PSYCHOLOGICA L INVESTIGATION S EXPERIMENTS AS Psychology QUESTION

PSYCHOLOGICA L INVESTIGATION S EXPERIMENTS AS Psychology

QUESTION: WHAT MAKES A PIECE OF RESEARCH AN EXPERIMENT? AS Psychology

Variables A basic experiment has two variables. A variable is. . . A thing which can vary or change. In psychological experiments we use two types of variables: Independent Variable – experimenter is the variable the manipulates Dependent Variable – is the variable the experimenter measures

ACTIVITY! Each person will read out their experiment description If you have the card with the correct IV, stand up and read it Then it’s the turn of the person with the correct DV

IV: TIME OF DAY TESTED IV? DV? DV: NUMBER OF WORDS RECALLED Do students recall more words from a list in the morning or evening?

IV: TESTED IMMEDIATELY OR AFTER 30 MINS IV? DV? DV: NUMBER OF FACES IDENTIFIED Can students identify actors’ faces better straight after a film or after a delay of 30 mins?

IV: MUSIC OR NO MUSIC IV? DV? DV: A LEVEL GRADES Does listening to music while revising affect A level grades?

IV: 4 OR 8 HOURS SLEEP IV? DV? DV: TIME TAKEN TO REACT TO A STIMULUS Are reaction times slower for drivers who have had 4 hours sleep or 8 hours sleep?

IV: FOOTBALL FAN OR NOT IV? DV? DV: NUMBER OF SCORES RECALLED FROM A LIST Will football fans be able to remember a list of football scores better than non-football fans?

IV: PARTICIPANT GENDER IV? DV? DV: FACIAL EXPRESSIONS CORRECTLY IDENTIFIED Do women read facial expressions better than men?

IV: COMPETING WITH OTHERS OR ALONE IV? DV? DV: NO. OF PRESS-UPS COMPLETED Will participants complete more pressups when in competition with other people than alone?

IV: TEA/COFFEE/CO KE DRUNK OR NO DRINK IV? DV? DV: GRADE IN A MATHS TEST AFTER A NEW TOPIC Does caffeine affect ability to understand new mathematical concepts?

What is a hypothesis? ? ? A hypothesis is a statement or prediction of the results you expect to find after your experiment. It must include descriptions of the IV and DV

Examples from studies you know: Maguire: There will be a difference between the hippocampi of taxi-drivers and non-taxi-drivers Griffiths There will be no differences in the skill levels of RGs and NRGs Dement & Kleitman There will be an association between REM sleep and dreaming

What does ‘operationalisation’ mean? Ensuring that variables are in a form that is easily testable / measurable; it has to be very specific so that the reader knows exactly what you mean and how you are going to measure that variable

Try operationalising these DVs: Educational attainment Memory Driving skill Happiness Helpfulness

Null Hypotheses As well as writing an ‘experimental’ hypothesis when carrying out research, you will also need to write a null hypothesis. What is a null hypothesis? A null hypothesis is a statement that the IV will make no difference to the DV

Your hypotheses might be: Null hypothesis There will be no difference in the exam performance of students whether they have a computer in their home or not Alternative hypothesis: Students who have a computer at home will achieve higher grades in their AS exams than those who don’t.

Your hypotheses might be: Null hypothesis Alternative hypothesis: People eating 5 portions of fruit and vegetables a day will live longer than those who don’t.

Your hypotheses might be: Null hypothesis There will be no difference in the lifespans of those who eat 5 portions of fruit and veg a day and those who don’t. Alternative hypothesis: People eating 5 portions of fruit and vegetables a day will live longer than those who don’t.

Your hypotheses might be: Null hypothesis Alternative hypothesis: Men whose wives stay at home while they go out to work will have a happier marriage than those wives work

Your hypotheses might be: Null hypothesis There will be no difference in the happiness of marriages whether the wife stays at home or goes out to work Alternative hypothesis: Men whose wives stay at home while they go out to work will have a happier marriage than those wives work

One-tailed and two-tailed hypotheses NOTE!: (these both refer to the alternative hypothesis, not the null)

One-tailed and two-tailed hypotheses One-tailed hypotheses are predictions that state One-tailed hypotheses the direction the results will go in. This is also known as a ‘directional hypothesis’. It states that not only will be there be an effect but Eg: Students willberemember you know what effect that will words better in a cold room than a warm one

