CHAPTER 1 INTRODUCTION
1.2 Motivation and research questions
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pointing out the shortcomings of the Cohort theory, it could not deny that
Marslen-Wilson’s Cohort theory aroused many concerns for the following decades.
Actually, many issues that are still active in the field of spoken word recognition now
are either closely related to the Cohort theory or trying to modify the defects of the
original model.
1.2
Motivation and research questions
Four groups of questions will be discussed in this study. Questions to be asked
involve the following.
(i) Is the word-initial information such important as Cohort theory predicts? If
this is the case, then any stimuli in the experiment of this study whose initial
segment is replaced by the hiccup noise cannot be perceived correctly. If the
word-initial information is not as crucial as what the Cohort theory predicts,
then those stimuli whose word-initial segments are disrupted can still be
perceived correctly by the listeners. However, if the results show what
Cohort theory predicts is wrong, then it raises the question about the status
of the acoustic onset and offset in spoken word recognition. That is, is it the
onset or the offset that is the most crucial for spoken word recognition in
Mandarin?
Among the models of spoken word recognition, there are two different
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arguments concerning the importance of the initial segment. Cohort theory
(Marslen-Wilson & Welsh, 1978) proposed that a set of representations in
memory are activated by the acoustic input, known as the word-initial
cohort. All of the words which have the same initial acoustic information as
the input signals are activated in the listener’s mind. Therefore, the early
Cohort theory put much emphasis on the importance of the word-initial
input, suggesting that spoken word recognition would break down if the
initial input is seriously disturbed. However, other models of spoken word
recognition did not emphasize the importance of the word-initial input to
such an extent. The Merge model (Norris, McQueen, & Cutler, 2000)
focused on the overall similarity between the acoustic inputs and the words
being activated. It suggests that word-initial segment is not of critical
importance. Even though the word-initial information is severely damaged,
the particular word can still be activated and recognized depending on the
rest of the acoustic information. Although a great number of studies have
been conducted to investigate the importance of the word-initial information
in the recognition of spoken words, few studies focused on the role of the
final segments in spoken word recognition (Wingfield, Goodglass, &
Lindfield, 1997). In addition, most of the studies concerning this issue
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focused on English or some western languages such as Dutch; very few
focused on the role of the initial and final segments in spoken word
recognition in Mandarin. Hence, these questions based on the gaps
mentioned above will be tackled in this study.
(ii) What is the status of different segments in spoken word recognition? If the
initial consonant is the most important segment in spoken word recognition,
then the result of the experiment will predict the longest reaction time and
lowest accuracy when the initial consonant is replaced by the hiccup noise.
However, if it is the prenuclear glide, vowel, postnuclear glide, or the final
nasal that occupies the prestigious status in spoken word recognition, then
the result of the experiment will presage the longest reaction time and
lowest accuracy when the prenuclear glide, vowel, postnuclear glide, or
final nasal, is replaced by the hiccup noise.
One of the active questions in the field of spoken word recognition is about
the nature of lexical and sublexical representations. Research on the lexical
competition mainly put emphasis on the competition between the
representations of words. Nevertheless, another crucial issue regarding the
spoken word recognition is the nature and existence of sublexical
representations. Marslen-Wilson and Warren (1994) argued against the
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existence of sublexical representations. They suggested that phonetic
features maps to words directly, without any intermediate sublexical
representations. Other researchers, in contrast to Cohort theory, argued for
the nature and the existence of sublexical representations though different
models proposed different viewpoints about the interactions between
segmental and lexical representations. At present, much evidence is in favor
of the existence of sublexical representations, in contrast with Cohort theory.
However, there is still a gap in that few studies focused on the role of
different segments in a word. Thus, the questions concerning this gap will
be dealt with in this study.
(iii) Can the spoken words be recognized successfully if the tones of the words
are leveled? What is the interaction between Mandarin tones and segments
in the recognition of spoken words? Which segment, namely, the initial
consonant, prenuclear glide, vowel, postnuclear glide, or final nasal, is the
most influential segment for the perception of Mandarin tones? If the
segment which is replaced by hiccup noise results in the wrong perception
of the particular tone, it can be inferred that the segment carries the most
important acoustic information of that tone. If the segment which is
replaced by hiccup noise is perceived correctly concerning its tone, it
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suggests that the acoustic information in that segment is not enough to cause
the incorrect perception of Mandarin tone.
In the history of speech perception, the issues regarding how the
acoustic signals map to phonetic features, how phonetic features map to
phonemes, how phonemes map to syllables, and how syllables map to
words, have already been tackled by a number of researchers. These issues
are segmental. Other issues concerning suprasegmental have also been
explored. For example, studies about segmentation of words in fluent
speech suggested the prosodic solution to the segmentation problem, which
stated that listeners parse the speech stream by exploiting rhythmic
characteristics of their language (Cutler, 1996; Cutler & Norris, 1988).
Although a great number of studies have been conducted to investigate both
segmental and suprasegmental issues about speech perception, few concern
the status of Mandarin tones in speech perception. Therefore, the status of
Mandarin tones will be investigated in this study.
(iv) Does frequency effect affect Mandarin spoken word recognition? If
frequency effect really exists in Mandarin, then the reaction time of the high
frequency words will be shorter than that of the low frequency words. To
the contrary, if the frequency effect plays no role in Mandarin spoken word
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recognition, the reaction time of the high frequency words will not be
longer than that of the low frequency words.
A number of previous studies have already proved that low frequency
words are more difficult to be picked up by high frequency words in spoken
word recognition (Monaco, 2007; Savin, 1963; Broadbent, 1967; Elliott,
1987). Nevertheless, few studies examined this phenomenon in Taiwan
Mandarin. As a result, the study will examine this effect in Taiwan
Mandarin.
Given the gaps mentioned above, in this study, we intend to investigate several
issues concerning Mandarin word recognition more thoroughly and completely.