Briefly delayed reinforcement effects on variable-ratio and yoked-interval schedule performance.
Brief unsignaled delays boost response rates on interval schedules but leave ratio schedules almost untouched.
01Research in Context
What this study did
Guest et al. (2013) worked with pigeons pecking keys for food.
Birds faced two schedules side-by-side: a VR and a yoked VI.
Both schedules sometimes paid off after a quiet 2-second delay.
The team watched whether the short wait changed how fast the birds pecked.
What they found
The little delay made VI pecking speed up and burst into short, fast bursts.
The same delay did almost nothing to VR pecking.
So schedule type, not just delay, controls the effect.
How this fits with other research
Rogers-Warren et al. (1976) saw response rates drop when delays grew longer under IRT>t schedules.
Guest et al. (2013) show a short, fixed delay can actually raise rates, but only on interval schedules.
The two studies seem opposite until you notice schedule type and delay length differ.
Gettinger (1993) first used yoked VR-VI schedules to show ratio strain.
Guest et al. (2013) borrow that yoked design to prove delay effects are schedule-specific, extending the earlier work.
Why it matters
If you use brief delays to manage problem behavior or teach new skills, check your schedule.
On interval schedules a tiny wait may spike responding; on ratio schedules it likely won’t.
Match your delay plan to the schedule you run in session.
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Join Free →Test a 2-second unsignaled delay during a VI schedule and count if responses rise, then try the same delay on a VR to see the difference.
02At a glance
03Original abstract
Most investigations of briefly delayed reinforcement have involved schedules that arrange a time-plus-response requirement. The present experiment examined whether briefly delaying reinforcement on schedules that have a ratio requirement differs from results with schedules that have a time-plus-response requirement. Four pigeons responded on a two-component multiple schedule. One component arranged a variable-ratio (VR) 50 and the other a variable-interval (VI) schedule in which the distribution of reinforcers was yoked to the preceding VR schedule. Across a series of conditions, delays were imposed in both schedules. These delays were brief (0.25- or 0.5-s) unsignaled delays and, as control conditions, a 5-s unsignaled delay and a 0.5-s delay signaled by a blackout of the chamber. In the yoked-VI component, the brief unsignaled delay increased response rates in six of nine opportunities and increased the proportion of short interresponse times (IRTs) (<0.4 s) in eight of nine opportunities. In the VR component, the brief unsignaled delay increased response rates and the proportion of short IRTs in only two of nine opportunities. For two of the three pigeons that were exposed to the 5-s unsignaled delay, response rates and the proportion of short IRTs decreased in both of the components. The 0.5-s signaled delay did not systematically change response rates nor did it change the distribution of short IRTs relative to the immediate reinforcement condition. The results replicate effects reported with time-based schedules and extend these observations by showing that changes commonly observed in VI performance with briefly delayed reinforcement are not characteristic of VR responding.
Journal of the experimental analysis of behavior, 2013 · doi:10.1002/jeab.41