Once a field is defined, the entries within that column must be consistent with the definition. For instance, if the field is defined as Color the entries red, green, and blue are acceptable entries in the list, but Helvetica, Times, and Palatino are not. Several different fields can be defined within the same list. In fact, this is the advantage of the list structure. The color, font, and position of an event can be varied simultaneously.
All values associated with that item apply to the current trial.
Thus, each item in a list defines a unique trial in the experiment.