Eye Gaze and Eye Movement in Japanese Sign Language
(English)
Eye gaze and eye movement in Japanese Sign Language are linguistic elements, as
they are in American Sign Language (Thompson 2006) and German Sign Language
(Hosemann 2009). Ichida mentioned that eye gaze and eye movement in Japanese
Sign Language were semantically related to human action of “looking” (Ichida 1997).
We conducted eye tracking experiments to examine how 10 native signers and 10
non-native signers (5 deaf and 5 hearing) produce eye gaze and eye movement while
they are signing the same sentences. We tracked their eyes by the head mounted
eye-tracking technology (eye-mark-recorder), and we also developed a way to record
positions and movements of pupils in the image on the TV monitors (by auto-tracing
device of PV Studio).
First, we chose the VTR image of a native signer’s signing as the model (a DVD of
Japanese Sign Language lesson highly evaluated on the market). We asked examinees
who were native signers to look at the TV monitor, then asked them to express the same
sentences (the same sentence structures with the same lexical items) which we
video-recorded and measured by the eye tracker. Secondly non-native signers signed
the same sentences, but they failed at eye gaze and eye movement, which we measured.
Thirdly, the native examinees took the teachers’ role to the non-native signers. The
students (non-native signers) imitated the teachers repeatedly which we measured by
the eye tracker, until the teacher admitted that their eye gaze and eye movement were
correct. We asked the native signers to correct the eye gaze and eye movement of
non-native examinees.
We picked up the eye gazes and eye movements which were the same among the
native signers, and we examined which eye gaze and which eye movement the teachers
considered as errors.
We determined the position and movement of the students’
pupils which made the teachers (native signers) stop correcting. Also the teachers
explained what kind of difference the error of eye gaze and movements caused. Thus
we determined the correct eye gazes and eye movements in Japanese Sign Language.
We found that one of the characteristics of eye gaze in Japanese Sign Language
was the one which functions as, or co-occurs with, existential verbs. This kind of eye
gaze is related to action of “looking”. Other findings are as follows:
1. eye gaze functioning as pronouns and adverbs on its own
2. eye gaze functioning as pronoun with pointing
3. eye gaze functioning as adverb (location/time) with pointing or other manual
sign
4. eye movement showing movement of human beings and things
5. eye movement, with classifiers, showing movement or shape
6. eye gaze functioning case marking with predicate verbs (agreement)
7. eye movement which shows human action/movement of looking or gazing
Among the above, 1 is a free morpheme. There are also prosodic morphemes,
which means the sentence is unnatural without them, and there are bound morphemes,
which means the sentence is ungrammatical without them.