Lexicality as a Determinant of the Category-Order Effect

Abstract

The current study examined the category-order effect (COE hereafter) identified by Brooks and Watkins (1990) where memory span is facilitated by the order of presentation of salient stimuli. In previous research (Brooks and Watkins, 1990; Greene and Lasek, 1994), when numbers preceded words recall performance on the entire list was improved. To examine to what degree lexicality is involved in the COE, the authors modified Brooks and Watkins’ paradigm by presenting a unitary string (as opposed to a sequential list) containing four random non-repeating numbers and four letters representing four conditions: random letters, rhyming letters, four letter pseudo-words (consonant-vowelconsonant-vowel strings, CVCV hereafter), and four letter words. The results of this study indicate that COEs are stronger in conditions where the letters have lexical properties, such as the CVCV and word conditions. In contrast to past results, this study found better list recall when words and CVCV preceded numbers.