Introduction --- The study aims to extend the research on the influence of environment selection on cheating behavior (Houdek, 2017; Houdek, Bahník, Vranka, & Hudík, 2019). We hypothesize that if a person wants to cheat, they prefer an environment where they can cheat. Therefore, dishonest people should be willing to pay for participating in the cheating-enabling environment. The study intends to explore how costly assignment affects the decision to choose such an environment and subsequent cheating. On the one hand, a positive price may discourage some cheaters to choose the cheating-enabling environment, although they would have chosen such an environment if the price was zero. On the other hand, those who choose the cheating enabling environment may cheat more if the price is positive than if the price is zero because the positive price may be used as justification for cheating. We also consider another factor that may be used to justify entering into the cheating-enabling environment – namely, behavior of others. In particular, before participants make their decisions whether to enter it or not, we will publicize the share of participants who wanted to participate in the cheating-enabling environment in a similar past experiment. We expect that if the publicized number of participants who choose the cheating-enabling environment is low, less people will decide to choose the cheating-enabling environment. Similarly, if the publicized number of participants who choose the cheating-prohibiting environment is low, less people will decide to choose the cheating-prohibiting environment. **Hypotheses and expectations** - Hypothesis 1: In the fee condition, participants will be less likely to choose the cheating-enabling environment in comparison with the no-fee condition. - Hypothesis 2: Participants who chose the cheating-enabling environment in both the fee and no-fee conditions will cheat more in the fee condition than in the no-fee condition. - Hypothesis 3: In comparison with choosing the cheating-prohibiting environment, choosing the cheating-enabling environment is associated with a higher level of cheating in the cheating-enabling condition in one of the first two rounds. - Hypothesis 4: Information on a low share of participants who chose to participate in the cheating-prohibiting environment will lead to a lower preference for the cheating-prohibiting environment than information on a low share of participants who chose the cheating-enabling environment. - We also expect that selection of the cheating-enabling environment and higher level of cheating will be associated with low values on the Honest-Humility scale of HEXACO and with the three traits measured by the Short Dark Triad scale. Methods --- **Participants** We will run the experiment from November to December 2019 with participants from our laboratory subject pool consisting mostly of students at Czech universities. The planned minimum sample size is 500. If the minimum sample size is reached before December 20th, we will continue to collect data until the December 20th or until the funds available for the data collection are spent. The whole experiment will be administered in Czech using a custom-written Python program. Participants first sign informed consent and read a short overview of all parts of the experiment. Then, they continue to work, self-paced, according to the instructions shown on their computer screen. **Design and procedure** The first part of the experiment is a modified mind game (Jiang, 2013). In our variant of the game, participants earn money when they correctly predict whether the outcome of a fair die roll will be odd or even. Rules of the game are explained before it begins, and participants’ understanding is checked using a short quiz. There are two different versions of the game: in the BEFORE version, participants state their predictions before the die is rolled, and then they see the outcome. Therefore, no cheating is possible. In the AFTER version, participants are asked to make their predictions in their mind and remember it. Then a roll is made, and they are shown the outcome, and they have to state whether they predicted it correctly or not. As the actual prediction is only in participants’ minds, they can cheat and misreport even their incorrect predictions as correct. Participants play five rounds of the game, with twelve rolls in each round. They are informed beforehand that one round will be selected at random, and they only get the money earned in the selected round. In the first two rounds, every participant plays one round of the game in the AFTER and one in the BEFORE version, in a random order. Before the third round begins, participants read short descriptions of both versions of the game, and then they choose whether they want to play the next round in the BEFORE or AFTER version. One half of participants is offered the choice with one difference: if they choose the AFTER version, they have to pay a fee. The BEFORE version is not associated with any fees for any participants. The fourth round is the same; but the participants are given the condition (fee or no-fee) that they did not receive in the third round. In the fifth round, participants again choose between the BEFORE and AFTER version; this time without any fees. Before making their decision, one half of participants learns that a low proportion of participants wanted to participate in the AFTER version in a similar past experiment and the other half learns that this was true for the BEFORE version of the task. The second part of the experiment is a lottery. Participants can earn money solely due to luck. At the beginning of the experiment, participants are informed that it will be impossible to tell how much they earned in different parts of the experiment (it will not be possible to tell whether their earnings are based on cheating in the first task or on luck in the second task). In the lottery, participants start with a small amount of money and can decide to roll a virtual die and double their earnings every time they roll an even number. Before each roll, they can decide to stop and take their current earnings. However, when they roll an odd number, the lottery ends and they lose all their previous earnings. In the last part of the experiment, participants answer socio-demographic questions and fill several questionnaires, namely 60-items HEXACO scale (Ashton & Lee, 2009) and Short Dark Triad scale (Jones & Paulhus, 2014). Participants are informed before the questionnaires that there are attention check items in the questionnaires and that they can earn an additional reward if they manage to answer all of them correctly. At the end of the session, participants also answer questions about how they perceived the two versions of the dice-rolling task and complete a short debriefing in which they answer open-ended questions about the aims of the different parts of the experiment. Finally, participants are thanked for their participation, informed of the total earned sum of money, paid, and dismissed. **Materials** The program used to run the experiment is in Files. **Analysis plan** H1 will be tested using logistic mixed-effect regression with the choice of the version as the dependent variable and presence of a fee as the tested predictor. Block number and an interaction with block number with presence of a fee will serve as covariates. The model will include random intercepts for participants. H2 will be tested using linear mixed-effect regression with the number of reported correct predictions as the dependent variable and presence of a fee as the tested predictor. Block number and an interaction with block number with presence of a fee will serve as covariates. The model will include random intercepts for participants. The analysis will be conducted only with participants who chose the AFTER version of the task in both block #3 and #4. H3 will be tested using linear regression with the number of reported correct predictions in the AFTER version in the first two blocks as the dependent variable and the number of choices of the AFTER version in blocks #3 and #4 as the tested predictor. The model will include the order of the versions in third and fourth blocks as a covariate. H4 will be tested using logistic regression with the choice of the version as the dependent variable and the information condition before the fifth block as the tested predictor. The model will include the number of choices of the AFTER version in blocks #3 and #4 as a covariate. Apart from the four main hypotheses, we will test the effects of personality characteristics in various exploratory analyses. Except for cases of technical difficulties during the administration, we do not plan to exclude any participants from the main analyses. For analyses using questionnaire data, we will exclude participants who did not answer all the attention checks correctly. References --- Ashton, M. C., & Lee, K. (2009). The HEXACO-60: A short measure of the major dimensions of personality. *Journal of Personality Assessment, 91*(4), 340-345. doi: 10.1080/00223890902935878 Houdek, P. (2017). A Perspective on Research on Dishonesty: Limited External Validity Due to the Lack of Possibility of Self-Selection in Experimental Designs. *Frontiers in Psychology, 8*(1566), 1-6. doi: 10.3389/fpsyg.2017.01566 Jiang, T. (2013). Cheating in mind games: The subtlety of rules matters. *Journal of Economic Behavior & Organization, 93*, 328-336. doi: 10.1016/j.jebo.2013.04.003 Jones, D. N., & Paulhus, D. L. (2014). Introducing the short dark triad (SD3) a brief measure of dark personality traits. *Assessment, 21*(1), 28-41. doi: 10.1177/1073191113514105