Do Lions Have Manes? For Children, Generics Are About Kinds Rather Than Quantities
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Child Development, March ⁄ April 2012, Volume 83, Number 2, Pages 423–433
Do Lions Have Manes? For Children, Generics Are About Kinds Rather
Than Quantities
Amanda C. Brandone Andrei Cimpian
Lehigh University University of Illinois at Urbana-Champaign
Sarah-Jane Leslie Susan A. Gelman
Princeton University University of Michigan
Generic statements (e.g., ‘‘Lions have manes’’) make claims about kinds (e.g., lions as a category) and, for
adults, are distinct from quantificational statements (e.g., ‘‘Most lions have manes’’), which make claims about
how many individuals have a given property. This article examined whether young children also understand
that generics do not depend purely on quantitative information. Five-year-olds (n = 36) evaluated pairs of
questions expressing properties that were matched in prevalence but varied in whether adults accept them as
generically true (e.g., ‘‘Do lions have manes?’’ [true] vs. ‘‘Are lions boys?’’ [false]). Results demonstrated that
children evaluate generics based on more than just quantitative information. Data suggest that even young
children recognize that generics make claims about kinds.
A central task of early childhood is to learn broad & Flukes, 2008), and they have been hypothesized
generalizations about categories in the world. Chil- to play a central role in human reasoning (Gelman,
dren must learn that lions have manes, milk builds 2003; Prasada, 2000). Nevertheless, an issue that
strong bones, and stoves are hot. Generic sentences remains unresolved concerns how the meaning of
such as ‘‘Lions have manes’’ provide an important these utterances is represented.
means of conveying such knowledge (Gelman, Within the linguistic and philosophical litera-
2003). Generics make claims about kinds (e.g., lions tures, there has been considerable debate over how
as a category) rather than individuals (e.g., the lions to characterize the semantics of generics (for a
at the zoo) and express generalizations about review, see Leslie, 2008). Leslie (2007, 2008) has
shared properties of category members (Carlson, argued that the truth of a generic statement does not
1977; Carlson & Pelletier, 1995). Generics also link depend on how many kind members possess the
to core properties, as they express predicates that property in question; there is no straightforward
are relatively enduring (not transient), timeless (not mapping between statistical facts about the world
contextually bound), and inherent (not accidental) and judgments about generics (see also Carlson,
(Carlson & Pelletier, 1995; Prasada, 2000; see also 1977; Carlson & Pelletier, 1995; cf. Prasada & Dill-
Prasada & Dillingham, 2006). Generics appear fre- ingham, 2006). Consider these examples. ‘‘Lions
quently in natural speech, including conversation have manes’’ is true, but ‘‘Lions are male’’ is false,
with young children (e.g., Gelman, Goetz, Sarnecka, even though only male lions ever possess manes.
‘‘Mosquitoes carry the West Nile Virus’’ is true,
even though less than 1% of mosquitoes are actually
This research was supported by an NSF Graduate Research
Fellowship to Amanda C. Brandone, University of Illinois funds
infected. Conversely, ‘‘People are right-handed’’ is
to Andrei Cimpian, Princeton University funds to Sarah-Jane false, despite the fact that the vast majority of indi-
Leslie, and NICHD Grant HD-36043 and NSF Grant BCS- viduals are right-handed. Examples such as these
0817128 to Susan A. Gelman. We are grateful to the children,
parents, and teachers at the UM Children’s Center for participat-
demonstrate that when deciding on the truth value
ing in this research. We also thank Kristin Lang, Jenna Hedglen,
Ben Boldt, Melissa Yako, and the Concepts and Theories in
Human Development and UIUC Cognitive Development Labs
for assistance in data collection.
Correspondence concerning this article should be addressed to 2012 The Authors
Amanda Brandone, Department of Psychology, Lehigh Univer- Child Development 2012 Society for Research in Child Development, Inc.
sity, Bethlehem, PA 18015. Electronic mail may be sent to All rights reserved. 0009-3920/2012/8302-0004
acb210@lehigh.edu. DOI: 10.1111/j.1467-8624.2011.01708.x424 Brandone, Cimpian, Leslie, and Gelman of a generic, people rely on more than just statistical abstract conceptual knowledge (e.g., ontology, information. animacy, function), including a conceptual distinc- Recent empirical work confirms that, for adults, tion between individuals and kinds (e.g., Carey, generic meaning does not reduce to quantification— 1985, 2009; Gelman, 2003; Gelman & Brandone, that is, to considerations of how many members of 2010; Gopnik & Meltzoff, 1997; Wellman & Gelman, the kind have the property. Two main findings 1998). However, others have proposed a more have emerged from this research. First, adults’ bottom-up process of lexical and conceptual devel- acceptance of generics is not accounted for by the opment in which perceptual features of the envi- prevalence of the predicated properties alone. (It is ronment get linked to concrete linguistic features of only in certain circumscribed cases that statistical the input via associative learning (e.g., Colunga & frequency is sufficient to make a generic true; Smith, 2005; Sloutsky & Fisher, 2004; Sloutsky, Prasada & Dillingham, 2006, 2009.) For example, Kloos, & Fisher, 2007; Smith, Jones, & Landau, Khemlani and colleagues (Khemlani, Leslie, & 1996). These theoretical perspectives offer distinct Glucksberg, 2009; Khemlani, Leslie, Glucksberg, & proposals for how children might interpret gener- Rubio-Fernandez, 2007) showed that adults judged ics. If children’s concepts go beyond the available some generics such as ‘‘Ducks lay eggs’’ and ‘‘Mos- evidence and incorporate abstract knowledge, then quitoes carry the West Nile virus’’ to be true children may be able to