Semantic Radical Activation in Japanese
Two-kanji Compound Recognition

Koji Miwa, Gary Libben, & Harald R. Baayen
Alberta Conference on Linguistics
October 20, 20071

Research Question What is a semantic radical?

‘brainʼ‘lung’‘skin’‘waist’‘bowel’: for body parts
 Semantic radicals are a kind of orthographic morphemes that haveno phonological counterpart.
 Does this anomalous morpheme play a detectable role during
reading of two-character Japanese compounds ?

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Previous Research Decompositional models: hierarchy of lexical representation
Character features

Semantic radical

Character (morpheme)

Compound3

Previous Research Evidences for radical processing in visual word recognition
Flores d’Arcais & Saito (1993)
 Flores d’Arcais, Saito, Kawakami (1995)
 Feldman & Siok (1997)
 Feldman & Siok (1999)
 Saito, Yamazaki, & Masuda (2002)
 Yencken & Baldwin (2006)
 Feldman & Siok (1997) and Feldman & Siok (1999)- Larger semantic radical family leads to shorter RTs

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Some problems
All previous studies on semantic radical processing have one of theseproblems: Isolated character presentation- although most Japanese words are compounds.
- might have encouraged strategic radical decomposition
 isolated semantic radical presentation- it is not rare that radicals do not occur in isolation.
The present study extends previous research using lexical decision by:
 Considering semantic radical function in compounds
 Using better non-words.
- NOT illegal combinations of radicals- BUT illegal combinations of characters

5Experiment: LD with Priming(1,000 ms)*Prime Stimulus(230 ms)

Backward Masks##(200 ms)

Target Stimulus

SOA 430 ms(word or non-word ?)6

Experiment: LD with PrimingOriginal Hypothesis:
Repetition of semantic radicals induce a facilitatory priming effect.
 Participants- 30 native speakers of Japanese Material- 46 prime-target pairs of two-kanji words- 46 prime-nonword pairs

Priming did not work (non-significant) !
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Implications

 Are semantic radical functional only when unnatural non-words
trigger radical decomposition ? was our experiment flawed ?
 No, it was not.
To see this we need to make use of analyses of covariance using awide range of predictors.

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Lexical Predictors (of targets) Decompositional models: hierarchy of lexical representation
Character
Characterfeaturesfeatures（Right) Radical Stroke, Target Right Stroke, Target Left Stroke
Left Radical Stroke

Semantic
Semanticradical
radicalLog (Right) Radical Freq, Log (Right) Radical Type Freq,
Radical Transparency, Log Left Radical Freq, Log Left Radical Type Freq

Character
Character(morpheme)(morpheme)
Log Target Right Token Freq, Log Target Right Type Freq
Log Target Left Token Freq, Log Target Left Type Freq
Target Right AoA, Target Left AoA

CompoundCompoundTarget Word Freq
9A problem of Collinearity

 Many of the 21 variables
are highly correlated.
(e.g. radical properties)

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PCA Regression: Method

1.

We orthogonalized the predictors with principle component analysis.

2.

We accepted that some measures would be telling a similar story.

3.

We used the principal components as predictors.

4.

We interpreted significant principal components by looking at theloadings of the original predictors.

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PCA Regression: Result In our principle component analysis, three PCs emerged as
significant predictors (PC1, PC3, and PC5).

Estimate

Std. Errort value

p value

6.598590.02960

222.90.000

Trial facilitatory -0.02063

0.00494

-4.18

0.000

PC1 inhibitory

0.031180.00862

3.62

0.000

PC3 facilitatory -0.04017

0.01366

-2.94

0.003

PC5 facilitatory -0.03333

0.01646

-2.03

0.043

(Intercept)

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PCA Regression: Results
inhibition

facilitation

inhibition

facilitation

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Lexical Predictors (of targets) Decompositional models: hierarchy of lexical representation
Character
Character featuresfeatures(Right)（Right) Radical
Radical Stroke,
Stroke,Target
TargetRight
RightStroke,
Stroke,Target
TargetLeftLeftStroke
StrokeLeft
Left Radical
Radical Stroke
StrokeSemantic
Semantic radical
radicalLog
Log (Right)(Right) Radical
RadicalFreq,
Freq,Log
Log(Right)(Right)Radical
Radical
TypeType
Freq,
Freq,
Radical
Radical Transparency,
Transparency, Log
Log Left
Left Radical
RadicalFreq,
Freq,Log
LogLeft
Left
Radical
Radical
Type
Type
Freq
Freq

Character
Character (morpheme)(morpheme)
Log
Log Target
Target Right
RightToken
TokenFreq,
Freq,Log
Log
TargetTargetRight
Right
TypeType
Freq
Freq
Log
Log Target
Target Left
Left Token
Token Freq,
Freq, Log
Log Target
Target LeftLeftType
TypeFreq
Freq
TargetTarget Right
RightAoA,AoA,Target
TargetLeft
Left
AoA
AoA

