The first rule for activity selection is that cues have got to capture the person's attention. Ignored cues are useless. Within ACL 4, cues are grouped in classes to assist your selections.
The person's information processing system synthesizes the information into a new experience that is: evaluated, compared with other experiences, and a choice is made about whether to sustain their attention, or not.
Sustained attention is a combination of personal choice and available mental energy.