Children’s Comprehension of Implicit Messages to Interpret Ambiguous Requests

by

Ariana Christina Simone

A thesis submitted in conformity with the requirements for the degree of Master of Arts, School & Clinical Child Psychology

Department of Applied Psychology & Human Development

Ontario Institute for Studies in Education University of Toronto

© Copyright by Ariana Christina Simone 2018

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Children’s Comprehension of Implicit Messages to Interpret Ambiguous Requests

Ariana Christina Simone

Master of Arts, School & Clinical Child Psychology Department of Applied Psychology & Human Development

Ontario Institute for Studies in Education University of Toronto

2018

Abstract The current study explored young children’s ability to use past linguistic information to make

pragmatic inferences in a referentially ambiguous situation. Eighty-three 2.5-year-old and 3-

year-old children heard a speaker convey her preference for an absent object, using either

negative (i.e., “I do not like ducks”) or affirmative (i.e., “I like ducks”) sentences. When two

objects become perceptually present (i.e., duck and turtle), the speaker gave an ambiguous

request (“Can you give one to me?”). Results showed that three-year-old children were

successful in using the speaker’s past affirmative information to reason about which object she

desired, however, inferencing abilities were hindered following negative sentences. Two and a

half-year-old children did not succeed with neither affirmative nor negative sentences. This work

provides important insight into how young children interpret implicit verbal messages to make

inferences about another person’s communicative request.

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Acknowledgements I would like to give my greatest thanks to Dr. Patricia Ganea for her guidance and efforts in the

design and completion of this study. I would also like to express my gratitude to Dr. Chloe

Hamza, for her criticisms and support have only made my research better. I also wish to thank

Hilary Sweatman and Linke Yu for their time and efforts spent assisting with participant

recruitment and stimuli design. Lastly, a big thank you goes to the members of the Language and

Learning Lab for their guidance and encouragement.

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Table of Contents Acknowledgements ......................................................................................................... iii Table of Contents ............................................................................................................ iv List of Tables .................................................................................................................... v List of Figures ................................................................................................................. vi 1 Introduction .............................................................................................................. 1

1.1 Inferencing Using Nonlinguistic vs. Linguistic Information ................................ 1 1.2 Desire Reasoning ............................................................................................. 3 1.3 Understanding of Verbal Negation .................................................................... 5 1.4 Desire Reasoning through Verbal Negation ..................................................... 6 1.5 Current Study.................................................................................................... 7

2 Methods ................................................................................................................... 8 2.1 Participants ....................................................................................................... 8 2.2 Measures and Procedure ................................................................................. 9

2.2.1 Main Experimental Task ................................................................................ 9 2.2.1.1 Familiarization Phase .............................................................................. 10 2.2.1.2 Test Phase .............................................................................................. 10 2.2.2 Verbal Negation Task .................................................................................. 11 2.2.2.1 Familiarization & Pre-Test ....................................................................... 11 2.2.2.2 Teaching Phase ....................................................................................... 11 2.2.2.3 Test Phase .............................................................................................. 12 2.2.3 NIH Toolbox Picture Vocabulary Test (TPVT) ............................................. 13 2.2.4 MacArthur Bates Communicative Development Inventories ....................... 13

2.3 Coding ............................................................................................................ 13 3 Results ................................................................................................................... 14

3.1 Main Analyses ................................................................................................ 14 3.1.1 Three-year-olds ........................................................................................... 15 3.1.2 Two and a half-year-olds ............................................................................. 15 3.1.3 Age Group Comparison .............................................................................. 15

3.2 Control Analyses............................................................................................. 16 3.2.1 Child’s Preference ....................................................................................... 16 3.2.2 Verbal Negation Comprehension ................................................................ 16

4 Discussion ............................................................................................................. 17 5 Conclusion ............................................................................................................. 21 References.................................................................................................................... 22

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List of Tables

1 Table 1: Mean Age and Age-adjusted Receptive Language (TPVT) Standard Score by Condition and Gender, 3-year-old sample…………………………….…25

2 Table 2: Mean Age and Age-adjusted Expressive Language (CDI) Score by Condition and Gender, 2-year-old sample……………………………………...…..26

3 Table 3: Correct and Incorrect Object Selections in Main Experimental Task, by Age and Condition………………………………….…………………………..….27

4 Table 4: Children’s Reported Object Preference by Age and Condition…………28

5 Table 5: Children’s Correct Responses on Verbal Negation Comprehension Task, by Trial Type…………………………………………………………………….29

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List of Figures

1 Figure 1. Stimuli used in the main experimental task………………...……………30 2 Figure 2. Stimuli used in the verbal negation comprehension task……..………..31

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1 Introduction

The ability to make pragmatic inferences is a crucial feature of mature communication. Explicit

messages are not always conveyed in conversation, and it is often necessary to consider past

linguistic information that was shared between individuals to interpret messages in conversation.

For example, if you receive the ambiguous request “Can you hand it to me?”, implying that the

speaker is wanting a particular object, you must use past information shared between you both to

infer which object she is looking to receive. In this instance, the speaker may have previously

said something like “Where did my wallet go?”, and subsequently “There it is!”, which gives

context to the later ambiguous request “Can you hand it to me?”. This ability to use past

information from a shared experience is a crucial pragmatic skill that must be intact to make

appropriate inferences about others’ referential intents (Clark & Marshall, 1981). This ability is

an important milestone of pragmatic competence, signalling the presence and use of inferential

skills during communication. In the current study, we examined whether preschoolers can use

previously shared information about a speaker’s desire to disambiguate her intended referent.

1.1 Inferencing Using Nonlinguistic vs. Linguistic Information

Previous research has demonstrated that infants as young as one year of age are capable of using

nonverbal/non-linguistic information to make inferences about an individual’s intended referent

(e.g., Akhtar, Carpenter & Tomasello, 1996; Baldwin, 1991, 1993; Repacholi & Gopnik, 1997;

Tomasello, Strosberg, & Akhtar, 1996). For example, Tomasello and Haberl (2004) tested 12-

and 18-month-old infants who played with two adults and two toys. After a few minutes, one

adult left the room while a third and novel toy was introduced. When this adult returned, she

looked at all three toys aligned on a tray, and showed great affective excitement (i.e., smiling,

saying “Wow! Cool!”). This adult then asked the infant the ambiguous question, “Can you give

it to me?”. Infants at both ages successfully handed the adult the novel toy, demonstrating their

ability to solve the referential ambiguity by thinking back to which toys the adult had already

interacted with, and which one was novel and exciting (Tomasello & Haberl, 2004).

