Delay versus trace heart-rate classical discrimination conditioning in rabbits as a function of interstimulus interval

Alexander A. Manning, Neil Schneiderman, Daniel S. Lordahl

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Each of 48 rabbits received 1 adaptation, 8 acquisition, and 1 extinction session in a heart-rate (HR) classical discrimination conditioning experiment using 2 tone CSs and a shock UCS. The experiment was a 2 * 3 factorial design with delay vs. a 5-sec trace CS procedure as 1 dimension and interstimulus intervals (ISIs) of 7, 14, and 21 sec. as the other. Major findings were that (1) level of conditioning (CR +) and discrimination (CR + minus CR-) varied inversely with ISI, (2) better discrimination was observed under the delay than under the trace procedure, and (3) magnitude of HR conditioning and discrimination revealed an inverted U shaped function over acquisition sessions. (PsycINFO Database Record (c) 2006 APA, all rights reserved).

Original languageEnglish (US)
Pages (from-to)225-230
Number of pages6
JournalJournal of Experimental Psychology
Issue number2 PART 1
StatePublished - May 1 1969
Externally publishedYes



  • delay vs. trace heart rate classical discrimination conditioning, interstimulus interval, rabbit

ASJC Scopus subject areas

  • Medicine(all)

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