mouse-tracking data are
stored in wide format, i.e., where one row contains the data of one trial and
every recorded mouse position and variable is saved in a separate variable
(e.g., X_1, X_2, ..., Y_1, Y_2, ...). This is, e.g., the case when collecting
data using <a href="http://www.mousetracker.org/" class="external-link">MouseTracker</a> (Freeman &amp;
Ambady, 2010). From this data.frame, <code>mt_import_wide</code> creates a
mousetrap data object containing the trajectories and additional data for
furt