Improving the generalized mnemonic performance of a Down's syndrome child.

One child with Down syndrome practiced digit-span lists every day. The lists changed each time so no two were the same.

The trainer used a multiple-baseline design across three list lengths. They tracked correct recalls during training and on brand-new lists the child had never seen.

Correct recalls jumped well above baseline for every list length. The gains also showed up on the untrained lists, a sign of real generalization.

Memory improved only after the varying practice started, not before, so the training caused the change.

Porter et al. (2008) ran a later, parent-led version of digit-span training. Parents coached at home and saw only small gains, mostly in kids with stronger language. The 1978 lab method used new lists every trial; the 2008 method kept the same short list for days. The tighter, fresher variety in 1978 likely drove the bigger lift.

Lowe et al. (1974) also used a multiple-baseline design to teach greetings to children with intellectual disability. They proved that rotating trainers boosted generalization across staff. Hamm et al. (1978) applied the same rotate-items logic to memory, showing the tactic works for cognitive skills too.

Together the papers say: keep the stimuli fresh and the people varied if you want the skill to travel.

You can borrow the 1978 trick tomorrow. Mix new digits into every span trial instead of drilling one list until mastery. Track generalization with cold probes the child has never practiced. The tiny change costs nothing but can widen memory gains for clients with Down syndrome or other developmental delays.