Conceptual perspective and lexical choice in acquisition

COGNITION Cognition 64 (1997) 1–37

Conceptual perspective and lexical choice in acquisition Eve V. Clark* Department of Linguistics, Stanford University, Stanford, CA 94305, USA Received 21 May 1996; accepted 20 March 1997

Abstract Adult speakers choose among perspectives when they talk, with different words picking out different perspectives (e.g., the dog, our pet, that animal). The many-perspectives account of lexical acquisition proposes that children learn to take alternative perspectives along with the words they acquire, and, therefore, from the first, readily apply multiple terms to the same objects or events. And adults offer children pragmatic directions about the meanings of new words and hence about new perspectives. In contrast, the one-perspective account proposes that children are able, at first, to use only one term to talk about an object or event. Evidence for the many-perspectives account comes from a range of sources: children spontaneously use more than one term for the same object (horse and chair for a toy horse); they construct novel words to mark alternate perspectives (Dalmatian-dog vs. dog); they shift perspective when asked (from cat to animal, or sailor to bear for anthropomorphic characters); and they readily learn new terms for talking about already-labelled kinds. Children sometimes fail to learn new words or fail to relate them to words already known, but only in situations that lack adequate pragmatic directions.  1997 Elsevier Science B.V. Keywords: Conceptual perspective; Pragmatics; Lexical acquisition; Pragmatic directions

1. Introduction When speakers plan an utterance, they choose a specific PERSPECTIVE on what they wish to speak about. This perspective, marked by word-choice, allows them to present to their addressees a specific conceptualisation of an object, property, relation or event. Word choices allow speakers to conceptualise the same entities and events in different ways. And they therefore allow speakers to highlight properties pertinent to the goal of the discourse. As Lakoff and Johnson (1980) put it, ‘In making a statement, we make a choice of categories because we have some reason for focusing on certain properties and downplaying others [1980, p. 163].’ Depend* E-mail: [email protected] 0010-0277/97/$17.00  1997 Elsevier Science B.V. All rights reserved PII S00 10-0277(97)000 10-3

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ing on one’s conversational goal, one might refer to a neighbour variously as the cellist, the mother of three, my cousin or the Mayor. One might refer to cars, people and pets, with a similar range of expressions, cars as the cars, the traffic, the traffic jam or the vehicles; a group of people crossing a road as those people, those families or some tourists, with subsets of them as the parents, the children, the two teenagers, and so on. And when looking at the family dog, one might refer to it as Rover, the family pet, our dog, Tim’s pup, the collie, the rubbish-bin, the destroyer of shoes or even the vacuum-cleaner (e.g., Cruse, 1977; Ravn, 1988; Vossen, 1995). The choice of conceptual perspective on each occasion will depend on who the speakers are talking to, what they talking about, and why. In any conversation, the speaker’s purpose depends on both local and global goals. Locally, for instance, the speaker may wish to get the addressee to attend to a particular object, and achieves this with, say, ‘You know the bicycle Jan lets you borrow?’ Globally, this utterance could provide just the first step in persuading the addressee to lend that bicycle to the speaker. Choice of perspective is fundamental in how speakers categorise the world they talk about. Perspective applies equally to objects, properties, actions, and events, everywhere that a speaker can take two (or more) conceptual perspectives. For example, in talking about both a dachshund and an Alsatian, the speaker may choose just dog (a single perspective on both objects); or, in talking about a dachshund and a Siamese, he may choose dog and cat (two different perspectives) even though they too could have been looked at from the same perspective with animal. Or, for talking about the dachshund, the speaker could use one of several expressions, dachshund, pet or dog, with each marking a different perspective. Speakers can also relate one perspective to another, by indicating that a Siamese, for example, is a kind of cat; that a hedgehog looks like a prickly ball, or that a mast is part of a boat. In each instance, the speaker is indicating what relation links the perspectives marked by the two words. In summary, one can take different conceptual perspectives on the same entity, and one can take the same perspective on two or more different entities. Here, my emphasis will be on cases where speakers take different perspectives on the same entity. The notion of conceptual perspective is important to lexical acquisition because of two radically different proposals: One is that children (like adults) can take different perspectives on the same object or event, and so accept and produce multiple terms for the same referent from as soon as they have the necessary words. This is the many-perspectives view. The other is that children at first take only one perspective on each object or event because this simplifies their word-learning in the early stages. As a result, they can accept and produce just one word for a referent-type. This is the one-perspective view. The support for these two views comes from different sources, but I will argue that once the pragmatic contexts of word acquisition are taken into account, the data in fact support only the first of these proposals. In this paper, I begin by considering what speakers achieve with specific choices of perspective, and then turn to how speaker and addressee establish the same conceptual perspective. I then offer a preliminary comparison of the many-perspec-

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tives account with a one-perspective account, and outline the predictions each makes about lexical acquisition. Before taking up these predictions in detail, I look at what very young children know about spatial perspective for themselves and others. I then return to conceptual perspective and show how evidence from a variety of sources strongly supports the many-perspectives over the one-perspective account.

2. The goals of lexical choices The perspective choices speakers make should be able to serve a variety of purposes because they are goal-driven. For example, they should be able to highlight criterial properties, affect the amount of detail addressees take into account, and affect the interpretations they make. In what follows, I review evidence for these predictions. 2.1. Criterial properties Highlighting allows speakers to focus their addressees’ attention on what they have identified as the properties or qualities pertinent to the goal of the exchange on that occasion. For instance, in a conversation about music, the speaker may wish the addressee to attend more to a player’s instrument (the cellist) than to her political affiliation (the Democrat). In a conversation about education, the speaker may wish his addressee to think about someone’s profession (the teacher), but, on another occasion, to focus on who lives next door (your neighbour). The multiplicity of expressions available in a language allows speakers to take alternate perspectives and thereby pick out just those properties most pertinent to the goals of a particular exchange (see also Geeraerts, 1994; Geeraerts et al., 1994; Vossen, 1995). Highlighting specific properties is also at work when people pick out instances of what have been called ad hoc categories (Barsalou, 1983; Barsalou, 1992). For example, people can highlight a particular property of a category instance. On different occasions, the speaker may use doorstop to refer to a brick, a shoe, a jar full of pennies, or a wedge, when each is being used with that function. Each of these entities could be picked out with many other expressions, but doorstop highlights just the property relevant to holding a door open. While psychologists like Barsalou have emphasized the ad hoc nature of the category thus formed (‘things that can hold doors open’), speakers themselves use their word choices to indicate just which conceptual category they are concerned with on each occasion. They may identify a brick on one occasion as the doorstop, on another as the support (for a bookshelf, say), and on yet others as the brick, depending on the goal of the conversation. Their choices of perspective, marked by the words used, indicate which properties of that entity they wish to highlight for the addressee on each occasion.1

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A clear example of this appeared in a Wall Street Journal article of July 2, 1996, where the headline read “Recyclers seek ‘recovered fiber,’ but toss ‘wastepaper’ in the trash.”

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2.2. Degree of detail When addressees hear a word, it not only helps them identity the intended referent, but also leads them to store a certain kind of information in memory. Consider the following task: people are shown a picture of several objects, as in Fig. 1, and are told either ‘The fish is lying beside the bread knife’ or ‘The flounder is lying beside the bread knife.’ Depending on whether the addressees heard the fish or the flounder, they respond differently in a follow-up recognition test. In that test, both groups see a series of pictures of fish and are asked to point out all those that look like the one seen originally. Those who heard the fish allow much greater divergence from the original than those who heard the flounder (Jo¨rg and Ho¨rmann, 1978). The more specific expression, the flounder, invites more attention to details in the picture, and this leads to more accurate choices in the recognition test. That is, people accept fewer pictures than when they’ve heard fish, and the pictures they do accept are closer in detail to the original picture shown (see also Dubois and Denis, 1988). 2.3. Interpretation The word choices speakers make also affect how addressees interpret what they see. For example, different terms used for the same drawing affect how people identify and later remember the object depicted. In one classic study of simple outline drawings such as the two sample forms shown in the centre column of Fig. 2, two groups were given different terms for the same pictures. The upper picture, for example, was called a bottle for one group, and a stirrup for another; and the lower one was called either an hour-glass or a table (Carmichael et al., 1932). The expression people heard shaped their interpretation of the original drawing. Later, when asked to reproduce the drawing, those who had heard bottle, for example, distorted their drawings to resemble a bottle, while those who had heard stirrup distorted theirs to resemble a stirrup, as indicated in Fig. 2. People recon-

Fig. 1. Level of detail in recognition memory–the fish vs. the flounder (based on Jo¨rg and Ho¨rmann, 1978).

