UNBLOCKING WITH QUALITATIVE CHANGE OF UNCONDITIONED STIMULUS

Citation
Ap. Blaisdell et al., UNBLOCKING WITH QUALITATIVE CHANGE OF UNCONDITIONED STIMULUS, Learning and motivation, 28(2), 1997, pp. 268-279
Citations number
22
Categorie Soggetti
Psychology, Experimental","Psychology, Biological
Journal title
ISSN journal
00239690
Volume
28
Issue
2
Year of publication
1997
Pages
268 - 279
Database
ISI
SICI code
0023-9690(1997)28:2<268:UWQCOU>2.0.ZU;2-Y
Abstract
Conditioned barpress suppression was used to examine the effects of qu alitative changes in the unconditioned stimulus (US) between Phases 1 and 2 of a blocking paradigm. In Phase 1, rats received pairings of a conditioned stimulus (CS) with footshock. In Phase 2, experimental sub jects received a single trial of the same CS or a different CS compoun ded with a second stimulus and followed either by a footshock or an ic e water dunking. These two USs were equated in their potential to elic it conditioned suppression of barpressing. Less blocking of the second stimulus (i.e., unblocking) was observed in subjects that received a qualitative change in US between phases than in subjects for which the US was consistent between phases. This unblocking effect is discussed with respect to the differences between various models of conditionin g and several prior successes and failures to demonstrate unblocking. (C) 1997 Academic Press.