interpret generics as being despite knowing that a large percentage of the about abstract kinds and as distinct from state- kinds lacks the predicated properties; however, ments about how many members of the kind have they rejected other generics such as ‘‘Books are the relevant property. If, on the other hand, chil- paperbacks’’ and ‘‘Canadians are right-handed’’ dren’s cognition is limited to statistical computa- despite knowing that most members of those kinds tions and associative learning, then children may have the predicated properties. Furthermore, instead interpret generics as synonymous with Cimpian, Brandone, and Gelman (2010) found that quantified statements. adults were willing to accept even some novel Much of the recent evidence regarding children’s generics (e.g., ‘‘Lorches have purple feathers’’) at production and comprehension of generics is sug- low prevalence levels (below 50%). gestive of the possibility that generics are not Second, research has shown that adults’ accep- equivalent to statements about frequency even for tance of generics reflects biases in their conceptual young children. Children as young as 2½ years of representations. For example, Cimpian, Brandone, age produce generics (Gelman, Goetz, et al., 2008; et al. (2010) found that generic predications of prop- Gelman, Waxman, & Kleinberg, 2008) and do so erties that were described as distinctive or danger- more often when the context encourages a focus on ous (e.g., venomous scales) were accepted more kinds (Brandone & Gelman, 2009; Gelman, Goetz, often than generic predications of other similar et al., 2008; Gelman, Waxman, et al., 2008). For properties (e.g., shiny scales), presumably because example, preschoolers produce more generics when properties that are either distinctive or dangerous talking about animals than artifacts (Brandone & to humans are privileged in our kind representa- Gelman, 2009; Gelman, Goetz, et al., 2008; Gelman, tions (see also Leslie, 2007, 2008). Similarly, Cim- Waxman, et al., 2008)—consistent with evidence pian, Gelman, and Brandone (2010) and Gelman suggesting that animal categories are more richly and Bloom (2007) showed that considerations about structured and ‘‘kind-like’’ than artifact categories the nature and origin of the predicated properties (e.g., Keil, 1989). These data suggest that children (e.g., whether they are innate vs. acquired) are suffi- understand generics to be making claims about cient, independently of prevalence, to determine how kinds. However, production data are ambiguous: adults reason about generic sentences. When children produce a generic (e.g., ‘‘Birds fly’’), Together, these data suggest that, at least for we cannot be certain whether they are referring to adults, generics do not reduce to quantificational the kind or to a quantified set (e.g., all or most birds). statements. An important remaining question is So far, the evidence from comprehension studies whether this is also the case for children: Do chil- also cannot definitively rule out the possibility that dren understand generic meaning as distinct from children understand generics as quantificational. quantification? This question has important impli- Preschoolers seem to recognize that generics (a) cations for broader theoretical questions regarding refer beyond individuals in the immediate context the nature of children’s concepts. Some have (Cimpian & Markman, 2008; Cimpian, Meltzer, & argued that as young children build their lexical Markman, 2011; Gelman & Bloom, 2007; Gelman & and conceptual repertoires, they are guided by Raman, 2003), (b) are broad in scope but allow for
Do Lions Have Manes? 425
exceptions (Chambers, Graham, & Turner, 2008; kind yet true of only one gender (e.g., ‘‘Lions have
Gelman & Bloom, 2007), and, more specifically, (c) manes’’) and (b) those for which predicates are not
imply scope that is intermediate between ‘‘all’’ characteristic of the kind yet also true of only one gen-
and ‘‘some’’ (Hollander, Gelman, & Star, 2002). der (e.g., ‘‘Lions are boys’’). (Note that because of the
Although these studies demonstrate sophisticated age of our participants, we substituted the terms boys
understanding of generics in preschoolers, their and girls for males and females. Pilot testing con-
results are still compatible with the possibility that firmed that children understood these terms as refer-
children interpret generics as equivalent to quantifi- ring to the gender of the animals and did not
cational statements about individuals (e.g., perhaps interpret them to mean human boys and human girls.)
as equivalent to ‘‘most’’ statements). Pairs of characteristic and noncharacteristic state-
Thus, existing data provide suggestive, but not ments (e.g., ‘‘Lions have manes’’ vs. ‘‘Lions are
conclusive, evidence that children do not interpret boys’’) were chosen such that, within each pair, the
generics as making purely quantificational claims. property predicated in the noncharacteristic state-
In the current experiments, we examine this ques- ment (e.g., being male) served as a precondition for
tion directly. Specifically, we ask: Do young chil- the property predicated in the characteristic state-
dren interpret generics as reflecting only statistical ment (e.g., having a mane) and thus applied to a
facts about the world? Or, as in the case of adults, superset of the animals to which the characteristic
do judgments about the truth of generics depend property applied. To ensure that participants were
on additional information? aware of these inclusion relations, we tested their
knowledge of the gender requirements for the
properties predicated in the characteristic state-
ments (e.g., ‘‘Do boy lions have manes?’’ ‘‘Do girl
Study 1
lions have manes?’’). Only items on which partici-
We compared children’s judgments about pairs of pants demonstrated requisite knowledge (e.g., that
statements that, although matched in prevalence, only boy lions have manes) were analyzed.
