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Although the semantic relationships among words have long been acknowledged as a crucial component of adult lexical knowledge, the ontogeny of lexical networks remains largely unstudied. To determine whether learners encode relationships among novel words, we trained 2-year-olds on four novel words that referred to four novel objects, which were grouped into two visually similar pairs. Participants then listened to repetitions of word pairs (in the absence of visual referents) that referred to objects that were either similar or dissimilar to each other. Toddlers listened significantly longer to word pairs referring to similar objects, which suggests that their representations of the novel words included knowledge about the similarity of the referents. A second experiment confirmed that toddlers can learn all four distinct words from the training regime, which suggests that the results from Experiment 1 reflected the successful encoding of referents. Together, these results show that toddlers encode the similarities among referents from their earliest exposures to new words.
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Psychological Science
24(10) 1898 –1905
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DOI: 10.1177/0956797613478198
Research Article
Ever since Quine (1960) pointed out the complexity of
mapping a new label to its proper referent, a large litera-
ture has emerged concerning how children learn words.
Most of this research, however, assumes that the goal of
word learning is to map a word to its correct referent or
category of referents. Although mapping is a crucial com-
ponent of word learning, a tremendous amount of addi-
tional information comes along with hearing a new word.
Imagine a child hearing a novel animal labeled for the
first time: “That’s a dog!” Obviously, the child needs to
learn the label-referent mapping. However, he or she
could also encode useful information about other nearby
objects (such as a leash or a ball), the background con-
text (e.g., a park vs. a kitchen), or the similarity between
this new animal and his or her pet cat.
If the full complexity of the perceptual and semantic
input available to young children is considered, word learn-
ing becomes a multidimensional problem that extends
beyond label-referent associations. It has been shown that
skilled language users exploit this rich structure; adult
semantic knowledge is not organized like a dictionary of
label-referent pairings. Instead, the lexicon is a complex
semantic network that represents relationships among
words (e.g., McClelland & Rogers, 2003; McNamara, 2005;
Steyvers & Tenenbaum, 2005). This has been demonstrated
most clearly with the semantic priming paradigm, in which
participants are faster to respond to a target word if it is
related to a prime word than if it is not. Adults show
semantic priming effects for many types of lexical-seman-
tic relationships, including feature overlap, thematic role
similarity, and verb-noun relationships (e.g., McNamara,
2005; Neely, 1991).
Despite extensive research on adult semantic knowl-
edge, little is known about the ontogeny of lexical net-
works. In particular, how do lexical-semantic relationships
emerge over the course of word learning? Lexical knowl-
edge continues to develop throughout childhood (Carey,
XXX10.1177/0956797613478198Wojcik, Saffran
Semantic Relationships
Corresponding Author:
Erica H. Wojcik, University of Wisconsin–Madison, Department of
Psychology, 1202 W. Johnson St., Madison, WI 53703
The Ontogeny of Lexical Networks: Toddlers
Encode the Relationships Among Referents
When Learning Novel Words
Erica H. Wojcik and Jenny R. Saffran
University of Wisconsin–Madison
Although the semantic relationships among words have long been acknowledged as a crucial component of adult
lexical knowledge, the ontogeny of lexical networks remains largely unstudied. To determine whether learners encode
relationships among novel words, we trained 2-year-olds on four novel words that referred to four novel objects,
which were grouped into two visually similar pairs. Participants then listened to repetitions of word pairs (in the
absence of visual referents) that referred to objects that were either similar or dissimilar to each other. Toddlers listened
significantly longer to word pairs referring to similar objects, which suggests that their representations of the novel
words included knowledge about the similarity of the referents. A second experiment confirmed that toddlers can
learn all four distinct words from the training regime, which suggests that the results from Experiment 1 reflected the
successful encoding of referents. Together, these results show that toddlers encode the similarities among referents
from their earliest exposures to new words.
word learning, lexical development, semantic networks, cognitive development, language development, learning
Received 7/17/12; Revision accepted 1/17/13
Semantic Relationships 1899
1985) and into adulthood (Ameel, Malt, & Storms, 2008),
so it is possible that representations of lexical relation-
ships emerge later in the word-learning process. However,
infants are sensitive to statistical relationships among
newly learned words (e.g., Lany & Saffran, 2011), and
adults can track multiple levels of statistical information
in parallel (Romberg & Saffran, 2013; Yurovsky, Yu, &
Smith, 2012). It is thus possible that from their earliest
exposures to new words, young children encode not
only label-referent associations but also the relationships
among the referents. Recent studies have demonstrated
that by 21 months of age, infants show semantic priming
effects for highly familiar words (Arias-Trejo & Plunkett,
2009). However, it is not known whether young children
encode the relationships among the referents of novel
words as they begin to learn those words, or alterna-
tively, if individual word representations need to be
robust before these connections are encoded. The cur-
rent study was designed to address these issues.
There are many facets of semantic relatedness that
might be encoded by young learners, such as functional
or thematic similarity. In the current study, we focused on
visual similarity because it is an early organizing feature
in nonlinguistic categorization (e.g., Behl-Chadha, 1996;
Quinn, Eimas, & Rosenkrantz, 1993; Sloutsky, 2003). The
fact that 2-year-olds attend to shapes during word learn-
ing suggests that visual characteristics are prioritized (i.e.,
Samuelson & Smith, 2005). Semantic priming studies also
suggest that visual similarity is a component of adults’
lexical representations (Schreuder, Flores d’Arcais, &
Glazenborg, 1984; Yee, Ahmed, & Thompson-Schill,
2012). We thus chose to begin our investigation of the
ontogeny of lexical relationships by manipulating the
visual similarity of novel referents.
