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  • 1. Research Methods Aims Hypotheses Variables Operationalisation Experiments(Laboratory/Field/Natural) ExperimentalDesigns How does a psychologist design an investigation?
  • 2. ResearchMethods Aims The starting point forany research studyis to generate appropriate aims. Aims are general statements ofwhat the studyis tryingto do and whyit is being carried out.Forexample, the aim is to investigate whethergiving children vitamin pills improves their IQ. Hypotheses The aim ofteninvolves testing one ormore hypotheses. A hypothesis is a clear, testable statement. It is a prediction made at the beginningof the study,written in the present tense. For example, participants wholearn a wordlist before sleeping recall more wordsthan those wholearn the list after waking. There are two kinds ofhypothesis: 1. A directionalhypothesispredictsthe direction in whichresults are expected to occur.For example, more wordsare recalled correctlyfrom a list whenusingrehearsal as a memory improvement technique thanwhen nomemory improvement techniqueis used. Inthis case, weare predictingnot only that there will be a difference between the numberof wordsrecalled, butthat more will be recalled in one conditionover another. 2. A non-directionalhypothesisdoesnot predict the expected directionof the difference.For example, there is a difference inthe number ofwordscorrectly recalled from a list when presented with backgroundmusic thanwhen nomusic is presented. This hypothesis still makes a prediction,but doesn’t state whichconditionwill lead to better recall. Example Directional/Non-directional Psychologyteachers preferthe taste of Coca-Colatothe taste of Pepsi. The consumptionof daily fishoil supplementswill have aneffectonthe concentrationlevelsof childrenwhencompleting schoolwork. Womensolve jigsawpuzzlesfasterthanmen. There will be adifference betweenthe numberof attemptsneededtolearn a simple maze bya groupof five ratsand byOne Direction. Womenare more likely thanmentowaitfora greenlighttoappearat a pedestrian crossingbefore crossing. There will be adifference betweenthe scoresof malesandfemalesona standardIQ test. There will be adifference betweenthe numberof tomatoesproducedby plantsingrow bagsand plantsinthe ground. Bullswill charge more oftenwhenpresentedwitharedrag, than when presentedwithablue rag. Childrenaged5-10 are able toname more cartooncharacters than teenagers aged13-18. Championshipfootballersscore fewerpenaltiesthan2nd divisionplayers. Variables
  • 3. ResearchMethods A variable is just something that can change, or vary. In an experiment theresearcher is trying to find out whether a particularvariable, the independent variable (IV) has an effect on a specific aspect of human behaviouror mental process, thedependant variable (DV). However, in order to be certain that any changes in the behaviourbeing measured are caused by themanipulationof theindependent variable,everything else must becontrolled bythe researcher and kept constant. For example, in an experiment investigating the effect of noise (IV) on memory (DV)all othervariables, called extraneous variables, must be controlled,such as thetime given to each participant to learn thematerial to be memorised, thetesting room, temperature and thetime of daythe testing takes place.If these extraneous variables are not controlled thentheycan confound thefindings of a study, and so become confoundingvariables. The variables in an experiment are referred to as theIV and theDV. However, in a correlational investigationtheyare referred to as co-variables since theaim is to discover whethertwo variables are related to each other,not whetherone (IV) directly affects another(DV). Research Study Extraneous Variable(s) How could it be overcome? An investigationinto the effect of organisationon memory. A list of 50 items that couldbe bought at a supermarket were used. One group saw thewords organised into categoriessuch as fruit, dairyproducts and cleaning materials. The other group saw the same words presented randomly. An investigationinto the effects of day care on aggression. A group ofchildren who started daycare before theageof two years were compared with a group of childrenwho started after theageof two years. The researcher assessed each childandgave them an aggression score. An investigationinto the effect of rewards in highereducation.One collegeoffered a £20.00 reward to its students for each AS level they achieved at gradeA. A different college in the same area didn’t giveany monetary awards to its students for achieving an A grade. Operationalisation
  • 4. ResearchMethods The term operationalisationmeans defining all variables in such a way as to beable to measure themin a specific way. For instance, there is no single way to best measure some psychologicalconcepts,such as aggression and memory. Therefore, psychologistsdefine each variablein terms of theoperations takento measure it. For example, in an investigationthat involves measuring memory, thepsychologist couldoperationalise memory in terms of the number ofcorrectly recalled words from a list of twenty. This is a very specificmeasurement. What is an experiment? Hypothesis Operationalisation Independent Variable Dependent Variable Gender affects sports performance There is a gender difference in thenumber of basketballhoopsscored in ten minutes. being instructed to form a mental imageof each word or being given no instruction thenumber of words correctly recalled from a list offifty A person experiencing a sad moodwill comfort eat The viewing of a happy movie will leadto less popcornbeing consumed compared to theviewing of a sad movie. number of Facebookfriends number of real- life friends an audience made up of 50 adults or no audience thetime taken to completea jigsaw puzzle Daycare affects a child’s sociability A childwho starts day care before theageof 2 years has fewer friends thana childwho starts daycare after theage of 2 years.