vary in their acceptability as generics. Consider, for By equating the prevalence of the information
example, ‘‘Lions have manes’’ versus ‘‘Lions are expressed in the two types of statements and vary-
male.’’ Since only male lions have manes, ‘‘Lions ing whether or not the predicated property was
have manes’’ applies to at most as many lions as characteristic of the kind, we could distinguish
‘‘Lions are male.’’ Yet, despite the similar underlying responses driven by prevalence information from
statistics of these two statements, only ‘‘Lions have responses driven by knowledge about kinds. If chil-
manes’’ seems acceptable, arguably because having dren interpret generics as reflecting purely statisti-
manes is a characteristic property of the kind lion, cal facts about the world, they should be equally
whereas being male is not. The question of what likely to accept the characteristic and noncharacter-
makes a property characteristic of a kind is an istic statements because the properties predicated
exceedingly complex one (see Leslie, 2007, 2008; in each are roughly equivalent in prevalence. If, on
Prasada & Dillingham, 2006, 2009). For current pur- the other hand, children interpret generics as claims
poses, a property was deemed ‘‘characteristic’’ if it about kinds like adults do, then they should be
involved (a) a salient physical property (e.g., ‘‘Lions more likely to accept the characteristic than the
have manes’’), (b) a means of gestation (e.g., ‘‘Birds noncharacteristic statements. We predicted that
lay eggs’’), or (c) a means of nurturing the young children’s understanding of generics would not be
(e.g., ‘‘Pigs give milk to their babies’’). A property driven solely by statistical facts about the world;
was deemed ‘‘noncharacteristic’’ if it involved attrib- thus, acceptance of the characteristic items should
uting a gender to the kind (e.g., ‘‘Lions are male’’). be greater than acceptance of the noncharacteristic
Theoretically, this does not exhaust all the possibili- items.
ties for characteristic versus noncharacteristic prop-
erties; nevertheless, these were the guidelines
selected to operationalize characteristic and non- Method
characteristic properties in the current study.
Participants
The previous example illustrates the research
strategy used in this study: We compared the likeli- Fourteen children (7 males, 7 females; M =
hood that participants would accept as true each of 5.36 years, SD = .52) and 14 undergraduates (5
two kinds of statements presented in generic form: males, 9 females) participated. Two additional chil-
(a) those for which predicates are characteristic of the dren were excluded because they did not know any426 Brandone, Cimpian, Leslie, and Gelman
of the gender properties. An additional 28 under- Table 1
graduates participated in pretesting (see below). Study 1: Part 1 Items
Children were recruited from schools in a Midwest-
Item type Item
ern city. Undergraduates were recruited from the
subject pools at two large public universities. Par- Characteristic Do birds lay eggs?a
ticipants were predominantly European American Do pigs give milk to their babies?a
and from middle-income homes. Do horses grow their babies in their
tummies?
Do lions have manes?a
Materials and Procedure Do deer have antlers?
Do goats have horns?a
Part 1.. Participants evaluated the truth or falsity
Noncharacteristic Are birds girls?a
of 20 items presented in question form (e.g., Do
Are pigs girls?a
lions have manes?) in one of four semirandom orders. Are horses girls?
Participants responded by answering definitely yes, Are lions boys?a
definitely no, or a little yes, a little no. The a little yes, Are deer boys?
a little no response was included to increase the Are goats boys?a
sensitivity of the measure by creating a midpoint Filler Do tigers have stripes?
response, which allowed participants to show Do cats have tails?a
doubt about an item without completely rejecting Do kangaroos hop?
it. Answer choices corresponded to pictures of a Do cows say moo?a
thumb pointing up, down, and sideways. To moti- Do dogs have wings?
Do snakes have feet?a
vate the task, children were asked to help an alien
Do hamsters fly
learn about animals on Earth. Children responded
Do fish say woof?a
by pointing to the thumb pictures. Undergraduates
responded to written questions by circling the a
Indicates items used in Study 2.
appropriate thumb images.
Items consisted of six characteristic and nonchar-
acteristic item pairs (see Table 1). Within each pair, Part 2.. In this part, we tested participants’
the characteristic item expressed a property that is knowledge of the gender requirements for the char-
characteristic of the target kind yet present in only acteristic properties (e.g., that only male lions have
one gender (e.g., ‘‘Do lions have manes?’’). This manes). Participants were asked about 10 proper-
gender information then served as the predicate for ties: 6 characteristic properties (from Part 1) that
the corresponding noncharacteristic item (e.g., ‘‘Are apply to individuals of only one gender, 2 filler
lions boys?’’). Because the property predicated in properties that apply to individuals of both genders
each noncharacteristic item was a precondition for (e.g., both boy and girl tigers have stripes), and 2
the property predicated in the corresponding char- filler properties that do not apply to individuals of
acteristic item, characteristic and noncharacteristic either gender (e.g., neither boy nor girl dogs have
properties were roughly equivalent in prevalence wings). Participants were asked separate, sequential
(see the Adult Pretests section below). Eight filler questions about whether these properties apply to
items with clear, obvious answers were also the males and females of the species (e.g., ‘‘Do boy
included (four characteristic, four noncharacteristic; lions have manes? Do girl lions have manes?’’).
see Table 1) to screen out children who did not Question pairs were presented in one of four semi-
understand the task. The filler items expressed random orders. Whether the female or male version
properties that are also considered characteristic of the question appeared first was counterbalanced
(e.g., ‘‘Do tigers have stripes?’’) or noncharacteristic across subjects.
(e.g., ‘‘Do dogs have wings?’’) of their target kind; Participants responded by answering definitely
however, because in all cases the properties in these yes, definitely no, or a little yes, a little no. Children
filler items are present or absent in both genders pointed to indicate their answer to a second alien’s
and thus do not allow for prevalence-matched com- questions about ‘‘boy animals and girl animals.’’
parison items, these items were not included in our Undergraduates circled the appropriate thumb
central analyses. Children responded correctly to image. If participants responded incorrectly to a
the vast majority of the filler items (M = 97.3%). Part 2 question, that item pair was excluded from
Every child answered all or all but one of the filler their Part 1 data. Responses were considered
items correctly. incorrect if participants answered either of theDo Lions Have Manes? 427
questions incorrectly (e.g., saying that boy lions do
Results
not have manes or that girl lions do). To be con-
servative, the intermediate answer choice was Our central analysis involved the proportion of
counted as a negative response. Both children and definitely yes responses for the characteristic and
undergraduates knew the majority of the facts noncharacteristic items. We conducted a 2 (item
tested in Part 2 (MChildren = 4.07 of 6 possible; type: characteristic, noncharacteristic; within sub-
MUndergraduates = 4.93). ject) · 2 (age group: children, undergraduates;
Adult pretests.. To confirm that the predicates of between subjects) analysis of variance (ANOVA).
