Temporal generalization gradients following an interdimensional discrimination protocol

We investigated the effects of interdimensional discrimination training in the temporal generalization gradient. In a matching-to-sample task, pigeons learned to choose key S after a T-s houselight sample and key NS in the absence of the houselight sample. For one group of pigeons, T = 20 s; for another, T = 10 s. Subsequently, houselight duration was varied to obtain temporal generalization gradients. Results showed that (a) proportion S increased as houselight duration ranged from 0 s to T s and then remained high for houselight durations longer than T; (b) the gradients were well described by negative-exponential functions; (c) these non-flat gradients were present from the beginning of testing, and; (d) the average gradients obtained with T = 20 s and T = 10 s overlapped when plotted in relative time. We conclude that temporal control does not require explicit discrimination training along the temporal dimension, and that temporal generalization gradients obtained with an interdimensional protocol show the scalar property of timing. We discuss how these findings challenge current models of timing.
This work was supported by Portuguese Foundation for Science and Technology (FCT) [Grant number PTDC/MHC-PCN/3540/2012] to Armando Machado. Ana Catarina Vieira de Castro was supported by an FCT doctoral grant [Grant number SFRH/BD/43398/2008], by ERDF funds through the Operational Competitiveness Programme-COMPETE, and by National Funds through FCT under project FCOMP-01-0124-FEDER-029527 [Grant number PTDC/MHC ETI/4890/2012], and Marco Vasconcelos was supported by an FCT Investigator Grant [Grant number IF/01624/2013].
info:eu-repo/semantics/publishedVersion