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Cognitive
Development,
13, 323-334
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HOW CHILDREN
OBJECTS WITH
reserved.
NAME
SHOES
Susan S. Jones
Linda B. Smith
Indiana
University
Many studies report a shape bias in children’s learning of object names. However, one previous study suggests that the shape bias is not the only perceptually based bias displayed by children learning count nouns. Specifically,
children attended to texture as well as shape when extending a novel name to
novel objects with eyes. Two experiments attempt to extend this finding, asking whether children will also attend to texture in the presence of another cue
to animacy-shoes.
In Experiment 1, 80 2- and 3-year-olds participated in
either a Name generalization or Similarity judgment task. The novel objects
were identical except that for half of the children the objects had shoes. In the
Similarity condition, children made their judgments by overall similarity. In
the Name condition, 2-year-olds extended the novel name by shape across
objects both with and without shoes. In contrast, 3-year-olds generalized the
novel name by shape when the objects had no shoes but by texture when the
objects had shoes. Experiment 2 challenged this finding, using a forced
choice procedure and objects that differed from the named exemplar more
markedly in shape. Twenty 3-year-olds participated in a Name generalization
task, half for objects with shoes, half for objects without shoes. Again, children attended reliably more to texture when the objects had shoes than when
they had no shoes. The results are discussed in terms of the development of
different perceptually based biases and the relation of such biases to a taxonomic bias in early word learning.
Children are smart learners of object names. Their smartness is particularly
obvious in their generalizations
of newly learned names to new instances. Often upon
hearing a word used to name just one perceptually
present object, young children
generalize that name to new instances in ways that seem sensible and nearly right
to the adult observer (e.g., Markman,
1989; Mervis, Mervis, Johnson, & Bertrand,
This research was supported by
Direct
all correspondence
Bloomington,
Manuscript
IN 47405-I
received
NICHD Grant #HD2X675
to: Susan S. Jones, Department
301 <jonesI
August 19,1996;
of Psychology, Indiana
University,
@indiana.edu>.
revision accepted
December
3, 1997
323
324
Jones and Smith
1992). From these results, there is general agreement that children know something about how nouns map onto categories-knowledge
that apparently makes
the learning of object names simple (Golinkoff, Mervis, & Hirsch-Pasek, 1994;
Jones & Smith, 1993; Markman, 1989; Waxman, 1994). There is, however, disagreement in the literature about just what it is that children know.
In general, there are two classes of answers to the question of what children
know about how nouns map onto object categories (Imai, Gentner, & Uchida,
1994; Jones & Smith, 1993). The first is that children know that names for concrete things refer to categories that are well organized by shape (Imai et al., 1994;
Landau, Smith, & Jones, 1988). The second is that children know that nouns name
objects that are the same taxonomic kind (e.g, Markman & Hutchinson, 1984;
Waxman & Gelman, 1986).
Clearly, these two contrasting views are difficult to distinguish empirically as
many taxonomically related objects (and particularly those at the basic level) are
also similar in shape (see Imai et al., 1994). Nonetheless, a number of recent studies have specifically contrasted shape similarity and taxonomic relatedness as
bases for children’s noun generalizations (e.g., Baldwin, 1992; Imai et al., 1994;
Poulin-Dubois
& Tilden, 1993). The results strongly agree: young children systematically generalize novel names across objects by shape even when those generalizations violate taxonomic boundaries.
The purpose of the present study is to show that shape is not the sole determiner
of children’s generalizations of object names, and in so doing to raise an alternative account of children’s smart noun generalizations-one
that may unify the
ideas of a shape bias and a taxonomic bias. Our starting point is a prior empirical
demonstration that children do not always generalize a newly learned count noun
exclusively by shape (Jones, Smith, & Landau, 1991). This prior result has been
largely ignored in discussions of a shape versus taxonomic bias (see Imai & Gentner, 1993; Waxman, 1994), perhaps because it is just one result or perhaps
because it does not fit simply either with a shape bias or a taxonomic bias.
Accordingly, our goal is to extend the empirical base, to show again that children’s naming is smarter than a mere shape bias.
