Chapter 2 Literature Review
3.4 Discussion
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3.4 Discussion
There was no significant difference on the proportion of looks between the tonal
competitor and the unrelated distractor. The mismatch of the first segments may
override the possible effect of the tone in the activation stage. Therefore, subjects
would nearly consider the tonal competitor as the unrelated distractors.
When could tone be accessed during the spoken character recognition? The
divergent time of the curves between target and the segmental competitor could be
extrapolated as the time point when listeners could distinguish the tonal difference of
segmental competitor from target. The result showed that the divergent time of the
segmental competitor and the target was at about 601-700-msec. This divergent time
was earlier than the offset of the target (at about 703msec), which suggests that tone
may begin to affect the spoken character processing before subjects catch the whole
acoustic information.
While the results suggest that tonal information could affect the spoken character
processing before the end of the auditory stream, however, the divergent time of the
curves between the tonal competitor and target was the same among four tones. If
tonal information had impact on the processing, fixation proportions of tonal
competitor should have significant differences in different time bin among four tones.
Different tonal characteristics could not affect listeners’ decision on choosing the
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target. This result could imply that the tonal information has weak influence on the
spoken character processing.
Additionally, weak tonal effect could be the reason why the curves of segmental
competitor diverged from the target in later time, comparing to the time when the
curves of target diverging from unrelated distractor. Owing to the totally different
syllable structure between target and unrelated distractor, the time when listeners are
able to distinguish two characters could consider to be the earliest time listeners could
identify the tonal and segmental information. It was worth suspecting that tonal
information could affect spoken character processing in an earlier time.
The weak and late tonal effect might be because of the great segmental disparity
between the tonal competitor and target. As the auditory stimuli unfold, the initial
segments of the character of tonal competitor make participants consider it different
from the target and thus fixate less on it in an early time. The great segmental
differences of tonal competitor might be the reason why tone could not take effect
during spoken character processing.
The last issue was the characteristics of tone in processing spoken character. There
was a latest time of divergence between the segmental competitor and the target in
Tone 3, in which of Lai and Zhang (2008) that the last isolation point in a gating
paradigm is in Tone 3. However, in the present study, the order when the curves of
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competitor and target diverged in Tone 1, Tone 2, and Tone 4 were inconsistent with
the order of Isolation Point in Lai and Zhang (2008).
To sum up, the result of experiment one showed that tone would constrain before
the unfolding of the whole syllable information. However, the totally different
segmental structure between the target and the tonal competitor caused listeners
barely consider the tonal competitor as unrelated distractor. Experiment two examined
the earlier time point when tone would affect lexical processing when the initial
segments were the same.
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53
Experiment Two
In Experiment 2, the design was similar as experiment one. However, the targets
shared the same initial cohort (two segments) with two types of competitors. One type
of the cohort competitors shared the initial cohort and has the same tone with the
target (cohort-tone competitor, CTC), the other shared the cohort but the tone is
different from targets (cohort-only competitor, COC). For the unrelated distractor,
similar as experiment one, the tonal and segmental structure was totally different from
the target and the competitors.
The time point of divergence between the curves of target and the competitors, and
between the competitors and the unrelated was examined. Thus, if tone affected the
processing in early phase of spoken character recognition, the time point of
divergence between the curves target and the competitor would be earlier in
cohort-only competitor than in cohort-tone competitor. In addition, the proportion of
looks to cohort-only competitor would be lower than that of the cohort-tone
competitor. On the contrary, if the tone information did not affect the spoken character
processing in early time, the curve of the cohort-only competitor would be similar as
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the cohort-tone competitor. Table 6 illustrates the predictions for the accounts whether
tone is accessed in initial character in Experiment 2.
Table 6. Predictions of two accounts for initial tonal processing in Experiment 2
Accounts Predictions
Fixation Proportion Divergent time between TAR and competitors 1. Tone is
accessed early CTC > COC COC is earlier than CTC 2. Tone is
accessed late CTC = COC Comparable time point
4.1 Method
4.1.1Participants
Thirty-two participants, including 21 females and 11 males were recruited through
on-line sign-up sheets and paid to participate in the experiment. Their mean age was
21.7 years old, ranging from 19 to 25 years old. All participants had normal or
correct-to-normal vision and were native speakers of Mandarin Chinese.
