Transposition of line-length discrimination in Africanpenguins (Spheniscus demersus)

摘要

Four penguins (Spheniscus demersus) were trained to discriminate linelength in a simultaneous discrimination task. After the birds' performances reached adiscrimination criterion, the reinforcement ratio was decreased to .33. After the ratioof correct trials reached .90 in three successive sessions with a partial reinforcementprocedure, probe-test sessions were introduced. In the probe-test trials, untrainedlines were presented paired with the trained lines. The four probe-test trials weremixed into 45 discrimination trials. In the probe-test trials, the penguins that had beentrained to peck shorter lines pecked the untrained shorter line rather than the longerline that was reinforced in the discrimination trials. In contrast, those birds that hadbeen trained to peck the longer line pecked the untrained longer line, rather than theshorter line which was reinforced in the discrimination trials. All four birds demon-strated transposition in the line-length discrimination task.