1. Lesson 4

2. In a laboratory experiment involving a medical consultation role-play, participants were randomly allocated to one of two conditions. In Condition A, a doctor used diagrams to present to each participant a series of facts about high blood pressure. In Condition B, the same doctor presented the same series of facts about high blood pressure to each participant but without the use of diagrams. At the end of the consultation, participants were tested on their recall of facts about high blood pressure. Each participant was given a score out of ten for the number of facts recalled. In this case, the psychologists decided to use a laboratory experiment rather than a field experiment. Discuss advantages of carrying out this experiment in a laboratory. (4 marks)

3.  What research methods do you know already?

4. What is the experimental method? Key features?  Isolate cause and effect  Eliminate alternative explanations of observed relationships between variables What are the four different type of experimental methods?  Laboratory  Field  Quasi  Natural

5. Laboratory A study that takes place in highly controlled conditions where the experimenter manipulates the independent variable and measures the effect it has on a dependent variable. Control over extraneous variables Replicability: important factor in determining generalisability of our effects. Complex equipment, requiring careful setting and maintenance can be used. Only place where highly technical and accurate measures can be made, with random errors reduced to a minimum. Human insight and research (e.g. research into authority/biological psychology)  Narrowness of the IV and the DV (e.g. Bandura – operational measures threat to construct validity)  Behaviour studied out of context in an artificial setting is meaningless  Inability to generalise (Asch, 1971)  Artificiality  Mundane realism: may not represent real life  Demand characteristics

6. Field: A study that takes place in a real world setting where the experimenter manipulates the independent variable and measures the effect it has on a dependent variable; the experimenter sets the study up. Capture natural behaviour as it occurs in every day life. High mundane realism (behaviour more valid and authentic) Less likely to be aware of the aim of the study  Occur greater threats to validity of findings: loss of control over extraneous variables (e.g weather conditions).  Loss of precision because critical variables have not been, and cannot be controlled.  Replicability harder  Expensive and time consuming  Ethical issues if participants are unaware

7. Quasi Natural IV. Controlled environment A study where the IV occurs naturally so the experimenter cannot control allocation to conditions and the research environment is set up by the experimenter so the research will take place in controlled conditions Cook and Cambell (1950/1960) Referred to quasi experiment as well controlled research designs that were ‘almost’ experiments but lacked one or more of the essential features of a true experiment.  Random allocation of participants to conditions, without which we have non- equivalent groups  Full experimental control over the IV Carried out under controlled conditions and share the strength of a lab experiment (Participants not randomly allocated by the experimenter into conditions of the IV. Researcher does not control the IV) Demand characteristics: aware of being tested Confounding variables: cannot be randomly allocated

8. Natural Natural IV. Natural environment a study where the IV occurs naturally so the experimenter cannot control allocation to conditions and the research environment is also naturally occurring, so the researcher does not set anything up Convenient set of conditions that no one has organised for research Opportunity for research that may not otherwise be conducted due to practical/ethical reasons. High external validity (study of real-life) Used to try to demonstrate the limitations of theories based solely on tightly controlled laboratory studies. Christianson and Hubinette (1993): people who are emotionally aroused have weaker memories of real events. Natural occurring event may happen rarely Participants may not be randomly allocated to conditions.

9. Lab and field experiments are true experiments as p’s can be randomly allocated to conditions. Natural experiment: The IV is naturally occurring so the experimenter cannot randomly allocate the p’s to the conditions. The researcher takes advantage of a situation that has occurred naturally, so the researcher does not set anything up. Quasi Experiment: The IV is natural so the experimenter cannot randomly allocate p’s to conditions. The research environment is set up by the experimenter so the research will often take place in controlled conditions

10. Television started to be transmitted to the small island of St Helena in 1995. Researchers observed the children’s aggressive behaviour before and after TV was introduced. A researcher investigated the theory of mind ability (understanding mental states in ourselves and others as well as knowing our mental states may be different from others) of p’s with Autism and p’s without autism by testing their ability to read emotions in a set of pictures showing just a persons eyes

11.  Extraneous are variables are unwanted variables that may affect the dependent variable.  There are two sorts of extraneous variables: random errors and constant errors.  Random errors cannot be predicted and are such things as a participants state of mind (random allocation to conditions will partly overcome random errors as they will balance out across groups).  Constant errors effect the dependent variable in a consistent way so are a more serious problem, but equally a well designed experiment should counter constant errors. An example of a constant error is in a repeated measures when the order of conditions is not reversed.  An uncontrolled constant error that affects the dependent variable in a systematic way is called a confounding variable; if a study is affected by a confounding variable the result of the study is not valid since cause and effect cannot be seen.

12. How can we minimise extraneous variables?  Replicable procedure  Standardised instruction  Controlled room environment  Reliable measurement  Consistency between the conditions

13. In a laboratory experiment involving a medical consultation role-play, participants were randomly allocated to one of two conditions. In Condition A, a doctor used diagrams to present to each participant a series of facts about high blood pressure. In Condition B, the same doctor presented the same series of facts about high blood pressure to each participant but without the use of diagrams. At the end of the consultation, participants were tested on their recall of facts about high blood pressure. Each participant was given a score out of ten for the number of facts recalled. In this case, the psychologists decided to use a laboratory experiment rather than a field experiment. Discuss advantages of carrying out this experiment in a laboratory. (4 marks)

14. What are the 3 types of experimental design?  Independent measures design  Repeated measures design  Matched pair design On the whiteboard. Draw a table. Outline the design and highlight the advantages and disadvantages of each

15. How do you control for participant variables? Person variables differing in proportion across different experimental groups, and possibly confounding results  Independent group design: always difficult to rule out participant differences as a possible source of variation between the results of two groups you are studying. ◦ Random allocation of p’s to conditions ◦ Pre-test of participants ◦ Representative allocation

16. How do you control for order effects? Effects from the order in which people participate in conditions.  Repeated measure design ◦ Counterbalancing ◦ Complex counterbalancing  Randomisation of condition order  Randomisation of stimulus items.  Elapsed time

17. Design a study to test whether there is a difference in the musical ability of left-handed students and right-handed students. You have access to a sixth form of 200 students. Identify the design that you would use (1 mark)  Award 1 mark for identification of an appropriate design Independent measures or matched pairs.

18. Please answer the exam questions on the handout given to you

19. Comparison between repeated measure and independent samples design