2 Research IssuesEcological Validity – degree of which behaviour observed in study reflects everyday life. Takes into consideration:Generalisability – the extent to which the findings can be generalised.Representativeness (mundane realism) – The extent to which the study mirrors real life.
3 TaskConsider some of the following experiments that we have already studied. Write down whether you think they are high or low in ecological validity (consider both generalisability and representativeness) and give reasons to justify your answer.Milgram’s 1963 study of obedience.Hofling et al, 1966 Nurses StudyRank and Jacobsen, 1977 Australian Nurses study.Mandel, 1998 Police Battalion 101.
4 Descriptive Statistics Measures of Central TendencyMeasures of DispersionVisual Display
5 Research IssuesEcological Validity – degree of which behaviour observed in study reflects everyday life. Takes into consideration:Generalisability – the extent to which the findings can be generalised.Representativeness (mundane realism) – The extent to which the study mirrors real life.
6 TaskConsider some of the following experiments that we have already studied. Write down whether you think they are high or low in ecological validity (consider both generalisability and representativeness) and give reasons to justify your answer.Milgram’s 1963 study of obedience.Hofling et al, 1966 Nurses StudyRank and Jacobsen, 1977 Australian Nurses study.Mandel, 1998 Police Battalion 101.
7 Descriptive Statistics Measures of Central TendencyMeasures of DispersionVisual Display
8 Measures of Central Tendency Finding the average of raw data using mean, median or mode.Mean – average (adding and dividing by n)Median – middle value in ordered listMode – most common
9 TaskThe class will be divided in to 5 groups. Each group needs to find the mean, median and mode of their topic.No. of coloured paper clips.No. of coloured pins.No. of SG passes at Credit level.No. of hours slept last night.No. of siblings (including step and half siblings).You must design this task yourself and decide what is the best way to collect the data etc.
10 EvaluationMean – makes use of all data collected but it can be misleading if there are extremes.Median – not affected by extreme scores but not al scores are taken into account.Mode – useful when in categories (ie coloured pins)
11 Measures of Dispersion Another way to describe the statistics is to show how spread out the numbers are.Range - difference between the highest number and the lowest. A set of numbers can have the same mean but a different range.Find the range from yesterday’s tasks.Standard Deviation – requires a mathematical calculator. Measures the spread of the data around the mean.
12 Visual Display Easy and quick way to interpret results. Use your data from yesterday’s task to create a bar chart which simply displays your relevant results.Remember to label the x and y axis.
13 Quantitative and Qualitative Data Quantitative Data – Numbers, raw scores, percentages, means (descriptive data)Easier to analyseSimplifies human behaviourQualitative Data – descriptions, words, pictures, meanings (interviews)Represents the complexity of human behaviour.More difficult to analyse
14 SamplingWhen choosing participants experimenters must choose a selection of the population which are representative of the target population. Types of sampling are:OpportunityVolunteerRandomSystematic
15 Sampling Opportunity - asking people off the street. Anyone who is available.Inevitably biasedVolunteer – advertsOffers access to variety of participants.Volunteer bias – more highly motivated
16 SamplingRandom – Randomly select participants from the complete list of target population.UnbiasedImpossible to obtain complete list.Systematic – selecting every nth member of the target population list.Often mistaken for random sampling – random means taken from a hat/picked from a list without a systematic approach.
17 Ethical IssuesFinding a balance between the aims of the experiment and the rights and wellbeing of the participants.Issues to be considered are:DeceptionInformed consentThe right to withdrawProtection from harmConfidentialityPrivacy
18 Deception Sometimes necessary to secure more accurate behaviour. However – deception is unethical, it may stop participants from giving informed consent (as they are not fully informed) and leads people to believe that psychologists are untrustworthy (not take part in an experiment again)Ethical committee should approve such deception after weighing up pros and cons (subjective).Debriefing (participants may still feel embarrassed).
19 Informed ConsentReveals true aim of the study and may make results invalid.Participants need this information in order to know whether they want to take part.Presumptive consent – asking a group of similar people to the participants if they would agree to take part in the study – if they say yes you can presume that the participants would also agree (what people say and do are very different things).
20 Protection from physical and psychological harm Some of the bigger psychological issues involve participant distress.No harm (physical or psychological) should come to any participants and any risk of harm should be no greater than in the real world.Difficult to predict the outcome of experiments eh Zimbardo’s Prison Experiment.
21 The Right to WithdrawMore difficult in observational field experiments (Piliavin’s Altruism on a train study)Everyone should have the option to quit, even with informed consent people may not be fully aware of what is going to happen.Participants may not withdraw even if they want to through a feeling of obligation.
22 ConfidentialityIf findings are published it may be difficult to promise complete confidentiality despite anonymity (St Helena), as some details may lead to participants being recognised.Data Protection Act – confidentiality is a legal right.Researchers shouldn’t record names.
23 PrivacyDifficult in field experiments. (Middlemist et al, 1976, Pee study)Everyone has a right to privacy.People should not be observed without informed consent unless it is in a public place (what is a public place?)Give retrospective consent and allowed to withhold data. (still acceptable? Someone has just watched you pee!)
24 Ethics Governing Bodies British Psychological Society (BPS) and American Psychological Association (APA).These bodies develop ethical guidelines (see handout) so as they are aware of what is acceptable and how to overcome any ethical issues.Does this absolve the experimenter of responsibility?