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THE SCIENCE OF PSYCHOLOGY Science is not facts! Science is a method!

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Presentation on theme: "THE SCIENCE OF PSYCHOLOGY Science is not facts! Science is a method!"— Presentation transcript:

1 THE SCIENCE OF PSYCHOLOGY Science is not facts! Science is a method!

2 What is Science?  The word science literally means knowledge, it comes from the Latin word scientia, meaning "knowledge"  Science is a methodology NOT facts!  Science is a way of finding out how the world works  Galileo Galilei is considered to be the father of modern science and one of the first philosophers to practice what later became known as the scientific method

3 Empiricism – ah the enlightenment!  At the core of science is the notion of Empiricism, broadly the tenants of empiricism are that all we can know about the world is accessible through sense data  its not quite as simple as what you see = the truth  It is through objective observation and controlled experimentation that we can find out how things work  David Hume and Francis Bacon both champions of the scientific method

4 Belief or Faith in science?  By definition one cannot believe in or have faith in science  One should not believe in science  There is evidence out there, all science does is uncover it and let it speak for itself  The scientific method is value neutral, it does not have an agenda (people however are biased and stupid)  The evidence is either there or it is not, simple as that!  Evidence is the name of the game!  Things that work – i.e. have evidence for them that is accessible through empirical research become ….SCIENCE. Alternative medicine that works becomes….. MEDICINE

5 Science Vs Faith ‘Science adjusts its views based on what’s observed, faith is the denial of observation so that belief can be preserved’

6 To the Critics of Science  So you don’t believe that evidence matters? Well go away and live in a cave. Don’t have antibiotics, electricity, computers, cars, hygiene, refrigeration, insulation, chemotherapy, phones, clean drinking water, paper, toilets, television, the internet, shampoo, soap, hot water, microwave ovens, roads, bridges, anaesthetic, concrete, steel, aluminium cans, canned food, synthetic rubber, plastic….etc, etc, etc.  If you don’t feel evidence is important then you cant use it to back your own case!  All of these things we thank science and empirical research for!  They seem very ready to criticise science as ‘just another way of looking at the world’ while accepting all the benefits that science brings  Why do they accept the benefits….. Well BECAUSE SCIENCE WORKS!  If you want to sledge science you need to explain all of the things science can do…. And better!

7 Why study research methods and empiricism?  Empiricism is how we know what we know about the universe and everything in it  Without an understanding of research methodology one cannot make judgement about the validity of research claims  IF YOU CAN’T TELL GOOD EMPIRICAL RESEARCH FROM PSEUDOSCIENTIFIC DRIVEL HOW CAN YOU DECIDE WHAT TO BELIEVE?

8 Good Research?  ‘Research’ has shown that ice cream sales are directly correlated with crime  ‘Research’ has shown that people prefer Pepsi to coke…..Q V’s M  ‘Research’ has shown that whites are intellectually superior to blacks….. IQ testing

9 IQ – racial trait?

10 THE SCIENTIFIC METHOD Physics, Chemistry, Biology and Psychology all ask different questions…. But they all get their answers the same way.

11 Studying people – getting a sample  Population – Not the population of Australia, all people who we are interested in studying.  Eg. All year 11 students, all female police officers, all interstate truck drivers  Sample – Who you use in your study, drawn from population of research interest. Supposed to represent population of research interest  Remember the coloured paper!

12 Sampling  Convenience Sampling – selecting participants who are readily available, targeting a specific area etc. Can produce a biased sample.  Random Sampling - A sampling technique, which ensures that every member of the population, has an equal chance of being selected. Can lead to a biased sample.  Stratified Sampling - A sampling technique, which involved dividing the population into distinct strata and selecting a separate sample from each stratum, in the same proportions, as they existed in the population.  The strata are usually characteristics such as e.g. age, sex, religion, IQ scores, cultural background, etc.