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Fig. 2. Descriptions and drawings–bottle vs. stirrup, hourglass vs. table (based on Carmichael et al., 1932).

struct pictures that are more consistent with the conceptual perspective expressed than with the original drawing. More recent studies have looked at these effects in communication tasks where two people, separated by a screen, have to make two arrays of pictures match without being able to look at each other’s array. When shown shapes like those in the centre column of Fig. 3, with the same entity introduced to one group as a flagman and to another as an angel, people who had been exposed to the same perspective took less time identifying each picture than those whose initial perspectives did not match (Wilkes-Gibbs, 1995; Wilkes-Gibbs and Kim, 1991). When asked to make drawings of the original figures, people showed that they interpreted them in the original perspective they’d been exposed to, as well as in the joint perspective established in the communication task. Their drawings were more neutral (and so closer to the originals) when they had had to adopt a joint perspective different from their private perspective (the first one they had been exposed to). Conceptual perspective also affects memory for events. For example, after watching a short film of a car accident where a car runs into a van, people offer very different estimates for the speed of the car depending on which verb is used. When asked, for example, ‘How fast was the car going when it crashed into the van?’ they gave higher estimates of the speed than when asked ‘How fast was the car going when it hit the van?’ (Loftus, 1979; Wells and Loftus, 1984). In summary, the speaker, in pursuing a goal, starts with a particular perspective and chooses words to convey it. These choices highlight some properties of an object over others. They also influence the amount of detail processed by the addressee, and the interpretation given to a picture or scene. And they affect memory for pictures and scenes. What people process depends directly on the perspectives they adopt.

Fig. 3. Descriptions and coordination–turtle vs. fish, flagman vs. angel (based on Wilkes-Gibbs, 1995).

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3. Competing perspectives The general pattern in conversation is for speakers to propose an initial perspective (e.g., the dog) and for their addressees to adopt it (the dog) as they in turn contribute to the conversation (Brennan and Clark, 1996; Clark and Wilkes-Gibbs, 1986; Garrod and Anderson, 1987; Garrod and Doherty, 1994; Schober, 1993; Schober, in press). But addressees can refuse to adopt the perspective offered and propose an alternative instead. Such conflicts can be seen in arguments. In the courtroom exchange that follows, a doctor is being tried for murder after having carried out a late abortion (Danet, 1980, p. 206): Attorney: You didn’t tell us, Doctor, whether you determined that the baby was alive or dead, did you, Doctor? Witness: The fetus had no signs of life. Here the prosecuting attorney proposes the baby, but the witness, the doctor on trial, puts forward his own perspective, marked by his choice of the fetus. In the next three exchanges, from a rape trial (Drew, 1992, pp. 488–489), the witness rejects the perspectives proposed by the examining attorney: Attorney: An’ you went to a: uh (0.9) ah you went to a ba:r? in XXX (0.6) is that correct? (1.0) Witness: It’s a clu:b. Attorney: It’s where uh (.) uh gi:rls and fella:s meet, isn’t it? (0.9) Witness: People go: there. Attorney: An’ during that evening: (0.6) uh: didn’t Mistuh YYY come over tuh sit with you (0.8) Witness: Sat at our table. These exchanges each illustrate competing perspectives: whether the place in question was a ‘bar’ or a ‘club’; whether it was a place for ‘girls and fellas’ to ‘meet’ or a place for ‘people to go’; and whether ‘Mistuh YYY’ came over to ‘sit with’ the witness or simply to ‘sit at the same table’. The range of perspectives a speaker may choose from is reflected, among other things, in the word choices available within the language. The number of conventional one-word expressions speakers can make use of may be more limited in some domains than others, but they always have multi-word options too, e.g., ‘Dalmatian’ vs. ‘fire-truck dog’ vs. ‘the kind of dog you find at fire-houses’, and so on. Speakers may have many options for some events, and fewer for others. Speakers of each language, then, must learn what is available, the range of lexical choices, for conveying the perspectives they choose on particular occasions. Each choice a speaker

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makes reflects the perspective designed to further the current purpose in the conversation. Perspective, in short, is always relative to the speaker’s goals in talking to the addressee. And, I will argue, children recognise this from the start. 4. Establishing a perspective To establish a perspective, speakers and addressees rely on a host of pragmatic directions every time they converse. Pragmatic directions offer guidance to how an addressee should treat the speaker’s utterances. They depend on non-linguistic information about the speaker’s locus of attention, used in establishing joint attention for speaker and addressee; about physical co-presence when the objects or events the speaker is talking about are accessible (audible or visible, say) to both speaker and addressee, as indicated by gaze, gestures, stance, and orientation, and about linguistic co-presence when the speaker, for instance, alludes, through use of specific nouns and verbs, to objects or events that had been experienced earlier and so are accessible through memory, or that had been talked about earlier in the conversation or on a previous occasion. Specifically, pragmatic directions to a child addressee may serve to indicate what meaning to assign to unfamiliar words, for instance, through ostensive statements like ‘That’s a wallaby’; and how to relate the meanings of familiar and unfamiliar terms. In spelling out the nature of such connections, pragmatic directions offer specific information about such relations as inclusion, parts, properties, and functions. In conversation, speakers make sure their addressees have access to the appropriate directions, and addressees look to these directions as they make interpretations and inferences about what they hear and see from the speaker. Pragmatic directions are relevant to all facets of language use, the mutual knowledge speakers and addressees have about each other and about the current conversation, the words and constructions chosen, the manner of delivery, direction of gaze, gestures, the physical setting of the conversation, and so on (e.g., Clark, 1996; Clark and Carlson, 1981; Levinson, 1983). Adults make use of the same range of pragmatic directions when talking to young children, but they also take into account limits on children’s abilities. In establishing a perspective, adults depend on several kinds of information. First, they rely on perceptual information to establish joint attention. If speaker and addressee are attending to the same entity or the same activity, they can both more readily assume that their shared focus of attention is what the speaker is talking about, so both have in mind the same referent. In adult conversations, addressees check on what speakers are attending to and coordinate with them to achieve joint attention. In conversations with young children, though, adult speakers need to monitor what the children are attending to in order to achieve the necessary coordination. And this is what they do (e.g., Barresi and Moore, 1993; Butterworth and Jarrett, 1991; Collis, 1977; Morissette et al., 1995; Murphy and Messer, 1977; Stern, 1985; Tomasello, 1995; Trevarthen, 1977). Table 1 lists three common types of perceptual information and indicates how each allows an adult to establish joint attention with a young child (Clark, 1995).

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Table 1 Engineering joint attention 1 2 3

The child is looking at X, so the adult follows the child’s gaze to look at X too, and both child and adult can now see that the other is looking at X The child is pointing at X, so the adult follows the child’s point to attend to X, and both child and adult can now see that other is attending to X The child is oriented towards X, so the adult follows the child’s orientation to X, and both child and adult can now see that the other is attending to X

Infants are also adept at getting adult attention in order to achieve their goals. They co-opt them as instruments to an end, as early as six months of age (e.g., Mosier and Rogoff, 1994). By 9–12 months, they can get adults to open things, offer things out of the children’s own reach, and achieve a variety of goals they could not manage on their own (e.g., Bates, 1976; Leung and Rheingold, 1981; Rheingold et al., 1987). In doing this, they first attract adult attention and then make clear what they want through combinations of gestures, vocalisations, and eventually words. As they get older, children also learn to attend to what adult speakers are focusing on, and to take that as pertinent to communication. Joint attention is critical for speakers and addressees if they are to be sure that they are both talking about the same thing. Joint attention is the first step. Stronger evidence that adult and child are attending to the same thing comes from two further sources: physical, on the one hand, and linguistic, on the other. Speaker and addressee need to be aware not only of each other’s focus of attention but also of just what that attention is on through physical co-presence (Baldwin, 1991, 1993; Corkum and Moore, 1995; Moore and Corkum, 1994). That is, they can be all the more sure that they have the same objects or events in mind if those elements are physically present with the speaker and addressee. Examples of physical co-presence and some inferences they license for the child are summarised in Table 2 (Clark, 1995). Talk about the here-and-now, common in conversation with young children, depends on physical co-presence of just the types listed in Table 2 where child and adult are in the presence of the object or activity that provides their joint focus of attention. The ability to check on and attend to the locus of adult attention is especially important when adults talk about entities that the child is not currently focusing on. And some researchers have estimated that between 30% and 50% of Table 2 Physical co-presence 1

