Stimulus Material

The ERTS Script language offers a variety of different data types to define the stimulus material of your experiment:

Picture Visual stimulus material (including instructions) is defined with the PICTURE data type. This data type supports a variety of different flavors like text, graphics, and video (mp4, webm, ogg), vector graphics, or Gabor patches. A picture can be displayed on any screen location in different alignments and rotations.

Position The POSITION data type defines screen locations on which a picture will be displayed. ERTS uses a logical coordinate system in millimeters which may be adjusted to individual monitor dimensions.

A position definition may consist of multiple screen coordinates to form circles, grids, or lines. When displaying a picture, the position definition and an index referring to the location within this definition must be specified. A position definition may also serve as a set of screen locations which may be filled with random pictures.

Tone The tone data type is used to define all types of auditory stimuli. ERTS supports the definition of sine wave tone (CHROME only) and external sound files (mp3, wav, ogg).

Color The color data type is used for defining foreground and background colors. Colors can be defined in RGB or HSV color space.

Font This data type defines text fonts which can be used to display text pictures. What font is available depends somewhat on the OS and browser.

Set The set data type can be used to form sets of data objects for supporting random processes. A set definition may consist of a list of data objects like pictures, positions, tones, colors, or fonts. During the experiment you can then randomly draw from a set and use it to realize randomization that goes beyond the permutation of trials.