Transposition in pigeons: Reassessing Spence (1937) with multiple discrimination training

Abstract

We studied transposition in pigeons, using multiple-pair discrimination training. Four birds discriminated two pairs of circles: 1+2- and 5+6- or 1-2+ and 5-6+ (digits denote circle diameters and plus and minus signs denote reward and nonreward, respectively). Four other birds discriminated four pairs of circles: 1+2-, 1+3-, 4+6-, and 5+6- or 1-2+, 1-3+, 4-6+, and 5-6+. Finally, 4 birds discriminated only one pair of circles: 1+2-, 1-2+, 5+6-, or 5-6+. Testing included five new pairs-1/5, 2/3, 2/6, 3/4, and 4/5-that distinguished absolute from relational accounts of transposition. The pigeons' relational responding rose from one- to two- to four-pair training. The similarity of the testing stimuli to one another also affected relational responding: Transposition increased with highly dissimilar stimuli. Neither Spence's (1937) theory nor existing relational accounts could predict the obtained pattern of relational responding. Copyright 2005 Psychonomic Society, Inc.