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A smaller body of research has investigated infants’ ability to use past linguistic information to

make similar inferences, and has consistently shown that this skill develops slightly later on.

Ganea and Saylor (2007) demonstrated that children at 15-months of age can use linguistic

information from shared communication to make inferences about a speaker’s ambiguous

request for an object. A search paradigm was used in which infants heard an experimenter

mention an absent object (i.e., telephone) several times while searching around a room (i.e., “I

really want to find the telephone! Can you help me find the telephone?”). When the experimenter

subsequently brought the child into a new room, there were two objects presented (i.e., telephone

and shoe). The child was given the ambiguous request, “Can you give it to me?”. To be

successful in this task, infants had to consider past speech information and infer that what the

speaker desired was the object she had previously spoken about. By 15 months, infants were

successful in this task, when the ambiguous request came soon after the relevant linguistic

information was encoded. When a small delay was inserted between the time the information

was heard and the request, only 18-month-olds were able to reliably use the past linguistic

information to disambiguate the request. This demonstrates some limitation on infants’ ability to

use information from memory to interpret a person’s communicative request.

A limitation noted by Ganea and Saylor (2007) is that infants may be solving this ambiguous

referential task without necessarily making an inference about the speaker’s mental state.

Children might be selecting an object merely based on the label they heard multiple times (i.e.,

telephone), and using a mapping strategy to match this label to the object they see later on. In a

second study where the request was made by a different person than the one who labelled the

objects initially, children were selecting objects at chance, demonstrating that they were not

using the simpler mapping strategy in this case. However, it is still possible that in the situation

where the ambiguous request was made by the same person who also labelled the objects

previously, the children may simply rely on this simpler strategy without making any inferences

about the person’s mental state.

One way to determine whether children make inferences about the speaker’s intended referent by

considering their mental state is by having an ambiguous situation where the language they hear

about the object is negative. In such case, the negative language associated with the object label

they hear will imply that the experimenter does not want the mentioned object. For example, if a

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child hears “I do not like trucks”, and is then presented with a truck and a doll while hearing the

same experimenter say “Can you give one to me?”, can young children reason that the item the

speaker should want is the one they have not heard her talk about (i.e., in this case, the doll)? A

simple mapping reasoning strategy in this case would not lead to successful performance, as the

child should select the object that the experimenter did not previously mention. Thus, the current

study examines whether young children can use past linguistic information about and

individual’s desire to determine what she wants, particularly when the information is expressed

through negation.

The task used in the current study introduces information about a person’s dislike for one type of

object through verbal negation (i.e., “I do not like X”), and it requires the children to make an

inference about that person’s desire when she subsequently makes an ambiguous request for an

object. This task is more cognitively demanding than Ganea and Saylor (2007), as children now

need to be able to understand 1) other people’s verbally conveyed desires, and 2) negation

language. Therefore, the target age of the current study was chosen as 2.5- and 3.5-years-old to

ensure that children have no difficulty with these aspects of the paradigm.

1.2 Desire Reasoning

Children in the current study had to be at an age where they could successfully reason about

other people’s mental states and linguistically conveyed desires. There is increasing evidence

that children’s understanding of most mental states emerges early in the second year of life (e.g.,

Behne, Carpenter, Call, & Tomasello, 2005; Liszkowski, Carpenter, & Tomasello, 2008; Vaish,

Hepach & Grossmann, 2018), including the ability to reason about others’ desires. A classic

experiment by Repacholi and Gopnik (1997) provides early empirical evidence that children as

young as 18 months can engage in some form of desire reasoning, using affective cues (i.e.,

disgust vs. satisfaction facial expressions) as their source of information. This study required the

infants to predict which type of food the experimenter would desire after receiving the affective

information. Fourteen-month-old infants responded egocentrically, offering the food they

themselves preferred. Conversely, eighteen-month-olds made appropriate inferences, even when

the experimenter's desire differed from their own (Repacholi & Gopnik, 1997). However, studies

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using language to communicate a person’s preference find later success in children’s ability to

make inferences about another individual’s desire.

In a study by Saylor and Troseth (2006), children had to use previous verbal expressions of

desire to determine the meaning of a novel object label. The paradigm tested 2.5 and 3-year-old

children by highlighting, through language, the experimenter’s preference for one particular toy.

The experimenter either offered a preference that coincided or conflicted with the child’s own

preference. Children were later presented with novel stimuli while an experimenter asked for one

object using a novel label (i.e., “Can you give me the dax so I can play with it?”). Results

showed that 3-year-old children, but not 2.5-year-old children, could map labels onto referents

solely using verbal desire information. This result highlights children’s ability to use information

about desires for word learning purposes during the preschool period. The results also provide

evidence that when children are expected to reason about desires conveyed verbally, it is not

until age 3 that they show reliable performance (e.g. Saylor & Troseth, 2006).

The paradigm used by Saylor and Troseth (2006) had children hear both affirmative and negative

desire information towards a set of objects. That is, the experimenter would first ask the children

which of two novel items they themselves preferred, and then either agree with the child by

verbally stating that she also likes that toy and dislikes the other toy, or disagree with the child

by saying that she likes the other toy, and dislikes the toy that the child chose. A more

challenging task, as introduced by Cassidy and colleagues (2005), gives solely affirmative or

solely negative desire information, such as “She likes X”, and then asks the child to infer which

object she would want (i.e., object X). This type of task requires children to make inferences

about other’s mental states, as the preference is not always specifically highlighted. As such,

Cassidy and colleagues (2005) tested 3-year-olds’ ability to predict a character’s behavior based

on the verbally expressed desire. In this task, participants were first asked to choose which of

two stickers they preferred, then listened to a story where a character explicitly stated his or her

like/dislike towards one of two stickers. Children were subsequently required to predict which

sticker this character would choose. Results demonstrated that by age 3, children can infer that if

someone likes a type of activity (expressed verbally), they would want to engage in that activity.

Most importantly, 3-year-olds could correctly infer a character’s choice even when that choice

was different from their own preference (Cassidy et al., 2005). This finding has been replicated

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using similar paradigms with 3-year-olds (e.g., Rakoczy, Warneken, & Tomasello, 2007;

Schuhmacher & Kärtner, 2016), demonstrating that by age 3, children can accurately reason for a

desired outcome from two mutually exclusive perspectives. Earlier research suggested that older

2-year-olds can use linguistic information about preference to guide inferences about a

character’s desire with some accuracy (Wellman & Woolley, 1990), however, more recent

evidence has shown that performance improves following children’s third birthdays (Saylor &

Troseth, 2006).

