Spaces Enhance Word Segmentation andComprehension in Tacit Reading
Mayumi Toshima1 , Tetsuo Ishikawa2,3,4 , and Ken Mogi4
1

Department of Informatics,Graduate University for Advanced Studies
2-1-2 Hitotusbashi, Chiyoda-ku, Tokyo, 101-8430, Japanmamitako@nii.ac.jp
2
Department of Computational Intelligence and Systems Science,
Tokyo Institute of Technology
G3-46, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8502, Japani@brn.dis.titech.ac.jp
3
Centre for Advanced Research on Logic and Sensibility, Keio University
2nd Floor Mita Toho Bldg. 3-1-7 Mita, Minato-ku, Tokyo, 108-0073, Japan4Sony Computer Science Laboratories, Inc.
Takanawa Muse Bldg. 3-14-13 Shinagawa-ku, Tokyo, 141-0022, Japankenmogi@csl.sony.co.jp

Abstract. There are a lot of types of written language systems all over
the world. The Japanese writing system uses ideographic and phonetic
symbols without spaces between words, where the ability of finding theboundary between words is expected to have a positive correlation withthe ability of general language comprehension. Is such a correlation tobe found in languages (e.g., English) where words are conventionallyseparated by spaces between them? Here we report a study on how spaces
put on the boundary of two adjacent words enhance tacit reading texts.
We conducted a “slash task” where our subjects whose first language
was Japanese were instructed to place a slash between adjacent wordsof sentences written continuously without spaces between the words intypical, short and easy sentences. Our data illuminates the role of “activesegmentation” in language comprehension.
Keywords: Language, word, segmentation, learning, tacit reading.

1Introduction

Languages are important elements in human cognition, and play an essential
role in the communication among humans. In the process of cognitive development of one’s mother tongue, a progress in the ability of the first language isaccompanied by an increasing difficulty in acquiring other languages. Such a cognitive phenomenon occurs because of the characteristics of our brains [1][2][3].
The nature of the first language acquired results in significant differences in
the construction of efficient neural network systems, which in turn affect second
language acquisition [4][5][6].
D. Liu et al. (Eds.): ISNN 2011, Part I, LNCS 6675, pp. 76–82, 2011.
c Springer-Verlag Berlin Heidelberg 2011!

Spaces Enhance Word Segmentation and Comprehension in Tacit Reading

77

Reading words consist of perceiving language symbols visually and assigningthem appropriate meanings. Some of the difficulties encountered in second language acquisition are due to the differences in the system of writing between thelanguages. Among the various languages in the world, there are two distinctive
systems of writing, i.e., ideographs and phonograms. In both of these writing
systems, sentences are constructed of strings of words. In Japanese writing, thesegmentation between the words is given implicitly, where the letters are written
continuously without placing spaces between the words; both of the Chinese letters [7] which contain ideograms and phonograms and the Thai letters [8] whichcontain phonograms do not need spaces as well. In English and other European
languages, spaces are placed between the words. It is interesting to compare thecognitive process of language segmentation between these two types of writing
systems, i.e., one with spaces and one without spaces between words. Previousstudies indicate that unspaced English texts influenced the speed of oral reading[8] and eye movement behaviors [9].
In the domain of speech perception, continuous auditory sequences containno “spaces” (i.e., pauses). However it is known that (i) 8-months old infants canrecognize the word boundaries [10], (ii) ERP N400 is correlated with word onset
in continuous auditory stream [11] and (iii) the recursive neural network can findEnglish word boundaries in unspaced texts [12].
Here we report a study on effects of spaces enhancing segmentation in tacit
reading. In order to conduct the experiments, we invented “slash tasks”; when
one finds word boundary in unspaced text, he or she is required to put a slash
down on the boundary. To measure one’s reading competency, several types oftests have been conducted. Most of them (e.g., [8]) require reading strings ofletters aloud. Therefore, those tests depend not only on reading competence
but also on speaking ability. Our slash tasks, on the other hand, only require
the subjects to mark slashes between words while reading tacitly. Subjects wereuniversity students whose first language was Japanese. The subjects conducteda “slash task” where they were instructed to place a slash between adjacent
words of typical English sentences written continuously without spaces between
the words.

2

Experiment

Materials and Methods
32 subjects (12 females, mean age 19.6±1.7) whose native language was Japaneseparticipated. All were undergraduate students, right-handed by self report, withnormal or corrected to normal vision.
Two independent variables were designed in the experiments. (1) Spacing:spaced or unspaced texts, all written in English; (2) Coherence: coherent orincoherent texts (Fig. 1). The order of tasks was counterbalanced with coherence.
The subjects were asked to put slashes between words in a coherent/incoherent
text with/without spaces within four minutes. Reading time was recorded by
self-report. After that, all the subjects took a word recognition test, making an

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M. Toshima, T. Ishikawa, and K. Mogi

Coherent and Spaced (COH-SPA) text

Coherent and Unspaced (COH-UNS) textIncoherent and Spaced (INC-SPA) text

Incoherent and Unspaced (INC-UNS) text
Fig. 1. Stimuli (4 types of texts)

Spaces Enhance Word Segmentation and Comprehension in Tacit Reading

79“old” or “new” judgment. Random sampled words were presented in this test
and the subjects were required to judge whether the words had been shown in
the previous slash task text (“old”) or not (“new”). Four sessions were conductedwithout intervals. The same subjects were required to take another type of test
in twenty minutes; this contained thirty questions taken from a TOEIC problem
book. TOEIC (Test of English for International Communication) is a widelyused test of English to measure learners’ ability to use English as a language
system (grammar, vocabulary and usages.).
The data were examined using ANOVAs with Space and Coherence as factors. Then, Games-Howell post-hot multiple comparisons were conducted. The
significance level was set at 0.05.