In our first experiment, 2-year-olds learned four novel
words that referred to four novel objects grouped into
two visually similar pairs. Although participants were
ostensibly taught object labels, the similarity structure of
the referents provided them with another type of infor-
mation that they could incorporate into their representa-
tions of the novel words. We then tested participants
using an auditory task previously developed to examine
toddlers’ knowledge of the relationships among highly
familiar words (Willits, Wojcik, Seidenberg, & Saffran,
2013). The question of interest was whether listening
preferences for pairs of novel words would be affected
by the visual similarity of the referents of those words in
the absence of the referents themselves.
Experiment 1
Experiment 1 was designed to investigate whether tod-
dlers encode the similarity structure among objects in
a small artificial lexicon. Toddlers show sensitivity to
semantic relationships among familiar words by 21 months
of age (Arias-Trejo & Plunkett, 2009) and can activate this
knowledge in the absence of visual referents by 24 months
of age (Willits et al., 2013). Because our task required the
activation of novel lexical representations, we tested a
slightly older age group (26- to 28-month-olds).
Participants were first trained on four label-object
pairs. Crucially, each object was visually similar to one
other object and distinct from the other two (see Fig. 1).
We then investigated whether toddlers were sensitive to
the similarities among the referents of the words they had
just learned. To do so, we compared participants’ listen-
ing times for word pairs that referred to similar objects
versus listening times for word pairs that referred to dis-
similar objects. This method allowed us to examine tod-
dlers’ nascent lexical representations in the absence of
visual referents, thus tapping into the encoded represen-
tations of the words they had just learned.
Participants. Participants were 32 full-term monolin-
gual English learners (16 male, 16 female) with a mean
age of 27.0 months (range = 25.11–28.4). Eight additional
toddlers were excluded from the analyses because of
fussiness (n = 7) or an average looking time greater than
2 standard deviations from the mean (n = 1).
Stimuli. The training stimuli consisted of four novel
labels (tursey, coro, blicket, pif), each paired with a single
novel object image. Although the objects were all different,
they were organized into two visually similar pairs: two
were blue ovals, and two were red stars (see Fig. 1). Label-
object pairings were counterbalanced across participants.
Fig. 1. The four novel objects that participants were trained on in the
two experiments. Each object was visually similar to one other object
and distinct from the other two. A novel label was paired with each
1900 Wojcik, Saffran
Each test trial consisted of repetitions of a word pair
(e.g., tursey, coro, tursey, coro . . .). Eight trials contained
word pairs that labeled visually similar objects, and eight
contained word pairs that labeled visually dissimilar
objects. Counterbalancing ensured that word pairs
referred to similar objects for half of the toddlers and to
dissimilar objects for the other half of the toddlers.
Referents were not displayed during the test phase.
Procedure. Toddlers were seated on a caregiver’s lap in
a sound-attenuated booth; the caregiver wore blacked-
out glasses and listened to music over headphones. Three
monitors were used: The training trials were presented
on a center monitor, and two side monitors were posi-
tioned 90° to the left and to the right, respectively. The
training phase (2.5 min) began with the four objects dis-
played in a grid for 10 s. During each subsequent training
trial (6 s), a single object was displayed on either the left
or the right side of the screen and was labeled twice:
Look at the __! There’s a __! or “See the __! This is a __!
The first two trials used familiar objects (ball and shoe) to
introduce the format. The next four blocks each included
four novel-object trials, with each label-object pair pre-
sented once per block (randomized).
The test phase immediately followed training. Each of
the 16 test trials began with a central attention-getter
paired with music. Once the toddler looked to the center
monitor, the neutral visual stimulus (a spinning pinwheel)
began to play on one of the two side monitors. When the
toddler looked to that side, a word pair was repeated
from speakers mounted directly below the monitors until
the infant looked away for more than 2 s or for a total of
20 s. Half of the trials consisted of repetitions of word
pairs with similar referents, and the other half consisted of
repetitions of word pairs with dissimilar referents. Each
block of four trials included two similar-object and two
dissimilar-object trials. After the experiment, parents filled
out the MacArthur-Bates Communicative Development
Inventories (CDI; Short Form Level II; Fenson et al., 2000).
Results and discussion
The question of interest was whether toddlers’ listening
times to word pairs were influenced by the visual similar-
ity of their referents (in the absence of those referents).
Thus, we compared listening times to word pairs that
referred to similar or dissimilar objects. A paired-samples
t test revealed a significant effect of trial type (similar
object vs. dissimilar object), t(31) = 3.91, p < .001, η
.331. Toddlers preferred to listen to labels referring to
similar objects (7.99 s, SE = 0.50) compared with labels
referring to dissimilar objects (6.54 s, SE = 0.38; see Fig.
2). We also calculated a preference score for each toddler
by subtracting his or her mean listening time on
dissimilar-object trials from his or her mean listening time
on similar-object trials. Of the 32 participants, 25 had a
positive preference score, which indicates that they lis-
tened longer on similar-object trials than on dissimilar-
object trials (see Fig. 3).