the characteristic and noncharacteristic items are The dependent variable was a proportion score
considered equally prevalent, we conducted two based on the number of times participants selected
pretests with separate groups of undergraduates. In the definitely yes response out of the total number of
the first, 16 undergraduates estimated the preva- item pairs on which they demonstrated requisite
lence of the properties (e.g., having manes, being knowledge in Part 2.
male) used in the main task. For example, partici- Results revealed the predicted main effect of
pants were told, ‘‘It is estimated that there are item type, F(1, 26) = 34.22, p < .001, gp2 = .57. As
roughly 32,000 individual lions in the world. Please shown in Table 2, both children, F(1, 13) = 11.27,
estimate what percentage of those individual lions p = .002, gp2 = .30, and undergraduates, F(1, 13)
have manes.’’ Participants estimated the character- = 24.16, p < .001, gp2 = .48, gave significantly more
istic and noncharacteristic properties to be roughly definitely yes responses for characteristic than non-
equal in prevalence, F(6, 10) = 0.39, p = .87, apply- characteristic items. (The proportion of definitely no
ing to an average of 54.3% and 49.6% of category and a little yes, a little no responses are also dis-
members, respectively. played in Table 2.) This pattern of results held for
In the second pretest, a separate group of 16 10 of 14 children, p = .012, and 11 of 14 under-
undergraduates performed a comparative judgment graduates, p = .006 (sign tests). Results also
for each item pair. They were asked, for example, revealed a nonsignificant trend toward an effect of
‘‘Which do you think there are more of? (a) Boy age group, F(1, 26) = 3.23, p = .084, gp2 = .11, with
lions; (b) Lions that have manes; (c) They are equal.’’ children tending to choose definitely yes more often
Across all item pairs, the dominant response was than undergraduates (Ms = 0.61 and 0.43, respec-
‘‘They are equal.’’ Participants selected this response tively).
on 67.7% of trials, significantly more often than Additional analyses were conducted to compare
expected by chance (33.3%), t(15) = 3.54, p = .003. the proportion of definitely yes responses against
Participants selected the characteristic response rates expected by chance (.33, Table 2). As pre-
(e.g., ‘‘Lions that have manes’’) on 6.3% of trials (sig- dicted, for the characteristic items both children,
nificantly less likely than expected by chance), t(13) = 6.20, p < .001, and undergraduates, t(13) =
t(15) = 12.84, p < .001, and the noncharacteristic 4.37, p = .001, selected the definitely yes response at
response (e.g., ‘‘Boy lions’’) on 26.0% of trials (at rates greater than expected by chance. This was not
chance levels), t(15) = 0.72, p = .49. Overall, pretest the case for the noncharacteristic items. Children,
results confirmed that adults consider the character- t(13) = 1.41, p = .18, and undergraduates, t(13) =
istic and noncharacteristic properties to be roughly 1.24, p = .24, selected the definitely yes response for
equal in prevalence. these items at chance levels.
Table 2
Mean Proportion (Standard Deviation) of Responses by Response Type, Age Group, and Item Type
Proportion of responses (SD)
Study Age group Item type Definitely yes A little yes, A little no Definitely no
1 Adult Characteristic .65 (.28)* .35 (.28) .00 (.00)*
Noncharacteristic .21 (.36) .78 (.35)* .01 (.04)*
Children Characteristic .76 (.26)* .17 (.24)* .07 (.19)*
Noncharacteristic .46 (.35) .47 (.37) .07 (.20)*
2 Children Characteristic .86 (.33)* .03 (.10)* .11 (.30)*
Noncharacteristic .29 (.45) .71 (.45)* .00 (.00)*
*Indicates p < .05 for comparisons against chance (.33).428 Brandone, Cimpian, Leslie, and Gelman
they were confused by the structure of these ques-
Discussion
tions (‘‘Are Xs Ys?’’). To explore this possibility, we
Study 1 addressed the question of whether tested an additional 10 children (M = 5.19 years) on
young children equate generics with quantification a similar task in which participants responded to
by comparing children’s true and false judgments questions that were structurally equivalent to the
about pairs of statements that, although matched in noncharacteristic items but varied in whether their
prevalence, vary in whether or not they are consid- correct answer was yes or no. This task included six
ered acceptable generics by adults. Results showed items each for which the correct answer was (a)
that children were more likely to accept generics definitely yes (e.g., ‘‘Are princesses girls?’’ ‘‘Are
that express characteristic than noncharacteristic daddy bears boys?’’), (b) definitely no (e.g., ‘‘Are
properties. These findings suggest that young chil- ladies boys?’’ ‘‘Are mommy ducks boys?’’), and (c)
dren do not interpret generics as statements about a little yes, a little no (e.g., ‘‘Are kids girls?’’
the number or proportion of individual category ‘‘Are baby birds boys?’’), for a total of 18 items. We
members that possess a particular property. reasoned that if children’s responses to the non-
Instead, even young children recognize that gener- characteristic items were driven by confusion with
ics make claims about kinds. the structure of these questions, then children
The argument that children do not interpret should encounter the same difficulty on this task.
