TRANSVERSE PATTERNING IN PIGEONS

Pigeons were trained to choose between colored lights (A, B, C, and D) , first in a two-pair ambiguous-cue problem (A+B-, B+C-), and then, wi th all colors nondifferentially reinforced, in a three-pair loop probl em (A+B-, B+C-, C+A-) followed by a four-pair loop problem (A+B-, B+D- , D+C-, C+A-). Systematic efforts were made to simulate the data with a variety of models incorporating one or another of three conceptions of stimulus compounding prominent in the literature on compound condit ioning. One conception is that the components of a compound stimulus a re altered by interaction; the second is that they are not altered, bu t only supplemented with a new (compound-unique) component generated i n the interaction; and the third is that the components entirely disap pear in a configurational transformation. The ambiguous-cue data could be simulated accurately with each of the models, but the loop data wi th none of them. A convincing explanation of performance in loop probl ems remains to be found.