How do you see Meursault acting on instinct instead of emotion?

The week flies by because now that we have seen a typical workday there is no need to show us others in the routine. They will each be rather similar. The pleasure highlights are pointed out as Meursault goes to the movies twice and then sees Marie on Saturday. This day is given in much greater detail because the pattern is more instinctive than desire driven. Part of his instinct involves the desire for activities like swimming and sex but it seems Meursault does them out of instinctual practice rather than the actions being pleasure driven.