3Results

We found that the main effects of Coherence (p = 0.031) and Space (p < 0.001)
show significances on the reading time, but their interaction indicates no significance (p = 0.087). The mean reading time of COH-SPA (the Coherent-Spacedcondition) and INC-SPA (the Incoherent-Spaced condition) were not significantly different (p = 0.73). Those two conditions required shorter mean timethan COH-UNS (the Coherent-Unspaced condition) (p < 0.001) and INC-UNS(the Incoherent-Unspaced condition) (p < 0.001). The mean reading time of
COH-UNS and INC-UNS were rather comparable (p = 0.28) (Fig. 2).

Fig. 2. Average reading time of 4 types of the texts (Mean±SD)

The number of errors in reading was the number of failures to find word boundaries. The main effects of Coherence (p = 0.007) and Space (p < 0.001) on thenumber of errors and also their interaction (p < 0.001) were found. According to the multiple comparisons, the amounts of the errors indicated significant

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M. Toshima, T. Ishikawa, and K. Mogi

Fig. 3. Errors in reading of 4 types of the texts (Mean±SEM)

differences among all of the combinations of each condition: INC-SPA < COHSPA < COH-UNS < INC-UNS (INC-SPA vs. COH-SPA: p = 0.03, COH-SPA
vs. COH-UNS: p < 0.001, COH-UNS vs. INC-UNS: p < 0.001) (Fig. 3).

Fig. 4. “Old” or “new” judgment performances (Mean±SEM)

The correct rate of word recognition was defined as the rate of correct-old(“hit”) and correct-new (“correct rejection”) responses. Note that the chancelevel of word recognition accuracy was 50 percent because of the two-alternative(“old” or “new”) forced choice. The main effect of Space on the correct rate ofword recognition was significant (p < 0.001), but that of Coherence was not significant (p = 0.078). The interaction between them was significant (p = 0.003).

Spaces Enhance Word Segmentation and Comprehension in Tacit Reading81

The multiple comparisons showed that the INC-SPA correct rate of word recognition, the old and new judgment performance was lower than other conditions(INC-SPA vs. COH-SPA: p = 0.03, INC-SPA vs. COH-UNS: p = 0.001, INCSPA vs. INC-UNS: p < 0.001) (Fig. 4).

4Discussion

Spaced texts and coherent texts were read faster than unspaced texts and incoherent texts, respectively. It is suggested that spaces work efficiently as a sortof punctuation systems. Without spaces, the subjects had to find the blocks ofletters with meanings; it was necessary for the subjects to segment the words
attentively and intentionally.
When doing the tasks without spaces, most of the subjects were observed
leaned toward the texts and putting the tip of the pen closer to the written
letters, as if they were tracing invisible lines drawn under the strings of letters.
These behaviors were not observed when they were doing the tasks with spaces.
Without spaces, the subjects had to be more careful to find the segments of theletters with meanings; therefore, their postures were different from those of when
doing the tasks with spaces.
For the all subjects, unspaced English sentences are rather unfamiliar even
if they see Japanese (their first language) sentences which have no spaces between characters and letters; they are sufficiently used to reading Japanese with
its ideographic and phonetic symbols. Their scores of reading “Hiragana” and“Katakana” (phonetic symbols) and “Kanji” (ideographic symbols) are not significantly varied. The relationship between the first language and the second
language word segmentation competence should be clarified in the further researches.
Errors were observed in all of the conditions. No subjects got perfect scoresin all tasks. The least errors were observed when doing “Incoherent and Spaced(INC-SPA)” task, not “Coherent and Spaced (COH-SPA)” one. This may suggest that the subjects should pay more attention when they are given more
unfamiliar or unusual texts than familiar and usual texts.
The correlation between “the speed and correctness” and “TOEIC scores”
showed no significance in the present study. However, according to preceding
researches (data not shown), it is possible to think that the ability of recognizing the blocks of words that we call it “active segmentation” should be correlated with certain cognitive and comprehension system when reading written
languages.
The slash task has a possibility of application to language education and clinical assessment of aphasia and dyslexia [13][14] as it is not explicitly influenced
by articulating or speaking ability. It also has the following advantages: (i) Onlya pen and a bundle of paper are needed, and no complicated and expensive devices such as eye movement trackers are necessary. (ii) It requires at most about
120 seconds. (iii) It is possible to conduct classroom experiments with many
participants simultaneously.

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Acknowledgments. We thank Noriko Kando, Tomomitsu Herai, Eiichi Hoshino,Shinichi Nozawa, Ayako Onzo, Kei Omata, Takayasu Sekine, Tamami Sudo,
Tsugumi Takano, Fumiko Tanabe, Fumihiko Taya, Toru Yanagawa for theirhelpful discussion.

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