The effects of stimulus magnitude and duration during pretrial delivery of preferred items to increase compliance

Researchers asked children with autism to follow simple instructions. Before each request, the kids got a favorite item for free.

The team compared two sizes of edible treats and two lengths of iPad time. They used an alternating-treatments design to see which package helped compliance most.

Big cookies and two-minute iPad turns won. Compliance rose when the pretrial item was large or lasted longer.

Small crackers or ten-second iPad clips did little. Size and time matter more than just handing something over.

Lipschultz et al. (2017) saw no gain when free items were given on a fixed schedule. The difference: their items were small and brief, matching the weak condition in Hodges. Magnitude, not schedule, seems key.

Bullock et al. (2006) also used free items and got better compliance. Their treats were larger, aligning with the high-magnitude win here. The studies together show the item has to be worth it.

Miller et al. (2025) stretched leisure time and kids picked iPad over snacks. They proved longer access raises value; Hodges shows that same longer access also smooths later demands.

Next time you prime a client, give the whole cookie or a full two-minute iPad turn. A nibble or ten-second peek wastes your prep. Watch if compliance jumps, then fade the size or duration once the routine sticks.