The results of Experiment 1 suggest that when tod-
dlers are learning new words, they do not just learn the
associations between labels and their referents; they also
encode relationships among the referents. The visual
similarity of the referents affected which word pairs tod-
dlers preferred to listen to in the absence of the referents
themselves. Because the label-object pairings were coun-
terbalanced across participants, the pattern of results can-
not be due to idiosyncratic preferences for some labels or
label pairings over others. The information that toddlers
encoded about the visual similarities among referents
affected their behavior in an auditory test.
However, there is an alternative hypothesis that could
explain these results without recourse to the encoding of
the similarity structure of the referents. It is possible that
the toddlers failed to learn the four unique label-object
pairs during training. Instead, they may have categorized
the similar objects together, treating their labels as syn-
onyms, or they simply may not have learned the words
robustly enough to distinguish among the visually similar
referents. For example, if tursey and coro referred to the
two blue ovals, it could be that toddlers treated the labels
as interchangeable or were confused about which word
Visually Dissimilar Visually Similar
Object Type
Mean Looking Time (s)
Fig. 2. Results from Experiment 1: mean looking time as a function of
whether spoken words referred to visually dissimilar or visually similar
objects. Error bars show standard errors.
Semantic Relationships 1901
referred to which object. If the data reflect this alternative
hypothesis, and toddlers underlearned the lexical struc-
ture provided in Experiment 1, the results do not address
our original hypothesis concerning the encoding of simi-
larity structure among the referents but instead simply
reflect category learning (blue ovals vs. red stars). To
tease apart these two hypotheses, we conducted a sec-
ond experiment designed to determine whether the
training procedure from Experiment 1 resulted in the
specific learning of all four label-object pairs.
Experiment 2
In this experiment, we used the same training procedure
as in Experiment 1. However, instead of assessing lexical
representations using an auditory task as in Experiment
1, we tested word-learning outcomes with a looking-
while-listening task (see Fernald, Zangl, Portillo, &
Marchman, 2008). We investigated whether toddlers
could learn all four label-object pairs as distinct lexical
entries given the training regimen from Experiment 1. If
so, this would support our original interpretation of the
results of Experiment 1: namely, that toddlers’ listening
preferences reflect their newly acquired knowledge
about the similarity structure of the referents.
Participants. Participants consisted of a new sample of
24 full-term, monolingual English learners (11 male, 13
female) with a mean age of 27.8 months (range = 26.11–
28.12). Seven additional toddlers were excluded from the
analysis because of inattentiveness (n = 4) or experi-
menter error (n = 3). The remaining participants were
comparable with the Experiment 1 participants in their
expressive MacArthur-Bates CDI scores (64 vs. 67.2,
respectively, out of a possible score of 100), t(54) = 0.52,
p = .61.
Stimuli and design. The training stimuli were identi-
cal to those used in Experiment 1. On each of the 16 test
trials, two of the novel objects were displayed, one on the
bottom left and one on the bottom right of the screen.
Toddlers heard a prerecorded sentence directing them to
one of the objects. Half of the test trials contrasted similar
novel objects (i.e., either the two blue ovals or the two
red stars). The other half contrasted dissimilar objects
(i.e., one blue oval and one red star). These two trial
types allowed us to examine the robustness of the tod-
dlers’ representations of the novel words. In particular,
successful word recognition on the similar-object trials
required participants to have encoded the fine-grained
details differentiating two perceptual neighbors, whereas
successful word recognition on the dissimilar-object trials
did not.
Procedure. The training procedure was identical to that
in Experiment 1. The test phase began with two trials
using familiar objects (shoe and dog); these trials were
intended to orient participants to the task. Next, partici-
pants viewed the novel-object trials in four blocks of four
trials each. The test trials began with two objects pre-
sented in silence (1.5 s). Participants then heard one of
the objects labeled in a sentence frame (“Where’s the __?”
or “Find the __.”). This was followed by an attention-
getting phrase, such as “Can you see it?” or “Do you like
it?”, and 1 s of silence.
Each test block consisted of one trial for each label.
The blocks consisted of two similar-object trials and two
dissimilar-object trials. The target picture (i.e., the picture
that was labeled) was presented equally on the left and
right side within blocks, and each of the object pictures
was displayed an equal number of times on the left and
Listening-Time Preference Score (s)
Fig. 3. Results from Experiment 1: scatter plot showing mean listening-
time preference scores. Preference scores were calculated by subtract-
ing each participant’s mean listening time on dissimilar-object trials
from his or her mean listening time on similar-object trials.
1902 Wojcik, Saffran
right throughout the test phase. Trial order was counter-
balanced across participants. After the experiment, the
parents filled out the MacArthur-Bates CDI (Short Form
Level II; Fenson et al., 2000).
