No specific stimulation was programmed for the sessions.
The second phase served to compare the colouring activity with a music condition and the non-stimulation (baseline/control) condition.
These three conditions were implemented according to a multi-element baseline design [21].
All sessions started with the research assistant accompanying Stuart to the table and inviting him to sit and relax (during the baseline/control condition), to sit and listen to his presumably preferred music (during the music condition) and to sit and colour pictures with the available crayons (during the picture colouring condition).
The order of the conditions changed systematically.
The third phase of the study served as a choice phase.
Stuart was allowed to choose between the picture colouring and the music conditions before each session.
The condition chosen was then implemented within the following session.
The fourth phase alternated sessions with the colouring activity (i.e. the condition regularly chosen during the third phase) and baseline sessions [21].
The fifth phase included only sessions with the colouring activity.
The research assistant could intervene once during the sessions, if Stuart had been wandering for 2 or 3 minutes.
The intervention consisted of verbally encouraging Stuart to sit at the table and relax or listen to the music or engage in the colouring activity (depending on the condition available).