Attention and timing: dual-task performance in pigeons

Pigeons were exposed to an analog of a 'dual-task' procedure used to test a ttentional models of timing in humans. After separate training on an audito ry duration discrimination and on a variable ratio (VR) schedule, VR episod es lasting for 5 s were superimposed on the stimuli to be timed, either ear ly (E) or late (L) during the trial. Trials with VR yielded underestimation of the target durations (increased % of 'short' choices), relative to tria ls without VR, and this effect was stronger under the L than under the E co ndition. Data were similar to those collected with humans and support atten tional models of timing according to which the simultaneous non-timing task uses processing resources which are diverted from the timing mechanisms. ( C) 1999 Elsevier Science B.V. All rights reserved.