4.1.2 Material
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4.1.2.1 Stimuli
There were 140 monosyllabic Chinese characters in the experimental stimuli,
including 28 target characters, 28 cohort-tone competitor character, 28 cohort-only
competitor characters, and 56 unrelated characters. The segmental structure of these
stimuli comprised 70 CVC, and 70 CGVC. The stimuli was consisted of 36 characters
with Tone 1, 35 characters with Tone 2, 35 characters with Tone 3, and 34 characters
with Tone 4. The features of target and competitors were controlled as follows. First
of all, the frequency of these characters were controlled in a range between 7~200, as
computed from the CKIP Electronic Dictionary (The CKIP Electronic Dictionary is
an electronic lexicon for Mandarin Chinese containing 88,000 entries). There was no
significant difference in character frequency across the target and the cohort-tone and
cohort-only competitors (F (2, 81) = 2.105, p=.128). Secondly, the average stroke of
these characters were controlled in a range between 5~20. There was no significant
difference of the stroke across the target and two types of competitors were balanced.
(F (2, 81) = 0.122, p=.885). Lastly, the average number of homophone was under 10.
There was no significant difference in the average number of homophone across the
target and the two types of competitors (F (2, 81) = 1.172, p=.315).
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Table 7. Means and SDs of character frequency, strokes, and homophone number for target, cohort-tone competitor and cohort-only competitor
Frequency Stroke Homophone
Note. TAR: target; CTC: cohort-tone competitor; COC: cohort-only competitor; UR:
unrelated distractor
4.1.2.2 Recording
The target and the competitors were recorded by a 25-year-old female Chinese
native speaker through the Audio-technica MB 4k/c cardioid condenser microphone.
The recording data was digitalized at a sampling rate of 44100 Hz, 16 bits through the
software Praat. The mean durations of target, cohort-tone competitor, and cohort-only
competitor characters were 745.3 msec, 741.5 msec, and 755.2 msec, respectively.
4.1.2.3 Auditory Stimuli Pretest
To ensure that the tone of the auditory stimuli was clear for the subject to recognize,
a survey was conducted. Four females and one male whose average age was 26.4
years old took part in the survey. The participants listened to all of the auditory stimuli
and then ticked off the tone (Tone 1 to Tone 4) and typed the Chinese character they
considered to be. The result showed that average of the accuracy of each experimental
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stimulus was 99%.
4.1.3 Design
Two conditions were manipulated in this experiment. There were two syllable
structures CVC and CGVC in the present study. The initial cohort in CVC syllable
structure was CV, and the initial cohort in CGVC syllable structure was CG. The
cohort-tone competitors shared cohort structure and tone with the target. The
cohort-only competitors shared only the cohort structure with the target. For each
target, the two types of competitors shared the same rhyme. For example, a stimuli set
included a target / tang1 / ‘soup’, a cohort-tone competitor / tai1 / ‘fetus’, a
cohort-only competitor / tai4 / ‘peaceful’, and two unrelated distractors (the segmental
and tone were different from target: / pʰow3 / ‘to cut open’, and / xən2 / ‘scar’). An
experimental trial comprised one target, one competitor, which was either cohort-tone
competitor or cohort-only competitor, and two unrelated distractors. The entire
experiment consisted of 62 trials, including 56 experimental trials, 4 filler trials and 2
practices. The filler trials and practice trials were not included for analysis. The
experimental trials were mixed and randomly distributed into four lists. In each of the
lists, the number of each condition was equal and the conditions were
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counterbalanced across subjects. There were two blocks of 32 trials, of which the first
two trials were fillers. The relationship between the target and the competitor in the
first block was exchanged in the second block.
4.1.4 Layout of visual stimuli
The layout of visual stimuli was same as Experiment 1.
4.1.5 Apparatus & procedure
The apparatus and procedure follows that of Experiment 1.
4.2 Data analysis
All the analyses and measures were the same as in Experiment 1.
