PIGEONS TRANSFER BETWEEN CONDITIONAL DISCRIMINATIONS WITH DIFFERENTIAL OUTCOMES IN THE ABSENCE OF DIFFERENTIAL-SAMPLE-RESPONDING CUES

Pigeons were trained to perform two independent zero-delay conditional discriminations involving the same differential outcomes (i.e., food vs. a feeder light) and were then tested by replacing the samples from one of the tasks with those from the other. Differential responding t o the two samples was required in Phase 1, in Phase 2, in neither phas e, or in both phases. Half the pigeons in each group were then tested with associations that were either consistent with the presumed outcom e expectancies established during Phases 1 and 2 (positive transfer co ndition) or inconsistent with those expectancies (negative transfer co ndition). The magnitude of the transfer effect was largest in the grou p that could use differential sample responding as a cue to mediate tr ansfer, but significant transfer effects were also found in the groups that could use only outcome expectancies. Thus, differential sample r esponding contributes to, but does not account for, the differential-o utcomes effect.