generics as equivalent to quantification rests on the This was not the case. Although all the items in
finding that children were less likely to reply defi- the control task were structurally analogous to the
nitely yes to the noncharacteristic items. We argue noncharacteristic items in the main study, children
that children did so because they (a) recognize that responded appropriately on an average of 78.0% of
generics make claims about kinds and (b) do not trials. Importantly, children had no trouble
consider the noncharacteristic items to be true of responding definitely yes where appropriate, doing
their kinds. However, there may be alternative rea- so on 82.4% of items for which it was the correct
sons why children were less likely to accept the response. These data suggest that children’s low
generics that involved noncharacteristic properties. level of definitely yes responses to the noncharacter-
One possibility is that children’s responses were istic items on the central task was not due to the
influenced by the relative novelty of the noncharac- unusual structure of these items. Note that this con-
teristic stimuli. Children may be less likely to have trol task also speaks against two additional con-
heard statements expressing the noncharacteristic cerns. First, the animal items (e.g., ‘‘Are daddy
properties of the target categories than statements bears boys?’’) rule out the possibility that children
expressing their characteristic properties, which interpreted questions such as ‘‘Are lions boys?’’ to
may in turn make children less likely to agree with mean ‘‘Are lions human boys?’’ (This possibility
these less familiar items. Although a stringent test was remote anyway, as children would presumably
of this possibility would require a study with novel have favored definitely no rather than a little yes, a
categories, at least one aspect of the current study little no if they had interpreted the questions in this
suggests that novelty effects cannot account for way.) Second, this task rules out the possibility that
children’s responses. Consider the filler items in children had more trouble responding to the non-
Part 2 expressing properties that are characteristic characteristic items because they had difficulty
of both genders (e.g., ‘‘Do boy ⁄ girl tigers have dealing with relations between sets (e.g., relations
stripes?’’). It is unlikely that children have previ- between the set of lions, boys, and boy lions; see
ously heard statements expressing these properties Markman, 1989; Piaget, 1952).
(because the properties do not vary by gender A final alternative explanation we considered
and; thus, parents would be unlikely to talk about was that participants may have responded differ-
the genders separately). Nevertheless, children ently to the characteristic and noncharacteristic
responded definitely yes on these items 78.6% of the items as a result of semantic differences due to how
time. The fact that children consistently gave defi- the items were framed. All of the characteristic
nitely yes responses on questions they have likely items either used the verb to have to attribute a
not heard before casts doubt on the possibility that physical feature to the kind (e.g., ‘‘Do lions have
the novelty of the noncharacteristic stimuli led to manes?’’), or else used a verbal predicate to attribute
their low acceptance levels. a habitual action to the kind (e.g., ‘‘Do birds lay
Another possibility is that children provided eggs?’’). In contrast, all of the noncharacteristic
fewer definitely yes and more a little yes, a little no items used nominal predicates (i.e., the verb to
responses on the noncharacteristic items because be + count noun) to attribute a gender to the kindDo Lions Have Manes? 429
(e.g., ‘‘Are lions boys?’’ ‘‘Are birds girls?’’). This dif- well as of items that are not characteristic of the
ference in syntactic frames is potentially problem- kind yet also true of only one gender. However, to
atic if statements about what a kind is carry control for the possibility that the item effects
different implications than statements about what a observed in Study 1 were driven by semantic differ-
kind has or does. ences due to how the characteristic and noncharac-
There is some evidence to suggest that this might teristic items were framed (about what a kind is vs.
be the case. In particular, several studies have what a kind has or does), in this study both the char-
shown that using nominal versus verbal predicates acteristic and noncharacteristic items were framed
to describe a characteristic of an individual influ- in terms of what the kind is. For example, to match
ences judgments about the permanence of that char- the noncharacteristic item ‘‘Are lions boys?’’ the
acteristic. For example, Gelman and Heyman (1999) characteristic item ‘‘Do lions have manes?’’ was
showed that 5-year-olds judge novel personal char- replaced with ‘‘Are lions animals with manes?’’ If, as
acteristics as more stable over time and context argued, children’s responses in Study 1 were driven
when they are expressed using a nominal predicate by whether or not the predicated properties are
(e.g., ‘‘She is a carrot-eater’’) than when they are viewed as characteristic of their kinds, then children
expressed by a verbal phrase (e.g., ‘‘She eats carrots should again be more likely to endorse generics that
whenever she can’’; see also Cimpian, Arce, Mark- express characteristic than noncharacteristic proper-
man, & Dweck, 2007; Markman, 1989). Likewise, ties, even when both types of items are presented
Reynaert and Gelman (2007) showed that adults with nominal predicates using the verb to be.
judge physical and mental illnesses described using
nominal predicates (e.g., ‘‘He is a baxtermic’’ and
‘‘He is baxtermic’’) as more permanent and stable Method
than those described using verbal predicates (e.g.,
Participants
‘‘He has baxtermia’’). Thus, when describing charac-
teristics of an individual, nominal and verbal predi- Twelve children (5 males, 7 females; M =
cates seem to carry different implications. 5.10 years, SD = .47) participated. Four additional
Of particular interest here is the question of children were excluded because they did not know
whether statements about what a kind is versus any of the gender properties. The children, all of
what a kind has or does require different amounts of whom were recruited in a small Midwestern city,
statistical evidence to be accepted as true. Specifi- were predominantly European American and came
cally, given the permanence and centrality that is from a range of socioeconomic backgrounds.
implied when properties are described using nomi-
nal predicates, it may be that more statistical evi-
Materials and Procedure
dence is required to agree with a statement about
what a kind is than to agree with a statement about Part 1.. Children evaluated the truth or falsity of
what a kind has or does (see Gilson & Abelson, 12 items. Eight of the items were based on the four
1965). On this view, participants may have been characteristic and noncharacteristic item pairs with
less likely to endorse the noncharacteristic than the which children from Study 1 were most familiar
characteristic items not because of differences in (see Table 1 for a full list). In addition, there were 4
whether or not the predicated properties are filler items (2 characteristic, 2 noncharacteristic).
viewed as characteristic of their kinds, but rather Every child answered all or all but one of the filler
because greater statistical evidence is necessary to items correctly. Importantly, all items used nominal
endorse statements about what a kind is. To predicates using the verb to be (e.g., characteristic:
address this possibility, in Study 2 we examined ‘‘Are lions animals with manes?’’; noncharacteristic:
children’s responses to characteristic and nonchar- ‘‘Are lions boys?’’; filler: ‘‘Are tigers animals with
acteristic item pairs that are both presented with stripes?’’). All other aspects of the design were
nominal predicates using the verb to be. identical to Study 1.
