Preference for less segmented fixed-time components in concurrent-chain schedules of reinforcement.
Extra segments in a schedule quietly lower preference, so keep reinforcement paths simple and direct.
01Research in Context
What this study did
Warren et al. (1986) let pigeons pick between two fixed-time schedules. One schedule was a simple tandem. The other was a chained schedule broken into extra segments.
The birds chose by pecking keys in the first link. Longer first links made the split between tandem and chained more obvious.
What they found
The pigeons slightly favored the tandem schedule. The longer the first link, the clearer the preference.
Segmentation acted like a small tax on value.
How this fits with other research
Wacker et al. (1985) saw the same tilt one year earlier. Together the papers show the effect is steady across small set-ups.
Reed et al. (1988) later twisted the dial. They varied how much of the interval was segmented. Preference still tracked the ratio, proving the 1986 finding holds in finer grain.
Henton (1972) looked like a clash. His pigeons showed no preference between chained and tandem. The catch: he removed the stimuli that usually mark chain links. Without those cues, conditioned reinforcement vanished, so choice flattened. Same birds, same schedules, but a stripped procedure erased the gap.
Why it matters
For clients on token or DRO boards, keep the path to reinforcement short and smooth. Every extra step or token phase trims value, especially when the wait is already long. Try cutting needless segments or merging steps before you add more prompts.
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02At a glance
03Original abstract
A concurrent-chain procedure was used to examine choice between segmented and less segmented response-independent schedules of reinforcement. A pair of independent, concurrent variable-interval 60-s schedules were presented in the initial link, along with a 1.5-s changeover delay. A chained fixed-interval fixed-time and its corresponding tandem schedule constituted the terminal links. The length of the fixed-interval schedule in the terminal link was varied between 5 s and 30 s while that of the fixed-time schedule was kept at 5 s over conditions. The first components of both terminal-link schedules were accompanied by the same stimulus. Except in the baseline condition, the onset of the second component of the terminal-link chained schedule was accompanied by either a localized (key color) or a nonlocalized (dark houselight) stimulus change. Stimulus conditions were constant during the terminal-link tandem schedule. With three exceptions, pigeons demonstrated a slight preference for the tandem over the chained schedule in the terminal link. Furthermore, this preference varied inversely with the length of the first component. In general, these results are consistent with previous studies that reported an adverse effect on choice by segmenting an interval schedule into two or more components, but they are inconsistent with studies that reported preference for signaled over unsignaled delay of reinforcement.
Journal of the experimental analysis of behavior, 1986 · doi:10.1901/jeab.1986.46-175