Results and discussion
The primary question was whether participants could
learn four distinct word-referent pairs, given that each
object was highly similar to one other object. Looking
behavior was coded frame by frame (see Fernald et al.,
2008). For each 33-ms frame, we calculated the propor-
tion of trials on which toddlers were looking to the target
To determine whether toddlers successfully learned
the word-referent pairs, we compared looking behavior
before and after the audio presentation of the target
word. If participants learned the word, the proportion of
looking time to the target object after hearing its label
should increase. A baseline window (from 450 ms to
2,450 ms) represented prelabeling behavior. The target
window started at 2,750 ms, beginning 300 ms after the
noun onset to allow for the planning of eye movements
(Fernald et al., 2008), and was 1,500 ms in duration. We
calculated the mean proportion of looks to the target for
each toddler across frames during the baseline and target
windows. Trials were excluded if there were more than
10 consecutive frames in which the participant was not
attending to the stimuli (32 out of 386 total were
A paired-samples t test was used to compare looking
during the baseline and target windows. Participants
looked significantly more to the target object during the
target window than during the baseline window, t(23) =
4.78, p < .001 (see Table 1). This suggests that the tod-
dlers learned the novel words. However, as noted previ-
ously, there were two types of test trials: dissimilar-object
trials, in which toddlers had to locate the target given one
of the blue objects and one of the red objects, and simi-
lar-object trials, which required a decision between either
two blue or two red objects. It is possible that the overall
learning effect was driven by the easier dissimilar-object
Follow-up analyses were conducted to examine the
dissimilar-object and similar-object trials separately. A
paired-samples t test comparing the baseline and target
windows for the dissimilar-object trials revealed that the
participants looked significantly more to the target object
during the target window than during the baseline win-
dow, t(23) = 3.28, p < .005. We found the same pattern for
the more challenging similar-object trials, t(23) = 3.06,
p < .01 (see Fig. 4 and Table 1). To compare performance
on the two trial types, we calculated difference scores for
each subject by subtracting baseline-window accuracy
from target-window accuracy for both similar- and dis-
similar-object trials. A paired-samples t test comparing
those difference scores revealed no significant difference
between trial types, t(23) = 0.41, p = .69. These results
suggest that our participants’ representations of the novel
words were robust and included sufficient detail to per-
mit learners to distinguish between the visually similar
The results from Experiment 1 left open the possibility
that toddlers did not learn distinct label-referent associa-
tions for the visually similar objects; they could have
encoded only the broad visual features and treated the
Table 1. Results From Experiment 2: Mean Proportion of
Looks Infants Made to the Target Object in the Baseline and
Target Windows
Trial type Baseline window Target window
All .50 (.009) .60 (.022)
Dissimilar object .51 (.018) .62 (.031)
Similar object .49 (.013) .59 (.025)
Red star .47 (.028) .61 (.041)
Blue oval .50 (.025) .61 (.032)
Note: Standard errors are given in parentheses.
Proportion of Looks to Target
Time (ms)
Dissimilar Trials
Similar Trials
Target Window
Fig. 4. Results from Experiment 2: mean proportion of looks infants
made to the target object as a function of time and trial type. The verti-
cal line marks the beginning of the target window (300 ms after the
onset of the spoken word, to take into account eye movement plan-
ning; Fernald, Zangl, Portillo, & Marchman, 2008). Error bars show
standard errors.
Semantic Relationships 1903
similar-object labels as synonymous at test. A separate
word-comprehension task was needed to ensure that
toddlers could learn the four distinct words from our test-
ing regime. The results from Experiment 2 demonstrate
that the toddlers formed a strong enough representation
of the visual object associated with each word to be able
to distinguish it from a visually similar neighbor. This
finding supports the hypothesis that the participants in
Experiment 1 learned the novel words as distinct lexical
items and encoded the relationships between them. The
results from Experiment 1, therefore, are likely due to
successful encoding of the relationships among similar
referents during the word-learning process.
General Discussion
When people think about word learning, they tend to
focus on how children acquire the mapping between
sounds (or signs) and their referents. However, it has
been shown that the links among meanings underpin
people’s conceptual knowledge (see McClelland &
Rogers, 2003). The current study was designed to take a
first step toward understanding the ontogenesis of the
associations composing a semantic network by looking
at what toddlers learn about semantic relationships dur-
ing their initial exposure to new words.
In Experiment 1, we investigated whether toddlers
encode the relationships among word referents when
learning novel words. Participants were taught four novel
words that referred to four novel objects consisting of
two visually similar pairs. Toddlers listened significantly
longer to word pairs labeling visually similar referents
than to pairs of labels for visually dissimilar referents in
the absence of the referents themselves. Because the
only difference between the pairs of words was the simi-
larity of their referents, these results suggest that early
lexical representations include information about the
similarity structure of the words’ referents, even for words
toddlers have just learned.
To examine the possibility that the results did not
reflect the encoding of word relationships, but instead
the conflating of labels for visually similar items, we
exposed the participants in Experiment 2 to the same
training regimen. We found that the toddlers successfully
learned the four novel word-referent pairings as distinct
lexical entries. Together, our two experiments suggest
that although toddlers learn novel word-referent associa-
tions, they also encode the relationships among these
Our findings are particularly striking because the train-
ing procedure is similar to what is used in most tradi-
tional word-learning studies; it was not designed to
highlight the relationships among the referents. The
training provided ostensive labels for four novel objects,
but toddlers learned more than just this one type of asso-
ciation. They also took into account other relationships,
such as those among the referents.