1.3 Understanding of Verbal Negation

The current study required children to have mature comprehension of verbal negation, and to use

negation language to reason by elimination. Reasoning by elimination, or the process of

becoming increasingly certain of an answer as other possibilities are eliminated, is a form of

inferencing that is necessary to be successful in the current study. For example, when an

outcome is limited to two possibilities, A or B, knowing that the solution is not A indicates that it

must be B. This ability has been investigated in young children (e.g. Call & Carpenter, 2001;

Mody & Carey, 2016) in paradigms where a child is asked to determine the location of a target

object between several hiding locations, when given perceptual information (i.e., shown that one

or more locations are empty). Children have shown to be successful in this type of task by 20

months (Feiman, Mody, Sanborn & Carey, 2017). However, a more complex task involves the

use of verbal negation to hint at the location of a hiding object.

Only few studies have investigated young children’s ability to use input in the form of verbal

negation (i.e., “The food is not in this cup”) to reason by elimination. English speaking infants

are reliable users of “no” and “not” in their own speech for the purpose of denial (i.e., “Do you

want to go to sleep?” “No”) by around 18 months of age (Pea, 1980; Thornton & Tesan, 2013).

However, they may not be able to use verbal negation to reason by elimination until much later

(Kim, 1985; Feiman, Mody, Sanborn & Carey, 2017). Mascaro and Sperber (2009) tested 3- and

4-year-old children’s ability to reason through verbal negation by presenting them with two

potential hiding locations for an object and giving them the language information they needed to

determine its location (i.e., “The sweet is not in the green box”). Children in both age groups

were highly successful in this task, indicating that this deductive inferencing ability emerges by

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age 3. Recent research by Feiman and colleagues (2017) used a similar search paradigm with

younger children aged 20, 24, and 27 months. Similar to Mascaro and Sperber (2009), children

searched for an object after hearing either an affirmative or a negative verbal phrase. Results

demonstrated that children in all age groups performed well in affirmative trials of this task,

however only 27-month-old infants robustly succeeded in negative trials. It is unsurprising that

affirmative trials are simpler for young children, as the child does not need to make the

additional step of negating a representation of where the ball is, nor inhibit attention to the

container they have heard named. It is clear that the ability to reason through elimination through

verbal propositional phrases, such as, “The ball is not in the bucket”, emerges early in the second

year of life (e.g., Feiman, Mody, Sanborn & Carey, 2017).

1.4 Desire Reasoning through Verbal Negation

To our knowledge, only one study has explored young children’s ability to use verbal negation to

make an inference about what another individual desires. In this experiment by Schulze,

Grassmann, and Tomasello (2013), young 3-year-old children were required to solve a speaker’s

communicative intent by listening to statements about personal likes and dislikes that indirectly

conveyed that the experimenter wanted to play with a particular object. In this design, there were

two experimenters (E1 and E2). E1 introduced two new toys and verbally labelled them (i.e.,

“Here I have a lion and an elephant”), and then invited the child to share one of the toys with E2

(i.e., “Let’s give [E2] the elephant”). E2 responded to these proposals in either a positive (i.e., “I

find elephants good”) or negative (i.e., “I do not find elephants good”) way. After hearing this

communication, the child was required to select a toy to give E2. Results revealed that 3-year-

olds were only successful in this task when E2’s verbal information matched E1’s proposal (e.g.

E1 wants to give E2 elephant, E2 expresses that she finds elephants good). However, when E2’s

expression did not match the intent of E1’s proposal (e.g., E1 wants to give E2 elephant, E2

expresses that she does not find elephants good), children’s object choice did not exceed chance

levels.

A limitation noted by Schulze and colleagues (2013) was that these findings may be a result of

the child wanting to please both experimenters, thus being torn over which playmates’

instructions to follow. To eliminate this conflict, a second study had the children observe E1 ask

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E2 if she would like to be handed a certain object (i.e., “Should [child] give you the elephant?”).

E2 stated her preference for the objects in the same way as in Study 1 (i.e., “I do not find

elephants good”). The authors speculated that this wording (i.e., posing as a question rather than

a demand) removed the conflict between the experimenters. In this version of the task, children

were able to select the appropriate object at above chance levels in all conditions, however

children still performed marginally better when E1’s object suggestion matched E2’s verbal

information. The authors concluded that 3-year-old children are able to incorporate solely verbal

communicative information to make relevant inferences about what another individual wants.

It is possible that even in the second study by Schulze et al. (2013), children still experienced

conflict in which E1 suggested handing E2 a certain object, and E2 followed by saying she did

not like that object. Although this is certainly less conflicting than Study 1, the children may

have still been wanting to please both playmates. Therefore, the current study will eliminate the

use of a second experimenter to avoid such conflict. In addition, the current study will make the

task more relevant to day-to-day life by incorporating absent reference comprehension, as

children often hear desire information without the perceptual presence of the objects they are

being told about.

1.5 Current Study

The current study tested children around their third birthday, when they were expected to

comprehend verbal negation statements and be able to reason about others’ mental states and

linguistically conveyed desires (e.g., Feiman, Mody, Sanborn & Carey, 2017; Cassidy et al.,

2005). To control for verbal negation comprehension, the current study included an explicit

verbal negation measure. In addition, the current study aimed to eliminate the possibility of

conflicting desires by using two stimuli that are equal in size and attractiveness, and for which

pilot testing revealed that children prefer them at equal rates. The ability to reason about verbally

conveyed desires that differ from one’s own has been shown to emerge around age 3, so the

current study also tested older 2-year-olds as this paradigm uses two equally attractive stimuli,

which reduces the interference of children’s own preference and the task difficulty.

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In the main task, children were given verbal information about an experimenter’s like or dislike

towards one particular toy. This verbal information was presented in the absence of any toys.

When two toys were then presented to the child with the ambiguous question “Can you give one

to me?”, the child was required to use previous verbal information to inform their object

selection. Since existing literature has found that young children understand the link between an

explicitly stated desire for an object and the corresponding object choice (e.g. Fawcett &

Markson, 2010; Saylor & Troseth, 2006; Wellman & Woolley, 1990), we used sentences stating

personal likes and dislikes that indirectly hinted at the experimenter’s preferred toy.

Thus, the current study tested 83 2.5- and 3-year-olds to answer the following questions: 1) Can

young children use desire information to make pragmatic inferences in a referential

communication paradigm? 2) Does hearing linguistic desire information in the form of verbal

negation hinder young children’s’ inferencing ability? In line with the findings of Ganea and

Saylor (2007), we hypothesized that children from both age groups will successfully infer the

speaker’s intended referent after hearing affirmative information about her preference. When

hearing negative information, we expected an age difference, with 3-year-olds being more likely

than 2-year-olds to infer a person’s desired object. This age difference was suspected as the type

of inferential reasoning process involved in processing negative information is more demanding.