The key prior result we seek to amplify is Jones, Smith, and Landau’s (1991)
finding that young children do not extend novel names for objects with eyes by
same shape alone: instead, they systematically form new nominal categories of
things with eyes on the basis of shared texture and shared shape. Jones et al. predicted this result from their analysis of the similarity structure of animate things
and their depictions (e.g., toys and figurines). They noted that textural properties
are one important basis for distinquishing between real animate objects and their
representations. Mannequins and dolls have the same shape as do people, but differ from people in their material substance (as well as their ability to move). Massey and Gelman (1988) have shown that preschool aged children are highly
sensitive to textural information.
Second, the texture of naturally occurring
objects with eyes is both less variable and more important than that of artifacts.
Children
Name Objects
325
with Shoes
Real sheep have the same surface texture; real chairs do not. Jones et al. reasoned
that if children learn the relation between having eyes and the importance of texture, and if they use this knowledge when forming new lexical categories, then
they should not attend exclusively to shape when naming objects with eyes. This
is precisely what they found for 3-year-olds, but not for 2-year-olds.
We seek to show here that this is not a unique result and that attention to shared
textures (as well as shape) does not depend solely on the presence of eyes. More
specifically, we propose that whenever the perceptible properties of the named
object suggest animacy, children attend to the texture of the named object. This
proposal is based on two further aspects of the Jones et al. (1991) results. First,
children’s interactions with the objects indicated that the presence of eyes did suggest animacy to the children. During the course of the experiment, the children
often played with the objects with eyes as if they were depictions of animate
things-making
them walk, kissing them, and laying them down while saying
“night-night”. Objects without eyes never elicited these behaviors. Second, children’s increased attention to texture in the context of eyes was independent of the
nature of the textural properties. That is, the presence of eyes shifted children’s
attention to texture even when the novel object was made of painted wood and
clearly an artifact and not a real, living thing. This last result suggests that the
effect of eyes does not emerge from conceptual knowledge about natural kinds
and the relevance of particular textures. Instead, the results fit the idea that the
world presents bundles of correlated features that predict the relevance of shape
and texture for lexical categories with those features, and that children learn these
statistical regularities. This line of reasoning suggests that eyes should not be special in their recruitment of attention to texture. Rather, any property that is predictive of animate things and their artifactual representations should recruit attention
to texture.
Accordingly, the perceptual property that we use in this experiment is shoes.
Objects with shoes have feet and move (or represent objects that move). The question for the present experiment then is whether the addition of shoes, like the addition of eyes, results in increased attention to texture in the task of generalizing a
novel object name. After presenting the empirical results, we will discuss how the
shape bias, the taxonomic bias, and a shape+texture bias for animates may all be
manifestations of the same underlying process-learning
about bundles of correlated features in the world.
EXPERIMENT1
Method
Participants.
Eighty children participated: forty 2-year-olds (range = 2;0-2;6,
A4 = 2;3) and forty 3-year-olds (3;0 to 3;5, M = 3;2). There were equal numbers
of males and females at each age level. Participants were recruited both from
326
Jones
and Smith
local preschools and from files of birth announcements.
Half the children at each
age level were assigned to the No-Shoes condition and half were assigned to the
Shoes condition. Within each of these conditions at each age level, half of the
children participated in a naming task and half in a similarity judgment control
procedure.
Stimuli.
The stimuli for the No-Shoes condition were similar to those used by
Jones et al. (199 1) and consisted of two subsets. The standard for one subset, the
“dax”, was a 5 cm tall x 5 cm wide inverted U-shaped piece of 1.2 cm thick wood,
painted blue. The standard for the second subset, the “rif’, was an unpainted
notched circle of the same wood, approximately 5 cm in diameter. The stimuli for
the Shoes condition were constructed identically to those of the No-Shoes condition except that white sneakers porportional to the sizes of the objects were
attached. The two exemplars for both the No-Shoes and Shoes conditions are
illustrated in Figure 1. All stimulus objects both with and without shoes were presented standing upright as drawn in the figure.
Four test stimuli were constructed for each exemplar in the two conditions: 1
object identical to the exemplar (ID), and 3 objects that each differed from the
exemplar on one of three perceptual dimensions: shape (SH), size (SZ), or texture
(TX). The shape-change test objects are also illustrated in Figure 1. The “dax”
size-change test objects were each 20 cm, and the “rif’ size-change objects were
25 cm in height. The texture-change test objects for the “dax” sets were constructed of sponge stiffened by blue paint. The texture-change test objects for the
“rif’ sets were constructed of wood like the exemplars, but covered in small scale
bubble-pak.