Part 2.. Part 2 was designed to test participants’
knowledge of the gender requirements for the
characteristic properties in Part 1 (e.g., that only
Study 2
male lions have manes). This section was identical
As in Study 1, we examined children’s endorse- in structure to Part 2 of Study 1; however, only
ments of items expressing properties that are char- the four characteristic properties from Part 1 and
acteristic of the kind yet true of only one gender, as four filler items were examined. If participants430 Brandone, Cimpian, Leslie, and Gelman
responded incorrectly to a Part 2 question, that item even when the characteristic and noncharacteristic
pair was excluded from their Part 1 data. Children items were framed in the same way, children were
demonstrated knowledge of the gender require- still significantly more likely to endorse generics
ments for roughly half of the properties tested that express characteristic than noncharacteristic
(M = 1.83 of 4 possible). (It is unclear why children properties. Together with the results of Study 1,
did not respond appropriately to more of the Part 2 these findings lend further support to our claim
items. The most common error was choosing defi- that when deciding on the truth value of a generic
nitely yes in response to questions about both male statement, what matters most is not the statistical
and female category members [M = 1.38 of 4 possi- prevalence of the property, but rather whether or
ble], potentially suggesting that these participants, not that property is viewed as characteristic of the
who were somewhat younger than those in Study kind.
1, had not yet learned how males and females differ
on some of the characteristic properties.)
General Discussion
Results
This article explored whether young children
Our central analysis involved the proportion of understand generic meaning as distinct from quan-
definitely yes responses for the characteristic and tification. We compared children’s responses to
noncharacteristic items. We conducted an ANOVA questions about properties that, although roughly
with item type (characteristic, noncharacteristic) as equivalent in prevalence (each applying to approxi-
a within-subject variable. The dependent variable mately 50% of kind members), differed in whether
was a proportion score based on the number of or not they are considered by adults to be generi-
times participants selected the definitely yes cally true of the kind (e.g. ‘‘Do lions have manes?’’
response out of the total number of item pairs on or ‘‘Are lions animals with manes?’’ vs. ‘‘Are lions
which they demonstrated requisite knowledge in boys?’’). As predicted, children were more likely to
Part 2. Results revealed the predicted main effect of accept generics that express characteristic than
item type, F(1, 11) = 17.33, p = .002, gp2 = .61. As noncharacteristic properties. These data expand
shown in Table 2, children gave significantly more upon the growing literature concerning children’s
definitely yes responses for characteristic than non- comprehension of generics (e.g., Cimpian & Mark-
characteristic items. This pattern held for 8 of 12 man, 2008; Gelman & Bloom, 2007; Gelman &
children, p = .008 (sign test). Raman, 2003; Hollander et al., 2002) in two ways.
Additional analyses were conducted to compare First, our findings suggest that children recognize
the proportion of definitely yes responses against that generic facts can be considered true even if
rates expected by chance (.33; see Table 2). As pre- they are not true of all or even most members of a
dicted, for the characteristic items children selected category (e.g., ‘‘Lions have manes’’). Second, our
the definitely yes response at rates greater than data suggest that children recognize that some gen-
expected by chance, t(11) = 5.54, p < .001. In eric statements can be considered untrue even if
contrast, children selected the definitely yes response they express properties that are fairly frequent (e.g.,
for the noncharacteristic items at chance levels, ‘‘Lions are boys’’). Overall, the data presented here
t(11) = )0.30, p = .77. provide the first direct evidence that, like adults,
young children do not interpret generics as state-
ments about the number or proportion of individ-
Discussion
ual category members that possess a particular
The purpose of this study was to evaluate the property. Our data reveal instead that, even for
possibility that participants were more likely to young children, generics make claims about kinds.
