Using G*Power (Faul et al., 2009) we calculated that we would need to include at least 63 participants in our study to achieve 95% power for the effect size that Sachdeva et al. (2009) obtained in their Study 1. In the original study, 46 students (18 males, 28 females, Mage = 18.8) from Northwestern University took part in the experiment as a partial fulfillment of a requirement in an introductory psychology course. In this study, we will include at least 63 students who participate as part of a course credit in the lab at Tilburg University. In this lab, data is typically collected for 1 week and this will usually result in 70-120 participants. We will run for one week and this will result in at least 63 participants. All participants will be randomly assigned to one of three conditions: A positive trait condition, a negative trait condition, and a neutral control condition. </p>
We obtained the original study materials of Sachdeva et al. (2009) (Appendix 2) and translated these materials to Dutch (Appendix 3). The materials will be presented as a paper-and-pencil questionnaire. Similar to the original study by Sachdeva et al. (2009), as a cover story, participants will be instructed that the study is about their handwriting styles. Depending on assigned condition, participants will be exposed to nine positive trait words, nine negative trait words, or nine neutral words and will be asked to copy each word four times and think about each word for 5-10 seconds. Next, they will be instructed to write a short story about themselves including the words they just copied. Subsequently, they will answer some neutral questions about the stories they just wrote and they will complete a short math-based filler-task. The dependent variable is the amounts of money (up to €10.00) participants are willing to donate to a worthy cause of their choice. They will be asked to indicate the cause they would like to support and write down the amount of money they would like to donate. They will be told that they have to pay this amount of money upon receiving confirmation e-mail from the experimenter. Finally, participants will complete a set of demographic measures (Appendix 5) and seven self-presentation items from self-monitoring scale (Lennox & Wolfe, 1984) (Appendix 7). </p>
Participants will complete the study as part of a series of experiments in separate cubicles in the lab at Tilburg University, the Netherlands. The experimenter who will be present in the lab is blind to condition. Prior to the experiment, participants will be asked to provide their informed consent. The experimenter will instruct the participants to get seated in a separate cubicle and to complete the paper-and-pencil questionnaire. After completing the series of experiments and the demographic measures, the participant will be instructed to leave the cubicle and to approach the experimenter to sign for their course credit. Participants will be debriefed and thanked for their participation. Similar to Study 1 by Sachdeva et al. (2009), participants will be debriefed that their willingness to donate is the dependent variable of the experiment and that they will therefore not receive a confirmation e-mail.
Plan for Confirmatory Analyses
Prior to analyzing the data, we will exclude participants who did not complete the IV correctly (i.e., participants who did not write a story about themselves using the 9 words) and participants who did not complete the dependent variable (i.e., participants who did not indicate an amount of money they are willing to donate). Next, we will analyze the demographic variables by requesting the descriptives and frequencies of the mean age, the male/female gender ratio and the nationality ratio of the participants. We will then analyze whether gender, nationality or age have any effects on the amount of money participants are willing to donate by means of ANOVAs and a linear regression. If it turns out that one (ore more) of these variables significantly (at the p = .05 level) affect willingness to donate, these variables will be included as covariates in the following analyses.
In the original study of Sachdeva et al. (2009), the amount of money participants indicated they would donate was compared across the three conditions using a one-way analysis of variance (ANOVA); no post-hoc tests are mentioned. We will first perform a one-way ANOVA similar to Sachdeva et al. (2009). If this one-way ANOVA is significant, we will perform post-hoc Tukey tests to compare further differences between the three conditions.<br>
The data may not be normally distributed, as we expect that a substantial amount of participants are not willing to donate any money at all. If this is the case, a Tobit regression is the preferred analysis to test the effect of recall on the amount of money participants are willing to donate, taking into account the participants who decided not to donate at all. For the self-monitoring scale, we will first calculate the Chronbach’s α. If the Chronbach’s α ≥ 0.65, we will analyze the effects of self-monitoring. We will perform a regression to test the effect of self-monitoring on the amount of money participants are willing to donate. We will perform spotlight analyses to analyze the licensing effect separately for low self-monitors and high self-monitors (similar to Cornelissen et al., 2013). For syntax of the planned analyses, see Appendix 9.</p>
<p>Known differences from original study<br>
• Participants in the study of Sachdeva et al. (2009) are from the USA and completed the study in English, whereas our participants will be from the Netherlands and will complete a Dutch translation of the study materials. We do not think that these differences in origin and language are critical for a fair replication of the original study, since Dutch and American cultures have proven to be very similar (Hofstede, Bond, & Luk, 1993). The results of our pilot test will show whether the words that were used to affect moral identity have similar effects for Dutch an American participants.
• In the original study, participants indicated the amount of money they were willing to donate in dollars; in our study, participants will indicate the amount of money they are willing to donate in Euros.
• In our study, participants will complete the self-monitoring scale at the very end of the procedure, after the dependent variable is assessed.
We do not expect any of these differences to influence the main results of our studies. </p>