivation -non directional = predicts that the independent variable will have an effect on the dependent variable, but the direction isn’t specified e.g. The presence of artificial light will have an effect of the effects of sleep deprivation Null Hypothesis -States that any effects are down to chance. -The IV will have no effect on the DV

16 Independent groups design by randomisation one participant is put into one group for each condition Matched pairs design Each participant is selected for only one group, but each is matched on a relevant factor Repeated measures design Each participant appears in each groups Order effects – perform better/worse in the second group Advantages and disadvantages independent groups – no order effects, larger sample size, no loss of participants between trials. Need larger sample size, individual differences matched pairs – no order effects, larger sample size, takes into account individual differences. Need larger sample size, subjective measures when matching participants repeated measures – requires fewer participants, controls the effect of individual differences, counterbalancing( separating the group into half and having each to one of the conditions then switching). Order effects.

17 Define the behavioural categories depends on the hypothesis Decide whether they should be based on interpretation or recording Observers are properly trained in their use so they use them in the same way to increase reliability Ask 2 observers to produce results at the same time

18 non-directive interviews and open questions allot of info, not essential to compare responses, interviewees feel involved, interviewer is well trained structured and closed questions info that is easy to analyse, reliable data, easy to compare, interviewer has limited training take into account individual differences of interviewer and interviewee Three key aspects of a good Q: standardisation reliability validity Standardised tests ones that have been administered to a large representative sample so that an individuals score can by compared against that of others Reliability consistent findings – test retest method Validity refers to the extent to which a questionnaire is measuring what it is supposed to be measuring

19 Operationalisation defining all variable n such a way that it is easy to measure them Pilot Studies A smaller preliminary study that makes it possible to check out standardised procedures and general design before investing time and money in the major study check standardised procedures checking details of study are appropriate may indicate if the participants don't understand the experiment useful when deciding between 2 ways of doing the study shed light on the appropriate amount of participants

20 anything that could affect the DV avoid extraneous variables that are also confounding variables Reliability refers to consistency of results test retest method split half technique Validity Internal = whether the results are due to the IV External = generalisability of results to other situations ethical commitees – psychologist, non-psychologists Ethical guidelines that must be followed, however they are always changing

21 Deception Informed consent Right to withhold data Protection from harm Deception Role play experiments Debriefing Informed consent 2 other types presumptive consent – if a set amount of people regard the procedure as appropriate then all people to prior general consent – consent before the experiment Deal by debriefing, right to withhold data Protection from harm physical harm psychological harm confidentiality right to privacy protection of the participants from psychological harm

22 Random Sampling systematic sampling Opportunity sampling Volunteer Sampling volunteer bias Sample size


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