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<Paper uid="W01-1302">
  <Title>Specification in terms of interactional properties as a way to optimize the representation of spatial expressions</Title>
  <Section position="4" start_page="2" end_page="2" type="intro">
    <SectionTitle>
2 Methodology
</SectionTitle>
    <Paragraph position="0"> The first stage of the study was concerned with formulation of hypotheses about particular character of perceptual and functional properties of the prepositions. For this purpose examples of the authentic usage of the prepositions in electronic corpora (the Brown corpus, the Lancaster-Oslo-Bergen corpus, the British National Corpus, the Times (March 1995)) were collected. The corpus data were supplemented by usage examples found in literary English and Russian texts. This stage revealed important distributional characteristics of the prepositions. For example, it was found that over very rarely combines with verbs denoting an upward motion, such as rise, raise, lift, heave, soar, while above often does. Hypotheses about a given preposition were formulated in terms of properties of referent scenes that tend to be described by this preposition. The hypotheses  The both prepositions denote the Figure's position on the frontal axis of the Ground.</Paragraph>
    <Paragraph position="1"> were tested in experiments with native speaking subjects.</Paragraph>
    <Paragraph position="2"> During the experiments subjects' judgements about appropriateness of the use of the prepositions in selected contexts were obtained. The methodology is based on the assumption that an expression is judged to be semantically acceptable in a context, if this context possesses semantic features that are either the same as those of the expression or do not contradict them; the expression is unacceptable, if the context contains semantic properties, contradicting those of the expression. Thus, presence of a semantic property in the meaning of a preposition was verified in the following manner. In the context, which possessed the examined semantic property, first one and then the other of the contrasted prepositions were placed. If there was a statistically significant difference in distribution between subjects' evaluations of the two sentences, presence of the property in the semantics of a preposition was taken to be verified. The use of linguistic data in the experiments is particularly suited for the purposes of the study, because it allows for dealing with non-perceptual semantic properties, as opposed to obtaining linguistic responses to purely perceptual stimuli, e.g. pictures of geometric shapes.</Paragraph>
    <Paragraph position="3"> 23 English-speaking subjects participated in the experiments. They represented the American and British varieties of English (20 and 3 subjects, respectively). Their age ranged between 25 and 60. All of them were college graduates. As Russian-speaking subjects, 45 graduate and undergraduate students of the English Language Department of Bashkir State University (Ufa, Russia) were recruited, their age ranging between 18 and 30.</Paragraph>
    <Paragraph position="4"> During the experiment the subjects were presented with questionnaires, each containing about 30 pairs of identical sentences, which differed only in the prepositions used. The sentences used were edited authentic examples of the use of the prepositions. The subjects were instructed to evaluate appropriateness of the use of the prepositions in the sentences according to a 5-degree scale. In case they perceived a sentence as ambiguous, they were asked to point it out and leave it unevaluated.</Paragraph>
    <Paragraph position="5"> The difference between the pairs of sentences thus formed was analyzed in terms of the Student t criterion and the chi-square criterion. The difference in evaluations between the sentences (and hence between the semantics of the prepositions) was taken to be established, if the a value was smaller than 0.05. In the following discussion, paired sentences with a&lt;0.05 are used as examples, with the preposition having smaller mean of evaluations marked by an asterisk.</Paragraph>
  </Section>
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