The demonstration that early lexical representations
include information about visual similarity among the ref-
erents can be construed as the referential analog to the
neighborhood density effects observed for the sounds of
words (e.g., Hollich, Jusczyk, & Luce, 2002). According to
this view, young learners encode the visual overlap
among the referents of different words much as they
encode the auditory overlap of their labels. If this is the
case, then what is known about early lexical representa-
tions can inform the study of early semantic representa-
tions. For example, Hollich et al. (2002) found that
17-month-olds acquired words forms from dense neigh-
borhoods (i.e., words that sound similar to many other
known words) more readily than words from sparse
neighborhoods. Because our results show that toddlers
encode information about visual relationships among ref-
erents, it is possible that novel objects with many similar
neighbors are more easily learned than those in a sparse
visual neighborhood. In fact, results from a connectionist
model looking at semantic growth suggest that novel
words that are semantically associated with many known
words are acquired more quickly than novel words with-
out many semantic associations (Hills, Maouene, Riordan,
& Smith, 2010). With the results from the current studies
in hand, researchers can use findings from the auditory
domain to advance the understanding of how semantic
relationships interact with word learning.
The current results can also help to expand how peo-
ple think about the word-learning literature. The majority
of word-learning tasks used with infants and young tod-
dlers involve brief training sessions designed to expose
participants to novel words, often on a two-dimensional
screen. Because of this stripped-down artificial situation,
it is unclear whether participants’ resulting knowledge is
wordlike. In these lab settings, infants may just be form-
ing an association between a sound and a picture.
Although this type of association is an important compo-
nent of word learning and knowledge (e.g., Smith & Yu,
2008; Vouloumanous & Werker, 2009), lexical representa-
tions are much richer than just associations between
labels and objects. Thus, it is important to determine the
character of novel word representations acquired in
experimental paradigms. The current study demonstrates
that during toddlers’ first encounters with novel words,
they are encoding more than just the label-object associa-
tions. In fact, even in the stripped-down environment of
a computerized word-learning experimental paradigm,
novel word representations include information concern-
ing the relationships among words. Our findings thus
provide evidence that when researchers employ tradi-
tional word-learning paradigms that teach new words in
1904 Wojcik, Saffran
short training sessions, they are indeed investigating
novel lexical entries, not just label-object associations.
More broadly, the results from this study show the
importance of expanding the study of word learning
beyond just the study of how young children learn which
labels go with which referents. Researchers can draw
from what is known about adult lexical representations to
investigate when and how toddlers acquire that knowl-
edge. For example, it is known that skilled language users
are sensitive to many other types of relationships beyond
the visual similarity of referents. Adults’ semantic knowl-
edge includes the functional relationships between words
(such as “broom” and “floor”; Moss, Ostrin, Tyler, &
Marslen-Wilson, 1995). It would be interesting to teach
toddlers different kinds of novel words, such as those
with overlapping functional or conceptual representa-
tions, to determine which types of relationships are
encoded in early lexical entries. Similar questions emerge
for words across multiple syntactic categories, in which
relationships among words might be somewhat more
abstract. By manipulating the structure of the artificial
lexicon, research can begin to further tease out the type
of information encoded by young word learners—along
with the dimensions of similarity that toddlers fail to
encode. Indeed, given the richness of early linguistic, con-
ceptual, and social environments, it is just as important to
discover which types of information learners ignore as to
discover which types of information they encode.
Researchers have just begun to explore early semantic
networks in young children. Notably, the auditory task
used in the current study is quite different from other
behavioral methodologies that have been used previ-
ously, such as the intermodal-preference-procedure (IPP)
priming task (e.g., Arias-Trejo & Plunkett, 2009). One
benefit of our auditory task is that it allows researchers to
test word knowledge in the absence of visual referents;
this was necessary for the present research because pre-
senting the toddlers with the referents would have pro-
vided them with the exact information that we were
trying to assess. Because the auditory task is novel, we
hope to further explore this methodology, in conjunction
with other techniques, such as the IPP priming task, to
uncover both the mechanisms behind our effect and the
characteristics of young children’s semantic networks.
Word learning is not just about mapping a label to its
referent and making the appropriate extensions to other
similar referents. Children must also learn how different
words are semantically related to each other. Adults
know many important relationships among words, and
this connectedness is a crucial component of people’s
semantic and linguistic systems. Investigating the emer-
gence of these relationships will help researchers more
fully understand the early word-learning process. By
demonstrating that young children encode the visual sim-
ilarity of referents during word learning, this study con-
tributes to an understanding of word learning and
presents a paradigm that can be used to further investi-
gate early encoding of semantic relationships and how
this knowledge interacts with early word learning.
Author Contributions
E. H. Wojcik and J. R. Saffran both developed the study concept
and design. Testing, data collection, data analyses, and inter-
pretation were performed by E. H. Wojcik under the supervi-
sion of J. R. Saffran. Both authors drafted and revised the
We thank the families who participated in the experiments as
well as the members of the Infant Learning Lab, specifically
Casey Lew-Williams, Brianna McMillan, and Hillary Stein. We
also thank Jill Lany, Casey Lew-Williams, and Katharine Graf
Estes for their comments on previous versions of this
Declaration of Conflicting Interests
The authors declared that they had no conflicts of interest with
respect to their authorship or the publication of this article.
This work was funded by a National Science Foundation
Graduate Research Fellowship to E. H. Wojcik and by grants
from the National Institute of Child Health and Human
Development (to J. R. Saffran; R37HD037466), the Waisman
Center (P30HD03352), and the James F. McDonnell Foundation
(to J. R. Saffran).
