Edited by: Matthew Wagers, University of California, Santa Cruz, United States
Reviewed by: Caitlin E. Coughlin, University of Kansas, United States; Kevin Schluter, New York University Abu Dhabi, United Arab Emirates
*Correspondence: Caroline M. Whiting
This article was submitted to Language Sciences, a section of the journal Frontiers in Psychology
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There is extensive evidence pointing to an early, automatic segmentation of written words into their constituent units (
A substantial body of evidence has revealed that complex words undergo an early, blind, and automatic segmentation into their constituent parts (Rastle et al.,
The point at which lexical semantics begins to exert influence on morphological processing is still a matter of debate. According to the form-before-meaning account, morpho-semantic properties of complex words determine the organization of central lexical representations, but not the process of lexical access (Marslen-Wilson et al.,
Here we approach the issue of semantic influences on morphological processing from a different perspective, asking about the role of semantic context in early morpho-orthographic segmentation. Can this bottom-up, stimulus-driven process of segmenting potential stems and suffixes be modulated by contextual constraints? The majority of evidence for morpho-orthographic segmentation has come from studies of words in isolation (
Extensive neuroimaging evidence has demonstrated top-down modulation of early processing in domains, such as speech perception (Davis and Johnsrude,
The existing morphological processing literature offers limited evidence. One recent eye-tracking study (Amenta et al.,
The effect of sentence context on morphological processing has also been investigated in a cross-modal priming study of German particle verbs (Zwitserlood et al.,
Our goal in this study was to incorporate a semantic context within the masked priming paradigm, to assess if there is an interaction between the context and the analysis of morpho-orthographic structure. In a standard masked priming study, morpho-orthographic segmentation of the prime is indexed by the facilitation of target word recognition (as compared to an unrelated control). When presented in isolation as masked primes, both semantically transparent and opaque forms (
Example experimental stimuli in the three prime contexts and three conditions.
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crop | farmer | FARM | jury | witness | WIT | lettuce | spinach | SPIN | |
smooth | farmer | FARM | tulip | witness | WIT | wool | spinach | SPIN | ||
smooth | mixer | FARM | tulip | jetty | WIT | wool | monkey | SPIN |
The primary focus of interest, however, was the context where the visible prime was semantically related to the masked prime. For semantically transparent words like
There are two possible outcomes here: blind morpho-orthographic segmentation could take place regardless of the context—purely based on the bottom-up input—thus both
In summary, the present study included three conditions and three prime contexts in a modified masked priming design, where an overt semantic prime was followed by a masked prime and a target. The three conditions were: (1) semantically transparent forms (
In the context where the masked prime is preceded by a semantically unrelated prime (Context 2; –Semantic +Mask; e.g.,
Finally, the current design included an additional control condition to test for the direct effects of semantic context on the target. This is because the semantic prime is related in meaning to both the masked prime and the target for semantically transparent forms in Context 1 (+Semantic +Mask; e.g.,
We included three experimental conditions that co-varied the presence/absence of a potential suffix, as well as the relationship between the stem and suffix. These included: (1) semantically transparent forms (e.g.,
To create different priming contexts, a further prime was included which was presented overtly prior to the masked prime. This overt prime was either semantically related or unrelated to the meaning of the masked prime, as measured by Latent Semantic Analysis (
A total of 30 items were selected for each condition (transparent, opaque, and stem only), and conditions were matched on target length, wordform frequency, neighborhood (N) size and bigram frequency; masked prime length, wordform frequency and % orthographic overlap between target and masked prime; and semantic prime length, wordform frequency, neighborhood size, bigram frequency, and semantic relatedness (Latent Semantic Analysis) between the masked prime and semantic prime (all
Stimulus properties across test conditions (mean values).