2 Methods

2.1 Participants Children included in the study were required to be typically developing, fluent English language

users. Participant children were recruited only if they heard and used English as their primary

language at home (at least 50% of the time). The majority of participants came from

White/Caucasian middle- to high-class families. Children were collected from a database of

parents who had voluntarily given their information to be contacted for participation in research

studies.

The final sample included 83 young children in two age groups: 39 old 2-year-olds (range: 30.1

– 34.9 months, M = 32.0 months, 18 female), and 44 young 3-year-olds (range: 36.2 – 43.3

months, M = 38.8 months, 22 female). This sample size was chosen based on the previous

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research on which the current study builds, specifically Ganea and Saylor, 2007. Data from an

additional 22 participants were excluded for failing to meet the language threshold (2 y/o = 4,

3y/o = 2), for not passing a colour identification pre-test (three 2-year-olds, two 3-year-olds),

failing (score of 0/2) the negative trials of the verbal negation control measure (six 2-year-olds,

three 3-year-olds), parental interference (one 2-year-old, one 3-year-old), right-side selection

bias (one 2-year-old, one 3-year-old), and for noncompliance with task instructions after multiple

prompting attempts (one 2-year-old, one 3-year-old).

2.2 Measures and Procedure

All children included in the sample were tested in a large experimenting room with a built-in

camera facing the child to record the session. In all tasks, the child and experimenter sat at a

child-sized round table, approximately one metre in diameter.

All 3-year-old children participated in each of the three types of task: (1) main experimental task,

(2) verbal negation task, (3) NIH Toolbox Picture Vocabulary Test (TPVT). The main task,

where the children searched for the hidden ducks and turtles, was always conducted first. The

order of the other two tasks (verbal negation task and TPVT) was counterbalanced across

participants. The 2.5-year-old children completed (1) main experimental task, and (2) verbal

negation task, respectively. 2.5-year-old children’s vocabularies were assessed by having the

child’s parent/caregiver complete the MacArthur Bates Communicative Development

Inventories (CDI), Level III.

2.2.1 Main Experimental Task

The main experimental task involved searching for animal toy objects in the experimenting

room, while hearing the experimenter verbally express her opinion towards one type of animal.

The hidden animals were small rubber ducks and rubber turtle bath toys, which were matched in

size and attractiveness. Pilot testing revealed that 2.5- and 3-year-olds were consistently able to

identify these two target items, ducks and turtles.

There were two between-subject conditions: affirmative ‘like’ and negative ‘dislike’ verbal

information. There were 8 counterbalancing orders such that children either heard the affirmative

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‘like’ or negative ‘dislike’ verbal information, with either the duck or turtle as the target object,

and with the correct object having left or right placement in front of the child.

2.2.1.1 Familiarization Phase

When children entered the testing room they saw a small toy slide on the child-sized table. The

experimenter told the child about the slide and expressed that she wanted to play with her slide

by sliding animal toys down. She also expressed that someone hid the animal toys away in the

room. She asked the child to help her search the testing room for some animal toys but did not

specify what types of animals were hidden. Each child was prompted to search for the animals in

three hiding locations, in the same order. The three search locations were a child-sized dresser

with three drawers, a large opaque and lidded box, and a tall cabinet with multiple shelves. In

every case, the target toys were successfully found in the third hiding location, the tall cabinet.

The rubber ducks and turtles were each placed in transparent plastic boxes and placed on a white

tray, side by side.

2.2.1.2 Test Phase

Throughout the child’s search, the experimenter continuously expressed either a liking for, or

dislike of a certain type of animal toy (i.e., “I really want to play with my slide. And do you

know what? I like/don’t like putting turtles down my slide. I do/do not like turtles!”). The

experimenter gave this information in only the verbal modality and in the same tone in both

conditions, with minimal gestural or emotional cues. In both conditions, the child heard the

experimenter’s expression of her desire 4 times throughout their search.

Once the children successfully found the target objects, they were praised for their help and

success. The tray of objects was carried to the child-sized table and placed in front of the child.

The child was then asked the ambiguous test question, “I want to play with my slide. I want to

put one of these animals down my slide *gesture towards both toys simultaneously*. Can you

give one to me?”. While saying “can you give one to me?”, the experimenter cupped both of her

hands together in the centre of the two possible choices to indicate that she would like to receive

an object. If the child handed the experimenter more than one type of animal toy, she said “I only

want to put one animal down my slide. Can you give one to me?”. Once the child selected a toy

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to give to the experimenter, they were praised and their response was recorded. The child and

experimenter played together with the slide for about 1-2 minutes, at which point the

experimenter asked for the child’s preference between the two toys. The children were asked

whether they liked the ducks more, the turtles more, or whether they liked them both the same.

The order of choices for this question was counterbalanced across participants. Children who did

not give a response to either or both of these test questions after several prompting attempts were

excluded from the analyses (see participants section).

2.2.2 Verbal Negation Task

2.2.2.1 Familiarization & Pre-Test

During the verbal negation task, the child and experimenter sat on opposite sides of the child-

sized table. A white tablecloth was draped over the table to conceal the experimenter’s hiding of

objects under the table. The children were first introduced to the materials: five boxes that were

blue, red, green, yellow and purple in colour, and a similar sized transparent container. The

boxes were all small enough that the children could easily open and manipulate them. Children

were also introduced to the gold coins that would be hidden inside the boxes for them to find and

retrieve. A piggy bank-like box was given to the children for placing the coins they would

subsequently find during the game. This task began with a pretest which required children to

point to each of the colours of the small cardboard boxes (i.e., “Can you show me which one is

the blue box?”). Spontaneous labelling of the colours was also accepted. Only children who were

able to identify the colours were included in the sample.

2.2.2.2 Teaching Phase

After completing the pre-test, children were told about the hiding game they would play together.

A teaching trial was given to familiarize children with the demands of the task. Two opaque

green cups were used. One coin was placed in one of the two cups under the table, and then

brought into the child’s view while still in the experimenter’s hands. The cups were tilted one at

a time towards the child for them to see inside, and then brought back to start position. The child

was then asked, “Can you show me where the coin is?”. The placement of the coin was

counterbalanced across left and right. Praise was given for correct searches. If a child did not

12

search in the correct location, this teaching trial was repeated a second time after telling the child

to watch the cups very carefully. All children passed this trial.