  • 5. ResearchMethods Anexperiment involves an investigation into whether an independent variable,eithermanipulated by the researcher or naturally occurring,hasan effecton anaspect of behaviour,termed the dependent variable.There are numberof waysof conductingexperimentseach with their own strengths andweaknesses. Laboratory Experiment This takes place in a carefully controlled setting. The researcher manipulates the independent variable, the thing that they decide to change,whilst measuring the effectsof that changeon the dependent variable, the thingthat they measure. A standardised procedureis used, so that eachparticipant is treated in exactly the same way.It is important tonote that it doesn’t have to be a sciencelab, a roomset aside fora Psychologyexperiment would still be classed as a laboratory. Field Experiment This takes place in a natural setting, like a towncentre,hospital wardor a work office.Aswith a laboratory experiment, the researcher still manipulates the independent variable and measures the effectsof that changeon the dependent variable. A standardised procedureis used, so that eachparticipant is treated in exactly the same way. Natural Experiment A naturally occurringindependentvariable is utilised, so the researcher doesn’t manipulate it themselves. Forexample, comparingthe effectson an infantof the length oftime spent in day care. The researcher cannotmanipulate how long a child spendsin day care, as this is decided by somebody else, usually the child’s parents.However, the researcher canutilise this naturally occurringvariable and conductaninvestigation. The experiment may take place in a laboratory or a natural environment. Example Laboratory/Field/Natural A psychologistbrought40 professional athletes into a medical research facility at his university and tested their physical stamina before and after taking a courseof multivitamins and minerals. A psychologistput upposters advertising for university studentsto take part in a study onreaction times. They had to pressa buttonona keyboard when an ‘x’ appeared on a screen. A psychologistwent shoppingin Newcastle wearing a Sunderland football shirt on matchday. He pretended to collapse on the pavement and counted whether more Newcastle or Sunderlandsupporterscame to help him. A psychologistvisited the toilets of his local nightcluband conductedastudy where he invaded the personal space ofother men at the urinals and noted how long it took forthem tostart urinating. A psychologistconducteda studywhere he comparedthe self-perceptions of patients sufferingfrom anorexia nervosa, bulimia nervosaand obesity. Strengths Weaknesses
  • 6. ResearchMethods Laboratory Laboratory Field Field Natural Natural
  • 7. ResearchMethods 1. As a research psychologist youhavebeen approached bythegovernment to investigatethe aggressive tendencies of a new breed of dog,the‘Chavadidas’,to see whetherit shouldbe placed on thegovernment’s dangerous breeds list or not. What would theprocedure for each of thefollowing typesof experiment consist of? Laboratory Field Natural 2. As a research psychologist youhaverecently read that taking omegafish oilsupplements can improve your brain function, aiding concentration, memory and possiblyeven intelligence.In preparationfor your AS Psychologyexaminations youdecideto undertake three experiments to investigatewhetherit is worth taking a course of omegaoils. What would theprocedure for each of thefollowing typesof experiment consist of? Laboratory Field Natural
  • 8. ResearchMethods What is an experimental design? The way in which the participantsare ‘organised’ into groups in an experiment is called the design of theexperiment. There are 3 different experimentaldesigns used by psychologists: 1. Independent groups:Thisinvolves different groups of participantsin each conditionof theexperiment. It may consist of a control conditionandone or more experimental conditions.For example, one group of participantstakea new anti- depressant daily,whereas theothergroup takeno drug. Thetwo groups are compared after 6 weeks in terms of the severity of theirdepressive symptoms. 2. Repeated measures:This involves the same group ofparticipantsin each conditionof theexperiment. For example, theparticipantsare given a speech to learn whilst thetelevisionplayed in the background and were then tested on their recall. They were thengiven a different speech to learn in a silent room and theirperformance was compared with their first performance. 3. Matched pairs: This involves different groups of participantsin each conditionof theexperiment. However, each participant in thefirst conditionof theexperiment is matched closelywith anotherparticipant in thesecond conditionon all thevariables considered to be relevant to theexperiment. For example, participantsmay be matched for age beforean investigationinto the effect of music on memory, since age mayconfound thefindings of thestudy. Task Alton Towers have commissioned youto conduct research into whether rollercoasters or water rides are more exciting for visitors. Howwould you carry out FIELD experiments using each design? Independent Groups Repeated Measures Matched Pairs
  • 9. ResearchMethods Design Advantages Disadvantages How could you deal with this issue? Independent Groups 1 1 2 2 Repeated Measures 1 1 2 2 Matched Pairs 1 1 2 2
  • 10. ResearchMethods Example Which experimental design was used? 1. In order to assess theeffects of fatigueon reactiontimes, a researcher gave participantsa target detectiontest in which theypressed a buttonevery time a dot appeared on a screen. The time between thedot appearing and thebuttonbeing pressed was recorded. The participantsdidthetest twice, once first thing in themorning and once last thing at night. 2. In order to compare theeffectiveness of two different typesof therapyfor depression, depressed patients were assigned to receive eithercognitive therapyor behaviourtherapyfor a 12-week period.The researchers attempted to ensure that thepatientsin thetwo groups hada similar severity of depressed symptoms by administering a standardised test of depression to each participant,thenpairing them according to the severity of theirsymptoms. 3. In order to assess theeffect of organisationon recall, a researcher randomly assigned student volunteers to two conditions.In conditionone theparticipantsattempted to recalla list of words that were organised into meaningful categories, whereas in conditiontwo the participants attempted to recall thesame words, randomlygrouped on thepage. 4. In order to assess thedifference in reading comprehension between 7 and 9-year-olds, a researcher recruited a group of each from a localprimary school.Theywere given thesame passageof text to read, and then asked a series of questions to assess their understanding. 5. In order to assess theeffectiveness of two different ways of teaching reading, a group of 5-year-olds were recruited from a primary school.Their level of reading abilitywas assessed, and then theywere taught using scheme 1 for 20 weeks. At theend of thisperiod,their reading was reassessed, and a reading improvement score was calculated.They were then taught using scheme 2 for a further 20 weeks and anotherreading improvement score for thisperiodwas calculated.The reading improvement scores for each childwere thencompared.
