This study was aimed to investigate the question why oddity-from-sample acquisition in animals always start at above chance level. A question was raised concerning the role of stimuli sequences and a possible bias introduced in responding. Thus, this study analyzed the effects of stimuli sequencing during response build up in the pigeon (pre-training) upon the acquisition of identity matching (IMTS) and oddity-from-sample (OFS) with three color stimuli and two comparisons. During pre-training one color was presented at the time in any one of three response key. Color presentation was randomized but for the restriction that the probability of two like colors being presented consecutively was the same as the probability of two non-like colors being presented consecutively. This controlled for any sequencing bias effects upon responding. Following, subjects were submitted either to IMTS or to OFS training. Results replicated those of the literature, indicating that stimuli sequencing control during pre-training has no effect upon matching and oddity acquisition.
Conditional discrimination; matching-to-Sample; oddity-from-sample