Length | 4.23 | 4.00 | 4.03 | 4.40 | |
Frequency | 41.26 | 26.67 | 21.07 | 36.25 | |
N size | 8.03 | 9.90 | 8.57 | 8.2 | |
Bigram Frequency | 1113.76 | 1399.93 | 1167.53 | 1199.93 | |
Target/Masked Prime Relatedness (LSA) | 0.48 | 0.09 | 0.05 | 0.10 | |
Target/Semantic Prime Relatedness (LSA) | 0.42 | 0.11 | 0.05 | 0.56 | |
Length | 6.23 | 5.93 | 6.47 | 6.63 | |
Frequency | 7.17 | 13.58 | 7.98 | 12.05 | |
N size | 2.53 | 3.23 | 0.77 | 2.07 | |
Bigram Frequency | 1033.67 | 1137.16 | 608.37 | 1058.29 | |
Target/Masked Prime % Overlap | 0.69 | 0.68 | 0.63 | 0.69 | |
Masked Prime/Semantic Prime Relatedness (LSA) | 0.48 | 0.49 | 0.54 | 0.11 | |
Length | 5.47 | 5.07 | 4.90 | 4.73 | |
Frequency | 41.5 | 67.67 | 56.65 | 47.06 | |
N size | 4.63 | 6.07 | 4.43 | 5.87 | |
Bigram Frequency | 1076.79 | 1868.01 | 1755.04 | 1430.91 |
A further set of 30 word targets were paired with a related semantic prime and an unrelated masked prime to create a +Semantic –Mask condition (e.g.,
A set of 120 pseudowords were created using the ARC Non-word Database (Rastle et al.,
The nine semantic prime-masked prime-target sets (3 conditions × 3 prime contexts) were pseudo-randomized into 3 versions (10 sets from each condition in each version) such that each target appeared only once in each version. Each participant saw one version, ensuring there was no repetition of the targets. The +Semantic –Mask condition (
Subjects were told that they would see a word followed by hash marks and a letter string in uppercase, and should decide as quickly and accurately as possible whether the uppercase string was a real word in English or not. They were not told about the existence of masked primes. A crosshair was displayed for 500 ms in the center of the screen followed by the semantic prime for 500 ms, a blank screen for 250 ms, the forward mask (hash marks) for 500 ms, a masked prime for 39 ms, and a target for 250 ms (see Figure
Timeline of a single trial.
A total of 77 subjects took part in the experiment (age range: 18–27, mean: 21; 52 female). One subject was subsequently removed from the analyses as they were not a native speaker. All remaining subjects were right handed native British English speakers, with no reading or learning difficulties. Written informed consent was obtained from all participants, and they were paid for their participation.
All errors (5.1% of trials) and all time-outs (defined as responses longer than 1,500 ms; 0.02% of trials) were removed. One item from the stem-only condition (
The mean reaction time (RT) for word targets was 556 ms, and 632 ms for pseudowords. To analyse the data we used linear mixed-effect models (Baayen et al.,
The dependent variable was log-transformed reaction time, and the main predictors were prime context (3 levels: +Semantic +Mask, –Semantic +Mask, Control), condition (3 levels: transparent, opaque, stem only), and the interaction between prime context and condition. We also included version, target length, masked prime length, semantic prime length, % orthographic overlap between target and masked prime, target N size, and log-transformed wordform frequencies of target, masked prime, and semantic prime as predictors. We used the Satterthwaite approximation for degrees of freedom (Satterthwaite,
In the overall 3 (prime context) × 3 (condition) analysis, there was a significant effect of prime context [
Given the significant overall interaction between prime context and condition, we first performed a series of planned comparisons to examine how context affected priming across the three conditions (for full results see Figure
Average priming effect in milliseconds (mean ± standard error), defined as the difference between the unrelated prime type context (Control) and the other prime contexts. ***Indicates significant at
Reactions times (RTs; mean and standard deviation) and error rates (%) for each condition in each context, and the overall priming effect compared to baseline (Control).
