Matching and Oddity Learning in the Pigeon: Transfer Effects and the Absence of Relational Learning

Abstract

Three experiments examined the extent to which pigeons trained on a matching or oddity discrimination with one pair of colours showed transfer when tested on a new matching or oddity discrimination with a new pair of colours. Experiment 1 examined the effects of key spacing and a delay procedure and replicated previous reports that in the transfer stage subjects given the same kind of problem (Non-shift condition) in general learn more rapidly than those given the opposite problem (Shift condition). However, this difference appeared only when pigeons given matching in both training and transfer stages were compared to those shifted from oddity to matching; it did not appear in birds transferred to oddity. Transfer was not significantly affected by key spacing or by the delay. Experiments 2 and 3 examined transfer from a non-relational conditional discrimination based on one set of colours to a subsequent matching or oddity task based on two new colours. Both a comparison between the results of Experiment 1 and 2 and the corresponding within-experiment comparison from Experiment 3 showed that transfer from conditional training to matching was as great as from prior training on matching, while prior training on oddity produced negative transfer on shift to matching. It was suggested that this negative transfer occurs because pigeons trained on oddity have not learned to override an initial bias towards the odd stimulus in an array. Whatever the correct explanation; the present results provide no support for the claim that pigeons solve matching or oddity discriminations relationally.

Shift Learning in Matching-to-Sample Discriminations in Rats as a Function of Overtraining

“…The present experiment replicated the effect of overtraining on shift learning in matching-(or nonmatching-) to-sample discriminations observed in Nakagawa (2001 c) That is, the symmetry of transfer effect was obtained in the present experiment. This finding was in line with the expectation according to the findings of Nakagawa (2001 c), whereas it did not agree with the findings of Nakagawa (1992aNakagawa ( , 1993a using rats, nor the findings of Wilson et al (1985) using pigeons, nor the findings of Hogan (1974, 1975) using pigeons. This discrepancy in transfer effect among these experiments might be caused by an additional preshift training (i.e.…”

“…The results had suggested that the rate of shift learning between shifted animals and nonshifted ones depended on whether they were tested with matching-to-sample or nonmatching-to-sample discriminations. That is, Wilson et al (1985) found the asymmetry of transfer effect in pigeons. They had claimed that the cause of this transfer effect seemed likely to be related to inherent bias toward the odd stimulus that occurred in both Phase 1 training and Phase 2 shift.…”

“…That is, it is possible that the difference in the rate of shift learning between shifted animals and nonshifted ones depends on whether they are tested with either a matching-to-sample discrimination or a nonmatching-to-sample discrimination in the shiftnonshift paradigm . For example, Wilson, Mackintosh, and Boakes (1985) found an asymmetry of transfer effect in a matching-(or nonmatching-) tosample discrimination in pigeons. In the experiment of Wilson et aI., some pigeons were trained with a matching-to-sample discrimination and others were trained with a nonmatching-to-sample discrimination using a pair of stimuli (i.e., blue and green).…”

Learning Processes in Matching and Oddity: The Oddity Preference Effect and Sample Reinforcement.

“…Following the demonstration that the shifted-nonshifted effect resulted from the OPE, Wilson et al (1985a) concluded, "When pigeons are transferred to novel stimuli, they characteristically revert to their oddity preference, and so it seems that even birds that have previously learned to ignore their preference may revert to it with novel stimuli" (p. 308). This statement implies that any novel-stimulus transfer may be due to an inadvertent OPE rather than a so-called higher order or relational comparison between the sample stimulus and the correct comparison.…”

Acquisition and Limited Transfer of Numerical Discrimination of Object Stimuli in Rats

“…Wilson, Mackintosh, & Boakes (1985) reported that pigeons could learn stimulus-specific conditional discrimination but not abstract same/different rules in a matching-to-sample task. had similar results for a same/different discrimination task of two stimuli, when a small number of training stimuli were used, but pigeons possibly applied abstract same/different rules for novel stimuli when trained with large stimuli sets.…”