An exemplary mouse-tracking dataset collected OpenSesame using the mousetrap plugin (Kieslich & Henninger, 2017). A preprocessed (as opposed to raw) version of the same data can be found in mt_example.



A data.frame with 38 rows and 19 variables. The data.frame is based on the combined raw data that were created using read_opensesame from the readbulk library. For ease of use, unnecessary columns were excluded.

The variables included relate to the item that was presented (Exemplar), the answer categories (Category1 and Category2), the subject identifier (subject_nr) the subjects' response (response_get_response), as well as the mouse-tracking variables (timestamps_get_response, xpos_get_response and ypos_get_response). Besides, a number of additional variables are included, e.g., some variables relating to the general settings of the experiment (e.g., the width and height of the screen in pixels).

Each mouse-tracking variable contains a list of values (separated by ', ')

  • one entry for each recorded position of the mouse. The position coordinates are given in pixels, such that values of zero for both xpos_get_response and ypos_get_response indicate that the cursor is located in the center of the screen. Both variables increase in value as the mouse moves toward the bottom right. Timestamps are given in milliseconds.


The data stem from a study based on experiment 1 by Dale et al. (2007). In this experiment, participants have to assign exemplars (e.g., "shark") to one of two categories (e.g., "fish" or "mammal") by clicking on the button corresponding to the correct category. All exemplars and categories were translated to and presented in German.

Across the 19 trials of the experiment, participants categorized 13 exemplars that were typical of their category and 6 atypical exemplars for which this was not the case. For the atypical exemplars (e.g., "whale"), the competing category ("fish") was selected to compete with the correct category ("mammal"). The hypothesis under investigation is whether participants' mouse trajectories deviate more towards the competing category for the atypical exemplars, indicating increased conflict between the response options.

Please note that mt_example_raw should only be used for exploring the features of the mousetrap package and not for any substantive analysis.


Kieslich, P. J., & Henninger, F. (2017). Mousetrap: An integrated, open-source mouse-tracking package. Behavior Research Methods, 49(5), 1652-1667. doi:10.3758/s13428-017-0900-z

Dale, R., Kehoe, C., & Spivey, M. J. (2007). Graded motor responses in the time course of categorizing atypical exemplars. Memory & Cognition, 35(1), 15-28. doi:10.3758/BF03195938