ISSN 1413-389X
The experiment aimed at analyzing how responding maintained by VI schedule would be affected when it was subsequently exposed to different values of VT and extinction. Eight female rats were initially exposed to baseline sessions in which lever presses operated a water dispenser on a VI-20-s schedule. Afterward, subjects were exposed to sessions of VT 10 s, VT 20 s, and VT 40 s (in either an increasing or a decreasing sequence) followed by a final extinction session, each of them initiated by a retraining condition on VI. Results did not demonstrate effects of VT 20 s over response rates. However, for most subjects, the VT 10 s, as well as extinction, generated lower response rates than VT 40 s, despite the higher frequency of water presentations on VT 10 s. Results suggest that the more numerous and shorter intervals between two consecutive water presentations may contribute to the understanding of this inverse relation involving response rates and the values of the response-independent schedules.
Keywords: Contingency, Contiguity, Variable Time Schedule, Variable Interval Schedule, Extinction, Rats.
Tomanari, G. Y., Vasconcellos, A. S., Yochiy, A., Stasieniuk, E. V. Z., Brizante, J. G., Geronymo, M. G. F. B. et al. (2006). Contingência e contigüidade: efeitos paramétricos do esquema de tempo variável sobre o responder em ratos. Temas em Psicologia, 14(1), 81-93