more issues w/ experiments

• demand characteristics: participants want to be helpful and therefore they pay attention to cues in the experimental situation that may guide their behaviour
• demand characteristics: study by Martin Orne = participants had to sit in a room on their own for 4 hours, 1 group of participants were asked at the beginning of the study to sign a form releasing the experimenter from responsibility if anything happened to them during the experiment
• demand characteristics: they were also given a panic button to push if they felt overly stressed, the other group were given no information to arouse their expectations
• demand characteristics: the 1st group showed extreme signs of distress during isolation, this can only be explained in terms of expectations created by the situation (Orne and Scheibe, 1964)
• demand characteristics: Orne invented the term demand characteristics to describe the effect of expectations and define them as 'the totality of cues that convey the experimental hypothesis to the [participant] become determinants of the [participants] behaviour (Orne, 1962)
• everyday demand characteristics: watching a football game at home you might sit relatively quietly but on a football ground you would chant and jump up and down, these different situations create different expectations and 'demand' different behaviours
• experimental demand characteristics: in an experiment participants are often unsure about what to do, they actively look for clues as to how they should behave in that situation, these clues are demand characteristics - which collectively convey the experimental hypothesis to participants
• experimental demand characteristics: a participant is given 2 memory tests (repeated measures) 1 = morning, 1 = afternoon, participants might try to guess why they are being given 2 tests and correctly work out that the study is looking at the effects of time of day on performance, this might lead the participant to try to perform the same on each test
• experimental demand characteristics: boys + girls are compared to see who is more friendly, a questionnaire is used to access friendliness, it is quite apparent that the questions are about friendships, this leads participants to guess the purpose of the questionnaire, the girls want to help and give answers showing how friendly they are, the boys are a bit contrary and give answers that show how unfriendly they are
• experimental demand characteristics: in both cases the result is that participants do not behave as they would usually, they have altered their behaviour as a consequence of cues in the research situation, thus demand characteristics may act as an extraneous (confounding) variable
• investigator effects: investigator effects are any cues (other than the IV) from an investigator that encourage certain behaviours in the participant and which might lead to a fulfillment of the investigator's expectations
• investigator effects: such cues act as extraneous or confounding variables, there is a study by Robert Rosenthal and Kermit Fode (1963)
• investigator effects: students were asked to train rats to learn the route through a maze, the students were told that there were 2 groups of rats one group consisted of 'fast learners' having been bred for this characteristic and the other comprised 'slow learners'
• investigator effects: in fact there was no difference between the rats
• investigator effects: the findings of the study showed that the supposedly bright rats actually did better, when the students were asked afterwards about their rats those w/ 'fast learning' rats described them as smarter, more attractive and more likable than the descriptions given by the other group of students, the only explanation can be that the student's expectations affected the rat's performance
• investigator effects: so ever rats were affected by investigator expectations how? = investigators unconsciously encourage participants by e.g. spending more time w/ 1 group of participants or being more positive w/ them e.g. research has found that males are more pleasant and friendly w/ female participants than w/ other male participants (Rosenthal, 1966)
• investigator effects: w/ human participants the way in which an investigator asks a question may lead a participant to give the answer the investigator 'want'
• indirect investigator effects: there are also indirect investigator effects such as the 'investigator experimental design effect', the investigator may operationalise the measurement of variables in such a way that the desired result is more likely or may limit the duration of the study for the same reason
• indirect investigator effects: the 'investigator loose procedure effect' refers to situations where an investigator may not clearly specify the standardised instructions and/or standardised procedures which leaves room for the results to be influenced by the experimenter
• in early psychological research the people in the studies were called 'subjects' a reason it changed to participants is because the term 'subject' implied that those involved must be obedient and are powerless whereas in fact psychologists owe them a great deal for their willingness to take part - its an equal partnership
• single blind design: in a single blind design the participant is now aware of the research aims and/or of which condition of the experiment they are receiving, this prevents the participant from seeking cues about the aims and reacting to them
• double blind design: in a double blind design both the participant and the person conducting the experiment are 'blind' to the aims and/or hypotheses, therefore the person conducting the investigation is less likely to produce cues about what they expect
• experimental design: if the researcher makes an experimental task sufficiently engaging the participant pays attention to the task and not the fact that they are being observed
• participant variables: a participant variable is any characteristic of individual participants, participant variables are not the same as participant effects, demand characteristics are an effect of participant's behaviour whereas a participant variable is a characteristic of participants
• participant variables: participant variables act as extraneous variables only if an independent groups design is used, when a repeated measures design is used, participant variables are controlled, in a matched pairs design participant variables are hopefully controlled
• participant variables: participant variables include age, intelligence, motivation, experience, gender etc.
• participant variables: students often identify gender as an extraneous variable and it may be, e.g. Alice Eagly (1978) reported that women may be more conformist than men, this means that having more women than men in one condition of an experiment might mask the effects of the IV
• participant variables: however it is important to realise that gender only acts as an EV in some circumstances e.g. we would not control gender in a memory experiment unless we have a reason to expect that it would matter, when considering participants variables as EVs we need to focus on those that are relevant to the task
• situational variables: situational variables are those features of a research situation that may influence participants' behaviour and thus act as EVs or confounding variables one example of a situational variable is order effects
• participant variables: improved participant performance may be due to practice (a confounding variable) rather than the IV, situational variables are only confounding if they vary systematically w/ the IV e.g. if all members of 1 group are tested in the morning and all members of the 2nd group are tested in the afternoon