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Eye-gaze of speaker (directed towards X) (a) The child infers that the speaker is attending to X, so the child should too (b) The child infers that the speaker’s gaze and words are relevant to X Gesture of speaker (directed towards X) (a) The child infers that the speaker is attending to X, so the child should too (b) The child infers that the speaker’s point and words are relevant to X Stance of speaker (leaning, oriented towards X) (a) The child infers that the speaker is attending to X, so the child should too (b) The child infers that the speaker’s stance and words are relevant to X

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adult utterances to one-year-olds may be about things the child is not initially attending to (e.g., Collis, 1977; Harris et al., 1983). Children also need to take into account any linguistic information in the speaker’s current utterance, as well as from prior exchanges, that points to what is being talked about. This is linguistic co-presence. When an adult introduces unfamiliar words, for example, infants at 1;2 attend to the locus of adult attention and switch their gaze to it. By 1;6, they consistently infer that the referent of an unfamiliar word (e.g., fox) must be whatever the adult is attending to at the time of the utterance (for instance, the adult is looking at a fox) (Akhtar and Tomasello, 1996; Baldwin, 1991, 1993). By age two, children take active account of what an adult knows or doesn’t know: where they have to ask for adult help in retrieving a toy (e.g., a bear), they are more likely to name the toy (‘bear’), name the location (‘box’), and point to the location (a box on a shelf) when the parent hasn’t seen the toy concealed beforehand than when the parent has (O’Neill, 1996). Linguistic co-presence is an important tool in discerning the speaker’s intentions. Users of a language assume that any difference in the terms chosen signals a difference in meaning: Choice of one term, fox say, marks one intention, while choice of another, wolf, marks a different intention (Clark, 1990, 1993; Moses, 1993). How much use children make of linguistic co-presence depends on how much they already know about their language, but even the youngest can make use of any terms already familiar to them. Linguistic co-presence builds on joint attention, and can enhance lexical learning (e.g., Akhtar et al., 1991; Dunham et al., 1993; Tomasello, 1995). Examples of inferences licensed by linguistic co-presence are given in Table 3 Table 3 Linguistic co-presence 1

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Utterance by the speaker with attention on X (a) The child infers that the speaker’s utterance is relevant to X, and should be treated as such by the child (b) The child infers that any unfamiliar terms in the speaker’s utterance are also relevant to X Introduction by the speaker of a contrasting term for X, either explicitly with both entities mentioned, X1 and X2, or implicitly, with only one, X (a) The child infers that the speaker is attending to what is mentioned, X, and that the child should too (b) The child infers that the speaker’s utterance is relevant to X Exhaustive alignment by the speaker of known terms and potential referents (a) The child infers that the speaker is aligning the successive terms mentioned with the candidate referents, so the child should too (b) The child infers that the speaker is using any unfamiliar term for one of the referents – for an unfamiliar one if there is one Use of a link from a familiar to an unfamiliar term by the speaker (a) The child infers that the speaker is indicating which semantic relation holds between the familiar term for X and a new, unfamiliar term, so the child should attend to this relation (b) The child infers that the speaker’s use of the unfamiliar term is relevant to use of the familiar term(s) for X

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(Clark, 1995). In the first type, in (1), children who have inferred that what the speaker is saying is relevant to whatever is in their joint focus of attention (a fox, say), should also infer that an unfamiliar term (e.g., fox, russet) refers to or describes that entity or event. The same goes for the situation type in (2), where the speaker produces an unfamiliar term for a familiar object or action, either along with a familiar term or on its own. In talking to young children, adults offer both familiar and unfamiliar terms. And here they often offer explicit pragmatic directions for how to assign meanings to the unfamiliar ones (e.g., Blewitt, 1983; Callanan, 1985, 1989; Callanan et al., 1995). Adults offer such directions about unfamiliar words to older children too, particularly as they introduce relatively rare words in everyday family conversations (Beals and Tabors, 1995a,b). In doing this, they simultaneously convey to children alternate perspectives on individual objects and events. In effect, each new word adults offer to children is an invitation to form a category (Waxman and Markow, 1995) and hence an invitation to take a particular conceptual perspective on the entity-type in question. In their pragmatic directions about how to relate different meanings to each other, adults simultaneously show children how to relate alternate perspectives on the same entity. For instance, is-a-kind-of indicates that the second term is superordinate to the first, as in ‘A flamingo is a kind of bird’, ‘A trout is a kind of fish’, ‘This is a jeep. A jeep’s a kind of vehicle’, ‘See this little animal? What is he? He’s a gopher. This animal is a gopher’. Examples of some common relations adults offer in their pragmatic directions are given in Table 4 (e.g., Blewitt, 1983; Callanan, 1985, 1989, 1990; Mervis, 1987; Shipley et al., 1983).2 For instance, is-a-part-of identifies parts or properties. When parents emphasize information about parts, they typically begin with the term for the whole object and then introduce a part or property. In one study of 667 such episodes in spontaneous conversations, parents introduced wholes before parts or properties 664 times (more than 99.9% of the time) (Masur, 1997). And when parents give a term for a part (to infants aged 1;5–1;10), they typically do so with a possessive construction, after introducing the whole, as in ‘Look what a lovely doll. Where is the doll’s nose?’ or ‘This is a rabbit; these are his ears’ (Ninio, 1980; Shipley et al., 1983). Parents also offer information about properties such as size, texture, or colour, and about the usual functions of objects, for instance, what a slide is for, or how a mixer is used.

5. Many perspectives all the time Adults present multiple perspectives even when talking to young one-year-olds. They use several different terms to pick out a single referent as much as 17% of the time when talking to infants (mean age 1;4) who can produce at most about 20 words. To slightly older children (mean age 1;11), who can produce at least 100 2 All the examples cited in Table 4, and in the text, are drawn from actual utterances addressed by adults to young children.

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Table 4 Some pragmatic directions for relating unfamiliar to familial terms 1 2

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Inclusion – X is a kind of/sort of Y ‘Oaks are kinds of trees’, ‘A pug is a kind of dog’ Sets and set membership – X is a Y ‘A cat and a dog are both animals’, ‘These trees make a forest’ ‘Furniture’s a group’, ‘All of them together are vehicles’ Definition – X is a Y ‘A puppy is a baby dog’, ‘A stag is a male deer’ ‘Machines help you do work’, ‘A bus is a vehicle’ Comparison – X looks like/is similar to Y ‘A zebra looks a bit like a horse’ ‘Tusks are like teeth’ Property identification – X has Y, X is made of Y, X is used for Y ‘A walrus has tusks’, [koala hear] ‘He looks awfully soft’ ‘A mixer is what we use to mix things up in the kitchen’ ‘The ball is made of rubber’ Part identification – X is part of Y ‘Your thumb is part of your hand’, [hammer] ‘You see this part? It’s called a claw’ [mixer] ‘That has two beaters on it’ Alignment – [with X and Y known] This is an X, this is a Y, and this is a Z ‘This is a bear, this is a lion, and this is a leopard’ ‘This is his paw, this is his toe, and this is his claw’ Function – X is for/is used for Y ‘Do you know what you do with a wrench? You tighten pipes’ ‘It’s a wick. You can’t burn a candle if you don’t have a wick.’

words (with a mean of 299), adults use multiple terms for the same referent twice as often, around 35% of the time (Callanan et al., 1995). In short, they assume from the start that children can grasp more than one perspective. They link unfamiliar terms with terms that are already familiar. This ensures exposure to networks of words, and connects new words to others already known, while, at the same time, exposing them to different perspectives on the intended referent. Under the many-perspectives view, even the youngest children can take alternate perspectives on the same entity or event, and can take for granted that changes in the expressions speakers use mark changes in perspective. This view contrasts with a one-perspective view, which assumes children can take account of only one perspective per entity or per event. Under such a view, in their first few years of language use, children should accept only one term for referring to a specific type of object, for example, and reject any additional terms that are offered. What is the evidence that one- and two-year-olds can take alternate perspectives? Findings from spatial perspective-taking suggest that children can take different physical perspectives on objects even before they begin to talk about them. We look at this ability next.

