MORPHOLOGICAL PROCESSES ANDREADING DIRECTIONS
Koji Miwa

Ton Dijkstra

Eberhard Karls Universität Tübingen	

Radboud University Nijmegen 	① Background③ Results

Horizontal vs. vertical reading• Past studies reported processing advantage ofhorizontal reading over vertical reading (Huey, 1898;Tinker, 1955), and this may be attributed to the different
visual span sizes (Yu, Park, Gerold, & Legge, 2010).
• However, it is not clear whether lexical processes differ
between the two reading directions.
• Japanese provides a fair test
ground for this issue because
vertical texts are seen
everywhere (e.g., novels,newspapers)

RT analysis• There was overall horizontal reading advantage.
• This horizontal reading advantage was observed forwords with high first character frequency, but not forwords with low first character frequency (Figure 1).

Japanese morphological processes

Eye movement analyses• There is an on-going
discussion regarding whether
compound words written in
logographic characters areprocessed from radicals(Saito, 1997; Taft, Zhu, &Peng, 1999) or fromcharacters (Miwa, Libben,Dijkstra, & Baayen, 2014).

• At the first fixation, character frequency effects werestronger than compound and radical frequency
effects in both horizontal and vertical reading.
• In vertical reading, first fixation durations became
shorter as the experiment went by (Figure 2).	

−3−1 0

1

2

420
380

ReadingDirection

VerticalHorizontal

340

580

Horizontal

ReadingDirection

660

Vertical620

RT (ms)• Does vertical reading induce a different pattern ofprocessing? (quantitatively and/or qualitatively)• Is the character-driven processing pattern observedin horizontal reading (Miwa et al., 2014)
generalizable to vertical reading?	

(2)
Figure 2	
First Fixation Duration (ms)(1) 1	
FigureResearch question−2−1

FirstCharacterFrequency

012Trial④ Summary② Experiment
Method• Participants: 21 Japanese speakers for horizontal
reading (Miwa et al., 2014) and 20 readers for verticalreading (the present study).
• Materials: Randomly selected 200 Japanesecompound words and 200 nonwords.
• Procedure: Participants’ eye movements weremeasured while they did lexical decision.
• The following measures were recorded.
• Response times (RT)Horizontal	 Vertical	
• First fixation duration• Second fixation duration• Number of fixations• Saccade amplitude
9th International Morphological Processing Conference (June 18-20, 2015 in Potsdam)• The following predictors were included in mixedeffects analyses in R.
• Reading direction (levels: horizontal, vertical)• Whole compound frequency• First character frequency• Second character frequency• First character radical frequency• Second character radical frequency• An overall processing advantage for horizontal reading
was observed early at the 1st fixation (when the firstcharacter was processed).
• Interestingly, the first character’s contribution wasqualitatively different depending on reading directions.
• However, most of the recognition process wasdirection-independent: Japanese compounds wereconsistently processed from characters.

The speaker’s attendance at this conference was sponsored by the Alexander von Humboldt Foundation (http://www.humboldt-foundation.de).