4.3 Result
The mean of reaction time and correct hits on matching the acoustic target character
to the character in visual display were computed for each participant. Mean reaction
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time for response was 1315.3 msec (SD = 275.3) and mean accuracy rate was 99 %
(Max = 100%, Min = 98%).
Figure 10 plots the fixation proportions of target, competitor, and unrelated
distractor for every millisecond from 200 msec, the time when visual display showing
to the target acoustic onset 0 msec until 1000 msec after acoustic target onset in
cohort-tone and cohort-only conditions. Starting from about 301msec, both of the two
competitors attracted more fixations than the unrelated distractors. As expected, the
time when the curve of target diverged from cohort-only competitor was earlier than
when the target curve diverged from cohort-tone competitor curve. In addition, as
illustrated in Figure 11, the fixation proportions of cohort-tone competitor was higher
than that of cohort-only competitor.
Figure 12 and Figure 13 plots the fixation proportions of target, competitor, and
unrelated distractor in CVC and CGVC syllable structure respectively for every
millisecond from 200 msec, the time when visual display showing to the target
acoustic onset 0 msec until 1000 msec after acoustic target onset in cohort-tone and
cohort-only conditions. For the syllable structure of CVC, the time when the curve of
target diverged from cohort-only competitor was earlier than when the target curve
diverged from cohort-tone competitor curve. However, as for CGVC, the time when
the curve of target diverged from cohort-only competitor was similar when the target
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curve diverged from cohort-tone competitor curve.
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Figure 10. Fixation proportions to targets, competitors, and unrelated distractors for trials with cohort-tone or cohort-only competitors in Experiment 2. The x-axis shows time in milliseconds from visual display onset, 200 msec before target acoustic onset, for the 1200 msec period.
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Figure 11. Fixation proportions to cohort-tone/cohort-only competitors across two experimental conditions in Experiment 2. The x-axis shows time in milliseconds from the display onset, for 1200 msec.
Figure 12. Fixation proportions to targets, competitors, and unrelated distractors in CVC syllable structure for trials with cohort-tone or cohort-only competitors in Experiment 2. The x-axis shows time in milliseconds from visual display onset, 200 msec before target acoustic onset, for the 1200 msec period.
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Figure 13. Fixation proportions to targets, competitors, and unrelated distractors in CGVC syllable structure for trials with cohort-tone or cohort-only competitors in Experiment 2. The x-axis shows time in milliseconds from visual display onset, 200 msec before target acoustic onset, for the 1200 msec period.
Figure 14. Fixation proportions to cohort-tone/cohort-only competitors in CVC and CGVC syllable structure across two experimental conditions in Experiment 2. The x-axis shows time in milliseconds from the display onset, for 1200 msec.
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We performed the analyses of variance (ANOVAs) by participants (F1) and items
(F2) for the fixation proportions in time bins of 100 msec, starting from the onset of
acoustic target for 1000 msec in cohort-tone and cohort-only condition (Table 8).
Additionally, we performed the same analyses as above-mentioned in CVC and
CGVC respectively (Table 9 and Table 10). As Table 8 illustrated, in both of the two
conditions, the differences among target, competitor, and distractor were significant
during 301 msec to 1000 msec. Table 9 showed that the differences among target,
competitor, and distractor were significant during 401 msec to 1000 msec in both
conditions. Table 10 showed that the differences among target, competitor, and
distractor were significant during 401 msec to 1000 msec in cohort-tone condition but
during 301 msec to 1000ms in cohort-only condition.