6. Developmental evidence for spatial perspective-taking How and when do children learn to take different spatial perspectives, that is, take

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the point of view of another (as in showing something to another person), predict the point of view of another (anticipating what someone else can see), or identify a point of view in words (describing what someone else can see) (Schober, in press)? How soon can children can use language to indicate a spatial perspective and to shift from one perspective to another? And when can they shift from one spatial perspective to another in pretence? 6.1. Spatial perspective Children appreciate physical point of view from early on. Twelve-month-olds show things to an adult by holding them up; they also point to things to draw attention to them. At 18 months, children often show adults things so that both child and adult have the object in their visual field. They show a picture to someone else by holding it out horizontally; they also display pictures pasted to the side of a cube by turning the cube so the picture is on the topmost surface. For a picture attached to the inside bottom of a cube, 18-month-olds tilt the cube away from themselves and towards the adult. And by 24 months, they consistently turn a picture away from themselves and towards the other when showing it (e.g., Lempers et al., 1976). As early as 18 months, in a wide range of settings, children are well aware that, for people to see something, they must be looking towards it and the target must be in their line of sight. By age two, children not only act on this knowledge, but also talk about it. The following episode offers a good illustration (Clark, diary data):3 D (2;0,9) was playing with two small plastic rabbits and a small figure; first, he placed all three on a low table, along one edge, so they faced his mother, and then said: – [∂] watching Eve, rabbits watch Eve. Then he carefully moved them across the table to an adjacent side, turning them through 90 degrees so they faced his father: – [∂] watch Herb. Fa: Can you make them watch television, can you make the rabbits watch television? – Yes. D then re-arranged them along another edge so they all faced the TV, and added some other toys to the array. Then, pointing at them, he said: – Eve, Eve, [∂] all watching TV. 3

This observation is drawn from an extensive daily diary kept of my son, D, from birth to age six. The diary data consist of daily observations that recorded the child’s utterances, surrounding adult utterances, and details of the context on each occasion (see further Clark, 1993).

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Two-year-olds have a clear understanding of the notion of front and the way objects need to face in a parade (in line, all facing the same direction) versus the way they stand to talk to someone (face to face) well before they acquire terms like front and back (Levine and Carey, 1982; see also Clark, 1980; Gopnik et al., 1994). Children begin to mark spatial point of view in their language around this age too. Between 12 and 18 months, they begin to use deictic terms like here or that, usually accompanied by pointing towards the location they are attending to. And around age 2;0, they begin to produce pronouns like I and you, for the speaker versus the addressee (e.g., Charney, 1980; Chiat, 1982; Clark, 1978; Deutsch, 1978; Loveland, 1984). They also make use of here (often at first said while offering or transferring objects) and there (at first typically with an aspectual meaning of completion) early on, although the deictic meanings of these terms, as well as of deictic verbs like come, go, bring, and take, all with the speaker as the point of origin or deictic centre, take several years to master fully (e.g., Clark, 1978; Clark and Garnica, 1974; Clark and Sengul, 1978; Cox, 1986; Webb and Abrahamsen, 1976). What is important is that children consistently produce their first deictic terms before 18 months, and their first deictic contrasts, for example, here vs. that, by about age two. Somewhat older children can talk about alternate perspectives as if they are temporarily standing in someone else’s shoes. They become capable of quite sophisticated spatial shifts as they place themselves, so to speak, at different vantage points. Around age four, they begin to talk about alternate perspectives by starting from different origins (Clark, diary data), as in the examples in (1)–(4): (1) (2) (3) (4)

D (3;11,17, in a wild animal park) – ANTS think people are walking trees. D (4;5,2, reading Kenneth Graham’s The reluctant dragon, with Mo; D holding his fingers 2 cm apart): – and I would be this big to the dragon. D(4;6,27, still thinking about giants): – For a GIANT, a year is just an hour, and an hour is just a minute!….And for an ANT, a hour is a year! D (4;9,2) – Mummy, a fork is like a rake to a mouse.

That is, from age four on, children can start from different origins, and make comparisons based on such dimensions as size and time. 6.2. Pretence From as young as one year old, children pretend that one object is in fact another as they play (e.g., Bates et al., 1979; Bretherton, 1984; Bretherton, 1989; Church, 1966; Piaget, 1951). They pick up a spoon and hold its bowl to their ear, treating the spoon as if it were a telephone receiver, but on other occasions, they demonstrate that they also know what spoons are and how to use them for eating. They treat a hand-towel as a blanket for covering up a sleeping toy, but on other occasions show that they know that hand-towels are for drying hands. They place a plastic bowl upside-down on their heads, as if it were a hat, in contrast to other occasions when they treat it as a container. That is, in such pretence, children know what the objects

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in question really are, but, for the moment, are deliberately treating them as if they were something else (Leslie, 1987; Leslie, 1988; Leslie and Frith, 1990). And by age two, children understand pretence by others (Harris and Kavanaugh, 1993). This ability to treat one thing as if it were another is underlined by the words children use in pretence. They refer to a spoon as spoon on occasions of eating, but as telephone in play when they hold it up to their ear; to a block as block when they are building, but as vroom or car when they run it along the edge of a table; and to a bowl as plate or bowl when they consider it as a container, but hat when they place it on their head. Children can take different perspectives in pretend-play from as early as 12 months. And they begin to use different words for the same object in its real versus pretend functions anywhere from 12 to 18 months on. By age two, children extend their pretend play by enacting different roles, as when they talk for dolls or toys. At two, for example, they adopt high squeaky voices for toys compared to people (e.g., Sachs and Devin, 1976), and by age four, they have become quite adept at taking on different styles of speech, marked by contrasts in voice-quality, vocabulary, and choices of different syntactic constructions, to signal differences in age, power, and gender for the characters they are pretending to be (Andersen, 1990). They also begin to use language more systematically to mark shifts from the actual world to a pretend-world and back. For example, three-year-olds playing with a doll’s house shift perspective from the (real) world outside to the (pretend) world inside with deictic terms. In the following exchange, the mother uses thirdperson references, which the child shifts to first-person forms to mark presence inside the doll’s house (Stro¨mqvist, 1984, p. 42): Mo: What furniture does the Maja doll want to have in her room then? Ch (very squeaky voice): I want to have the furniture in MY room. From around age four, children also use their language to mark the planning of pretend-play events that have yet to take place in contrast to the later acting-out of those events (e.g., Kaper, 1980; Lodge, 1979). They usually adopt the past tense to describe non-present events in their stage directions where they anticipate what they are going to do. These stage directions may be interleaved with the actual ‘play’ being carried out, as in the following interchange (Lodge, 1979, p. 365):4 A (in the game) Where are you going tonight? A (stage direction) You said you were going to the ball. 4

The stage directions sometimes contain an explicit ‘pretend’ as in the following exchange between two four-year-olds (Garvey, 1975, p. 42): A. Pretend this was my car. B. No! A. Pretend this was our car. B. All right. A. Can I drive your car? B. Yes, okay. (smiles and moves away; A turns wheel and makes driving noises).

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B (in the game) I’m going to the ball. A (in the game) Is the Prince going too? B (in the game) Yes, and I’m going with him. B (stage direction) You got cross and argued about it. A (in the game) Oh no you’re not, I am. B (in the game) We’ll see about that. Mother! B (stage direction) You were mother and she didn’t want you to go. A (in the game, different voice) You’re not going to the ball tonight! Here, the verbs in the past tense (said, were, got, etc.) are all used to mark stage directions. In summary, children can take alternate spatial perspectives on objects and events from at least as young as age two. They appreciate differences in physical view point and know how to accommodate different lines of sight; they can postulate different vantage points in considering how the world might look to others; and they can pretend and treat one object as if it were another. The prerequisite in each case is that they be able to take different perspectives on the same object or event. They have all they need for the many-perspectives account of word acquisition.