13 Biased sample  Major problem with poorly conducted research  Some sub groups in the population of research interest are not represented at all  Leads to a sample that does not represent the population  Results from a biased sample can not be generalised to a larger population

14 Hypotheses and Variables  Hypothesis – a testable prediction relating to the outcome of the research being conducted, a prediction that one variable (IV) will effect another variable (DV) in a certain way.  To write a hypothesis we need to know our variables – we are measuring the effect of ________ on _______? IV DV  Independent variable – the variable that is changed by the experimenter, interested in its effect. We want to see the effect of the IV on the DV  Dependent Variable – measures the effect of the IV, see if the IV has effected the DV

15 Hypotheses IV’s and DV’s  I want to find out if smoking marijuana will effect driving performance  Independent Variable – smoking marijuana  Dependent Variable – Driving a car  It is hypothesised that participants who smoke marijuana will perform worse on a driving test as compared to participants who have not smoked marijuana

16 The Operational Hypothesis  I want to test the effect of Smoking Marijuana on Driving Performance. Variables that need to be operationalised  Smoking Marijuana  Driving Performance  The population – who we are testing Operational Definitions  Smoking Marijuana – smoking one joint containing 500 milligrams of pure marijuana (not mixed with tobacco) 20 minutes before taking a driving test  Driving Performance -% score on VIC Roads, “Are you Road Ready?”driving simulator Operational Hypothesis  It is hypothesized that Victorian drivers aged 18 – 25 who have smoked marijuana (smoking one joint containing 500 milligrams of pure marijuana 20 minutes before taking a driving test) will perform worse on a driving test (obtain a lower % score on the VIC Roads “Are you Road Ready?” driving simulator) compared to participants who have not smoked marijuana.

17 Experimental Vs Control Groups Experimental Groups  Participants are exposed to the experimental condition (i.e. The IV is present – SMOKE MARIJUANA) Control Group  Participants who are exposed to the control condition (i.e. the IV is absent- DO NOT SMOKE MARIJUANA)  We compare the experimental group to the control group Random Allocation  All participants who have been selected for an experiment are just as likely to be in one group as the other.

18 Sampling

19 Extraneous Variables Extraneous Variables – can effect DV  A random variable other than the independent variable that can cause change in the dependent variable and therefore effect the results of an experiment  e.g. Individual Differences among participants - personal characteristics, ability, temperament, motivation etc.  When the effects of an extraneous/uncontrolled variable are confused, or confounded with those of the independent variable, then the extraneous variable has become a confounding variable  What else could effect Driving performance other than Marijuana use? – Eye Sight, age, driving experience, previous drug use etc.

20 Controlling Extraneous Variables – Research Designs Repeated Measures Design  Each participant is involved in both the experimental and control conditions  This design controls or eliminates any effects that might be attributed to participant's personal characteristics, since they remain constant  Also known as the within participants design  Can suffer from the Order Effect - effect of practice and fatigue  Counterbalancing can help this

21 Repeated Measures Design

22 Controlling Extraneous Variables – Research Designs Matched Participants Design – Paired up  Involves selecting pairs of participants who are similar in characteristics that can influence the dependent variable, on the basis of scores achieved on a pre-test, or a number of pre-tests  Participants are then ranked in accordance with their scores and then one of each pair is allocated to the respective groups (Experimental or Control)

23 Matched Participants Design

24 Controlling Extraneous Variables – Research Designs Independent Groups Design  Allocates participants to groups via a random procedure such as the toss of a coin, or by having each participant draw a numbered ticket from a container that holds the same number of tickets, as there are participants  Then all those who draw an even number might be allocated to the control group and all those who draw an odd number to the experimental group

25 Independent Groups Design

26 Research designs – Make all things equal…… except for the IV  All research designs attempt to ensure that the Experimental and Control groups are as similar as possible on all characteristics except for the IV  They aim to make the only difference between the groups whether they were exposed to the IV (experimental group) or not (control group)


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