The double-alternative, double-start experimental apparatus: A new procedure for measuring preference.

Green et al. (1984) built a two-route box for rats. Each route ended in the same place, but one gave mild shocks without warning.

The rats could pick either path on every trip. The box counted how often they chose the shock-free route.

Ten rats ran many trials. The goal was to see if the new box could spot which condition the animals liked less.

All ten rats kept picking the route that ended with unsignaled shock. The simple choice count gave a clear ranking.

The result showed the new tool works. It measured preference with just the animal’s own path picks.

Reberg et al. (1979) first showed rats treat shock signals differently. Their setup proved the idea; the 1984 box made it easier to count.

Geckeler et al. (2000) took the same choice idea to kids with severe ID. They used toys instead of shock and found the top pick worked as a reinforcer for two-thirds of the children.

Ivancic et al. (1996) later showed a twist: even the highest-ranked item can fail to reinforce some learners with profound disabilities. Preference does not always equal power.

You now have a quick way to rank options: let the learner choose between two stimuli and count the picks. Whether you work with toys, snacks, or breaks, a brief two-choice test can show you what to use first. If the top item fails to strengthen behavior, remember Ivancic et al. (1996) and probe again or switch to a different reinforcer.