Eye Movements in Reading Syntactically Ambiguous Sentences in Russian Language

Victor N. Anisimov, Anna S. Jondot, Olga V. Fedorova, Alexander V. Latanov

M.V. Lomonosov State University, Moscow

Moscow, 2015

30 min recording, sampling rate of 8 fps

First study of eye movements in reading syntactically ambiguous sentences

fixation

Syntactic ambiguity in English

(a) They gave her dog candies (b) They gave her dog candies They told her cat stories They told her cat stories

Two interpretations of the sentence:

Number of fixations normalized for 10 participants and reading every sentence with definite interpretation - (a) or (b).

Syntactic ambiguity in English

dog candies (b)

Num

ber

of fi

xatio

n

Number of fixations normalized for 10 participants in reading every sentence with definite interpretation - (a) or (b).

Num

ber

of fi

xatio

n

her dog (a)

The criminal shot

the servant of the actress who was on the balcony

the servant the actress

early closure late closure

Who was on the balcony?

Syntactic ambiguity

(early/late closure)

?dominates in English dominates in Russian

A priory interpretation complexity during reading structurally (syntactically) ambi-guous sentences slows reading in comparison with reading sentences without any syntactic ambiguity.

MethodMonitor for stimuli presentation

IR - mirror

IR - light

Hight-speed digital camera

Top view

45 deg.

Eye image, reflected from IR mirror, is projected to camera

matrix

Eye

Monitor

IR mirrors

• 29 subjects, 18-24 years old;• 20 sentences Global (G) and Control (C);• originally developed eye tracker based on fast

digital camera FV300;• sampling rate of 250 fps;• matrix resolution 640х480 pixels;• angular size of the monitor for text presentation

47 deg.;• average angular size of the character 0,6 deg.

Method (1st part)

Example of reading sentence with ambiguity

regression

1 s

2nd str

3id str

1st str

Example of stimuli (overall 40)

Eye movements parameters in reading 2nd string (test and control). Data averaged over all sentences and 30 subjects. Spread presented by standard error of mean, sample size in parenthesis).

Parameter Global (G) Control (C)Significant

level, р

Reading time (ms)1393±20 (1169)

1195±14 (1169)

<0,00001

Number of fixations (in one string)

5,29±0,05 (1169)

4,72±0,04 (1169)

<0,00001

Regression frequency (in one string)

0,662±0,029 (1169)

0,336±0,019 (1169)

<0,00001

Fixation duration (ms)207±1(5964)

200±1(5326)

<0,00001

Results. 1st experiment.

Anisimov et. al., 2014

Parameters of eye movements in reading 2nd string in G and C

Regressive saccadesComparison of regressive saccades in 1st and 2nd strings in reading sentence with global ambiguity and control

•F2(G1/G2)=47,61;

p<0,01, n=16

•F2(G1/C1)=0,80;

p<0,37, n=16

•F2(G2/C2)=62,9;

p<0,01, n=16

p<0,01

1st string 2nd string

G1 C1 G2 C2

Types of ambiguity

• G – global

• LE – local, early closure

• LL – local, late closure

• C – control

Gardener met daughter of the cook who went to school.Садовник встретил дочку кухарки, которая пошла в школу.

Girl caught snowflake that melt on the palm. Девочка поймала снежинку, которая растаяла на руке.

Sentences with and without ambiguity

· 31 subjects, 18-24 years old;

· 12 sentences LE, LL, G and C;

· originally developed eye tracker based on fast digital

camera FV300;

· sampling rate of 250 Hz;

· matrix resolution 640х480 pixels;

· angular size of the monitor for text presentation

47 deg.;

· average angular size of the character 0,6 deg.

Method (2nd part)

Example of reading sentence with ambiguity

Results. 2nd experiment. Eye movement parameters (M±SEM, sample size in parentheses) averaged over

all subjects in reading LE, LL, G and С.

In reading LL subjects demonstrate more fixations than in reading LE. Significant differences revealed by Student t-test criterion.

Number of fixations in reading sentences with local ambiguity.

In reading LL regression frequency significantly higher than in reading G. Number of fixations is quasi significantly higher than in reading G. Significant differences revealed by Student t-test criterion.

Regression frequency in reading sentences with ambiguity.

1. Syntactic ambiguity leads to slowing reading because of language processing complication.

2. LL is more complicated in terms of syntactic interpretation than LE.

3. Higher regression frequency and greater number of fixations in reading LL in comparison with reading G indicate that interpretation of LL is more complicated than interpretation of G.

4. Disambiguation of G in Russian (as well as in English) apparently doesn't provoke additional complexity of syntactic analysis and its interpretation is predetermined by domination of early closure (high attachment) principle in Russian to a considerable extent. The absence of any significant differences between eye movement parameters in reading G and LE proves this point.

Thanks for you attention!

latanov.msu@gmail.comviktoanisimov@ya.ru,