Response acquisition and fixed-ratio escalation based on interresponse times in rats.
Let the schedule grow the work for you—fast responders can reach FR 30 in four sessions without any hand shaping.
01Research in Context
What this study did
The team worked with 49 lab rats that had never pressed a lever before.
They set up a program that watched how fast the rat moved from one press to the next.
If the pause was short, the next food pellet needed more presses to earn.
The ratio climbed on its own until the rat hit FR 30.
What they found
Half the rats were pressing 30 times for one pellet within four short sessions.
No hand shaping, no clicker, no extra cues.
The schedule itself taught the new skill.
How this fits with other research
Schwartz et al. (1971) got rats to FR 10 in one hour with a food-tray gadget.
Sharp et al. (2010) push that ceiling higher, showing FR 30 can be reached just as fast.
Baker et al. (2005) saw quick lever pressing in mice, but added levers slowed some strains.
The rat study keeps the set-up simple: one lever, one rule, steady climb.
Why it matters
If you need a client to move from easy tasks to tougher work, let the schedule do the teaching.
Start with a low response count and let fast, steady responding trigger the next level.
You avoid prompt fading and extra stimuli.
Try it next time you shape a long chain of desk work or fluency drills.
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02At a glance
03Original abstract
The effectiveness of a fixed-ratio (FR) escalation procedure, developed by Pinkston and Branch (2004) and based on interresponse times (IRTs), was assessed during lever-press acquisition. Forty-nine experimentally naïve adult male Long Evans rats were deprived of food for 24 hr prior to an extended acquisition session. Before the start of the session, three food pellets were placed in the magazine. Otherwise, no magazine training, shaping, nor autoshaping procedure was employed. The first 20 presses each resulted in the delivery of a 45-mg food pellet. Then, the FR increased (2, 4, 8, 11, 16, 20, 25, 30) when each IRT in the ratio was less than 2 s during three consecutive ratios. Sessions lasted 13 hr or until 500 pellets were earned. On average, rats reached a terminal ratio of 11 (mean) or 16 (median) during the first session. Seven rats reached the maximum value of FR 30 and only one rat did not acquire the response. In most rats, a break-and-run pattern of responding characteristic of FR schedules began to develop in this acquisition session. Subsequently, the ratio-escalation procedure continued during daily 2-hr sessions. In these sessions, the starting ratio requirement was set at the terminal ratio reached in the previous session. Using this procedure, over half (26) of the rats reached the FR 30 requirement by the fourth session. These data demonstrate that a ratio-escalation procedure based on IRTs provides a time-efficient way of establishing ratio responding.
Journal of the experimental analysis of behavior, 2010 · doi:10.1901/jeab.2010.93-261