Emergence of reinforcer preference as a function of schedule requirements and stimulus similarity.

Smith et al. (1997) asked what happens when two reinforcers look almost the same. They set up two levers. Pressing each lever gave a snack. At first only a few presses were needed. Each day the team raised the number of presses.

They watched which snack the child picked as the work got harder. The kids had developmental delays. The team also tested pairs of snacks that looked very different.

When the work was light, kids picked both similar snacks about equally. When the presses climbed higher, one snack became the clear favorite. The similar pair now showed a strong preference.

For snacks that looked very different, choice stayed the same no matter how hard the work got. Effort made the small difference between similar items matter.

Duker et al. (1996) showed that top items from a quick choice test usually work best as reinforcers. Smith et al. (1997) adds a twist: even high-preference items can split further when effort rises and the items are almost alike.

Bromley et al. (1998) used the same rising fixed-ratio plan with people. They found that richer payoff can make clients choose the harder task. Together these studies say: both effort and payoff size steer choice.

Landon et al. (2003) kept effort steady and changed reward size instead. Bigger rewards created bigger preference jumps. Smith et al. (1997) shows that rising effort can create a similar jump when rewards are nearly identical.

Your client may pick two similar edibles equally during a quick preference test. Before you place that item into a hard program, probe again under the real response requirement. Add five or ten responses each round. If a clear winner shows up, use that one for tough tasks. This simple check can save you from stalled sessions and sudden refusal.