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519 (80) | 1.3 | 558 (83) | 6.1 | 576 (85) | 6.6 |
521 (73) | 1.3 | 542 (76) | 3.8 | 576 (84) | 6.8 | |
554 (69) | 3.7 | 562 (70) | 7.5 | 585 (72) | 9.1 | |
We began by examining masked priming effects across the three conditions in the –Semantic + Mask context, comparing it to the Control context. This was done to assess how our results relate to the literature on standard masked morphological priming (Rastle et al.,
Results showed a significant effect of prime context [
The next analysis tested priming effects across the three conditions in the +Semantic +Mask context, comparing it to the Control context, resulting in a 2 (prime context) × 3 (condition) design. Results showed a significant effect of prime context [
The results presented so far suggest that context strongly affects priming in the morphologically related transparent and opaque conditions. To test this explicitly, the third set of planned comparisons involved a direct comparison of priming effects in the transparent and opaque conditions across the three contexts. This resulted in a 3 (prime context) × 2 (condition) design. Results showed a significant effect of prime context [
To unpack this interaction, we examined the priming effects in the transparent and opaque conditions separately: firstly, for the masked prime only context (–Semantic +Mask vs. Control), and secondly, for the two prime context (+Semantic +Mask vs. Control) in a 2 (prime context) × 2 (condition) design. For the masked prime context, there was no significant interaction between prime context and condition [
Finally, we directly compared priming effects across contexts in each of the three conditions separately. For transparent forms (
For opaque forms (
For stem only forms (
The final RT analysis was the contrast of the two conditions where the overt semantic prime and target were related in meaning. This involved the transparent forms with two related primes (+Semantic +Mask;
The transparent condition with two related primes (
In the error analysis, we first examined the overall effects and the interactions as in the RT analysis, which included prime context (3 levels: +Semantic +Mask, –Semantic +Mask, Control) and condition (3 levels: transparent, opaque, stem only). For the errors, there was a significant effect of prime context [
In this study we aimed to test the possible interaction between top-down contextual information and bottom-up morphological analysis. Previous masked priming studies have demonstrated that words are automatically segmented into their constituent parts based on the presence of a stem and a suffix (Longtin and Meunier,
To test this, we constructed an adapted masked priming design, where an overt semantic prime preceded the masked prime. Semantic priming is a robust effect showing faster and more accurate responses to a target if it is preceded by a semantically related word (Neely,
To ground our results in the existing literature, we first established that complex words undergo an automatic morpho-orthographic segmentation when presented without an interfering context. To this end we tested priming effects in the context where the masked prime was related to the target but the semantic prime was unrelated to the masked prime (–Semantic +Mask), compared to the baseline (Control). Our results revealed a significant interaction between prime context and condition, showing that both semantically transparent and opaque words (
The addition of a semantic context, where the semantic prime is related to the masked prime (+Semantic +Mask;
A set of further comparisons directly contrasted morphological priming effects across the three contexts. These data showed that there was no significant difference between the amount of priming for morphologically transparent forms in the context of two primes and a masked prime only (35 and 33 ms, respectively). In contrast, the amount of priming for morphologically opaque forms in the masked prime only context (–Semantic +Mask) was significantly different from that seen in the two prime context (+Semantic +Mask; 20 and 4 ms, respectively), further confirming that external contextual environment modulates morpho-orthographic segmentation for opaque words only.
With the use of this adapted masked priming design, it is important to consider the possible effect of the direct relationship between the overt semantic prime and the target, since both are fully visible. This is especially true in the context where the overt prime is semantically related to the masked prime (+Semantic +Mask), and the masked prime is a transparent form (
To address this issue, we included a control condition in which the semantic prime was related to the target but the masked prime was unrelated (+Semantic –Mask; e.g.,
The finding that contextual information modulates morpho-orthographic segmentation for opaque words like
Whether or not the semantic makeup of an isolated complex word influences its morpho-orthographic segmentation from the very onset, our data unambiguously show that all words with a potential stem and a suffix undergo this automatic analysis—as illustrated by significant and statistically comparable priming for both semantically transparent and semantically opaque words (
One way of accounting for these results is to hypothesize that this reflects rapid integration of semantic information following morpho-orthographic segmentation, similar to the interpretation offered by Amenta et al. (
According to this alternative explanation, the observed reduction of priming for
Due to the very nature of the current (behavioral) data, we cannot pinpoint the exact processing level at which the overt semantic prime like
An important issue to address in future studies is how morphological segmentation is modulated by different types of contexts. In this study, we primed the whole-form meaning using a semantic prime, but further research could use stronger constraints, such as full sentences with high cloze probability, where we might see further reduction in masked priming for opaque forms. An additional question to pursue is how priming is affected by contexts that prime aspects beyond whole-form meaning—for instance, what would happen if
To conclude, we have provided novel evidence on the role of semantic context in modulating early morphological processing. The presence of a contextual cue to the meaning of the whole form eliminated the priming effect for semantically opaque forms, such that
This study was carried out in accordance with the recommendations of the Cambridge Psychology Research Ethics Committee with written informed consent from all subjects. All subjects gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by the Cambridge Psychology Research Ethics Committee.