7. Conceptual perspective and lexical development When do children realise that lexical choice indicates, for the addressee, which perspective the speaker is taking on a particular occasion? The MANY-PERSPECTIVES view assumes that speakers observe the principle of contrast, whereby any difference in form is taken to mark a difference in meaning (Clark, 1990, 1993). It also assumes that speakers can shift from one conceptual perspective to another through the lexical options they employ.5 Speakers can present a range of alternate perspectives, and they do so whether they are talking to small children or to other adults. Take the following hypothetical situation: Some birds are flying overhead and an adult, gesturing at them, says to a small child: ‘Voila` des oiseaux. Et encore un oiseau.’ The speaker next points at one particular bird and says: ‘Celui-la`, c’est un moineau.’ To another: ‘Et celle-la`, c’est une hirondelle.’ And to a third: ‘Et la`-bas, regarde le corbeau.’ 5 It also assumes that Speaker and Addressee know that they are referring to the same entity, through use of joint attention, physical co-presence, and linguistic-co-presence (see further Clark and Marshall, 1981; Clark, 1996, Chapter 4).

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How do the many-perspectives and the one-perspective accounts differ in the predictions they make about how children will respond to these new words? The many-perspectives view predicts that French children for whom oiseau (bird), moineau (sparrow), hirondelle (swallow) and corbeau (crow) are all unfamiliar words, will assign a meaning to oiseau that takes account of the fact that the adult used it for all the birds, and will try at the same time to work out how each of the other terms, used for individual birds, are related in meaning to oiseau. The basis for their assignments will depend on the pragmatic directions provided by the speaker, plus whatever linguistic and conceptual knowledge children already have to draw on (e.g., Akhtar and Tomasello, 1996; Tomasello and Barton, 1994). On some occasions, as here, children could readily infer that moineau, hirondelle, and corbeau designate subkinds of birds; on other occasions, they could make incorrect inferences about the meanings involved and have to adjust their interpretations later in order to fall in line with adult usage. The many-perspectives view predicts that even very young children will assume that multiple terms can refer to the same entity. Yet, like adults, children will observe contrast: the words oiseau and hirondelle must have different meanings even though they refer to the same entity, so the issue is to discover the precise relation that holds between the meanings of oiseau and hirondelle. The pragmatic directions in this situation consist of the pointing gestures to individual birds, following the adult’s use of oiseau for the birds as a group. What does the one-perspective view predict here? Since the adult is introducing unfamiliar words, one- or two-year-olds will most likely assign some meaning to the first new word encountered here, namely oiseau, but, having done that, they will reject the other three terms (moineaum, hirondelle, and corbeau) as referring to birds, because they cannot accept any further perspectives on the objects in question. So the one-perspective view predicts acceptance and use of only one term per entitytype. In fact, the one-perspective account has as a central tenet that young children cannot deal with more than one term per object. This, it is argued, is helpful during early lexical acquisition because it limits the options children must deal with as they assign meanings to unfamiliar terms (e.g., Markman, 1989). I turn now to evidence from children’s early word use, evidence that strongly supports the many-perspectives account over the one-perspective account. This evidence comes from a range of sources: young children’s spontaneous use and acceptance of multiple terms to refer to the same object; their rejections of one perspective on an object in favour of another; their uses of novel terms they themselves have constructed; their elicited uses of more than one term for the same entity, and their ready learning of new terms for already-labelled objects. 7.1. Multiple terms in early spontaneous speech Observational data show that very young children freely produce more than one term for the same entity. That is, they are capable of taking alternate perspectives on the same entity as they talk. They also, in the same discourses, accept different terms from the adults talking to them. Consider these examples (Clark, diary data):

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(5)

(6)

(7)

(8)

(9)

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D (1;7,1, looking at his bowl of cereal at breakfast): – Food. (A little later, still at the table, looking at his own and then his parents’ bowls of cereal): – Cereal. D (1;7,20, doing his animal puzzle; D named each animal type as he took it out [e.g., lion, tiger, zebra], then, on completion, with all of them back in, pointed and said): – Animal back. D (2;1,27, when his Mo asked what D was usually called) Mo: Are you ‘lovey’? D: No, I ‘Damon’, I ‘cookie’, I ‘sweetheart’! Herb ‘lovey’. D (2;2,24, playing with several small dolls) Mo: Do you call them people? D: They not people, they childrens. They kids. D (2;5,4, putting the waste-basket, usually called basket when he throws anything into it, down over his head)

In (5), D adds a second, more specific label, to indicate the kind of food in question; in (6), he again starts with specific terms for each animal, and then uses animal to encompass the whole collection or set. In (7), he readily uses (and thereby indicates his acceptance of) three different terms for himself and contrasts them with one identified as being used for his father. (His observations were correct.) In (9), with the shift in function, D switches perspective from basket to hider. Instances like these offer strong evidence that young children are not limited to just one perspective on any particular entity. Such uses are readily observable. Sometimes the conversations involve both adult and child proposing and accepting many different terms for the same referent, as in the following exchange (Brown corpus, Session 16, CHILDES Archive; Brown, 1973). Eve (2;1) and her mother have just been talking about all the people who don’t like a particular fan; Richard Cromer and Colin Fraser are the names of researchers working with the family, but only Fraser was present: Eve: These peoples. You and Fraser and Mom and Fraser and me. Mo: No, we don’t like the fan. Eve: We don’t like the fan. People and Mom and Fraser and Nanna and Papa and Cromer. Mo: They’re all people. Eve: Huh? Mo: They’re all people. Eve: And all children.

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Mo: No, they’re not children. Mom and Fraser are grown-ups and you’re a child. You and Sarah. Eve: Daughters. Notice that Eve accepts the term people for the individuals she had named, and she then applies two further terms herself, children and daughters, to a subset of them. At no point in the conversation did Eve have difficulty in allowing multiple terms for the same referents. This type of exchange is common with children as young as one and two years old. 7.2. Rejections: Perspectives or words? A second kind of evidence comes from children’s occasional rejections of one perspective in favour of another. Some two-year-olds, familiar with the term animal, reject it when it is used of an individual instance, a dog say. But they use it and accept it as long as it refers to a set of distinct animal types (Macnamara, 1982). For these children, animal initially appears to have a collection meaning like forest or army, and so cannot be applied to individuals (see also Valentine, 1942, p. 465, for a similar episode at age 2;6, again with animal). This meaning of animal is inconsistent with animal being used to pick out single instances of the type ‘animal’ (see Callanan and Markman, 1982; Markman and Seibert, 1976). Examples like this have often been cited as evidence for the one-perspective view, that children around age two reject unfamiliar words when these are offered as additional labels (e.g., Markman, 1987; Merriman and Bowman, 1989). Under this view, they reject animal, used of a dog, because they already know the term dog and won’t accept a second term for the same kind. But such episodes are not evidence for the one-perspective account: the children in question were quite content to use both dog and animal of the same entities as long as they differed in meaning, with dog for an individual and animal for a collection. To examine children’s rejections further, I extracted from the diary data for D every instance, up to age 3;0, where he had rejected a term offered by the adult speaker. Previous discussions have suggested that such rejections typically occur with adult use of a term not yet familiar to the child, offered in a setting where its meaning is not easily seen to contrast with the meaning of some appropriate term already known and used. The diary data suggest a different picture. There were 20 rejections in the diary. Of these, 16 were rejections of a second term already known to the child and used earlier for the pertinent referent. D was therefore rejecting not an unfamiliar term, but another term that could easily have been used on that occasion, as in (10)–(13): (10) D (1;10,9; Fa, reading to him about dolls, picks up a small Paddington bear) Fa: This is a doll. D: No, bear! (11) D (2;2,16; D playing with cars and trucks with a visitor)

