A comparison of blocked and mixed‐trial methods for teaching auditory–visual discriminations

Bentham et al. (2019) asked a simple question: when adults with intellectual disability need to learn to match a sound to a picture, is it better to practice one pair at a time or to mix the pairs from the start?

They used an alternating-treatments design. Each adult got both kinds of sessions. Blocked trials meant the same sound-picture pair repeated until the learner hit mastery. Mixed trials shuffled all pairs from the first trial.

Three adults with IDD served as their own controls. The team tracked how many trials each person needed to reach mastery under each format.

Blocked trials won every time. Every adult learned the sound-picture matches faster when the trials stayed the same for a block.

No one needed extra sessions once the blocked format started. Mixed trials always took longer, even though the final accuracy ended up the same.

The result lines up with Wunderlich et al. (2017). They also saw faster learning when preschoolers with ASD got receptive labels in a serial (blocked-like) order instead of a fully mixed order.

But DiSanti et al. (2020) seems to disagree at first glance. They found that a structured mix beat random rotation for kids with fewer than 50 words. The key difference is age and language level. Little kids with tiny vocabularies may need some mixing to avoid prompt dependency, while adults with ID learn best when the target stays the same for a run.

Vladescu et al. (2021) adds another layer: keeping stimulus sets small (3-6 items) also speeds acquisition. Bentham’s blocked format naturally keeps the effective set size tiny during each block, so both studies point toward the same takeaway—reduce the load at first, then expand later.

If you run auditory-visual conditional discrimination programs for adults or teens with ID, start with blocked trials. You will likely see mastery in fewer sessions and lower learner frustration. Once the first block is firm, rotate to mixed review to test generalization. This small tweak costs nothing and saves therapy hours.