CW, RC, and MB designed the study, acquired and analyzed the data, and wrote the manuscript.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
This work was supported by funds from the Department of Psychology, University of Cambridge to MB. CW is supported by the UK Biotechnology and Biological Sciences Research Council (BBSRC, BB/M009742/1). We would like to thank Kathy Rastle and Pienie Zwitserlood for their comments on a previous version of this manuscript. We would also like to thank members of the Neurolex team for their help with the study.
Stimuli for three test conditions. Stimuli for Semantic Prime Only (+Semantic –Mask) condition.
steam
boiler
boil
flag
banner
ban
ice
arctic
arc
plane
bomber
bomb
neck
belly
bell
thief
bandit
band
summit
climber
climb
wine
brandy
brand
church
basilica
basil
rain
cloudy
cloud
weed
clover
clove
sketch
cartoon
cart
smooth
creamy
cream
aluminum
copper
cop
theater
costume
cost
weird
creepy
creep
biscuit
cracker
crack
slang
dialect
dial
fantasy
dreamer
dream
rude
cranky
crank
magic
dragon
drag
pleasure
enjoyable
enjoy
volcano
crater
crate
art
easel
ease
crop
farmer
farm
cabinet
drawer
draw
atom
electron
elect
damage
faulty
fault
witch
fairy
fair
orange
ginger
gin
soft
fluffy
fluff
mane
filly
fill
language
grammar
gram
damp
gloomy
gloom
twinkle
flicker
flick
music
harmony
harm
accuse
guilty
guilt
tulip
flower
flow
whale
harpoon
harp
celebrate
joyful
joy
beef
gravy
grave
pray
heaven
heave
pencil
marker
mark
chisel
hammer
ham
fire
inferno
infer
kitchen
mixer
mix
satire
irony
iron
lion
monkey
monk
silt
muddy
mud
harbor
jetty
jet
fork
napkin
nap
heal
painless
pain
somber
listless
list
bed
pillow
pill
red
pinkish
pink
hotel
lobby
lob
clam
plankton
plank
saddle
rider
ride
coin
penny
pen
sermon
pulpit
pulp
steal
robber
rob
think
ponder
pond
team
rugby
rug
sprint
runner
run
law
punish
pun
awake
slumber
slum
mood
sadness
sad
dish
saucer
sauce
lettuce
spinach
spin
purchase
seller
sell
thin
skinny
skin
hospital
surgeon
surge
afraid
shaky
shake
foot
sneaker
sneak
kilt
tartan
tart
fear
shameful
shame
autumn
summer
sum
bus
taxi
tax
gloss
silky
silk
war
treaty
treat
ant
termite
term
tune
singer
sing
fade
vanish
van
wool
textile
text
hurricane
stormy
storm
stroll
wander
wand
drink
tipsy
tip
pool
swimmer
swim
jury
witness
wit
culprit
villain
villa
prize
grassy
award
hay
sleepy
barn
trout
murky
fish
hornet
construction
bee
admit
worker
blame
job
dancer
boss
tent
viewer
camp
star
graceful
comet
hawk
paler
crow
soap
glider
dirt
brake
learner
drive
construct
mourner
build
fence
windy
gate
pale
thirsty
gaunt
joint
sweetness
hinge
smile
fruitless
hug
joke
driver
laugh
harvest
sculptor
maize
yard
teacher
porch
wheat
hunter
rice
task
wrecker
skill
frost
cheerful
sleet
warm
honesty
sun
bone
weaver
spine
chair
worthy
stool
fruit
visitor
sweet
visit
bulky
trip
blouse
dusty
vest
shirt
chilly
wear
cry
voter
wail