Table 8. Analyses of variance by participant and item comparing mean fixation proportions to tonal and segmental competitors with those of the target and unrelated distractors from 1 msec to 1000 msec after acoustic target onset in Experiment 2
Condition Test 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000
F 1(2,62) 0.66 0.90 0.91 5.70 30.72 81.58 116.20 249.00 364.60 609.10
p 0.521 0.414 0.410 0.005 0.000 0.000 0.000 0.000 0.000 0.000
F 2(2,54) 0.45 0.54 0.57 3.33 19.41 77.86 162.20 183.70 321.10 485.70
p 0.642 0.584 0.569 0.043 0.000 0.000 0.000 0.000 0.000 0.000
F 1(2,62) 0.36 0.62 0.36 4.32 28.56 66.35 193.50 390.90 599.20 1055.00
p 0.701 0.541 0.702 0.018 0.000 0.000 0.000 0.000 0.000 0.000
F 2(2,54) 0.24 0.96 0.49 6.05 34.81 63.29 180.50 327.20 741.50 1758.00
p 0.790 0.390 0.614 0.004 0.000 0.000 0.000 0.000 0.000 0.000 All
Time bin (ms)
Cohort-Tone
Cohort-Only
Note: F 1 = 32 participants, F 2 = 28 items
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Table 9. Analyses of variance by participant and item comparing mean fixation proportions to tonal and segmental competitors with those of the target and unrelated distractors in CVC syllable structure from 1 msec to 1000 msec after acoustic target onset in Experiment 2
Table 10. Analyses of variance by participant and item comparing mean fixation proportions to tonal and segmental competitors with those of the target and unrelated distractors in CGVC syllable structure from 1 msec to 1000 msec after acoustic target onset in Experiment 2
The mean fixation proportions to target, competitor, and the unrelated distractors
and standard errors were shown in Figure 15. For each time bin, a one-way ANOVA
was performed for trials with cohort-tone or cohort-only competitors and their targets
and distractors, followed by the post-hoc comparisons (Table 11). The mean fixations
Condition Test 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 F 1(2,62) 0.06 0.68 0.92 2.67 11.32 31.64 -0.39 119.40 236.70 454.90
p 0.938 0.512 0.403 0.077 0.000 0.000 1.000 0.000 0.000 0.000 F 2(2,54) 0.04 0.54 0.69 2.08 7.72 37.54 71.36 81.06 227.80 659.10
p 0.958 0.590 0.509 0.145 0.002 0.000 0.000 0.000 0.000 0.000 F 1(2,62) 0.08 1.30 1.40 0.85 10.59 45.30 89.00 140.90 277.00 699.60
p 0.925 0.281 0.253 0.431 0.000 0.000 0.000 0.000 0.000 0.000 F 2(2,54) 0.12 2.17 2.91 2.07 19.71 30.83 73.82 117.30 323.00 702.90
p 0.892 0.134 0.072 0.147 0.000 0.000 0.000 0.000 0.000 0.000 CVC
Time bin (ms)
Cohort-Tone
Cohort-Only
Note: F 1 = 32 participants, F 2 = 28 items
Condition Test 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 F 1(2,62) 1.66 0.47 0.45 2.18 11.81 27.89 50.15 120.60 184.30 327.80
p 0.198 0.629 0.638 0.121 0.000 0.000 0.000 0.000 0.000 0.000 F 2(2,54) 1.35 0.23 0.35 1.28 14.02 39.77 102.20 109.20 118.50 138.20
p 0.276 0.796 0.711 0.294 0.000 0.000 0.000 0.000 0.000 0.000 F 1(2,62) 0.67 0.08 0.30 3.16 13.32 24.41 85.99 281.90 504.10 673.70
p 0.517 0.925 0.742 0.049 0.000 0.000 0.000 0.000 0.000 0.000 F 2(2,54) 0.41 0.12 0.52 3.88 16.23 31.47 105.30 238.00 462.10 1172.00
p 0.665 0.888 0.603 0.034 0.000 0.000 0.000 0.000 0.000 0.000 CGVC
Time bin (ms)
Cohort-Tone
Cohort-Only
Note: F 1 = 32 participants, F 2 = 28 items
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proportions to cohort-tone competitor and target was significantly different by
participants and by item analyses from 501-1000-msec. The mean fixations
proportions to cohort-only competitor and target was significantly different by
participants and by item analyses from 401-1000-msec. When the cohort-only
competitor diverged from the target was earlier than when the cohort-tone competitor
diverged from the target.
The mean fixations proportions to cohort-tone competitor and unrelated distracter
was significantly different by participants analyses from 301-1000-msec and by item
analyses from 401-1000-msec. The mean fixations proportions to cohort-only
competitor and unrelated distracter was significantly different by participants and by
item analyses from 301-1000-msec. When the unrelated distractors diverged from two
types of competitors was on a consistent time bin by participants analysis.
