Response rate viewed as engagement bouts: effects of relative reinforcement and schedule type.
Use log-survivor plots to see if your intervention boosts bout starts or within-bout speed.
01Research in Context
What this study did
The team watched pigeons peck a key for food. They used variable-interval (VI) schedules and sometimes added a variable-ratio (VR) requirement. They wanted to know if more food, bigger food, or extra work changed how often the birds started pecking and how many pecks they made in a row.
They drew log-survivor plots to split the stream of pecks into bouts. This let them count two things: how many times the bird began a bout and how many pecks happened inside each bout.
What they found
More food, larger food, and a higher chance of food all made the birds start more bouts. When the VR requirement was added, the birds still started bouts at the same rate, but they packed more pecks into each bout.
How this fits with other research
Katz et al. (2003) ran the same VI-plus-VR setup with rats pressing a lever. The pattern matched: extra work increased responses inside bouts, not starts. This direct replication shows the bout rule holds across species and responses.
Ferreri et al. (2011) took the bout tool further. They showed that food deprivation boosts bout starts (motivation), while added ratio requirements lengthen the pause between bouts (motor cost). The 2001 paper opened the door for this split.
Reed (1991) found that bigger reinforcers can slow VI responding. The 2001 study explains why: large food may cut bout starts but leave within-bout pecks unchanged. Same data, sharper lens.
Why it matters
When a client’s response rate climbs, you need to know if they are starting more bouts or firing faster inside each bout. Log-survivor plots give you that split in Excel. If starts rise, tweak motivation. If within-bout responses rise, check the response requirement. Use the right lever and your intervention lands faster.
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02At a glance
03Original abstract
The rate of a reinforced response is conceptualized as a composite of engagement bouts (visits) and responding during visits. Part I of this paper describes a method for estimating the rate of visit initiations and the average number of responses per visit from log survivor plots: the proportion) of interresponse times (IRTs) longer than some elapsed time (log scale) plotted as a function of elapsed time. In Part 2 the method is applied to IRT distributions from rats that obtained food pellets by nose poking a lighted key under various multiple schedules of reinforcement. As expected, total response rate increased as a function of (a) increasing the rate of reinforcement (i.e., variable-interval [VI] 4 min vs. VI 1 mi), (b) increasing the amount of the reinforcer (one food pellet vs. four pellets), (c) increasing the percentage of reinforcers that were contingent on nose poking (25% vs. 100%), and (d) requiring additional responses after the end of the VI schedule (i.e., adding a tandem variable-ratio [VR] 9 requirement). The first three of these variables (relative reinforcement) increased the visit-initiation rate. The tandem VR, in contrast, increased the number of responses per visit. Thus, variables that have similar effects on total response rate can be differentiated based on their effects on the componemts of response rate.
Journal of the experimental analysis of behavior, 2001 · doi:10.1901/jeab.2001.75-247