Transitive responding in hooded crows requires linearly ordered stimuli.
Ordered feedback along a line is the key that lets crows (and maybe kids) make untaught transitive choices.
01Research in Context
What this study did
The team worked with hooded crows in a lab.
They taught the birds to pick between pictures using overlapping conditional discrimination training.
Some crows got feedback that changed along a line, like size order. Others got the same feedback every time.
What they found
Only the crows with ordered feedback showed transitive responding.
This means they could pick the “middle” picture even when that pair was never directly taught.
The group with constant feedback never showed this leap.
How this fits with other research
Gladstone et al. (1975) also shaped crow behavior in a lab, but they used positional fading to create tool use. Both studies show crows learn well when cues are arranged in steps.
Hayes (1989) argues true stimulus equivalence has never been seen in animals. The 2004 study does not claim full equivalence; it only shows transitive relations, a smaller skill.
Older autoshaping papers like Lydersen et al. (1974) prove stimulus-reinforcer pairings control bird responding. The crow work extends this idea to more complex stimulus sets.
Why it matters
If you want derived relations in any learner, arrange the teaching stimuli along a clear line. Use size, color brightness, or number order for feedback. This gives the brain a ladder to climb. Try it next time you teach bigger-than, smaller-than, or first-middle-last concepts.
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Join Free →Pick three stimuli that differ on one clear line (small, medium, large). Teach A-B and B-C relations with feedback that keeps the line order. Then test A-C without training.
02At a glance
03Original abstract
Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These circles were made available for comparison to potentially help the crows order the stimuli along a physical dimension. For the other 4 birds, the circles corresponding to the colored cards had the same diameter (constant feedback group). In later testing, a novel choice pair (BD) was presented. Reinforcement history involving stimuli B and D was controlled so that the reinforcement/nonreinforcement ratios for the latter would be greater than for the former. If, during the BD test, the crows chose between stimuli according to these reinforcement/nonreinforcement ratios, then they should prefer D; if they chose according to the diameter of the feedback stimuli, then they should prefer B. In the ordered feedback group, the crows strongly preferred B over D; in the constant feedback group, the crows' choice did not differ significantly from chance. These results, plus simulations using associative models, suggest that the orderability of the postchoice feedback stimuli is important for crows' transitive responding.
Journal of the experimental analysis of behavior, 2004 · doi:10.1901/jeab.2004.82-1