Problem solving and strategy production in mentally retarded persons.

Leung (1989) read every paper on problem solving in people with intellectual disability. The author then wrote a story-style review of what works.

The review asked two questions. Can these learners invent their own steps to solve a problem? Will those steps carry over to new tasks?

Yes, they can invent steps and use them elsewhere. Two things must happen first. The person must clearly understand the task. The person must also practice with many different examples.

Without those two pieces, strategies disappear and do not travel to new settings.

Barthelemy et al. (1989) proved the idea in the same year. Two adults with severe ID learned short self-talk lines while they practiced many work problems. Later they solved brand-new job issues without help.

Boudreau et al. (2015) later looked at thirty years of self-instruction studies. Their big picture matches Leung (1989): teach the learner to talk himself through the task and give lots of examples.

Phillips et al. (2019) adds a warning. Kids with ID can follow written prompts in new places, but only after they train on several different task sets. One example is not enough.

Trimmer et al. (2017) shows the same rule in math class. Middle-schoolers with ID mastered money problems when teachers moved them from real coins to pictures to numbers. Varied examples made the skill stick.

Stop drilling the same worksheet twenty times. Instead, check that your client truly understands the goal, then mix up the materials. Use real objects, photos, and words. Ask the learner to say the steps out loud while she works. This simple pair—clear task understanding plus many examples—turns one taught skill into a flexible problem-solving tool you will see again and again.