Giving versus receiving, choosing the right statistical test, interpreting data, and data ethics: In what some people call the “hedonic treadmill,

” the pleasure we receive from something tends to go down over time. A rare night out at a fancy restaurant brings much happiness, but if you go every night, that effect diminishes. U.S. researchers wondered if this effect would be true for the happiness we feel when giving to others (O’Brien & Kassirer, 2019). Participants came to the researchers’ lab, where they received ve envelopes, each containing $5. Some participants were randomly assigned to spend $5 on themselves every day for 5 days or to spend $5 on someone else every day for 5 days. At the end of each day, participants completed a survey that assessed their happiness on a scale of 1–7. The accompanying graph shows the results.

Data from O’Brien and Kassirer, 2019.

a. For this example, state the variables, identify what type of variable each is, indicate which is the independent variable and which is the dependent variable, and note the appropriate statistical test. Explain why you suggested that test.

b. This graph shows differences among means, but does not show variability for each group. Why is it more ethical to show variability for each group, and how could this graph be designed to show variability? (Note: The original graph did show variability.)

c. Toward the beginning of their Methods section, the researchers reported: “All data, materials, and preregistration les can be found at https://osf.io/njea2/”

(p. 195). Explain what that means and what you might nd at the link.

d. The researchers wondered whether the difculty of the task—spending money on others (giving) versus yourself

(getting)—could have affected happiness. They asked the two groups to rate difculty and reported the following statistics for an independent-samples t test: “

(getting: M = 1.93, SD = 1.35;

giving: M = 2.00, SD = 1.37), t(90) =−0.24, p = 0.811, d = 0.05, 95%

CI for the mean difference = [−0.63, 0.50]” (p. 198).

Explain what each of these statistics means in the context of this experiment and in your own words.

e. Toward the end of their manuscript, the researchers reported: “All data and materials have been made publicly available via the Open Science Framework (OSF)

and can be accessed at osf.io/njea2” (p. 203). Explain what this means and explain why this is an example of good data ethics practices.

f. Were the researchers likely to have recruited their participants from a crowdsourcing site like MTurk?

Explain your answer.