agree with the characteristic than the noncharacter- These findings also speak to an ongoing debate
istic items in Study 1 because of semantic differ- about the nature of children’s concepts. There is
ences due to how these items were framed (i.e., as now substantial evidence to suggest that adults’
claims about what a kind has or does versus claims concepts cannot be characterized by statistical
about what a kind is). Thus, in Study 2, children information alone; they are better characterized as
were asked to judge characteristic and noncharac- theory-like explanatory structures that incorporate
teristic items that were both framed in terms of not only knowledge about shared features (includ-
what the kind is (e.g., ‘‘Are lions animals with ing nonobvious ones) but also causal–explanatory
manes?’’ vs. ‘‘Are lions boys?’’). We found that links between those features (e.g., Ahn, Flanagan,Do Lions Have Manes? 431 Marsh, & Sanislow, 2006; Murphy, 2002; Rips & because barking is part of what it means to be a Collins, 1993). The data presented here are consis- dog). tent with the notion that the concepts of young chil- Which properties are linked to their kinds in this dren also consist of more than just statistical principled way? A number of candidate property regularities (see also Gelman, 2003; Gopnik & types have been proposed. For example, properties Schulz, 2004; Keil, 2006). Young children’s interpre- may be predicated generically if they fit dimensions tation of generic sentences reveals that they treat specified by overhypotheses (e.g., each kind of ani- certain categories, including the animal categories mal has a characteristic diet, sound, mode of repro- examined here, as abstract generic kinds. duction; Shipley, 1993; see Leslie, 2007, 2008). Of course, both statistical information and Relatedly, properties that fit with people’s naı̈ve abstract conceptual knowledge likely play a role in causal theories about the relevant kinds have been children’s reasoning about kinds (e.g., Prasada & shown to be accepted when predicated in generic Dillingham, 2006, 2009). In fact, the current experi- form (Cimpian, Gelman, et al., 2010; Gelman & ments provide some evidence that both children Bloom, 2007). Leslie (2007, 2008) has proposed that and adults also recognize and consider the role properties that are especially striking or dangerous of prevalence information in evaluating the truth (e.g., ‘‘Sharks attack swimmers’’) may also be pred- of generic statements. Consider participants’ icated generically if they are viewed as part of a responses to the noncharacteristic items (e.g., ‘‘Are kind’s natural disposition (see also Cimpian, Bran- lions boys?’’). Both children and adults avoided the done, et al., 2010). However, as Leslie (2007, 2008) definitely no response on these items in favor of the points out, a property cannot be correctly predi- less definitive a little yes, a little no answer choice. cated of a kind if there is an equally salient, posi- This response may reflect participants’ awareness tive alternative property that applies to other that the noncharacteristic properties are true of at members of the kind. For example, ‘‘Lions are least some individuals within the target kinds. By boys’’ may be considered false because female lions selecting the a little yes, a little no response, partici- possess an equally salient alternative property (i.e., pants were able to convey their knowledge of the being female). In contrast, ‘‘Lions have manes’’ prevalence of the noncharacteristic properties while may be considered true because female lions lack still denying that these properties characterize the this property and do not exhibit a salient competing kind. This pattern of results is consistent with the feature. Overall, these proposals begin to address view that although children do not rely on preva- the important question regarding which sorts of lence considerations alone when evaluating state- properties get linked to their categories in princi- ments about kinds, they nonetheless do not ignore pled ways, which get linked to their categories via the statistical evidence. An important question for prevalence alone, and why. Further work, includ- future research is how children’s statistical learning ing developmental research, on these questions is mechanisms (e.g., Saffran, Aslin, & Newport, 1996) needed. In particular, research on how children interact with their abstract conceptual knowledge learn which properties are principled versus not and their finely tuned causal reasoning abilities and on the potential role of parental input in this (e.g., Gopnik & Schulz, 2007) to support conceptual learning process (e.g., Gelman, Coley, Rosengren, development (see Sobel & Kirkham, 2007; Tenen- Hartman, & Pappas, 1998; Gelman, Taylor, & baum, Griffiths, & Kemp, 2006). Nguyen, 2004) may be especially informative. An additional important question this work raises To conclude, our findings demonstrate that for concerns the nature of the differences between prop- children, as for adults (Cimpian, Brandone, et al. erties that can and cannot be truthfully predicated 2010; Cimpian, Gelman, et al., 2010; Khemlani of a kind. The question of what makes a property et al., 2007; Khemlani et al., 2009), generic meaning generically true of a kind does not yet have a precise does not reduce to considerations of how many answer. According to one view (Prasada & Dilling- individuals have the relevant property. Even when ham, 2006, 2009), there are two circumstances under children know how prevalent the relevant proper- which it may be legitimate to predicate a property of ties are among category members, they do not use an entire kind: (a) when a property is highly preva- this knowledge as the sole basis for evaluating the lent among kind members and (b) when a property truth of generic statements. Rather, considerations has a ‘‘principled connection’’ with the kind—that about whether generically predicated properties are is, when instances possess the feature by virtue of characteristic of their kind play a deciding role in being the kinds of things they are (e.g., dogs bark children’s reasoning about generic sentences.
432 Brandone, Cimpian, Leslie, and Gelman
References Gelman, S. A., & Heyman, G. D. (1999). Carrot-eaters and
creature-believers: The effects of lexicalization on chil-
Ahn, W., Flanagan, E. H., Marsh, J. K., & Sanislow, C. A. dren’s inferences about social categories. Psychological
(2006). Beliefs about essences and the reality of mental Science, 10, 489–493.
disorders. Psychological Science, 17, 759–766. Gelman, S. A., & Raman, L. (2003). Preschool children
Brandone, A. C., & Gelman, S. A. (2009). Differences in use linguistic form class and pragmatic cues to inter-
preschoolers’ and adults’ use of generics about animals pret generics. Child Development, 74, 308–325.
and artifacts: A window onto a conceptual divide. Cog- Gelman, S. A., Taylor, M. G., & Nguyen, S. (2004).
nition, 110, 1–22. Mother–child conversations about gender: Understand-
Carey, S. (1985). Conceptual change in childhood. Cam- ing the acquisition of essentialist beliefs. Monographs of
bridge, MA: MIT Press. the Society for Research in Child Development, 69(1, Serial
Carey, S. (2009). The origin of concepts. New York: Oxford No. 275).
University Press. Gelman, S. A., Waxman, S., & Kleinberg, F. (2008). The
Carlson, G. N. (1977). A unified analysis of the English role of representational status and item complexity in
bare plural. Linguistics and Philosophy, 1, 412–456. parent–child conversations about pictures and objects.
Carlson, G. N., & Pelletier, F. J. (Eds.). (1995). The generic Cognitive Development, 23, 313–323.
book. Chicago: University of Chicago Press. Gilson, C., & Abelson, R. P. (1965). The subjective use of
Chambers, C. G., Graham, S. A., & Turner, J. N. (2008). inductive evidence. Journal of Personality and Social Psy-
When hearsay trumps evidence: How generic language chology, 2, 301–310.
guides preschoolers’ inferences about unfamiliar Gopnik, A., & Meltzoff, A. N. (1997). Words, thoughts,
things. Language and Cognitive Processes, 23, 749–766. and theories. Cambridge, MA: Bradford Books ⁄ MIT
Cimpian, A., Arce, H. C., Markman, E. M., & Dweck, C. Press.