CompoundCompoundTarget Word
TargetWord Freq
Freq
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Summary The priming manipulation failed, but regression analyses show thatsemantic radicals are at work.
 Since we know that primes were processed, we know that ourtask was not flawed. It may well be that positive evidences in earlier
studies were due to the nature of non-words.
 The properties of semantic radicals that are important in reading are
1. Semantic radical type frequency (c.f. Feldman & Siok, 1999)
2. Semantic radical token frequency
3. Number of radical strokes
15Thank you
Acknowledgment
I would like to express my thanks to Dr.Gary Libbenand Dr.Harald Baayen for their guidance in all
aspects of this study and to members of of theCentre for Comparative Psycholinguistics for theirfeedbacks on the earlier version of this presentationand for their casual advices and insights

This research was supported by a Major Collaborative Research Initiative Grant (#412-2001-1009) from theSocial Sciences and Humanities Research Council of Canada to Gary Libben (Director), Gonia Jarema, Eva
Kehayia, Bruce Derwing, and Lori Buchanan (Co-investigators).

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Statistics using R

Baayen, R. H. (to appear). Analyzing linguistic data:
A practical introduction to statistics using R.
Cambridge University Press

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PCA
PC1
LogRadicalFreq
LogRadicalTypeFreq
LogTargetRightTypeFreq
LogPrimeRightTokenFreq
LogTargetRightTokenFreq
LogPrimeWordFreq
LogPrimeRightTypeFreq
LogTargetLeftTokenFreq
LogTargetLeftTypeFreq
LogTargetWordFreq
LeftRadicalStroke
TargetLeftStroke
LogLeftRadicalFreq
RadicalTransparency
LogLeftRadicalTypeFreq
TargetRightStroke
TargetLeftAoA
PrimeRightAoA
RadicalStroke
PrimeRightStroke
TargetRightAoA-0.32595441-0.32461342-0.25719829-0.24851236-0.22849805-0.20400900-0.19793693-0.19694687-0.16765199-0.06674472-0.06558624
0.03508257
0.05533828
0.18117849
0.18936575
0.22199603
0.22712781
0.23350434
0.25461382
0.26371383
0.29843572

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PCA
PC3
LeftRadicalStroke-0.31890508
LogTargetLeftTypeFreq-0.27377317
TargetRightAoA-0.27015008
LogPrimeRightTokenFreq-0.21593121
RadicalTransparency-0.19802870
LogPrimeRightTypeFreq-0.15852085
LogPrimeWordFreq-0.15197259
TargetRightStroke-0.13537410
LogTargetLeftTokenFreq-0.06331644
RadicalStroke-0.05751754
TargetLeftStroke-0.05340011
LogRadicalTypeFreq-0.03122143
LogLeftRadicalFreq
0.05025043
LogRadicalFreq
0.09020049
LogLeftRadicalTypeFreq
0.12549673
PrimeRightStroke
0.12576490
PrimeRightAoA
0.24687072
LogTargetRightTypeFreq
0.25513908
TargetLeftAoA
0.26796378
LogTargetWordFreq
0.39901548
LogTargetRightTokenFreq
0.43306385

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PCAPC5
LogLeftRadicalTypeFreq-0.590242019
LogLeftRadicalFreq-0.526935150
TargetLeftStroke-0.377893898
LogRadicalTypeFreq-0.151640066
LogPrimeRightTypeFreq-0.149656442
TargetLeftAoA-0.090099401
RadicalTransparency-0.063713697
LogRadicalFreq-0.061873990
LogPrimeRightTokenFreq-0.054440805
LogPrimeWordFreq-0.030480989
LeftRadicalStroke-0.014648391
PrimeRightStroke-0.004027343
LogTargetRightTypeFreq
0.028660268
TargetRightAoA
0.038024481
LogTargetRightTokenFreq
0.045912640
LogTargetWordFreq
0.078954418
RadicalStroke
0.080092633
LogTargetLeftTokenFreq
0.096903705
TargetRightStroke
0.152684837
LogTargetLeftTypeFreq
0.157344826
PrimeRightAoA
0.301901441

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Results: Observing the surface

 No apparent priming
effect. (p = 0.09)
 From an insignificant
result in lexical decision,
we cannot conclude
anything.

What actually happened within
800 ms of lexical decision
processing is a mystery.

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Stimuli used
Prime
Condition

Word

Morphology/Translation

Experiment

空港

ku-ko
‘airport’Control

砂嵐

suna-arashi‘sandstorm’Non-word

額縁gaku-buchi‘frame’TargetRadicalシ(water)

山(mt.)

糸(string)

Word

Morphology/
Translation

血液ketsu-eki‘blood’血液ketsu-eki‘blood’(water)

円筆

N/A

竹

Radicalシ(water)シ(bamboo)

RadicalSharedYesNoNo
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