An attempt was made to investigate the intradimensional
transfer of a simultaneously presented, double brightness discrimination
in male hooded rats. It was hypothesized that in
a paradigm designed to emphasize interstimulus cues over
individual stimulus cues, subjects would exhibit transposition
in testing, even when this involved approaching a previously
negative stimulus, and avoiding a previously positive stimulus,
under extinction conditions. Results of two tests (with a partial reinforcement retraining
session between them) indicated significant transposition
on all measures except trial of first choice on Test I
for the group trained to approach the brighter stimulus in any
pair presented. Results were interpreted as being in support
of relational theory which stresses the importance of dimensional
salience in the establishment of relational responding.