The Name and Similarity conditions differed only in the instrucProcedure.
tions given to the children. In the Name condition, the Experimenter presented the
exemplar at the beginning of each trial with the statement “This is a dax [rifl”. In
the Similarity condition, the Experimenter said only “Look at this.” In both conditions, children were then presented with one of the test items. Children in the
Name condition were asked “Is this [one] a dax [rifl?” Children in the Similarity
condition were asked “Does this [one] go with this one [the standard]?; is this one
like that one?”
There were 8 unique test items: 4 in the dax set and 4 in the rif set. Each of the
unique 8 items was presented twice for a total of 4 trials per type of test item
(identical, size change, shape change, texture change) or 16 trials per subject. Trials were presented to all children in one of two random orders. The children were
allowed to handle the exemplar and test objects throughout the experiment.
Results
Younger and older children in the Shoes condition but not in the No-Shoes condition made spontaneous comments and actions that attributed animate properties
Children
Name
Objects
with Shoes
327
EXEMPLARS
DAX
SHAPE-CHANGE
TEST
RIF
OBJECTS
EXPERIMENTS
1 & 2:
EXPERIMENT
2 ONLY:
Large
shape
change
Figure 1. Exemplars and shape-change test objects for stimulus sets with and without shoes. Both Experiments 1 and 2 used the small shape-change objects. Only
Experiment 2 used the large shape-change test objects.
to the daxes and rifs. They walked the stimuli to each other;
they made them dance. Comments included “That’s his
“They’re gonna fight”, and “That’s the Daddy”.
The similarity condition measures stimulus effects on
independent of what they know about naming objects. As
they made them kiss;
mouth”, “Bye-bye”,
children’s attention
Figure 2 shows, the
328
Jones and Smith
2 YEAR-OLDS
ID
SZ
SH
3 YEAR-OLDS
TX
ID
SH
TX
Figure 2. Experiment 1: Mean proportions of “yes” responses made by 2- and 3year-old in a Similarity judgment task when exemplars bad Shoes and when they had
No Shoes. Test items: ID = identical to the exemplar; SZ = different size; SH = different shape; TX = different texture.
mean numbers of “yes” responses to each type of test object in the Shoes and
No-Shoes conditions in the Similarity judgment task did not differ. In brief, the
presence of shoes did not alter children’s similarity judgments. A 2(Shoes/No
Shoes) x 2(Age) x 2(Dax/Rif) x 4(Item: Identical; Size change; Shape change;
Texture change) mixed analysis of variance of “yes” responses in the Similarity
condition yielded only a main effect of Item F(3,lOS) = 17.159, p ~001, was
entirely due to the fact that both age groups said “yes” more often to the test item
identical to each exemplar (M = 3.55, max score = 4) than to any of the other test
items (SZ: M = 2.23; SH: M = 2.10; TX: M = 2.45). Notice that none of the varying dimensions (size, shape, or texture) controlled children’s judgments more
than the others.
The key question is this: Do children form differently structured nominal categories when the named objects have shoes versus when they do not? Do they
know that objects with shoes and objects with no animacy features are named differently? Figure 3 shows the mean numbers of “yes” responses to each kind of test
object with and without shoes made by children in the Naming task. The same 4way mixed analysis of variance of the “yes” responses in the two Naming conditions yielded a main effect of age, F(1,36) = 5.08, p ~03, shoes/no-shoes, F( 1,36)
= 5.08, p <.03), and item F(3,108) = 34.55, p <.OOl. All three main effects were
subsumed by three interactions:
Shoes/No-Shoes
x Item (F(3,108) = 7.05, p
~001); Age x Item, (F(3,108) = 3.40, p ~02); and Shoes/No-Shoes x Age x Item
Children
329
Name Objects with Shoes
2 YEAR-OLDS
3 YEAR-OLDS
4.0
4.0
gj
3.5
8
3.5
3
2
sl
3.0
2.5
i
;“:
LY
b
2.0
g
2.0
$
1.5
p
1.5
5
1.0
z
1.0
3
0.5
2
0.5
0.0
ID
SZ
SH
0.0
TX
ID
cl
ITEMS
SZ
SH
TX
NasH”ES
n SH”~
ITEMS
Figure 3. Experiment 1: Mean proportions of “yes” responses made by 2- and 3year-olds in a novel Name generalization task when exemplars and test items had
Shoes and when they had No Shoes. Test items: ID = identical to the exemplar; SZ =
different size; SH = different shape; TX = different texture.
