Chapter 2 Literature Review
3.1 Method
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different because the time needed to identify different tones is varied (Lai & Zhang,
2008). As for the segmental competitor sharing the same segmental structure with the
target, it is expected that the fixation proportions to segmental competitor would be
higher than that of unrelated distractors.
The second set of analysis examines when the fixation proportion curves of target
and the competitors diverge. If tone has an early influence, the time point of
divergence between target and the segmental competitor may be early, similar to the
divergence of the target and unrelated distractors. However, if tone influences lexical
processing after the offset of the target, the divergence between target and the
segmental competitor may occur after the offset of the target. As for tonal competitor,
if the segmental incongruity can be detected early, the time point of divergence
between the target and the tonal competitor should be early.
3.1Method
3.1.1 Participants
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
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23.5 years old, ranging from 19 to 30 years old. All participants had normal or
correct-to-normal vision and were native speakers of Mandarin Chinese.
3.1.2 Material
3.1.2.1Stimuli
There were 140 monosyllabic Chinese characters in the experimental stimuli,
including 28 target characters, 28 tonal competitor characters, 28 segmental
competitor characters, and 56 unrelated characters. The segmental structure of these
stimuli comprised 60 CV, 60 CVC, and 20 CGVC. The stimuli was consisted of 36
characters with Tone 1, 32 characters with Tone 2, 29 characters with Tone 3, and 33
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 segmental and tonal competitors (F (2, 81) = 1.931, p=.152). Secondly,
the average stroke of these characters were controlled in a range between 5~20. After
deleting tone segmental competitor of which stroke was 20, there was no significant
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difference of the stroke across the target and two types of competitors was balanced.
(F (2, 78=2.514, p=.088).Lastly, the average number of homophone was under 10.
However, the difference was significant across the target and the competitors. (F (2,
81) = 9.608, p=.00).
Table 2. Means and SDs of character frequency, strokes, and homophone number for target, tonal competitor and segmental competitor
Frequency Stroke Homophone
Note. TAR: target; TC: tonal competitor; SC: segmental competitor; UR: unrelated distractor
3.1.2.2 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 CoolEdit Pro 2.0.The mean durations of target, tonal competitor, and
segmental competitor were 713.2 msec, 685.2 msec, and 710.1 msec, respectively.
3.1.2.3 Tonal recognition pretest
To ensure that the tone of the auditory stimuli was clear for the subject to recognize,
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a survey was conducted. Five female whose average age was 24.2 years old took part
in the survey. The participants listened to all of the auditory stimuli and then identified
the tone (Tone 1 to Tone 4) they considered to be. The result showed that average of
the accuracy of each experimental stimulus was 98%.
3.1.3 Design
Two conditions were manipulated in this experiment. The tonal competitors shared
only tone with the target. The segmental competitors shared only the segmental
structure with the target. Hence, for example, a stimuli set included a target /mɔ1/
‘touch’, a tonal competitor /wa1/ ‘dig’, a segmental competitor /mɔ3/ ‘wipe’, and two
unrelated distractors (the segmental and tone were different from target: /nu4/ ‘anger’,
and /tɕy2/ ‘chrysanthemum’). An experimental trial comprised one target, one
competitor, which was either tonal competitor or segmental 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 counterbalanced across subjects. There were two blocks of 32
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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.
3.1.4 Layout of visual stimuli
Stimuli were presented on a computer monitor (1024×768 pixels). The size of the
printed characters presented on the screen was 64×64 pixels in 標楷體 font, which
were about 2 centimeters on the monitor (One centimeter on the screen corresponded
approximately to 0.0133° of visual arc). Four black printed characters were presented
in a diamond array on a grey background. The distance of the four characters between
the characters to the fixation point was 104 pixels.
Figure 5. A sample display containing pictures of a target item (/mɔ1/ ‘touch’), a tonal competitor (/wa1/ ‘dig’), and two unrelated distractors (/nu4/ ‘anger’, and /tɕy2/
‘chrysanthemum’)
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3.1.5 Apparatus
Participants’ eye movements are recorded using Eyelink 1000 Desktop Mount
eye-tracker, manufactured by SR Research. Viewing was binocular, and eye
movements were recorded from their dominant eye. The eye tracker sampled gaze
position every millisecond. Participants were seated 70 cm away from the chin rest to
the screen. Stimuli are presented on a computer monitor (1024x768 pixels).
3.1.6 Procedure
Before the experiment, participants were given a consent form and tested for their
dominant eye. After the test, they were seated in front of the monitor with their heads
in a forehead and chin rest to eliminate head movement during testing. The instruction
was given at the beginning of the experiment. Participants were instructed how to
perform the experiment. The five-point calibration and validation were performed in
initial trial of each block (two blocks in total). After checking the calibration, an
experimental trial started and the participants were asked to fixate a cross, which was
in the middle of the monitor. The cross were not vanished until the end of the spoken
instruction 「 請 用 滑 鼠 點 選 」 was presented via the earphone
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(Audio-technicaATH-A700). An array of four characters was presented on the screen
before 200msec the auditory target word onset. Participants used mouse to click what
they heard on the computer screen with no time pressure. After the clicking, the next
trial initiated.
Figure 6. Experimental procedure and examples of a visual stimulus used in
Experiment One. The display contained words: 摸 (the target), 抹 (the segmental competitor), 怒 and 菊 (the unrelated distractors).