Choice and terminal-link response topography.
Pigeons and people both pick the option that ends with the easier move, proving response topography alone can steer choice.
01Research in Context
What this study did
The researcher put six pigeons in a two-key chamber. Each key started a chain that ended with food.
One chain ended with normal key pecks. The other ended with pushing a heavy treadle. Both chains paid off after the same delay.
Birds could hop between keys at any time. The team logged which key each bird picked.
What they found
Every pigeon chose the key that ended in pecking. They picked it on 80-a large share of trials even though both sides gave food after 60 seconds.
Pecking felt easier than stepping on a stiff pedal. The birds voted with their feet for the easier move.
How this fits with other research
Cariveau et al. (2022) later saw the same rule in kids. A teen picked the AAC tablet that delivered better snacks, not the one that looked nicer. Both studies show the final step itself can drive choice.
Pilgrim et al. (2000) used the same pigeon setup but changed link length instead of response form. They found birds like steady, predictable links. Grant (1989) adds that the move you make at the end also counts.
Petursdottir et al. (2023) now tell clinicians to stop asking "topography or selection?" and just test which response the learner likes best. The 1989 data give animal proof for that advice.
Why it matters
If a client keeps dropping a task, check the last response you require. Switching from a hard press to an easy touch, or from a long vocal to a short sign, can boost participation even when the payoff stays the same. Always run a quick two-option trial: same reinforcer, different final move, and let the learner vote.
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02At a glance
03Original abstract
Six pigeons responded under concurrent-chains schedules. For 3 birds, pecking was required in both initial links; for 3 others, treadle pressing was required. For all subjects, pecking was required in one terminal link and treadling in the other. The initial links consisted of independent variable-interval 60-s schedules. All birds were exposed to five pairs of terminal-link variable-interval schedules over 10 conditions: 6 s versus 54 s, 18 s versus 42 s, 30 s versus 30 s, 42 s versus 18 s, and 54 s versus 6 s. Comparisons of responding under nominally identical terminal-link variable-interval schedules showed that, without exception, higher choice proportions were obtained for the alternative correlated with terminal-link pecking. Moreover, terminal-link delay to reinforcement was shorter for terminal-link pecking than for terminal-link treadling chains. This factor, along with response force requirements, was implicated in explaining the present as well as previous findings of preference for pecking over treadling. It was found also that the delay-reduction hypothesis provided only a moderately accurate description of performance under concurrent chains in which different terminal-link response topographies are required. These findings suggest that quantitative models neglecting the effects of differing terminal-link topographies may be incomplete.
Journal of the experimental analysis of behavior, 1989 · doi:10.1901/jeab.1989.51-243