Independence of reinforcement delay and magnitude in concurrent chains.
Delay and magnitude stay separate in choice, so assess both before you thin the reinforcer list.
01Research in Context
What this study did
The lab tested pigeons on two keys. Each key led to a different reward.
One reward came fast but was small. The other came slow but was big.
The birds chose freely. The goal was to see if delay and size mix together or stay separate.
What they found
Delay and size acted like two dials, not one. Birds treated them as separate pieces of value.
This fits the matching law: choices tracked each dial on its own.
How this fits with other research
Frederiksen et al. (1978) pushed the same idea into shock-avoidance. Rats matched their responses to the safest schedule, showing the rule works for bad events too.
Lozy et al. (2019) seems to clash. Kids picked the shiny prize in a choice test, yet the less-shiny prize drove the same work when it was the only option. Choice and performance can split.
Catania et al. (1972) used a similar two-key set-up. They showed that changing the pay rate on one key also changed how well birds spotted odd shapes, again linking choice and outcome.
Why it matters
When you run a concurrent reinforcer assessment, remember delay and size do not blend into one value. Track them separately. If a kid picks the iPad over stickers, it may still be the sticker that keeps him seated when the iPad is absent. Test both ways before you drop a reinforcer from the menu.
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02At a glance
03Original abstract
A three-component concurrent-chains procedure was used to investigate preference between terminal-link schedules that differed in delay and magnitude of reinforcement. Response and time allocation data were well described by a generalized matching model. Sensitivity to delay appeared to be lower when reinforcement magnitudes were unequal than when they were equal, but when obtained rather than programmed time spent responding in the initial links was used in the model, the difference vanished. The results support independence of delay and magnitude as separate dimensions of reinforcement value, as required by the matching law, and the assumption of the contextual choice model (Grace, 1994) that sensitivities to delay and magnitude are affected similarly by temporal context. Although there was statistical evidence for interaction between successive components, the effects were small and transient. The multiple-component concurrent-chains procedure should prove useful in future research on multidimensional preference, although it may be necessary to control obtained initial-link time more precisely.
Journal of the experimental analysis of behavior, 1995 · doi:10.1901/jeab.1995.63-255