(F(3, 108) = 6.26, p c.001. To understand the sources of the three-way interaction,
post hoc comparisons of cell means were carried out via Dunn’s Multiple Comparison test (Bonferroni t-tests). Dunn’s test yielded a critical difference of 1.47
with p = .02 for a family of 16 comparisons.
As can be seen in Figure 3, shoes had different effects on the judgments of 2and 3-year-olds. Two-year-olds rejected items that differed from the exemplar in
shape regardless of whether those items did or did not have shoes. Thus, 2-yearolds showed a shape bias in both conditions. In contrast, 3-year-olds showed different patterns of “yes” responses depending on whether or not the stimuli had
shoes. In the No-Shoes condition, the 3-year-olds showed a clear shape bias.
However, when the stimulus objects had shoes, 3-year-olds accepted differentshape items (as well as different-size items) as members of the lexical category.
The items they consistently rejected were those that matched the exemplar in
shape but differed from it in texture. Thus, in the context of shoes, these children
showed a texture bias.
In summary, the main results are these: 2-year-olds generalized novel names for
objects with shoes and without shoes in the same way-by
shape. In contrast, 3year-olds generalized novel names for objects with and without shoes differently.
They attended to shape with shoeless objects, but to texture when the objects had
shoes.
330
Jones and Smith
EXPERIMENT2
The results of Experiment 1 extend the previous findings of Jones et al. (1991):
Shoes and eyes are both properties that suggest animacy and both yield novel
name generalizations
by 3-year-olds that are not exclusively based on shape.
However, there is one difference between the two results that might be meaningful. Jones et al. found that when objects had eyes, 3-year-old children used both
shape and texture as bases for generalizing a newly learned object name. The
results of Experiment 1 suggest that when objects have shoes, 3-year-olds attend
principally to texture. This difference might be due to stimulus differences
between the two studies. Jones et al. (1991) employed test objects that differed in
shape from the exemplar to a greater degree than the different-shaped test object
employed in Experiment 1. Perhaps children would attend to the shapes as well as
the textures of test objects with shoes if some of those shapes were more dramatically different from the shape of the exemplar.
We tested this possibility by examining 3-year-olds’ novel noun generalizations
when the test objects differed from the exemplar in shape by smaller or greater
amounts. In addition, we employed a forced-choice task that directly pitted sameness of shape against sameness of texture.
Method
Participants.
Twenty children participated, 13 females and 7 males (range =
3;0 to 3;6, M = 3;2). They were randomly assigned to two conditions-No-Shoes
and Shoes.
Stimuliand Procedure.
On each trial, children were presented with the
exemplar and two test objects. One test object differed from the exemplar in shape
only, the other in texture only. The exemplar was named with a novel count noun,
“This is a dax (rif)” and the child was asked which of the two test objects was also
a dax (rifl. Children completed a total of 8 trials4
in which the test object differing in shape differed by a small amount, and 4 in which the test object differing
in shape differed by a large amount (both small and large shape changes are illustrated in Figure 1). In each case, 2 of the 4 trials were “dax” trials and 2 were “rif’
trials.
Results
Children preferred the test object matching the exemplar in shape on 95% of the
trials when the objects did not have shoes but did so only 62% of the time when
the objects had shoes. This main effect of condition was the only reliable effect,
F(1,18) = 8.64, pc.01 to emerge from a 2 (Condition) x 2 (Magnitude of Shape
Change) analysis of variance for a mixed design. Neither the main effect of magnitude of shape difference nor the interaction approached significance (F < 1).
This experiment thus yields three findings. First, the results replicate those of
Experiment 1: children attend only to shape when the objects do not have shoes;
Children
Name Objects with Shoes
331
and they decrease their attention to shape while increasing attention to texture
when the objects have shoes. Second, although attention to texture is increased by
the addition of shoes, children still choose the object that matches in shape more
often than the one that matches in texture. Indeed, in this more sensitive forcedchoice task in which the shapes of some objects with shoes differed from the
shape of the exemplar by a large amount, children generalized the novel name
more often by shape than by texture-though
significantly less so than when the
objects did not have shoes. Third, there was no effect of magnitude of shape difference. Although children’s judgments did not differ from trial to trial depending
upon the degree of shape difference, it seems likely that the presence of some test
objects that differed greatly in shape may account for the overall increase in attention to shape relative to Experiment 1.
