Nigel Holt and Rob Lewis - Crown House Publishing.

14 | A2 PSYCHOLOGY: THE STUDENT’S TEXTBOOKCORRELATIONSadvantagesweaknesses●●Naturally occurring variables can be measured and ●●Cannot imply cause or effect, and variables area relationship between the two identified. This may almost impossible to control. Even if the analysislead to future research.indicates that there is no relationship we cannot becertain of that. It could be that something else thatwe have not measured or considered is happeningthat the analysis is not sensitive to.A correlation coefficient of near to +1 means thatthere is a strong positive correlation between thetwo variables. As one goes up, so does the other.For instance, the longer it rains, the wetter you willget if standing outside. This may not be a perfectpositive correlation because it may be that at somepoint your clothing becomes completely saturatedand, however much more rain falls on you, youcannot possibly get any wetter.Correlations are represented on scattergraphs (alsoknown as scattergrams). On page 13 we have threescatterplots identifying the relationships describedabove.Do not think that correlation means cause. It doesnot. Just because two variables are positively correlateddoes not mean that one causes the other.For instance, it is extremely likely that were you tocollect the data you would find that the numberof cars on the roads of the United Kingdom hasrisen steadily over the last 10 years. You would alsoprobably find that the number of people takingholidays abroad has gone up. The two variables(car sales and holidays abroad) are likely to bepositively correlated. We cannot conclude, however,that increased car sales have caused peopleto take more holidays. There may be a third factorthat we have not considered, such as ‘amount ofdisposable income’ that is related to both of thesevariables, but that we have not measured.Watch Out! Demandcharacteristics andinvestigator effectsThere are a few things to keep in mind whendesigning research. Demand characteristics, investigatoreffects, reliability and validity can all causeproblems for a researcher.Demand characteristics – Something in aresearch design may change a participant’sbehaviour. If this happens then your data will notgive you a true picture of what’s going on in yourstudy. For instance, participants who know somethingabout the procedure may alter their behaviourto provide the researcher with the responsesthey think the researcher would like. Researchersoften design ‘single blind’ procedures to eliminate,or at least attempt to eliminate, demand characteristics.These are procedures where participantsare kept naive about the aims of the research. Itis the job of the researcher to plan the study so asto minimise demand characteristics. Eliminatingthem is often very difficult indeed.Investigator effects – These are a little likedemand characteristics, but you should try not tomix them up! Research suffers with investigatoreffects when the researchers themselves influencethe behaviour of the participant in some way. Theymay not do so on purpose, but they may give awaytheir opinion in some way which may encourageInvestigator EffectsDemand CharacteristicsExtract from A2 Psychology: The Student’s Textbook © Nigel Holt and Rob Lewis ISBN: 9781845901004 www.crownhouse.co.uk