Practice Effects and Composition: A Reply to Anderson

Richard Alan Carlson, Walter Schneider

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Anderson (1989) argues that our results (Carlson, Sullivan, & Schneider, 1989) confirm several predictions of the ACT* account of skill acquisition, including the occurrence of composition. The ACT* theory does include mechanisms that can account for the major ordinal results of our experiment. However, the quantitative implications of the mechanisms that Anderson invokes to support the occurrence of composition result in unreasonable or inconsistent predictions for this data set. These mechanisms do not account for the observed effects in our control experiment, make the composition hypothesis difficult to falsify, and involve assumptions that negate the processing speed advantage that composition would provide. We also discuss several other points made by Anderson. Our results do provide weak support for some aspects of ACT*, while emphasizing the importance of quantitatively examining interrelations among mechanisms in complex models of skill acquisition.

Original languageEnglish (US)
Pages (from-to)531-533
Number of pages3
JournalJournal of Experimental Psychology: Learning, Memory, and Cognition
Issue number3
StatePublished - Jan 1 1989

All Science Journal Classification (ASJC) codes

  • Experimental and Cognitive Psychology
  • Language and Linguistics
  • Linguistics and Language


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