1. Research methods Designing an experiment Lesson 5

2. http://study.com/academy/lesson/quasi-experimental-designs- definition-characteristics-types-examples.html Define Quasi experiment. Comparison between repeated measure and independent samples design On the whiteboard…

3. Recap

4. On the whiteboards. Define the following: Extraneous/confounding variables relevant to experiments: Participant variables – Psychological qualities of p’s that might affect their performance on the task Demand characteristics – All cues, which convey to the p’s the purpose of the experiment. Order effects – order of the conditions having an effect on the participants’ behavior. Investigator effects – Any effects on the investigator’s behaviour on the research outcome.

5. Define the following controls… Counterbalancing An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the other order. Randomisation Use of ‘chance’ in order to control for the effects of bias Standardisation (instructions, environment, experience) Ensuring all participants are subject to the same experience Single & double blind procedures Single blind procedure: participant does not know the condition under which they are being tested Double blind procedure: experimenter does not know the condition under which the p’s are being tested

6. How could you control for Participant variables? – Random allocation of p’s to conditions – Pre-test of participants – Representative allocation Order effects? – Counterbalancing – Complex counterbalancing Randomisation of condition order Randomisation of stimulus items. Elapsed time

7. Hypotheses What is a hypothesis? testable, predictable statement. States the relationship between the variables being tested What are the qualities of a good hypothesis? Testability based on knowledge Simple Operational Open doors for further enquiry.

8. What is a one tailed and two tailed hypothesis? A one tailed (directional) hypothesis states the direction in which the results are expected to go People who have plentiful sleep (an average of 8 hours or more hours per night over a period of one month) have better marks in class tests than people with a lower sleep average. A two tailed (non- directional) hypothesis states that there is a difference between two conditions but does nor state the direction of the difference. People who have plentiful sleep (an average of 8 hours or more hours per night over a period of one month) have different marks in class tests than people with a lower sleep average.

9. Decide whether the following hypothesis are one or two tailed Alcohol affects reaction time Men who have beards are perceived as older than clean-shaven men The quality of beer affects bar takings The faster you type the more mistakes you make.

10. Ethics Please complete Ethics homework in your green RM pack For next Tuesday

11. Task: Experimental design For each of the studies answer the following questions: 1.Identify the independent variable 2.Identify the dependent variable 3.Identify the experimental design 4.What strength does this experimental design have in this study? 5.What limitation does this experimental design have in this study? 6.Write a directional hypothesis for the experiment.

12. Loftus and Palmer (1974) investigated whether leading questions affect answers to speed questions. Participants were shown films of traffic accidents; all groups were shown the same films. They were then asked to give a general account of what they had just seen and asked a series of questions about it. The critical question asked was ‘About how fast were the cars going when they HIT each other?’ The word ‘HIT’ was replaced by either ‘SMASHED’, ‘COLLIDED’, ‘BUMPED’ or CONTACTED’. Each group was asked with a different word. The results suggested that participants recall was influenced by the speed word used. The word ‘smashed’ led to the fastest speed estimate (mean = 40.8 mph) and the word ‘contacted’ the slowest (mean = 31.8 mph).

13. Bandura et al (1961) aimed to see if behaviour that is observed will be repeated. Participants (children aged 3- 5) were divided into three groups. Individuals were matched in the three groups according to their aggression levels that existed before this study began. Group one observed an aggressive adult model hitting a Bobo doll; group two observed the model acting non-aggressively and group three observed no model. All participants were then placed in a room with a Bobo doll and their behaviour was observed. Group one acted most aggressively. There was little difference between the aggression shown by groups two and three. The conclusion was that aggressive behaviour shown by a role model was imitated

14. Peterson and Peterson (1959) investigated how long simple information stayed in short term memory (STM) without repetition. On each trial the participants saw a trigram, which consisted of three consonants (e.g. BVM, CTG). A different trigram was used for each trial and each participant took part in each trial. They were asked to recall each trigram after a delay of seconds: 3,6,9,12,15 or 18. Once they were shown the trigram they had to perform an interference task, which prevented repetition of the trigram in STM. They were shown a random three digit number (e.g.866, 532) and had to count backwards from it in threes. After the appropriate time delay the trigram had to be recalled. The longer the time delay, the more the forgetting occurred in STM. After 3 seconds 80% of participants remembered the trigram, but after 18 seconds only 10% of the participants remembered the trigram.

15. Please answer the exam question on the handout given to you Exam question 2013

16. Designing an experiment What points do you need to consider when designing an experiment?

17. Class experiment Music can affect the ability to concentrate. Design an experiment that could be carried out in a classroom to test the effects of two different kinds of music on a task requiring concentration (e.g. word search). You must use a repeated measures design. You should: – fully operationalise the independent and dependent variables – provide details of how you would control extraneous variables – describe the procedure that you would use. – We will be carrying out the experiment so enough detail must be given in order for the class to do this!