Tasks We provide updated versions of all four tasks from *Kool et al., PLOS Computational Biology, 2016*, and *Kool et al., Psychological Science, 2017*. All tasks have been written using Josh deLeeuw's jsPsych toolbox [v6.1.0][1] (http://www.jspsych.org/). Both versions of the Kool 2Step tasks allow for flexible modification of the reward parameters. Reward parameters can be set to include negative reward (antimatter) as seen in Kool et al., 2016 (-4 to 5, SD = 2), or alternatively, may include only positive rewards (treasure) as seen in Kool et al., 2017 (0 - 9, SD = 2) . Any changes made to the **Min** and **Max** variables in the *Index.html* file indicating the boundaries for reward will be reflected across the experiment. Negative rewards (antimatter) can range from -5 to -1 and positive rewards (treasure) can range from 1 to 9 (yet, note the range should always include 0). This code only works well if the **Min** and **Max** variables are set within these bounds. All tasks require communication with a PHP server in order to run. You can achieve this by running them on your own domain, or by using a tool like XAMPP to run the PHP server locally. Once the tasks have been downloaded from OSF you may have to adjust permission settings for the folder or you will see a "Not found" error message. For details on how to run the task locally or online or adjust permission settings see the *Getting set up* PDF in the Files folder. In order to save the data, you will need to be able to connect to a SQL database on your server. The code has some default names for the tables it stores data in (e.g., daw_2step_data, kool_2step_data, sub_info), but feel free to change anything about the way the data storage is managed. Further details on storing data are also delineated in the *Getting set up* PDF in the Files folder. Contact If you have any questions, please do not hesitate to contact Bettina Bustos (bbustos@uiowa.edu) or Wouter Kool (wkool@wustl.edu). [1]: https://github.com/jspsych/jsPsych/releases/ "v6.1.0"