  • 11. ResearchMethods 1. Why it was necessary to use a matched pairs designin experiment 2? 2. If you were to redesign experiment 5to use a matched pairs design, what variable(s) would youuse to match theparticipantsand why? 3. Can you suggest whya repeated measures design would beinappropriate for experiment 3? 4. Are thereany disadvantages of a repeated measures design that couldaffect the findings of experiment 1? 5. How couldcounterbalancing beused in experiment 5? 6. Are thereany participant variables that couldhave affected thefindings of experiment 4? 7. How didtheresearcher in experiment 3 try to avoid theproblemof participant variables?
  • 12. ResearchMethods Task 1 A psychologist showed participants100 different cards, one at a time. Each card hadtwo unrelated words printed on it, eg DOG, HAT. Participantsin one group were instructed to form a mental image to link thewords. Participantsin theothergroup were instructed simply to memorise thewords. After allthe word pairs hadbeen presented, each participant was shown a card with thefirst word of each pair printed on it. Participantswere asked to recall thesecond word. Thefollowing results were found. a) What is theindependent variable (IV)in thisstudy? (2 marks) b) What is thedependent variable (DV)in this study?(2 marks) c) What experimental design was used in thisstudy? (1 mark) d) Explain one strength of this experimentaldesign in thecontext of this study. (2 marks) e) Explain howa psychologist couldfindout whetherthese results are reliable.(2 marks) Task 2 A researcher carried out an experiment to investigatehow many numbers couldbe heldin short-term memory. Theparticipantswere 15 childrenand 15 adults.Participants were asked to repeat lists ofrandom numbers, in thecorrect order, as soon as theywere read out bythe researcher. For example, when theresearcher said, “3, 4, 2, 8” theparticipant immediatelyrepeated “3, 4, 2, 8”. When theresearcher then said, “7, 5, 9, 6, 4” the participant immediatelyrepeated “7,5, 9, 6, 4”. One number was added to the list each time until participantswere unable to recallthe list correctly. Each participant’smaximum digit span was recorded.
  • 13. ResearchMethods a) Write an appropriatenon-directional hypothesisfor thisexperiment. (2 marks) b) Explain whythe researcher used an independent groupsdesign for this experiment. (2 marks) c) Write themode for each group in the tablebelow. (2 marks) d) What does thefrequency distributionshowabout the results? (3 marks) Task 3 A psychologist carried out an experiment using an independent groupsdesign. The psychologist wished to investigatetheeffectiveness of a strategyfor memory improvement. In one condition,participantswere taught amemory improvement strategy. In theothercondition,participantswere not taught thismemory improvement strategy.All participantswere asked to memorise 10 pictures of familiar objects.For example, the first was a doll,thesecond was an apple.All participantswere then given 50 pictures each, and asked to select theoriginal10. The psychologist didapilot studybeforecarrying out the experiment. a) Write a directionalhypothesisforthisexperiment. (2 marks)
  • 14. ResearchMethods b) Explain what is meant byan independent groups design. (1 mark) c) Explain one strength and one limitationofusing an independent groups design. (2 + 2 marks) Task 4 A researcher investigated the effect of age of starting day care on levels ofaggression. Four-year-old childrenattending a daynursery were used. Each childwas assessed by the researcher and given an aggression score. A high score indicated a high levelof aggression. A low score indicated alow level of aggression. The maximum score was 50. Table 1 Mean aggressionscores for four-year- old children who had started day care before the age of two or after the age of two a) Identifytheoperationalised independent variable and theoperationalised dependent variable in this study. (2 + 2 marks) Operationalised independent variable Operationalised dependent variable b) What do themean scores in Table 1 suggest about theeffect of ageat which children started daycare on children’saggression? (2 marks) c) Statean appropriatedirectionalhypothesisforthis study. (2 marks)

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