2.2.2.3 Test Phase

After completing the colour identification pre-test and teaching trial, each child received 6 test

trials: 2 control (C), 2 affirmative (A), 2 negative (N). There were 8 counterbalancing orders

such that half the orders began with affirmative trial, and half with a negative trial (A-C-N-A-C-

N or N-C-A-N-C-A). The pairs of boxes used in each trial were alternated so that a child would

not see the same pair of boxes two trials in a row. The blue and yellow boxes were always paired

together, as were the green and red boxes. Across all trials, the placement of the target coin was

counterbalanced across the left and right side and was never placed on the same side for more

than two consecutive trials.

The affirmative and negative test trials employed four coloured boxes (blue, yellow, green and

red). The procedure was very similar to that of Feiman and colleagues (2017), except that the

hiding locations used in the current study were different coloured boxes, and the experimenter in

the current study hid the coins under the table and out of the child’s sight, rather than behind an

occluder. One pair of coloured boxes was used per trial, making two possible hiding locations.

After a coin was placed in its hiding location, the boxes were brought into the child’s view

simultaneously. The boxes were held by the experimenter in such a way that that they were still

out of the child’s reach, so that the child would have to listen to the full verbal information

before selecting their choice. When the child was attentively listening, the experimenter

delivered an affirmative or negative phrase indicating the coin’s location (i.e., with a blue and

yellow pair of boxes in hand, “The coin is/is not in the blue box”). This phrase was presented

twice, followed by the test question, “Can you show me where the coin is?”. The experimenter

asked the test question while bringing the boxes into the child’s reach. If the child did not

respond, the test question was repeated. The procedure for affirmative and negative test trials

was identical, except for the verbal information delivered to the child.

Control trials provided a visual negation equivalent of the negative trials, to gather information

about the child’s ability to use negation information in the perceptual modality. In these trials,

the child searched between a purple opaque box and a transparent one. The coin was hidden in

13

the opaque container in both trials. In these trials, when the containers were brought into the

child’s view, the experimenter said “Watch carefully!”. The test question, “Can you show me

where the coin is?” was then asked while bringing both containers into reach.

In all trials, if the child chose the correct box, they were praised and encouraged to put their coin

into their “piggy-bank” box. If the child chose the incorrect box, the experimenter responded by

saying “It’s not in there, let’s look in this one!”, while opening up the opposite box and revealing

the correct location. This task took approximately 10 minutes to complete.

2.2.3 NIH Toolbox Picture Vocabulary Test (TPVT)

A final task, completed only by the 3-year-olds sample, was a measure of general language

ability. The TPVT is a measure of receptive vocabulary skills, and is administered in a

computerized adaptive format using an Apple iPad. The experimenter sat beside the child and the

iPad rested propped on the table. The child was given brief standardized instructions about the

“picture game” they would play together. In every trial, the iPad presented a word aurally and

displayed four pictures. The child was to choose the photo that matched the word that they heard.

Two practice trials were given to ensure understanding. Test trials continued until the child met

the task discontinue criteria, approximately 5 minutes. Standardized scores of receptive

vocabulary skills were obtained from each child, as calculated by the device’s software. Children

were excluded from analyses if his or her receptive vocabulary score fell below two standard

deviations below the mean.

2.2.4 MacArthur Bates Communicative Development Inventories

Two and a half-year-old children’s general vocabulary knowledge was measured using the

MacArthur-Bates Communicative Development Inventories (CDI), Level III, a paper and pencil

questionnaire completed by the child’s caregiver. Standardized vocabulary scores were obtained

from each child, and children were excluded from analyses if his or her standardizes score, as

calculated by the CDI scoring software, fell two standard deviations below the mean.

2.3 Coding

14

Children’s responses in each of main experimental task and verbal negation task were recorded

live by the experimenter. In both tasks, the experimenter recorded infants’ selection immediately

following their response to each test question. In cases where infants chose two objects at once,

the experimenter presented a clarification question asking them for only one object, and their

response to this question was coded as the response. If the child still failed to select one object

following this clarification question, they were excluded from the analyses.

In the main experimental task, children received a score of 0 for an incorrect object selection and

1 for a correct object selection. In the verbal negation task, children receive a score from 0-2 for

each type of trial, as there are two test trials of each type. A score of 2/2 represents perfect

performance. Only children who received a score of 1/2 or 2/2 were included in the final

analyses.

A second coder who was naïve to the research question and hypotheses coded 76% (63/83) of the

responses of the young children across age groups. The videotapes of each child were watched

by this second coder, and each of their choices in the main experimental task and verbal negation

task were recorded. Intercoder reliability was high for the object selection question of the main

experimental task: the two coders agreed on 100% of the 63 coded trials, Cohen’s k = 1.00,

p<.001. Intercoder reliability was also high for the question asking the child’s preference

between the two toys: the two coders agreed on 95% of trials (60 of 63 trials), Cohen’s k = .969,

p<.001. Lastly, intercoder reliability for the verbal negation task was similarly high: Cohen’s k =

.929, p<.001. The few disagreements were solved by a third coder who was also naïve to the

research questions.

3 Results 3.1 Main Analyses

Preliminary analyses were conducted to ensure that there were no between-group differences in

both age groups. Several independent samples t-tests showed that children’s mean ages as well

as their scores on a language measure were not significantly different across different genders (ps

> .469) or test order groups (ps > .542). Children’s mean age did not significantly differ across

conditions (ps > .197) for either age group, however for the 3-year-old sample, the group of

15

children in the negation condition had higher receptive vocabulary scores than the group of

children in the affirmative condition (p = .001). This was not the case for the 2.5-year-old sample

(p = .712).

The primary research question was to determine whether 2.5- and 3-year-old children could use

previous verbal information about a speaker’s desire to disambiguate a subsequent request for an

object. To evaluate whether children reliably chose the target object in response to the

experimenter’s request, the proportion correct was compared with chance levels (0.50) both

across and within conditions and age groups.

3.1.1 Three-year-olds

A binomial test revealed that across conditions, 73% of 3-year-old children (32/44 children)

responded correctly in the main experimental task, offering the experimenter the appropriate

object given her prior verbal information at rates above chance levels (p = .004). When separated

by condition, 3-year-old children succeeded at above chance levels when they heard affirmative

verbal information (82%, 18/22 correct), p = .004, however, they did not exceed chance levels

when given information using verbal negation (64%, 14/22 correct), p = .286. A Mann-Whitney

U test revealed that performance across conditions did not significantly differ for these 3-year-

old children, U = 198.0, p = .181.