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V: Where’s this truck going? D: That, that’s not a truck, that’s a fire-truck. (12) D (2;2,20, looking at a book with Fa) Fa: Look at those birds. D: That’s not birds, those PARROTS. (13) D (2;3,21, at supper) GrMo (to Mo): Shall I take your plate? (picks up plate) In each of these exchanges, the child was rejecting one familiar term (used on previous occasions for the referent in question) in favour of another familiar term: These are rejections of a perspective. The adult speaker offers one perspective on an entity through the term chosen to refer to it, and the child rejects it in favour of another one. The four remaining rejections were of unfamiliar terms. But, having been introduced to the new term and to the relation it bore to his own, the child took up the new term and applied it appropriately, either within minutes, or within days. The introductions of new terms in the diary data were nearly always related to familiar terms by the pragmatic directions is a sort of or is a kind of. Children readily take up terms offered by adults, as in the following exchanges between Abe and his mother (CHILDES Archive, Kuczaj data): (14) Abe (2;5,29, looking at a picture of a cup): That’s a glass. That’s mine glass. Mother: That’s a cup, isn’t it? Abe: That’s mine cup. We got that cup Daddy. (15) Abe (2;9,19, wanting to eat an orange) Mother: Here you go. Abe: Fix it. Mother: You want me to peel it? Abe: Uhhuh. Peel it. That is, children take up the terms offered by adults, whether these are offered in lieu of the child’s initial choices, as in (14) and (15), or as a further perspective, related to the original one proposed by the speaker. Under what circumstances might children legitimately reject an unfamiliar term? If they thought it had exactly the same meaning as another word, they should reject it on the basis of contrast, since two different forms can not have the same meaning (Clark, 1990, 1993). But sameness of meaning is not equivalent to sameness of reference. Two distinct expressions can still refer to the same entity, as when my neighbor, the cellist, and the history teacher all designate the same person, but from different perspectives. So rejecting one perspective in favour of another is very different from rejecting all but one perspective, as in the one-perspective view. 7.3. Constructing novel words Further evidence that children accept and use more than one term for a particular

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referent comes from their lexical innovations. Two-year-olds, for example, spontaneously construct compound nouns that serve as subordinate terms, usually at a level just below basic level terms. That is, children this age often have two levels in a number of domains, with basic-level terms (e.g., dog) providing the upper level and compounds (e.g., fire-dog) the lower one. In English, such compounds are constructed from a modifier noun followed by a (basic-level) head noun, with the appropriate stress pattern (primary stress on the modifier, tertiary stress on the head), as in DALMATIAN-dog and VOLVO-car. Some typical examples are listed in (16): (16) (a) GR (1;7) crow-bird [a crow] (b) HL (1;11) oil-spoon [a spoon used for cod liver oil] (c) EP (2;0) rat-man [colleague of Fa’s in lab] (d) R (2;0) fire-dog [stray dog found at the site of a fire] (e) GR (2;1) spear-page [page with picture people with spears] (f) D (2;2) tea-sieve, water-sieve [small and large strainers] (g) AG (2;3) car-smoke, house-smoke [car-exhaust, chimney smoke] In creating these compounds, children made clear that they knew which category an instance belonged to, through the head noun (e.g., a kind of bird) as well as the subkind, through the modifier (crow-) (Clark, 1993). Such spontaneous coinages suggest that children this age should be able to interpret novel compounds appropriately, identifying both the category membership and the subkind information from the head and modifier nouns respectively. They should also be able to produce such compounds when asked. They can and do. They know that a bicycle-truck, for example, is a kind of truck, and a frog-pan a kind of pan. And they use the modifier to decide which subcategory is being identified: the applein apple-knife picks out a knife used for cutting apples, not one for cutting bananas (for English: Clark et al., 1985; for Hebrew: Berman and Clark, 1989). In short, twoyear-olds understand that the terms knife and apple-knife could both pick out the same knife. The same children could also produce novel compounds for several subkinds of a higher-level category. In a typical elicitation context, illustrated in Fig. 4, the experimenter identified her own tree as ‘a bird-tree’ and then asked the child what the others were, or simply identified her tree as ‘This is mine,’ and went to say: ‘Look at yours. What’s this? What’s this?’ pointing in turn at each of the trees. Two-year-olds readily constructed such novel compounds as pencil-tree and carrot-tree in both conditions (Clark et al., 1985; see also Gelman et al., 1989; Taylor and Gelman, 1989; Waxman and Senghas, 1992; Waxman et al., 1991). In short, by age two, children can talk about instances of the same type from more than one perspective. Dogs on occasion can be dogs or they can be poodles, or poodle-dogs; trees can be trees or apple-trees; and birds can be birds or crow-birds. If children do this by two (or earlier), the difficulty they are said to encounter with more than one level in a taxonomic hierarchy must be in part a local difficulty in

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Fig. 4. Eliciting novel compound nouns (based on Clark et al., 1985).

learning individual words like animal. Most studies of children’s knowledge of levels have focused on basic-level and superordinate terms (e.g., dog and animal), rather than on basic-level and subordinate ones (e.g., dog and spaniel).6 7.4. Eliciting perspective shifts Can children shift from one conceptual perspective to another? If children can do this when asked, they should be able to supply different terms for the same referent in response to questions that require a shift in perspective. But some perspective shifts may be harder than others. Shifts that depend on knowledge of particular word meanings have to wait for children to acquire those words. For example, shifts from whole to part or from one domain to another depend on children’s knowing the relevant words, as in dog vs. tail, or dog vs. pet. Shifting from one level to another (dog to animal, for example) may be harder than shifting from one domain to another (dog to pet). This would be consistent with the general finding that superordinate terms are hard to learn (e.g., Callanan and Markman, 1982; Smith, 1979). Children can shift perspective by age two. In one study, two-, three-, and fouryear-olds were asked to accept and produce multiple labels for the same referents as they looked at a picture-book with pages of Richard Scarry-like animals dressed to represent various human professions, as illustrated in Fig. 5 (Clark and Svaib, 1997). The questions required that children shift perspective either by moving from one domain to another (e.g., dog to sailor), or from one level to another (e.g., dog to animal). All the children both understood and produced multiple terms, and did so most of the time. The youngest two-year-olds realised that an object could be both a cat and an animal, or both a pilot and a dog, although they found domain shifts slightly harder than level shifts (90% versus 96% correct). By age three, children were able to make the two types of perspective shift equally well (with 98% correct 6

It may well be harder for children to learn the meanings of higher level terms because they designate less coherent categories, with fewer properties in common than basic-level and subordinate ones (Markman, 1985; Tversky and Hemenway, 1984).

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Fig. 5. Eliciting perspective shifts (based on Clark and Svaib, 1997).

for level- and 99% for domain-shifts), although there were qualitative differences between the two types of shift. For example, when children relied on innovative nouns (6% of the time), they were more likely to do so in marking shifts in domain (92%) than in level (8%). Typical examples include fish-cat [a cat fishing], jumproper [cat holding a lasso], and caker [a pig baking bread] from two-year-olds; fisher-guy [a pig fishing], rope-people [two animal cowboys], mailer [a dog delivering letters] from three-year-olds; and cat-nurse [a cat pushing a wheelchair], drummist [a rabbit beating a drum], and airplaner [a pig flying a plane], from four-year-olds (Clark and Svaib, 1997). These two- and three-year-olds probably did not yet have as extensive a vocabulary for professions as for animal kinds, so at times they needed to coin a word to mark the shift in perspective. Other studies have also found that young children accept and apply more than one term for the same referent. Three- and four-year-olds can label objects at three levels (superordinate, basic, subordinate) when asked questions pitched to the appropriate level but containing an inappropriate term (Waxman and Hatch, 1992). For example, with a picture of a rose, the experimenter asked ‘Is this a dandelion?’ to elicit a subordinate level term (rose); ‘Is this a tree?’ to elicit a basic level term (flower); and ‘Is this an animal?’ to elicit a superordinate level term (plant). All the children, regardless of age, supplied the most terms in response to basic-level questions (89%), next most to subordinate-level questions (77%), and fewest to superordinate-level questions (22%). Overall, three-quarters of the three-year-olds and all but one of the fours produced more than one term for the same referent on at least 50% of the trials, typically a basic-level and a subordinate-level term. In short, these children readily offered two terms, and sometimes three, for the same referent (see also Blewitt, 1994; Waxman et al., 1991). Four- to five-year-olds readily accept two terms for the same referent as long as they are from different hierarchical levels (e.g., seal, animal), but not if they are both

