Exclude the initial phase in a trial where the mouse was not moved. The corresponding samples (x- and y-positions and timestamps) in the trajectory data will be removed.

  use = "trajectories",
  save_as = use,
  dimensions = c("xpos", "ypos"),
  timestamps = "timestamps",
  reset_timestamps = TRUE,
  verbose = FALSE



a mousetrap data object created using one of the mt_import functions (see mt_example for details). Alternatively, a trajectory array can be provided directly (in this case use will be ignored).


a character string specifying which trajectory data should be used.


a character string specifying where the resulting trajectory data should be stored.


a character vector specifying the dimensions in the trajectory array that contain the mouse positions.


a character string specifying the trajectory dimension containing the timestamps.


logical indicating whether the timestamps should be reset after removing the initial phase without movement (see Details).


logical indicating whether function should report its progress.


A mousetrap data object (see mt_example) from which the initial phase without mouse movement was removed. If the trajectory array was provided directly as data, only the trajectory array will be returned.


mt_exclude_initiation removes all samples (x- and y-positions as well as timestamps) at the beginning of the trial during which the mouse was not moved from its initial position. The last unchanged sample is retained in the data.

If reset_timestamps == TRUE (the default), it subtracts the last timestamp before a movement occurs from all timestamps , so that the series of timestamps once more begin with zero. If the argument is set to FALSE, the values of the timestamps are unchanged.

Please note that resetting the timestamps will result in changes in several mouse-tracking measures, notably those which report timestamps (e.g., MAD_time). Typically, however, these changes are desired when using this function.

See also

mt_measures for calculating the initiation time.

mt_exclude_finish for removing a potential phase without mouse movement at the end of the trial.


Pascal J. Kieslich

Felix Henninger


mt_example <- mt_exclude_initiation(mt_example,