3.1.2 Two and a half-year-olds

Across the two conditions of the main experimental task (affirmative and negative), 54% of 2.5-

year-old children (21/39 children) responded correctly. A binomial test revealed that children in

this age group did not offer the experimenter the appropriate object given her prior verbal

information at above chance levels (p = .749). When separated by condition, 2.5-year-old

children failed to select objects at above chance levels after hearing both affirmative verbal

information (56%, 10/18 correct), p = .815, or information using verbal negation (52%, 11/21

correct), p = 1.00. Performance across conditions did not significantly differ for this age group,

U = 183.0, p = .846.

3.1.3 Age Group Comparison

16

To examine whether there were age differences in performance on the object selection task, a

Mann-Whitney U test was conducted. Children’s success in choosing the target object in

response to the experimenter’s request did not differ as a function age (p = .076), indicating that

both age groups generally showed similar patterns of performance.

3.2 Control Analyses

3.2.1 Child’s Preference

When asked about their own preference, the majority of children (36/83, 43%) stated that they

did not prefer ducks vs. turtles (they liked them “both the same”). A remaining 27/83 children

(33%) preferred turtles, and 20/83 children (24%) preferred ducks.

To determine whether children in the object selection task were not selecting a toy based on their

own preference for the items (ducks vs. turtles), binomial tests were used to compare children’s

object selection to their object preference, against chance. The chance level was set to 0.33 for

this analysis as children selected one of two toys to give to the experimenter, but were given

three options about their preference (i.e., “do you like ducks more, turtles more, or both the

same?”). Thus, there was a 2/6 (33%) probability that their object selection would match their

own object preference by chance.

Binomial tests revealed that both 2.5- and 3-year-old children’s responses in the main

experimental task were not biased by their own object preference. That is, children’s object

selection differed from their own object preference at above chance levels, for both age groups (p

< .001). Only 10/44 3-year-old children (23%) chose to give the experimenter a toy that they

themselves preferred. Similarly, 14/39 2.5-year-old children (36%) gave the experimenter their

preferred object.

3.2.2 Verbal Negation Comprehension

Children’s comprehension of explicit verbal negation was controlled for in the current study, by

only including children who succeeded on at least half of the verbal negation trials. The majority

of 3-year-old received perfect scores on each of affirmative (93.2%), negative (93.2%), and

control trials (95.5%). Of the 44 3-year-olds, only 3 children scored 1/2 on the negative trials of

17

this task, indicating that their comprehension of verbal negation is at chance levels. However, all

three of these children were in the affirmative verbal information condition, and correctly

answered the object selection test question in the main experimental task.

Out of 39 2.5-year-old participants, 9 (23%) scored 1/2 on the negative trials of the verbal

negation task. Only 2 of these 9 children were in the negative verbal information condition of the

main experimental task and did not respond correctly. Data from an additional 6 participants

were excluded for receiving scores of 0/2 on the negative trials of this task, demonstrating that

verbal negation comprehension may continue to develop into the third year of life. However, the

majority of children in this age group obtained perfect scores on affirmative (80%), negative

(77%), and control trials (87%).

4 Discussion

Young children’s ability to make appropriate inferences in the face of an ambiguous situation is

important for navigating the world around them. The emergence of this ability has critical

implications for children’s learning and socialization. The type of inferencing involved in the

current study required one to think back to information that was previously shared between two

individuals. Previous research has consistently demonstrated that young children have more

difficulty making inferences when the information they are given is solely verbal, rather than

either nonverbal or verbal but paired with gestural cues. For instance, infants as young as 18

months have been shown to understand false beliefs when tested using implicit or active

behavioural measures (Buttelmann, Carpenter, & Tomasello, 2009); however, when asked to

explicitly reason about false beliefs using language, it is not until the school-aged years that

children are successful (Wellman, Cross & Watson, 2003). The increased complexity associated

with language processing is discernable, and as a result, infant research relies heavily on implicit

paradigms.

The current study aimed to explore preschooler’s inferencing skills when presented with explicit

linguistic information about an individual’s desire, as this skill is crucial in the mature

conversational world. A limitation of previous research in this area is that young children can use

other, more simple strategies to be successful rather than making mature inferences. For

18

example, after hearing a certain object mentioned several times and subsequently being asked to

hand the experimenter an object, infants may simply map the label they previously heard with

the object they now see, without considering the mental state of the other individual (Ganea &

Saylor, 2007). To overcome this limitation, the current study used negation language which

required the children to think about what the experimenter had said, and consider their mental

state to appropriately select the opposite item. Verbal negation is a feature of language that has

shown to be more difficult for children to process (Pea, 1980). However, children in the current

study were at an age where they are expected to fully comprehend verbal negation language,

allowing us to gain insight into their ability to make true inferences in an ambiguous situation.

Thus, the current study examined whether young children can use negative verbal desire

information to make pragmatic inferences in a referential communication paradigm.

The ability to solve the referential ambiguity in current study required an understanding of (1)

other individual’s verbally expressed desires and (2) verbal negation. It has been previously

shown that young children’s theory of mind development, specifically desire understanding,

continues into the preschool years (e.g. Cassidy et al., 2005; Saylor & Troseth, 2006). The

findings of the current study are supportive of this, providing evidence that children’s desire

reasoning capabilities continue to develop into the third year of life. In the current study, 73% of

3-3.5-year-old children responded appropriately to the ambiguous request for an object.

However, when separated based on the type of language input heard, we found evidence that

processing desire information using verbal negation is especially challenging for young children.

While 82% of 3-year-olds answered correctly after hearing affirmative desire information (i.e.,

hearing that the experimenter likes ducks or turtles), only 64% of them made inferences based on

negative information (i.e., hearing that the experimenter dislikes ducks or turtles). This result is

in line with previous research (e.g., Feiman et al., 2017), and provides support for our hypothesis

that negative language information is more difficult to make inferences from than affirmative

information, as it involves the additional step of negating a representation of the mentioned

object, and inhibiting attention to the object that has been named.

In a control task which tested children’s explicit comprehension of verbal negation, the majority

of children in both age groups were successful, with performance increasing with age. This

finding was expected, as previous research has demonstrated that children are reliably able to use

19

verbal negation to inform their search location by 27 months of age (Feiman et al., 2017). The

results of the current study are in line with this finding, as children were similarly successful in

an almost identical task. However, when required to reason about linguistic desire information in

the form of verbal negation (e.g., “I do not like turtles), both age groups showed difficulty. This

appears to be a more challenging process, possibly because it requires children to consider the

mental state of the other individual. A search task containing factual information, such as “The

coin is not in the blue box”, is qualitatively different than subjective desire information such as

“I do not like turtles”, because of mental state reasoning and the connection between one’s desire

and their preferred action. In addition, the outcome of the search task is definite (e.g., if not in A,

then must be in B), whereas not liking turtles does not mean that one necessarily likes ducks.