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... Instead, the segmented components are organized around functional (e.g., "things that are held, " MacWhinney, 2014) and semantic (e.g., "person/object, " Lieven et al., 2003;Dabrowska and Lieven, 2005) relationships in addition to distributional patterns. These components can, but need not, correspond to individual words, as children are sensitive to the statistical properties of multiword sequences (Bannard and Matthews, 2008;Skarabela et al., 2021) in addition to associative (Wojcik and Saffran, 2013) and positional (Wojcik and Saffran, 2015) information. Thus, apart from lexical items segmented from longer sequences, the components can include words along with their article (in Spanish, "la-pelota, " as opposed to "la" and "pelota, " Arnon and Ramscar, 2012) and longer chunks spanning multiple words, accounting for the jump from e.g., "I want milk" to "more milk" to, finally, "I want more milk" 3 (MacWhinney, 2014). ...
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Traditional accounts of language postulate two basic components: words stored in a lexicon, and rules that govern how they can be combined into meaningful sentences, a grammar. But, although this words-and-rules framework has proven itself to be useful in natural language processing and cognitive science, it has also shown important shortcomings when faced with actual language use. In this article, we review evidence from language acquisition, sentence processing, and computational modeling that shows how multiword expressions such as idioms, collocations, and other meaningful and common units that comprise more than one word play a key role in the organization of our linguistic knowledge. Importantly, multiword expressions straddle the line between lexicon and grammar, calling into question how useful this distinction is as a foundation for our understanding of language. Nonetheless, finding a replacement for the foundational role the words-and-rules approach has played in our theories is not straightforward. Thus, the second part of our article reviews and synthesizes the diverse approaches that have attempted to account for the central role of multiword expressions in language representation, acquisition, and processing.
... Conversely, another way to address this issue is to use novel items so that perceptual features of objects can be systematically manipulated. Indeed, there is a growing body of work following this general approach-with examples including studies where novel items vary in either their pairwise perceptual similarity [87] or the density of their respective categories in toddlers' productive vocabularies [83]. The results of these studies suggest toddlers are sensitive to and encode patterns of pairwise similarity in lexical representations even for newly learned words-processes that could give rise to the pattern of results revealed in the current study. ...
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While recent research suggests that toddlers tend to learn word meanings with many “perceptual” features that are accessible to the toddler’s sensory perception, it is not clear whether and how building a lexicon with perceptual connectivity supports attention to and recognition of word meanings. We explore this question in 24–30-month-olds (N = 60) in relation to other individual differences, including age, vocabulary size, and tendencies to maintain focused attention. Participants’ looking to item pairs with high vs. low perceptual connectivity—defined as the number of words in a child’s lexicon sharing perceptual features with the item—was measured before and after target item labeling. Results revealed pre-labeling attention to known items is biased to both high- and low-connectivity items: first to high, and second, but more robustly, to low-connectivity items. Subsequent object–label processing was also facilitated for high-connectivity items, particularly for children with temperamental tendencies to maintain focused attention. This work provides the first empirical evidence that patterns of shared perceptual features within children’s known vocabularies influence both visual and lexical processing, highlighting the potential for a newfound set of developmental dependencies based on the perceptual/sensory structure of early vocabularies.
This study examined the effect of a shape cue (i.e., co-speech gesture) on word depth. We taught 23 preschoolers (M = 3;5 years, SD = 5.82) novel objects with either shape (SHP) or indicator (IND) gestures. SHP gestures mimicked object form, but IND gestures were not semantically related to the object (e.g., an upward-facing palm, extended toward the object). Each object had a unique IND or SHP gesture. Outcome measures reflected richer semantic and phonological learning in the SHP than in the IND condition. In the SHP condition, preschoolers (a) expressed more semantic knowledge, (b) said more sounds in names, and (c) generalized more names to untaught objects. There were also fewer disruptions to prime picture names in the SHP condition; we discuss the benefit of a co-speech shape gesture to capitalize on well-established statistical word learning patterns.
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Recent years have seen a flourishing of Natural Language Processing models that can mimic many aspects of human language fluency. These models harness a simple, decades-old idea: It is possible to learn a lot about word meanings just from exposure to language, because words similar in meaning are used in language in similar ways. The successes of these models raise the intriguing possibility that exposure to word use in language also shapes the word knowledge that children amass during development. However, this possibility is strongly challenged by the fact that models use language input and learning mechanisms that may be unavailable to children. Across three studies, we found that unrealistically complex input and learning mechanisms are unnecessary. Instead, simple regularities of word use in children's language input that they have the capacity to learn can foster knowledge about word meanings. Thus, exposure to language may play a simple but powerful role in children's growing word knowledge.
