Risky Shift Experiment: Understanding Group Decision-Making

1. RISKY SHIFT: INTRODUCTION Week 5 Practical

2. RISKY SHIFT WEEK 5 PRACTICAL LECTURE PRACTICAL WEEK 1 NO LECTURE NO PRACTICAL WEEK 2 NONPARAMETRICS 1 1ST PRACTICAL WEEK 3 NONPARAMETRICS 2 1ST ANALYSIS WEEK 4 1ST ANALYSIS (BY HAND) WEEK 5 2ND PRACTICAL SAMPLING DISTRIBUTIONS WEEK 6 2ND ANALYSIS HYPOTHESIS TESTING WEEK 7 2ND ANALYSIS (BY HAND) RELATED T-TEST WEEK 8 3RD PRACTICAL INDEPENDENT T-TEST WEEK 9 3RD ANALYSIS INDEPENDENT ANOVA WEEK 10 DEPENDENT ANOVA 3RD ANALYSIS (BY HAND)

3. RISKY SHIFT WEEK 5 PRACTICAL BY THE END OF THE SESSION, YOU SHOULD BE ABLE TO: Conduct the Risky Shift practical and understand the rationale behind the experiment. Appreciate the way in which the study was carried out and the hypotheses the study is testing. Begin to explore the downloaded data set with respect to testing the experimental hypotheses. Make a start on writing up your INTRODUCTION and METHOD sections for your lab report.

4. Work alone, making sure you have a handout and something to write with. Read the PRE questionnaire instructions before filling out the questionnaire itself. When you have finished the PRE questionnaire, wait for further instructions. You will have 10 minutes to answer the questionnaire, so think carefully! RISKY SHIFT PART 1

5. RISKY SHIFT EXPERIMENT

6. Take a seat in the group that has been assigned to you. Discuss each of the five situations and reach a unanimous decision for each one. After reaching your decisions, complete the GROUP questionnaire and wait for further instructions. You will have 10 minutes to do this, so discuss carefully (2 minutes on each). RISKY SHIFT PART 2

7. RISKY SHIFT EXPERIMENT

8. Work alone again, making sure you have a handout and something to write with. Please complete the POST questionnaire. When you have finished the POST questionnaire, wait for further instructions. You will have 10 minutes to answer the questionnaire, so think carefully again! RISKY SHIFT PART 1

9. RISKY SHIFT EXPERIMENT

10. RISKY SHIFT INTRODUCTION THE RISKY SHIFT When discussions lead group members to make riskier decisions than they would as individuals. (Kenrick, Neuberg and Cialdini, 2002) Post decisions also tend to be riskier than the pre decisions. Risky shift was evident 2-6 weeks after the group discussion. (Stoner, 1961; Wallach, Kogan and Bem, 1962) One possible explanation is diffusion of responsibility: each group member dilutes personal responsibility for acting by spreading it among all the other group members. People feel less responsible about the decisions taken and, if things go wrong, attribute blame to the decisions made in group.

11. RISKY SHIFT METHOD DESIGN We have ratings collected from a within-subjects design using 3 levels. PRE GROUP POST HYPOTHESES Our current experiment raises three hypotheses (after Wallach et al., 1962) Q1: Is the average level of risk different across the PRE, GROUP and POST assessments? Q2: Is the average level of risk recorded in the PRE assessment different from the risk recorded in the GROUP assessment? Q3: Is the average level of risk recorded in the POST assessment different from the risk recorded in the PRE assessment?

12. RISKY SHIFT METHOD PARTICIPANTS We’ve already collected the data for you! DOWNLOAD AND SAVE THE FILE ‘RISKYSHIFTDATANEW.SAV’ Here is some demographic information that might be useful. 24 female, 24 male; Age range: 18-32 years; Mean: 24 years; S.D.: 2.8 years [This an opportunity sample of students at the University of Sussex.] Participants were divided up into 8 groups of 6 and an equal number of males and females were allocated to each group. DOWNLOAD AND SAVE THE FILE ‘RISKYSHIFTDEBRIEF’

13. RISKY SHIFT METHOD DESIGN You’ll notice some neat things about the design of the questionnaire: RISK SCORE 1 3 5 7 9 11 11 9 7 5 3 1 Ratings are scores 1 to 11, with 1 being the most risky and 11 the least risky. The order in which the options are presented is reversed for 3 of the 5 of the items.

14. RISKY SHIFT RESULTS These columns show mean risk score at PRE, GROUP and POST. The first 2 columns show subject id and group membership. You will also find average risk scores for each example collapsed over PRE, GROUP and POST.

15. RISKY SHIFT DATA TYPES Nominal “Name” E.g. Gender Ordinal “Order” E.g. Horse racing Ratio “Real zero” E.g. Height Interval “Imaginary zero” E.g. Likert scale

16. RISKY SHIFT WHAT TEST TO USE? THE FLOW CHART

17. RISKY SHIFT NOTES FOR WRITE UP INTRODUCTION Like a funnel- all roads should lead to the rationale for the experiment. What were the previous studies that lead up to the current one? What were the important psychological concepts and / or distinctions? What was the outline of the current study and what were the hypotheses? METHOD Must include enough detail for someone else to replicate the experiment. Standard structure: Participants / Materials / Design / Procedure. Refer the reader to appendices if including lengthy materials (hint hint). Avoid bullet points or lists because the method section is prose too.

18. RISKY SHIFT WEEK 5 PRACTICAL BY THE END OF THE SESSION, YOU SHOULD BE ABLE TO: Conduct the Risky Shift practical and understand the rationale behind the experiment. Appreciate the way in which the study was carried out and the hypotheses the study is testing. Begin to explore the downloaded data set with respect to testing the experimental hypotheses using an appropriate test. Make a start on writing up your INTRODUCTION and METHOD sections for your lab report.

19. RISKY SHIFT DISCUSSION GET TOGETHER IN GROUPS OF THREE OR FOUR AND REFLECT ON TODAY’S EXPERIENCE USING THE FOLLOWING QUESTIONS Apart from diffusion of responsibility, what else could cause a risky shift? Could you overhear other groups? Were there other problems in the way the experiment was carried out? If you were to carry out the experiment again, what would you change?