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terms at the same level (e.g., seal, dog) (Au and Glusman, 1990). But if they are bilingual, they do allow two terms from the same level for the same referent as long as they come from different languages (e.g., English dog and Spanish perro). In short, these four- and five-year-olds act just like adult speakers in their patterns of use for terms from different levels and terms at the same level. Finally, when three- and four-year-olds are shown hybrid objects such as a crayon in the shape of a dinosaur and are asked questions about them, they readily produce multiple terms for the same object (Dea´k and Maratsos, 1997). For example, the experimenter might begin with ‘What is this? What’s it called?’, Child: A dinosaur; ‘What kind of thing is a dinosaur? A plant?’, No, it’s an animal; then as the experimenter began drawing with the crayon: Oh, it’s a crayon. In one study, 29 of the 32 children questioned (90%) produced at least two words for at least six of the eight objects. Dea´k and Maratsos also elicited both production and comprehension of multiple terms such as woman, mother, and police officer applied to a single character in a story. Again, both the three- and the four-year-olds accepted and produced multiple terms. To conclude, from at least age two on, children are able to understand and produce alternative terms for the same referent when asked questions that assume a shift in perspective. Two-year-olds find it slightly easier when the perspective-shift involves a change of domain, e.g., from animal-types to professions, rather than just a change of level, but this difference has vanished by age three. 7.5. Learning new terms for familiar objects When children hear a second term in the context of familiar, already-named objects, they readily assign a contrasting meaning to the new term. What appears to be critical is first, whether children already know a term for referring to the target object, and second, how the new term is introduced. For example, when three- and four-year-olds (mean age 3;8) saw two objects, one familiar and one not, and heard the experimenter say ‘Show me the blicket’, they chose the unfamiliar object as the referent over 80% of the time (Markman and Wachtel, 1988). Such assignments of unfamiliar terms to unfamiliar objects replicate earlier findings (e.g., Dockrell, 1981; Taylor and Gelman, 1988): the pragmatic inference under such circumstances is that a speaker who wished to pick out the familiar object would have used the familiar term for that object; since the speaker used blicket instead, she must intend to refer to the other, unfamiliar, object. However, when the speaker introduces a new term as referring either to a whole object or to a part of an object, children make different assumptions. The task is the following: After children were asked to identify some familiar objects and their parts, they were taught new terms in connection with either familiar or unfamiliar objects. In the familiar condition, children were first told, for example, that they would see a boom, and then shown a picture of a familiar firetruck, with the experimenter asking ‘Which one is the boom? This whole thing [E circling the whole firetruck with her finger] or just this part [pointing to the boom]?’ These children opted for a part-meaning 57% of the time, and for a whole-object meaning 43% of

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the time. In the unfamiliar condition, with the same procedure (e.g., with the finial of a pagoda), they opted for a part-meaning only 20% of the time and a whole-object meaning 80% of the time. In short, with an already named object, children were willing to assign a second term to pick out the same referent nearly half the time (Markman and Wachtel, 1988).7 In three further experiments, even when they were given nouns for substance or material (e.g., pewter, rattan), three- and four-yearolds persisted in assuming that these terms could in fact refer to objects for which they had no other term (58% and 75% of the time in studies 4 and 5). And where they already had a term for the object (e.g., the cup), they still treated a word like pewter as a further term for the same entity 40% of the time (study 5). That is, these children frequently assumed that more than one term was appropriate for a particular object. Finally, when two-year-olds (2;1 and 2;10) hear two terms for the same referent from two different speakers, they accept both terms between 44% and 66% of the time (Mervis et al., 1994). What are these children doing? According to the many-perspectives hypothesis, they are taking a new perspective. In fact, when two-year-olds (mean age 2;2) apply a new term to a category instance for which they already know a word, they typically limit its use (Taylor and Gelman, 1988, 1989). Are they thereby treating the new term as a proper name,8 as a term for a subkind within the known category (here, the category of dogs), or as a part of the whole object? When children (1;11 to 2;3) were taught a second term (fep) for an instance of a familiar category (dog) for which they already had a word (dog) (Taylor and Gelman, 1989), they readily interpreted the new term as referring to a subkind of the familiar, named category. That is, they would pick both dogs pictured when these looked alike (both terriers) as referents for fep, but only the original instance for fep when the two dogs pictured were different (a terrier and a poodle). And no child who learnt fep later rejected dog. That is, these children readily adopted a second perspective on instances of a familiar category. They favoured a subkind interpretation for the new terms. Older children (aged three, four, and five) show the same preference (Callanan et al., 1994). Yet children sometimes fail to learn two terms for the same referent. The reason, I suggest, is that children need to be able to infer how the words applied to the same referent differ in perspective. They must be able to make some reasonable inference in context. But what do children this age already know about language use in conversation? 7.6. Pragmatics in conversation From early on, children display their pragmatic skills in conversation. As young 7 This option was not available in this experiment in the unfamiliar condition, but was in a subsequent one: There when children were first presented with an unfamiliar term for an unfamiliar object and then given a second unfamiliar term in relation to the same object, they opted for a part-interpretation (an option made explicit in the test question, as before) 85% of the time. But also as before, they opted for a whole-object interpretation—68% of the time—when no prior term was given for the unfamiliar object. 8 But Gelman and Taylor (1984) showed that children as young as 18 months were sensitive to the presence vs. absence of an article as marking a common noun vs. proper name meaning.

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as age two, they respond appropriately to many requests, and, in doing so, they appear to draw on their pragmatic knowledge about the immediate situation, as in (17) where the child, appropriately, takes the adult action to be a reminder to eat (Clark, diary data): (17) D (1;11,28, talking at breakfast, as Fa tapped the edge of D’s bowl with a spoon): – Herb hitting [∂] bowl. Father: Why was I hitting your bowl? Why was I hitting your bowl? D (grin, as picked up his spoon): [∂] eat [∂] cornflakes. Children respond to a range of requests, both direct and indirect, from an early age (e.g., Ervin-Tripp, 1970, 1977; Shatz, 1978a,b). Their earliest responses appear to depend on their assessment of the situation and the action called for, rather than on detailed understanding of the language in the request per se. To requests for action and for information, for instance, one- and two-year-olds consistently respond with actions (Shatz, 1978a,b). By age two, children treat any why not question as a request for action, provided some action is possible (Ervin-Tripp, 1970, p. 82): (18) (a) Mo: Why don’t you put it in the wastebasket? Sally (2;0): Throw away? (b) Mo: Why don’t we bring out the swing? Carol (2;10): Yes. Yes I do. By age three, children’s replies to indirect requests also reveal an ability to give explicit analyses of the situation, as in the following responses from one child (aged 3;3) to indirect requests from his mother (Ervin-Tripp, 1977, p. 182): (19) (a) Mo (in car): I’m cold. Child: I already shut the window. (b) Mo (TV on in next room): It’s noisy in here. Child: Do you want me to shut the door? Observations like these suggest that children start early in making inferences about the expectations speakers may have under various circumstances. Included here are assessments of what people expect when they ask questions, and when they repeat the same question (the first answer did not provide the expected information). Children’s pragmatic skills are exemplified in their growing conversational skill. Yet what children know about conversational practice isn’t always adequate for specialized situations: …[They] are both sophisticated and limited users of the rules of conversation that promote effective communication: sophisticated when it comes to the use of conversational rules in everyday, natural talk; limited in specialized settings which require knowledge of the purpose intended by speakers who have set aside the rules that characterize the conventional use of language [Siegal, 1991, pp. 1–2].

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When we turn to experimental studies, we find that researchers often violate normal pragmatic assumptions about conversation. One common violation is in the way children are asked questions (e.g., Shipley, 1975; Siegal, 1991). In conversation, the speaker normally asks questions either to obtain information or to get the addressee to do something. But in test situations, the adult speaker already knows the information being requested and is simply testing to see whether the child knows it too. When the speaker asks just one question, it may not be obvious to a child that this is a test, but when she asks the same question more than once, then the child has reason to interpret it differently from the adult. For example, an adult may repeat a test question in order to make sure that the child really does know the answer and is willing to stick by it. But in a normal conversation, the speaker would have repeated a question only after receiving an answer that was adjudged inappropriate or inadequate in some way. In such situations, the repeated question would be construed as a request for a change in response. The pragmatic inferences applicable to questions in conversation often do not apply in experimental settings. Because children have a difficult time in many experiments working out what the adult really wants, they may take into account factors that should be irrelevant (Donaldson, 1971, 1978). For example, in some conservation tasks, children are shown two sticks the same length, aligned to be parallel, and asked ‘Are they the same?’ Children typically answer ‘yes.’ But if the experimenter then moves one of the sticks so the ends are no longer aligned and repeats the question, three-, four-, and even five-year-olds typically now answer ‘no.’ The change of position is taken to be relevant to the speaker’s repeated question. When children are trained to ignore irrelevant changes, or changes introduced by accident, they do much better (e.g., Gelman, 1969; McGarrigle and Donaldson, 1975; McGarrigle et al., 1978). If children interpret a repeated question as a direction to alter their first judgement, they should do better in conservation tasks when they are questioned only once, after observing the change designed to test whether they can conserve a property like length. When six-year-olds are shown two sticks the same length, first with ends aligned, then moved out of alignment, and only then asked ‘Are they the same?’, the children are not only more likely to answer correctly, they also do better on subsequent standard conservation tasks (Rose and Blank, 1974). When four-, five-, and six-year-olds are asked either one or two questions about conservation of number, those who first hear a one-question version of the task later produce more conservation responses in the standard two-question version than do children who get the standard task first and then the one-question version (59% versus 19%) (Siegal, 1991; Siegal et al., 1988). Experience first with the one-question task helps make clearer to the children what the experimenter wants.9 These studies show that children consistently construe questions according to usual conversational practices. Where such practices fail to hold, younger children are likely to misread the adult speaker’s intentions. This in turn can result in mis9 In fact, misleading questions promote non-conservation in adults as well as children (Winer et al., 1988). Equally, classic inclusion questions can be re-worded so children who previously ‘failed’ now answer them appropriately (Shipley, 1975; see also Donaldson, 1978; Siegal, 1991).