GENERAL DISCUSSION
These results show that by 3 years of age, the potency of shape in controlling children’s novel word generalizations depends on the kind of object named. This finding affirms the same prior conclusion by Jones et al. (1991). Thus, the present
study provides new evidence that shoes as well as eyes cue chidren to the
increased relevance of texture to lexical categorization.
Further, the results of
Experiment 1 suggest that increased attention to texture in the case of shoes, as in
the case of eyes, emerges with development. We believe that these findings provide new insight into how children’s word learning is so smart and how it becomes
ever smarter as children learn more and more words.
Why Do Shoes ZnjZuence Lexical Categorization?
Past research has shown
that category learners from infants to adults are highly sensitive to correlated
properties among members of the same category (Medin & Wattenmaker, 1987;
Younger, 1990). Moreover, analyses of common noun categories suggest that
these categories strongly exhibit bundles of correlated properties (e.g., Markman,
1989; Murphy & Medin, 1985; Rosch, 1973). For example, feathers, wings,
beaks, and particular kinds of feet go together. Further, research on both natural
and laboratory category learning in both children and adults shows that these correlations provide a means for shifting attention among object properties in category relevant ways (Medin & Wattenmaker, 1987; Mervis, Johnson, & Scott,
1993). This evidence suggests that the system that enables children to acquire
noun meanings may not be one that pushes attention to one particular property but
rather one that makes use of the natural clusters of correlations among the properties of objects in the world.
And in the real world, objects with shoes have feet, and feet are regularly found
with other specific object properties-for
example, with having a particular kind
of texture, a particular kind of movement, a particular arrangement of object parts,
and within limits, somewhat variable shape. If children learn these correlations
332
Jones and Smith
and use them to guide word learning, then they should weight shape less heavily
and texture more heavily when extending names of objects with feet. Our data
show that they do.
Learning About Categories and Kinds.
Smith, Jones, and Landau (1996;
Smith, 1995) proposed an attentional learning hypothesis to explain the origin and
development of the shape bias in children’s naming of novel artifacts. By this
hypothesis, attention to shape in the context of naming emerges as a natural consequence of general associative processes. Briefly, considerable research in psychology shows that whenever two properties regularly co-occur in the world, the
presence of one comes to automatically recruit attention to the second. Thus,
Smith et al. (1996) proposed that children learn to attend to shape in the context
of naming because syntactic frames associated with count nouns (e.g., “this is a”)
regularly co-occur with successful categorization by shape.
The very same processes may be invoked to explain children’s learning that texture matters for objects with shoes or eyes. Indeed, by the attentional learning
hypothesis, any statistical regularities among contextual cues and object properties that are regular enough should come to organize attention. Thus, this hypothesis predicts that if the contextual cue of a count noun syntactic frame regularly
co-occurs with object rigidity and the relevance of shape, then object rigidity in
the context of a count noun frame should cue attention to shape. Similarly, this
hypothesis predicts that if the contextual cue of a count noun frame is regularly
associated with shoes and attention to texture as well as shape, then shoes in the
context of a count noun frame should cue attention to texture and shape. The
attentional learning hypothesis, then, predicts that the mechanism underlying children’s word learning should be smarter than a mere shape bias. As children learn
more and more words, and about more and more bundles of properties relevant to
naming, more and more attentional biases should emerge--each
fit to and cued by
specific object properties.
But if children acquire such bundles of correlated properties, have they not
acquired taxonomic kinds? And if children use these bundles of properties to
guide new word learning, will they not preferentially link words to taxonomic
kinds? Taxonomic kinds by definition are categories of things that are alike in
many richly interconnected ways (Markman, 1989). Thus, knowledge about kinds
is at least in part knowledge about bundles of correlated features. From this perspective, the debate about whether a shape bias or a taxonomic bias guides children’s count noun learning is misguided. Both biases are manifestations
of the
same kind of knowledge created by the same associative processes.
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