One-tailed and two-tailed hypotheses Two-tailed hypotheses are predictions that do Two-tailed hypotheses not state the direction the results will go in. This is also known as a non-directional hypothesis. It states that you think there will be an effect but you don’t know exactly what that effect will be Eg: There will be a difference in the number of words students remember in a hot or cold room

One-tailed or two? ? Think – does this state what the effect will be, or just that there will be an effect? Boys score differently on aggressiveness tests from girls

One-tailed or two? ? Think – does this state what the effect will be, or just that there will be an effect? People remember the words that appear early in a list better than the words that appear later

One-tailed or two? ? Think – does this state what the effect will be, or just that there will be an effect? People given a list of emotionally charged words recall less than participants given a list of emotionally neutral words

One-tailed or two? ? Think – does this state what the effect will be, or just that there will be an effect? Hamsters are better pets than budgies

One-tailed or two? ? Think – does this state what the effect will be, or just that there will be an effect? Words presented in a written form are recalled differently from those presented in a pictorial form

Pick one of the following scenarios and write a null and an alternative hypothesis for it; then state whether you have written a one-tailed or two-tailed alternative hypothesis Do students recall more words from a list in the morning or evening? Can students identify actors’ faces better straight after a film or after a delay of 30 mins? Does listening to music while revising affect A-level grades? Are reaction times slower for drivers who have had 4 hours sleep or 8 hours sleep? Will football fans be able to remember a list of football scores better than non-football fans? Do women read facial expressions better than men? Do better-qualified people borrow more library books than people with few qualifications?

Experimental Design Independent Groups Repeated Measures Matched Pairs • Different participants take part in each ‘condition’ of the study, e. g. one group studies with TV, one group • The same participants take part in two different conditions, e. g. studying for one test with TV, one without TV • Participants are matched (e. g. two students with similar scores on earlier tests) and one takes part in each condition

EXPERIMENT 1 - real words v. nonsense You are going to take part in two experiments to demonstrate how each of these designs work in practice. Repeated measures design Learn the items paper frontword of you. You willon bethe given oneinmore list. You 1 have 1 min to study the afterand this then time 1 turn the sheet over minute toitems, memorise minute to and write down as many of the words items as you can remember. write down as many You haveremember 1 minute to do this.

That was a repeated measures design experiment because. . . ? The same participants did both conditions (Nonsense and real words)

Independent measures design; words v pictures Each participant only takes part in one condition, e. g. Words or pictures. Half the participants are allocated to one condition and half to the other Let’s have a go at that now!

EXPERIMENT 2 - words v. pictures Independent measures design You will ALL be a given a piece of paper for which you must memorise the ten items for ten items 1 minute and then you will be asked to write down as many items as you can remember in 1 minute.

That was an independent measures design experiment because. . . ? Different participants did both conditions (Words and pictures)

Experimental design. . . s h t g n e See textbook p 15 e s s e n k r t a S e W ? ? s Ensure that you can think of strengths and weaknesses for repeated measures and independent measures designs. How might you overcome them? What about matched pairs?

Strengths and weaknesses of experiments in general, compared with other research methods Strengths Enable you to test hypotheses by manipulating of an IV; therefore can assume cause and effect Scientific as follow standardised procedures, enabling replication Weaknesses Often low in ecological validity as the situations don’t reflect everyday life Control extraneous variables, improving reliability Often produce quantitative data which can be analysed May stress participants due to unfamiliar tasks/surroundings Often don’t get deep understanding due to lack of qualitative data Practical problems mean sample sizes are often small, reducing generalisability

Strengths Weaknesses Lab experiments High levels of control means only the IV can affect the DV Low in ecological validity meaning doesn’t tell us about real life behaviour Field experiments Lower levels of control Higher in ecological validity Quasi experiments Only way of studying some IVs such as gender Other features of the group may be confounding variable Independent measures No order effects No demand characteristics as they don’t guess the purpose of the study Other features of the group may be confounding variable Repeated measures Removes individual differences as you are comparing the group against themselves Order effects Greater likelihood of demand characteristics Matched participants Extraneous variables are Other variables may still well controlled exist

How might you have to use this information on the exam paper? Let’s have a look. . .

Section B A researcher wants to conduct an experiment to investigate if there is a difference in the memory ability of primary school pupils in the morning compared to the afternoon. Each pupil will be assessed in both the morning and the afternoon. a) Describe and evaluate one way in which memory could be measured in this investigation (10) b) Explain the difference between an independent and repeated measures design (4) c) Outline one strength and one weakness of using a repeated measures design for this investigation (6)