Word learning studies traditionally examine the narrow link between words and objects, indifferent to the rich contextual information surrounding objects. This research examined whether children attend to this contextual information and construct an associative matrix of the words, objects, people, and environmental context during word learning. In Experiment 1, preschool‐aged children (age: 3;2‐5;11 years) were presented with novel words and objects in an animated storybook. Results revealed that children constructed associations beyond words and objects. Specifically, children attended to and had the strongest associations for features of the environmental context but failed to learn word‐object associations. Experiment 2 demonstrated that children (age: 3;0‐5;8 years) leveraged strong associations for the person and environmental context to support word‐object mapping. This work demonstrates that children are especially sensitive to the word learning context and use associative matrices to support word mapping. Indeed, this research suggests associative matrices of the environment may be foundational for children's vocabulary development. We examined children's attention to and memory for the associations between words, objects, people, and broader environmental context encountered during a word learning episode. Experiment 1 revealed that children had the strongest associations for features of the word learning context (i.e., person and scene context). Experiment 2 revealed that children could leverage stronger associations for the person and scene context to map words and objects. Children construct contextually‐grounded associative matrices to support word mapping and thus researchers should shift to focusing on contextual information when developing word learning theories. This article is protected by copyright. All rights reserved
A pervasive goal in the study of how children learn word meanings is to explain how young children solve the mapping problem. The mapping problem asks how language learners connect a label to its referent. Mapping is one part of word learning, however, it does not reflect other critical components of word meaning construction, such as the encoding of lexico‐semantic relations and socio‐pragmatic context. In this paper, we argue that word learning researchers' overemphasis of mapping has constrained our experimental paradigms and hypotheses, leading to misconceived theories and policy interventions. We first explain how the mapping focus limits our ability to study the richness and complexity of what infants and children learn about, and do with, word meanings. Then, we describe how our focus on mapping has constrained theory development. Specifically, we show how it has led to (a) the misguided emphasis on referent selection and ostensive labeling, and (b) the undervaluing of diverse pathways to word knowledge, both within and across cultures. We also review the consequences of the mapping focus outside of the lab, including myopic language learning interventions. Last, we outline an alternative, more inclusive approach to experimental study and theory construction in word learning research. This article is categorized under: Psychology > Language Psychology > Theory and Methods Psychology > Learning We review how despite advances in our understanding of early word representations, there remains an overemphasis on the mapping problem. After outlining the consquences of the mapping focus, we also discuss more inclusive approaches to the study of word learning.
Children’s everyday learning environment is semantically structured. For example, semantically related things (e.g., fork and spoon) usually co-occur in the same contexts. The current study examines the effects of semantically structured contexts on preschool-age children’s (N = 65, 33 girls, age range: 52–68 months) use of statistical information to learn novel word-object mappings. Children were assigned into one of two conditions, in which objects from the same semantic category repeatedly co-occurred in the same trials (Same-category condition) or objects from different categories repeatedly co-occurred in the same trials (Different-categories condition). Children’s word learning performance in the two conditions were comparable. However, their errors at test suggested that information extracted by children in the two conditions differed. Importantly, children in the Same-category condition extracted both statistical and semantic relationships from the stimuli.
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How words are associated within the linguistic environment conveys semantic content; however, different contexts induce different linguistic patterns. For instance, it is well known that adults speak differently to children than to other adults. We present results from a new word association study in which adult participants were instructed to produce either unconstrained or child-oriented responses to each cue, where cues included 672 nouns, verbs, adjectives, and other word forms from the McArthur–Bates Communicative Development Inventory (CDI; Fenson et al., 2006). Child-oriented responses consisted of higher frequency words with fewer letters, earlier ages of acquisition, and higher contextual diversity. Furthermore, the correlations among the responses generated for each pair of cues differed between unconstrained (adult-oriented) and child-oriented responses, suggesting that child-oriented associations imply different semantic structure. A comparison of growth models guided by a semantic network structure revealed that child-oriented associations are more predictive of early lexical growth. Additionally, relative to a growth model based on a corpus of naturalistic child-directed speech, the child-oriented associations explain added unique variance to lexical growth. Thus, these new child-oriented word association norms provide novel insight into the semantic context of young children and early lexical development.
While semantic and syntactic properties of verb meaning can impact the success of verb learning at a single age, developmental changes in how these factors influence acquisition are largely unexplored. We ask whether the impact of syntactic and semantic properties on verb vocabulary development varies with age and language ability for toddlers aged 16 to 30 months in a large sample (N = 5520, NLate Talkers = 821; NTypically Developing = 4699, cutoff = 15th percentile) of vocabulary checklist data from the MacArthur-Bates Communicative Development Inventory (MBCDI). Verbs from the MBCDI were coded for their syntactic and semantic properties, including manner/result meanings, durative/punctual events, and syntactic complexity. Both late talkers and typically developing children were less likely to produce syntactically complex verbs at younger ages as compared to older ages. Group differences emerged for manner/result: Typically developing children were more likely to produce manner verbs at all ages, but late talkers were more likely to produce result verbs. Regardless of group, children who produced more manner versus result verbs also had larger verb vocabulary sizes overall. These results suggest that late talkers and typically developing toddlers differ in how they build their verb vocabularies.
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There is consensus that the adult lexicon exhibits lexical competition. In particular, substantial evidence demonstrates that words with more phonologically similar neighbors are recognized less efficiently than words with fewer neighbors. How and when these effects emerge in the child's lexicon is less clear. In the current paper, we build on previous research by testing whether phonological onset density slows lexical access in a large sample of 100 English-acquiring 30-month-olds. The children participated in a visual world looking-while-listening task, in which their attention was directed to one of two objects on a computer screen while their eye movements were recorded. We found moderate evidence of inhibitory effects of onset neighborhood density on lexical access and clear evidence for an interaction between onset neighborhood density and vocabulary, with larger effects of onset neighborhood density for children with larger vocabularies. Results suggest the lexicons of 30-month-olds exhibit lexical-level competition, with competition increasing with vocabulary size.