This rationalization will be discussed further below.

The current study’s results from 2.5-year-old children were especially surprising and

unsupportive of our initial hypothesis. This age group did not succeed in solving the referential

ambiguity after hearing both affirmative and negative information. It was expected that negative

information would be difficult for them to inference from, as young 3-year-olds are still prone to

error. However, unlike 3-year-olds, these 2.5-year-olds did not infer that hearing an experimenter

say she “likes” something means that she would want it. This may be due to a lack of

understanding of the link between “I like” and “I want”. Although the term “desire” has been

used throughout, the experimenter in the current study did not in fact provide overt desire

information about her preferred action (such as “I want/do not want that one”), but rather her

opinion towards one particular object (i.e., “I like ducks”). Children were therefore required to

draw inferences about the actress’ preferred action based on her expressed opinion, rather than

her explicit desire. The reason for having the experimenter express opinion rather than overt

desire in the current study was as follows: if children were presented with overt desire

information, it could be argued that children’s inferences simply relied on the actress’ overtly-

stated goals of “wanting” or “not wanting” an object, rather than reasoning about her mental state

and inferencing accordingly. Moreover, it is possible that one reason that young children do not

perform reliably well on tasks of desire understanding (e.g., Vaish et al., 2018) is that these tasks

require children to infer actions from opinions or emotions, which is more challenging than

inferring actions from overt desires. Thus, the 2.5-year-olds in the current study may not have a

full understanding of the connection between opinions and actions. It is likely that if presented

20

with “I want/I do not want” phrases, these children would have been successful, however this

may not be a true test of inferencing abilities.

Another possible explanation to consider is that the relationship between opinions and actions is

not always predictable. There are often situations in which people want or need to interact with

things that they have expressed negative opinions about (e.g., showing disgust at vegetables but

then eating them anyway), or conversely, avoid things they have positive opinions about (e.g.,

sugary desserts). How children deal with such inconsistencies between opinions and actions in

their world proposes an interesting question for future research.

A final and important rationalization for the null result in 2.5-year-olds is that the procedure we

employed was too difficult for this age range. It is possible that these young children may have

been overwhelmed by the salience of the test objects when they needed to consider desires, or

that the cognitive processes involved in this task (e.g., working memory) are not yet at an

appropriate developmental level to be successful in this task. Future research may seek to

explore the role of individual cognitive differences in using language information to fulfill

another individual’s desire.

Children’s object selections in the current study were not biased by their own preference for one

animal object over the other. Children offered the experimenter the same object that they

themselves preferred at lower rates than would be expected by chance. This finding is line with

other desire reasoning research, such as Repacholi & Gopnik (1997), who showed that infants as

young as 18 months do not act egocentrically when asked to offer another person a food item. A

recent study by Schuhmacher and Kärtner (2016) tested young 3-year-olds in a similar paradigm

where a puppet expressed a verbal desire that differed from the child’s own. When the children

were asked to offer a sticker to the puppet, the majority of children used the prior verbal

information to select the appropriate sticker, not acting egocentrically. Importantly, the current

study demonstrates an earlier ability for young children to reason about conflicting desires

through language, as 2.5-year-olds in the current study did not select objects based on their own

preference at rates above chance.

There are a few limitations of the current study that warrant discussion. One limitation is that the

procedure required children to assume a connection between “I like” and “I want”, which is not

21

always directly predictable, as previously discussed. This disconnect may have contributed to the

task failure in 2.5-year-olds. Follow-up research will address this limitation by exploring young

children’s inferencing ability in contexts where the language information is more explicit – that

is, where bridging the opinion-action gap is not required for successful performance. If simply

bridging this gap is what 2-.5-year-old children are struggling with in the current task, then they

should be more likely to succeed in the future versions of the task.

Another important limitation surrounds the use of toy animals in the main experimental task,

when children heard desire information that did not necessarily pertain to toys, but rather real

animate species. For instance, after hearing the experimenter say “I do not like turtles”, and

subsequently having to choose between giving her a toy duck or toy turtle, the young children in

the current study may have interpreted the desire information as pertaining to animate objects,

and failed to generalize this preference to the toys in front of them. This is a plausible

explanation as it is not uncommon for children to interact with toy forms of animate objects in

which they dislike or are scared of, such as rubber sharks or stuffed monsters. To resolve this

possible conflict, future research may wish to express desire towards toys explicitly (i.e., “I do

not like toy turtles”).

5 Conclusion

The current study is one of the first to explore preschooler’s comprehension of other’s desires to

inform their inferences, when desire information is presented using verbal negation. Our results

suggest that although 3-year-olds understand the connection between a desire and a preferred

action, it may not be until beyond age three and a half that children can use verbally expressed

dislikes to turn to alternative choices. The current study also demonstrates that 2.5-year-old

children have difficulty using verbal desire information to guide their inferences more generally.

However, this difficulty is not due to a lack of understanding of negation language or an

egocentric desire bias. The task difficulty may be due to the mental state reasoning involved, or

the lack of one-to-one correspondence between desires and actions in everyday life. The results

of the current study provide information about the continuing emergence of desire understanding

to guide pragmatic inferences, and evoke an appreciation for the complexity of mature

conversation.

22

References

Akhtar, N., Carpenter, M., & Tomasello, M. (1996). The Role of Discourse Novelty in Early

Word Learning. Child Development, 67(2), 635–645.

Baldwin, D. A. (1991). Infants’ Contribution to the Achievement of Joint Reference. Child

Development, 62(5), 875–890.

Baldwin, D. A. (1993). Early Referential Understanding: Infants’ Ability to Recognize

Referential Acts for What They Are. Developmental Psychology, 29(5), 832–843.

Behne, T., Carpenter, M., Call, J., & Tomasello, M. (2005). Unwilling versus unable: infants'

understanding of intentional action. Developmental psychology, 41(2), 328.

Bucciarelli, M., Colle, L., & Bara, B. G. (2003). How children comprehend speech acts and

communicative gestures. Journal of Pragmatics, 35, 207–241.

Buttelmann, D., Carpenter, M., & Tomasello, M. (2009). Eighteen-month-old infants show false

belief understanding in an active helping paradigm. Cognition, 112(2), 337–342.

Call, J., & Carpenter, M. (2001). Do apes and children know what they have seen? Animal

Cognition, 3(4), 207–220.

Clark, H. H., & Marshall, C. R. (1981). Definite reference and mutual knowledge. In B. L.