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Figure 15. Mean fixation proportions to targets, competitors, and unrelated distractors for cohort-tone and cohort-only conditions in the 1,000 msec period following
acoustic target onset in Experiment 2. Each data point represents the average of fixation proportions across participants in the time bin of 100 msec and the error bars show the standard error of the data.2
2 The calculation of mean fixation proportions in each time bin included the area of target, competitor, unrelated distractors, cross , and the remaining areas outside the above-mentioned areas in the visual display
Fixation Proportion (Mean +/- 1 SE)
Cohort-Tone Competitor
Fixation Proportion (Mean +/- 1 SE)
Cohort-Only Competitor
TAR COC UR
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Table 11. Analyses of variance by participant and item comparing mean fixation proportions to competitors with those of the target and unrelated distractors from 1 msec to 1000 msec after acoustic target onset in Experiment 2
The mean fixations proportions to cohort-only competitor and target was
significantly different by participants analyses from 401-500-msec in Tone
1[401-500-msec: z1 = 3.32, p = .003]. The mean fixations proportions to cohort-only
competitor and target was significantly different by participants analyses from
501-600-msec in Tone 4[501-600-msec: z1 = 4.21, p < .001]. Lastly, the mean
fixations proportions to cohort-only competitor and target was significantly different
by participants analyses from 601-700-msec in Tone 2 and Tone 3
[601-700-msec :Tone 2: z1 = 5.47, p < .001; Tone 3: z1 = 6.60, p < .001 ].
The result indicated that in Tone 1, the divergent time between the curve of
cohort-only competitor and target was significantly earlier than Tone 4, which was
also earlier than Tone 2 and Tone 3. Figure 16 plots the fixation proportion over time
Condition Test 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 TAR - CTC z1 1.13 1.30 1.36 < 1 < 1 6.07 10.40 18.23 23.24 30.35
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in two conditions among four tones.
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Figure 16. Mean fixation proportions to targets, competitors, and unrelated distractors for cohort-tone and cohort-only conditions in the 1,000 msec period following
acoustic target onset in Experiment 2. Each data point represents the average of fixation proportions across participants in the time bin of 100 msec and the error bars show the standard error of the data. Fixation proportions to target, competitors and unrelated distractors over time for 4 tones are shown respectively.
The mean fixation proportions to target, competitor, the unrelated distractors and
standard errors were shown in Figure 17 for CVC syllable structure and Figure 18 for
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CGVC syllable structure. A one-way ANOVA was performed for trials with
cohort-tone or cohort-only competitors and their targets and distractors for each time
bin, followed by the post-hoc comparisons (CVC for Table 12 and CGVC for Table
13). In CVC, the mean fixations proportions to cohort-tone competitor and target was
significantly different by participants and by item analyses from 501-1000-ms. The
mean fixations proportions to cohort-only competitor and target was marginally
significant different by participants analyses and significantly different by item
analyses from 401-1000-ms. In CGVC, the mean fixations proportions to cohort-tone
competitor and target was significantly different by participants and by item analyses
from 501-1000-ms. The mean fixations proportions to cohort-only competitor and
target was also significantly different by participants and by item analyses from
501-1000-ms. Table 14 showed the time when mean fixation proportion had
significant difference between the competitor and its target and unrelated distractors
by participants in two conditions of Experiment 2.
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Figure 17. Mean fixation proportions to targets, competitors, and unrelated distractors in CVC syllable structure for cohort-tone and cohort-only conditions in the 1,000 msec period following acoustic target onset in Experiment 2. Each data point represents the average of fixation proportions across participants in the time bin of 100 msec and the error bars show the standard error of the data.
Figure 18. Mean fixation proportions to targets, competitors, and unrelated distractors in CGVC syllable structure for cohort-tone and cohort-only conditions in the 1,000 msec period following acoustic target onset in Experiment 2. Each data point represents the average of fixation proportions across participants in the time bin of
Figure 18. Mean fixation proportions to targets, competitors, and unrelated distractors in CGVC syllable structure for cohort-tone and cohort-only conditions in the 1,000 msec period following acoustic target onset in Experiment 2. Each data point represents the average of fixation proportions across participants in the time bin of