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In our recent book, we present a parallel distributed processing theory of the acquisition, representation and use of human semantic knowledge. The theory proposes that semantic abilities arise from the flow of activation amongst simple, neuron-like processing units, as governed by the strengths of interconnecting weights; and that acquisition of new semantic information involves the gradual adjustment of weights in the system in response to experience. These simple ideas explain a wide range of empirical phenomena from studies of categorization, lexical acquisition, and disordered semantic cognition. In this précis we focus on phenomena central to the reaction against similarity-based theories that arose in the 1980's and that subsequently motivated the "theory-theory" approach to semantic knowledge. Specifically, we consider i) how concepts differentiate in early development, ii) why some groupings of items seem to form "good" or coherent categories while others do not, iii) why different properties seem central or important to different concepts, iv) why children and adults sometimes attest to beliefs that seem to contradict their direct experience, v) how concepts reorganize between the ages of 4 and 10, and vi) the relationship between causal knowledge and semantic knowledge. The explanations for these phenomena are illustrated with reference to a simple feed-forward connectionist model; and the relationship between this simple model, the broader theory, and more general issues in cognitive science are discussed.
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The "looking-while-listening" methodology uses real-time measures of the time course of young children's gaze patterns in response to speech. This procedure is low in task demands and does not require automated eye-tracking technology, similar to "preferential looking" procedures. However, the looking-while-listening methodology differs critically from preferential-looking procedures in the methods used for data reduction and analysis, yielding high-resolution measures of speech processing from moment to moment, rather than relying on summary measures of looking preference. Because children's gaze patterns are time-locked to the speech signal and coded frame-by-frame, response latencies can be coded with millisecond precision on multiple trials over multiple items, based on data from thousands of frames in each experiment. The meticulous procedures required in the collection, reduction, and multiple levels of analysis of such detailed data are demanding, but well worth the effort, revealing a dynamic and nuanced picture of young children's developing skill in finding meaning in spoken language. On-line methods in children's language processing, John Benjamins: Amsterdam (pp. 97-135.).
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How might infant's existing vocabulary affect their ability to learn new words? Specifically, how does the density and token frequency of lexical neighbors in the speech surrounding a child affect that child's ability to learn new word-to-world mappings? The current paper presents a series of studies that demonstrate strong effects of lexical neighborhoods on 17-month-old infant's abilities to learn new words. These effects were created with only a small amount of exposure with little or no opportunity for semantic factors to overlap. Thus, it appears that simply hearing a word can make it easier or harder to learn depending on the number and frequency of items surrounding that word in the lexicon. Lexical neighbors are words that sound similar to a target item. Empirically, they are often defined as words that differ by a single phoneme
Language learners rapidly acquire extensive semantic knowledge, but the development of this knowledge is difficult to study, in part because it is difficult to assess young children's lexical semantic representations. In our studies, we solved this problem by investigating lexical semantic knowledge in 24-month-olds using the Head-turn Preference Procedure. In Experiment 1, looking times to a repeating spoken word stimulus (e.g., kitty-kitty-kitty) were shorter for trials preceded by a semantically related word (e.g., dog-dog-dog) than trials preceded by an unrelated word (e.g., juice-juice-juice). Experiment 2 yielded similar results using a method in which pairs of words were presented on the same trial. The studies provide evidence that young children activate of lexical semantic knowledge, and critically, that they do so in the absence of visual referents or sentence contexts. Auditory lexical priming is a promising technique for studying the development and structure of semantic knowledge in young children.
Semantic priming has been a focus of research in the cognitive sciences for more than thirty years and is commonly used as a tool for investigating other aspects of perception and cognition, such as word recognition, language comprehension, and knowledge representations. Semantic Priming: Perspectives from Memory and Word Recognition examines empirical and theoretical advancements in the understanding of semantic priming, providing a succinct, in-depth review of this important phenomenon, framed in terms of models of memory and models of word recognition. The first section examines models of semantic priming, including spreading activation models, the verification model, compound-cue models, distributed network models, and multistage activation models (e.g. interactive-activation model). The second section examines issues and findings that have played an especially important role in testing models of priming and includes chapters on the following topics: methodological issues (e.g. counterbalancing of materials, choice of priming baselines); automatic vs. strategic priming; associative vs. "pure" semantic priming; mediated priming; long-term semantic priming; backward priming; unconscious priming; the prime-task effect; list context effects; effects of word frequency, stimulus quality, and stimulus repetition; and the cognitive neuroscience of semantic priming. The book closes with a summary and a discussion of promising new research directions. The volume will be of interest to a wide range of researchers and students in the cognitive sciences and neurosciences.
Natural languages contain many layers of sequential structure, from the distribution of phonemes within words to the distribution of phrases within utterances. However, most research modeling language acquisition using artificial languages has focused on only one type of distributional structure at a time. In two experiments, we investigated adult learning of an artificial language that contains dependencies between both adjacent and non-adjacent words. We found that learners rapidly acquired both types of regularities and that the strength of the adjacent statistics influenced learning of both adjacent and non-adjacent dependencies. Additionally, though accuracy was similar for both types of structure, participants' knowledge of the deterministic non-adjacent dependencies was more explicit than their knowledge of the probabilistic adjacent dependencies. The results are discussed in the context of current theories of statistical learning and language acquisition.