Effects of serial versus concurrent task sequencing an acquisition, maintenance, and generalization.

The team compared two ways to run discrete-trial lessons. In serial lessons, kids mastered one task before the next began. In concurrent lessons, the same tasks alternated within one session.

All learners had intellectual disability. The study used an alternating-treatments design so each child got both lesson types.

Both lesson types taught the new skills at the same speed. Yet concurrent mixing helped the kids use the skills in new places and with new materials. How well they kept the skill later did not depend on the lesson order.

Lincoln et al. (1988) saw the same edge for concurrent training when they taught laundry steps to teens with severe handicaps. Their later probe showed the skill stuck around longer, too.

Perez et al. (2015) flipped the story in a DRA study. They found that serial rotation of two good choices beat a single concurrent choice at stopping problem behavior from coming back. Same serial-versus-concurrent question, but the best pick changed with the goal.

Davis et al. (1994) remind us that generalization does not always happen. They had to add extra steps after extinction until the drop in self-injury showed up with new staff and new rooms.

If you want broad use of a new skill, mix the tasks within the same table-time instead of blocking them. You lose no teaching speed and you may cut down on later generalization probes. Just remember: when the target is cutting resurgence, serial rotation can be the safer bet.