ABA Fundamentals

Choice behavior on discrete trials: a demonstration of the occurrence of a response strategy.

Silberberg et al. (1974) · Journal of the experimental analysis of behavior 1974
★ The Verdict

Quiet gaps between trials can make smart choice rules look like chaos; tighten the schedule and the real pattern shows.

✓ Read this if BCBAs running discrete-trial or DTT sessions who see sudden ‘no pattern’ data.
✗ Skip if Clinicians working only with free-operant or continuous tasks.

01Research in Context

01

What this study did

Researchers watched pigeons pick between two keys on separate trials.

They changed how long the bird waited between trials—short pause versus long pause.

Each correct pick earned food; the team recorded every choice to see if a rule guided them.

02

What they found

The birds followed a simple rule: pick the side most likely to pay off right now.

Long pauses added ‘noise’—missed pecks and sloppy timing—that hid the rule.

So the same brain process stayed in place; it just looked messy when gaps grew.

03

How this fits with other research

Lancioni et al. (2011) ran almost the same pigeon test but added uncertain rewards.

They also saw longer pauses hurting good choices, backing up the 1974 noise idea.

Meyer et al. (1987) moved the test to humans and got the same early-commit pattern, showing the rule crosses species.

Szempruch et al. (1993) found pigeons average recent wait times, a cousin idea that timing history—not just the last gap—steers the next move.

04

Why it matters

When client responding looks random, check for ‘execution noise’ before you switch programs.

Lengthened wait time, extra instructions, or fatigue can mask a solid rule.

Shorten gaps, give quick prompts, and watch if clean data re-appears—then you keep the effective strategy instead of abandoning it.

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Cut inter-trial pauses to two seconds and re-graph the next ten trials—see if the ‘random’ picks line up.

02At a glance

Intervention
not applicable
Design
single case other
Sample size
6
Population
other
Finding
not reported

03Original abstract

Three pairs of pigeons were trained to peck at two keys presented simultaneoulsy in discrete trials with intertrial intervals of 1, 22, or 120 sec. Left-key responses incremented the probability of reinforcement for the first right-key response and, conversely, right-key responses incremented the probability of reinforcement for the first left-key response. In terms of relative response rates, it was found that all birds' choices were described by a momentary maximizing strategy, but this fact was not reflected in the detailed sequential statistics for birds with the longer (22 or 120 sec) intertrial intervals. It was hypothesized that choice behavior, in general, may be accurately described by a momentary maximizing sequence, but that prior failures to demonstrate this were due to "errors" in executing the momentary maximizing sequence. These misappropriated responses, which are hypothesized to be randomly distributed among the responses defining the momentary maximizing sequence, caused successive choices to appear to be statistically independent when, in fact, they were not.

Journal of the experimental analysis of behavior, 1974 · doi:10.1901/jeab.1974.21-315