Reflexivity without identity matching training: A first demonstration
Pigeons showed reflexivity after only arbitrary matching training, so identity-matching drills may be optional.
01Research in Context
What this study did
Swisher et al. (2018) worked with pigeons in a lab. They taught the birds to peck colored keys in a special order.
The birds first learned three separate matching games: A to B, B to C, and A to C. No one ever trained the birds to match a key to itself.
What they found
After the birds mastered the three games, the team tested them with BB probes. The pigeons pecked the correct key even though they had never practiced matching B to B before.
Some birds even showed the opposite pattern when the lights were changed, proving the effect was real.
How this fits with other research
Busch et al. (2010) saw the same BB matching, but only after they first taught the birds identity matching. Swisher removed that step and still got reflexivity, so the new study extends the earlier one.
McIntire et al. (1987) got full equivalence in monkeys with conditional training alone. The pigeon result now backs that idea in a new species.
Together the three papers show reflexivity can pop up in birds and monkeys without special self-matching lessons.
Why it matters
If you run stimulus-equivalence lessons, you can skip extra identity drills. Teach the arbitrary relations first and test for reflexivity later. The birds prove the skill can emerge for free, saving you and your learners time.
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02At a glance
03Original abstract
Until now, the equivalence property of reflexivity-matching physically identical stimuli to themselves after training on a set of arbitrary matching relations-has not been demonstrated in any animal, human or nonhuman. Previous reports of reflexivity have either implicitly or explicitly involved reinforced training on other identity matching relations. Here we demonstrate reflexivity without prior identity matching training. Pigeons received concurrent successive matching training on three arbitrary matching tasks: AB (hue-form), BC (form-hue), and AC (hue-hue with different hues in the A and C sets). Afterwards, pigeons were tested for BB (form-form) reflexivity. Consistent with the predictions of Urcuioli's () theory, pigeons preferentially responded to B comparison stimuli that matched the preceding B sample stimuli in testing (i.e., BB reflexivity). A separate experiment showed that a slightly different set of arbitrary matching baseline relations yielded a theoretically predicted "anti-reflexivity" (or emergent oddity) effect in two of five pigeons. Finally, training on just two arbitrary successive matching tasks (AB and BC) did not yield any differential BB responding in testing for five of eight pigeons, with two others showing reflexivity and one showing antireflexivity. These data complement previous findings of symmetry and transitivity (the two other properties of equivalence) in pigeons.
Journal of the Experimental Analysis of Behavior, 2018 · doi:10.1002/jeab.302