Backward and forward blocking in human electrodermal conditioning: blocking requires an assumption of outcome additivity.

Full Abstract

Blocking was observed in two human Pavlovian conditioning studies in which colour cues signalled shock. Both forward (Experiment 1) and backward (Experiment 2) blocking was demonstrated, but only when prior verbal and written instructions suggested that if two signals of shock (A+ and B+) were presented together, a double shock would result (AB++). In this case, participants could assume that the outcome magnitude was additive. Participants given non-additivity instructions (A+ and B+ combined would result in the same outcome, a single shock) failed to show blocking. Modifications required for associative models of learning, and normative statistical accounts of causal induction, to account for the impact of additivity instructions on the blocking effect, are discussed. It is argued that the blocking shown in the present experiments resulted from the operation, not of an error-correction learning rule, nor of a simple contingency detection mechanism, but of a more complex inferential process based on propositional knowledge. Consistent with the present data, blocking is a logical outcome of an A+/AB+ design only if participants can assume that outcomes will be additive.

Learn Faster Today Improve your study skills

Author information

Author/s: Mitchell, Chris J (CJ); Lovibond, Peter F (PF);

Affiliation: School of Psycvhology, University of New South Wales, Sydney NSW 2052, Australia. chris.mitchell@unsw.edu.au

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The Quarterly journal of experimental psychology. B, Comparative and physiological psychology (Q J Exp Psychol B), published in England. (Language: eng)

Reference: 2002-Oct; vol 55 (issue 4) : pp 311-29

Dates: Created 2002/09/27; Completed 2002/12/31; Revised 2006/11/15;

PMID: 12350284, status: MEDLINE (last retrieval date: 11/6/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acoustic Stimulation
Adolescent
Adult
Association Learning
Conditioning (Psychology)
Conditioning, Classical - physiology
Cues
Discrimination Learning

This article has not been indexed for related articles as yet, however you can still use the live related article search links below.

See 100+ related articles.