Webber, A. K. Joshi, & I. A. Sag (Eds.), Elements of discourse understanding (pp. 10 – 63).

Cambridge, UK: Cambridge University Press.

Fawcett, C. A., & Markson, L. (2010). Similarity predicts liking in 3-year-old children. Journal

of Experimental Child Psychology, 105(4), 345–358.

Ganea, P. A. & Saylor, M. M. (2007). Infants Interpret Ambiguous Requests for Absent Objects.

Developmental Psychology, 43(3), 696–704.

23

Kim, K. J. (1985). Development of the Concept of Truth-Functional Negation. Developmental

Psychology, 21(3), 462–472.

Liszkowski, U., Carpenter, M., & Tomasello, M. (2008). Twelve-month-olds communicate

helpfully and appropriately for knowledgeable and ignorant partners. Cognition, 108(3),

732-739.

Mody, S., & Carey, S. (2016). The emergence of reasoning by the disjunctive syllogism in early

childhood. Cognition, 154(Complete), 40–48.

Pea, R. D. (1980). Logic in Early Child Language. Annals of the New York Academy of Sciences,

345(1), 27–43.

Rakoczy, H., Warneken, F., & Tomasello, M. (2007). This way!’’, No! That way!’’-3-year olds

know that two people can have mutually incompatible desires. Cognitive Development,

22(1), 47–68.

Repacholi, B., & Gopnik, A. (1997). Early Reasoning About Desires: Evidence From 14- and 18-

Month-Olds. Developmental Psychology, 33(1), 12–21.

San Juan, V., Chambers, C. G., Berman, J., Humphry, C., & Graham, S. A. (2017). The object of

my desire: Five-year-olds rapidly reason about a speaker’s desire during referential

communication. Journal of Experimental Child Psychology, 162, 101–119.

Saylor, M. M., & Troseth, G. L. (2006). Preschoolers use information about speakers’ desires to

learn new words. Cognitive Development, 21(3), 214–231.

Schuhmacher, N., & Kärtner, J. (2016). The Role of Peers and Siblings in Toddlers’ Developing

Understanding of Incompatible Desires. Social Development, 25(2), 435–452.

24

Schulze Cornelia, Grassmann Susanne, & Tomasello Michael. (2013). 3-Year-Old Children

Make Relevance Inferences in Indirect Verbal Communication. Child Development, 84(6),

2079–2093.

Thornton, R., & Tesan, G. (2013). Sentential negation in early child English. Journal of

Linguistics, 49(2), 367–411.

Tomasello, M., & Haberl, K. (2003). Understanding Attention: 12- and 18-Month-Olds Know

What Is New for Other Persons. Developmental Psychology, 39(5), 906–912.

Tomasello, M., Strosberg, R., & Akhtar, N. (1996). Eighteen-month-old children learn words in

non-ostensive contexts. Journal of Child Language, 23(1), 157–176.

Vaish, A., Hepach, R., & Grossmann, T. (2018). Desire understanding in 2-year-old children: An

eye-tracking study. Infant Behavior and Development, 52, 22-31.

Wellman, H. M., & Woolley, J. (1990). From simple desires to ordinary beliefs: The early

development of everyday psychology. Cognition, 35(3), 245–275.

Wellman, H. M., Cross, D., & Watson, J. (2003). Meta-Analysis of Theory-of-Mind

Development: The Truth about False Belief. Child Development, 72(3), 655–684.

Wright Cassidy, K., Cosetti, M., Jones, R., Kelton, E., Meier Rafal, V., Richman, L., & Stanhaus,

H. (2005). Preschool Children’s Understanding of Conflicting Desires. Journal of Cognition

and Development, 6(3), 427–454.

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Tables

1 Table 1: Mean Age and Age-adjusted Receptive Language (TPVT) Standard Score by Condition and Gender, 3-year-old sample.

Control Condition

Gender Age (months) TPVT Score

N M (SD) N M (SD)

M 11 38.92 (0.95) 11 100.73 (9.62)

F 11 39.04 (2.29) 11 101.36 (5.43)

Total 22 38.98 (1.71) 22 101.05 (7.63)**

Negation Condition

Gender Age (months) TPVT Score

N M (SD) N M (SD)

M 11 38.77 (1.43) 11 107.73 (8.10)

F 11 38.66 (2.27) 11 110.91 (7.09)

Total 22 38.72 (1.85) 22 109.32 (7.61)**

Notes. ** p < .001.

26

2 Table 2: Mean Age and Age-adjusted Expressive Language (CDI) Score by Condition and Gender, 2-year-old sample.

Control Condition

Gender Age (months) CDI Score

N M (SD) N M (SD)

M 10 31.81 (1.36) 10 54.44 (27.44)

F 8 31.59 (1.54) 8 44.25 (32.10)

Total 18 31.71 (1.40) 18 49.65 (29.23)

Negation Condition

Gender Age (months) CDI Score

N M (SD) N M (SD)

M 11 32.49 (1.64) 11 47.27 (25.73)

F 10 32.17 (1.51) 10 45.50 (23.62)

Total 21 32.34 (1.55) 21 46.43 (24.14)

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3 Table 3: Correct and Incorrect Object Selections in Main Experimental Task, by Age and Condition.

2-year-olds

Object Selection Control Condition Negation Condition

Correct 10 8

11 10 Incorrect

3-year-olds

Object Selection Control Condition Negation Condition

Correct 18

4

14

8 Incorrect

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4 Table 4: Children’s Reported Object Preference by Age and Condition.

2-year-olds

Object Preference Control Condition Negation Condition

Duck 6 5

6 7 Turtle

No preference 7 8

3-year-olds

Object Preference Control Condition Negation Condition

Duck 4 8

4 7 Turtle

No preference 10 11

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5 Table 5: Children’s Correct Responses on Verbal Negation Comprehension Task, by Trial Type.

0/2 % 1/2 % 2/2 % N

2.5-year-olds

Control 1 2.6% 4 10.3% 34 87.2% 39

Affirmative 3 7.7% 5 12.8% 31 79.5% 39

Negative -- -- 9 23.1% 30 76.9% 39

3-year-olds

Control 0 0% 2 4.5% 42 95.5% 44

Affirmative 1 2.3% 2 4.5% 41 93.2% 44

Negative -- -- 3 6.8% 41 93.2% 44 Notes. Children who received a score of 0/2 on negative trials were excluded from main analyses.

30

Figures

1 Figure 1. Stimuli used in the main experimental task.

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2 Figure 2. Stimuli used in the verbal negation comprehension task.