Original scientific paper
Categorization and vagueness: How are words stored in the mental lexicon
Ana Branka Šefer
; Sveučilište u Zagrebu
Magdalena Krbot
; Sveučilište u Zagrebu
Velimir Išgum
; KBC Zagreb, Klinika za neurologiju
Marijan Palmović
; Laboratorij za psiholingvistička istraživanja, Sveučilište u Zagrebu
Abstract
In this study event–related potentials method (ERP) was used to study the effect of vagueness
in language. In difference to philosophy, where vagueness is a source of Sorites paradoxes, in
linguistics vagueness is regarded as a design feature of human language. In this sense vagueness
is modeled in contemporary cognitive science as a feature that allows for keeping the actual
amount of exchanged information between the intelligent agents at minimum while preserving
the effectiveness of communication. The theory of meaning that accounts for vagueness in
language is Gärdenfors’ theory of conceptual spaces. According to this theory the concepts are
positioned in a continuum along a vector that represents a feature, e. g. tallness. Gärdenfors
introduces a crisp function that corresponds to categorization. The crisp function divides the
conceptual space into two parts (tall and non–tall regions in the given example). Categorizationis therefore essential for the account of vagueness because it is the source of vague concepts
(e.g. of being tall in a continuum of precise measures of tallness, say, in millimeters). In this
experiment we used a well–known picture matching paradigm in which participants had to
decide whether a word matches the given photograph or not (categorization task). The vagueness
condition was added by adding hyponyms as words to the categorization task, thus creating
four experimental conditions (non–vague match, vague match, non–vague mismatch and vague
mismatch). The difference in N400 component of ERP was expected for all vague and mismatch
conditions. However, two different components were obtained: both N400 for all mismatch
conditions (including vague) and P600 for vague conditions. Therefore, both the experimental
effect of vagueness was obtained and the results can be interpreted in terms of vagueness as
facilitation of language communication. These results also indicate that retrieving words from
mental lexicon is (at least) a two–phase process in which the word activated by the picture is
(1.) compared with the stimulus word and then (2.) integrated into the context. The first phase
is highly automatic and beyond speaker’s control while the second depends on the context:
vague words are correctly categorized, but require additional processing costs if there is no other
reason for using them.
Keywords
vagueness (psycholinguistics); cognitive model of human communication; mental lexicon
Hrčak ID:
62328
URI
Publication date:
17.12.2010.
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