S. (2007). Subtle linguistic cues affect children’s motiva- Gopnik, A., & Schulz, L. (2004). Mechanisms of theory
tion. Psychological Science, 18, 314–316. formation in young children. Trends in Cognitive Sci-
Cimpian, A., Brandone, A. C., & Gelman, S. A. (2010). ences, 8, 371–377.
Generic statements require little evidence for accep- Gopnik, A., & Schulz, L. (Eds.). (2007). Causal learning:
tance but have powerful implications. Cognitive Science, Psychology, philosophy, and computation. New York:
34, 1452–1482. Oxford University Press.
Cimpian, A., Gelman, S. A., & Brandone, A. C. (2010). Hollander, M. A., Gelman, S. A., & Star, J. (2002). Chil-
Theory-based considerations influence the interpreta- dren’s interpretations of generic noun phrases. Develop-
tion of generic sentences. Language and Cognitive Pro- mental Psychology, 38, 883–894.
cesses, 25, 261–276. Keil, F. (1989). Concepts, kinds, and cognitive development.
Cimpian, A., & Markman, E. M. (2008). Preschool Cambridge, MA: Bradford Book ⁄ MIT Press.
children’s use of cues to generic meaning. Cognition, Keil, F. C. (2006). Explanation and understanding. Annual
107, 19–53. Review of Psychology, 57, 227–254.
Cimpian, A., Meltzer, T. J., & Markman, E. M. (2011). Khemlani, S., Leslie, S. J., & Glucksberg, S. (2009). Gener-
Preschoolers’ use of morphosyntactic cues to identify ics, prevalence, and default inferences. Proceedings of
generic sentences: Indefinite singular noun phrases, the 31st Annual Conference of the Cognitive Science Society.
tense, and aspect. Child Development, 82, 1561–1578. Austin, TX: Cognitive Science Society.
Colunga, E., & Smith, L. B. (2005). From the lexicon to Khemlani, S., Leslie, S. J., Glucksberg, S., & Rubio-Fernan-
expectations about kinds: A role for associative learn- dez, P. (2007). Do ducks lay eggs? How humans inter-
ing. Psychological Review, 112, 347–382. pret generic assertions. Proceedings of the 29th Annual
Gelman, S. A. (2003). The essential child: Origins of essentialism Conference of the Cognitive Science Society. Nashville, TN:
in everyday thought. Oxford, UK: Oxford University Press. Cognitive Science Society.
Gelman, S. A., & Bloom, P. (2007). Developmental Leslie, S. J. (2007). Generics and the structure of the mind.
changes in the understanding of generics. Cognition, Philosophical Perspectives, 21, 375–405.
105, 166–183. Leslie, S. J. (2008). Generics: Cognition and acquisition.
Gelman, S. A., & Brandone, A. C. (2010). Fast-mapping Philosophical Review, 117, 1–49.
placeholders: Using words to talk about kinds. Lan- Markman, E. M. (1989). Categorization and naming in chil-
guage Learning and Development, 6, 223–240. dren: Problems in induction. Cambridge: Bradford Book ⁄
Gelman, S. A., Coley, J. D., Rosengren, K., Hartman, E., & MIT Press.
Pappas, A. (1998). Beyond labeling: The role of mater- Murphy, G. L. (2002). The big book of concepts. Cambridge,
nal input in the acquisition of richly-structured catego- MA: MIT Press.
ries. Monographs of the Society for Research in Child Piaget, J. (1952). The origins of intelligence in children. New
Development, 62(1, Serial No. 253). York: International University Press.
Gelman, S. A., Goetz, P. J., Sarnecka, B. S., & Flukes, J. Prasada, S. (2000). Acquiring generic knowledge. Trends
(2008). Generic language in parent–child conversations. in Cognitive Sciences, 4, 66–72.
Language Learning and Development, 4, 1–31.Do Lions Have Manes? 433 Prasada, S., & Dillingham, E. M. (2006). Principled and model. Journal of Experimental Psychology: General, 133, statistical connections in common sense conception. 166–188. Cognition, 99, 73–112. Sloutsky, V. M., Kloos, H., & Fisher, A. V. (2007). When Prasada, S., & Dillingham, E. M. (2009). Representation of looks are everything: Appearance similarity versus principled connections: A window onto the formal kind information in early induction. Psychological Sci- aspect of common sense conception. Cognitive Science, ence, 18, 179–185. 33, 401–448. Smith, L. B., Jones, S. S., & Landau, B. (1996). Naming in Reynaert, C. C., & Gelman, S. A. (2007). The influence of young children: A dumb attentional mechanism? Cog- language form and conventional wording on judg- nition, 60, 143–171. ments of illness. Journal of Psycholinguistic Research, 36, Sobel, D. M., & Kirkham, N. Z. (2007). Interactions 272–295. between causal and statistical learning. In A. Gopnik & Rips, L. J., & Collins, A. (1993). Categories and resem- L. E. Schulz (Eds.), Causal learning: Psychology, philoso- blance. Journal of Experimental Psychology: General, 122, phy, and computation (pp. 139–153). New York: Oxford 468–486. University Press. Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statis- Tenenbaum, J. B., Griffiths, T. L., & Kemp, C. (2006). The- tical learning by 8-month-olds infants. Science, 274, ory-based Bayesian models of inductive learning and 1926–1928. reasoning. Trends in Cognitive Sciences, 10, 311–318. Shipley, E. F. (1993). Categories, hierarchies, and induc- Wellman, H. M., & Gelman, S. A. (1998). Knowledge tion. Psychology, Learning, and Motivation, 30, 265–301. acquisition. In D. Kuhn & R. Siegler (Eds.), Handbook of Sloutsky, V. M., & Fisher, A. V. (2004). Induction and cat- child psychology: Vol. 2. Cognition, perception, and lan- egorization in young children: A similarity-based guage (4th ed., pp. 523–573). Hoboken, NJ: Wiley.
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