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assessments of what children actually know. To succeed in many test situations, children must learn to suspend their normal assumptions about conversational practice and invoke a different set of pragmatic rules. 7.7. Failures to assign new terms In some studies of word learning, children fail to assign new terms, and do not choose any candidate referents for the new words they have just been exposed to. This, it has been suggested, offers crucial evidence for a one-term-per-entity account of early word learning, a one-perspective view. Under what circumstances might children appear to endorse such a view? One is where they receive too little information about how two terms could be related, and hence what kind of perspective the new term marks. Consider one common format in word-learning studies (e.g., Merriman, 1986; Merriman and Bowman, 1989). The child is first presented with an unfamiliar object, is offered a term for that object several times (‘This is a ruk. Look at the ruk’), and is then asked to find one or more instances of that type in a small array of objects. All children succeed on this. The child is then shown an instance of the same object again but this time offered a different term for it (‘This is a dax’), with a repeat of the earlier exposure and test phases. Then the child is asked to pick out the referent of the first word taught: ‘Show me a ruk’ and often fails to do so. Where the experimenter offers no relation between ruk and dax, and simply uses them, one after the other, for the same objects, most children either (a) pick one or more appropriate referents only for the first word taught, and ignore or refuse to respond to the second, or (b) pick appropriate referents only for the second word taught, and don’t respond to the first. This suggests that they could have interpreted the situation pragmatically in one of two ways. Those who respond as in (a) appear to take in the first word, but are unable to work out how to apply the second, so they ignore it; those who respond as in (b) act as if they are confused by the first word and so opt to deal only with the second one. When speakers change terms with no explanation, children, like adults, must try to fathom why. If they are unable to do so, they may ignore one or other of the words just because they are confused. From such findings, researchers have argued that children do not allow more than one term to apply to a single referent. They have therefore argued for what is effectively a one-perspective account in the form of a ‘constraint’ on children’s hypotheses about meaning such as the assumption of mutual exclusivity in Markman (1987, 1989): ‘Each object, then, could have only one category label, and each label could refer to only one category of objects’ (Markman and Wachtel, 1988, p. 122). Notice that this assumption divides into two distinct parts: the first clause captures the notion of mutual exclusivity in reference, the one-perspective view. The second clause simply offers a version of the principle of contrast, that any difference in word form marks a difference in meaning (Clark, 1987, 1990), which is one basis for the many-perspectives view. According to the one-perspective account, children can rely on just one perspective per entity because this makes it easier for them to work out the meaning of new words. But, as they learn more terms, they give up mutual

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exclusivity and use more than one term to refer to objects and events.11 However, failure to apply two terms to the same referent under such circumstances, I suggest, is not evidence for the one-perspective view. They are better attributed to confusion over how the two terms, and hence two perspectives, are related. Let us see how. 7.8. Relating new terms to familiar ones Children, as we have seen, allow for different terms for the same referent from a very early age. But whether the new terms pick out the whole object (as in cat and pet, or boy and friend), a subkind (as in cereal and food, or Dalmatian and dog), a superordinate (as in animal and raccoon, or furniture and chair), or a part (as in collar and jacket, or handle and pan) depends on the inferences children are able to make on each occasion. Adults often specify the relation by offering pragmatic directions like is a kind of y, are all y’s, or is a part of y (see Table 4). But when they do not, children must rely on inferences based on whatever information is available from the array of referents physically present, the preceding conversation, and what they know about the speaker. If the relation between two words (two perspectives) is not given explicitly, children must make an inference about what the relation could be. Word-learning studies support both approaches: children make use of pragmatic directions when they get them, and they make inferences in the absence of such directions. In studies of new words in Markman and Wachtel (1988), children were asked explicitly whether they were picking out as the referent the whole object or just a part of it. These expressions, ‘the whole thing’ and ‘just this part’, offer the children explicit pragmatic directions about the intended relation of the new term to the term already known. And children make use of this in assigning part-of interpretations to words just learnt. When adults do not offer explicit pragmatic directions, children make use of whatever information they have about the objects being talked about (e.g., Taylor and Gelman, 1989). For instance, when children (aged 1;8 to 2;7) were taught a new word for a familiar category (dax for the category dog, exemplified by a picture of a terrier), their subsequent choices of referents for dax depended on the similarity of the new instances to the original. They treated two terriers wearing different collars as more similar than a terrier and a poodle wearing similar collars. In short, dissimilar instances are treated as subcategories of the known category. In other situations, children may take the locus of attention in context and assume that an unfamiliar word is relevant to the object or action that recurs across several events. For example, when two-year-olds see several different objects all performing 10 Researchers disagree, however, on the age at which such a mutual exclusivity bias emerges, how long children hold on to it, and just what kinds of information they rely on in over-riding it (e.g., Merriman and Bowman, 1989; Woodward and Markman, 1991). 11 In the case of events, children begin fairly early to make contrasting use of transitive vs. intransitive verb forms, lexical causatives vs. periphrastic causatives, and other such distinctions that can mark different perspectives on an event (e.g., Ammon, 1981; Bowerman, 1982, 1990; Behrend et al., 1995; Forbes and Farrar, 1995; Gleitman, 1990; Naigles, 1996).

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the same action (e.g., twirling), they take the speaker who at one point uses an unfamiliar word to be talking about the current object affected, but when they see the same object (e.g., a dog) performing several different actions, they take the speaker to be talking about the current action. The current focus in each context is treated as more likely to be the intended referent for a new word (e.g., Akhtar et al., 1996; Tomasello and Akhtar, 1995). Children who are offered no explicit pragmatic directions about the relation between a familiar term and a new one rely on all sorts of strategies in deciding on possible meanings and hence on possible referents for an unfamiliar word. Children consistently use what they already know about possible actions and relations if that is all they have to go by. For example, 18-month-olds who have not yet assigned meanings to in and on rely on what they know about containment and support to respond to requests like ‘Put the mouse in/on the box.’ If the location is a container, they place smaller objects inside it; if it is a supporting surface, they place them on top (e.g., Clark, 1973, 1977, 1980). These two coping strategies are used consistently by children under the age of 2;0 to 2;6. And when questioned about extent or amount, young children show a strong preference for choosing objects with greater extension (larger, longer, and taller objects, piles with greater amounts and glasses holding greater volume) over lesser extension (Klatzky et al., 1973). Such preferences can make it appear that even very young children ‘know’ the meaning of in or the meaning of long, but not the meanings of under or short (e.g., Clark, 1973; Donaldson and Wales, 1970). Some examples of common coping strategies are shown in Table 5. When children know the words but not the constructions they appear in, they make use of linguistic co-presence (the terms used), physical co-presence (the objects being talked about), and possible relations in the world to come up with a coping strategy. These sources of information often allow them to reach a plausible interpretation and hence to decide on how to construe the adult utterance. For example, young two-year-olds appear to interpret passive constructions appropriately as long as their construal, based on physical and linguistic co-presence, is congruent with the adult interpretation, as in The baby was fed by the mother. (Note that even young children know that mothers feed babies, not the reverse.) But where the children’s knowledge of plausible events and hence their construal fits Table 5 Some common coping strategies 1 2 3 4

Location: Assume smaller objects always go inside containers first, but, in the absence of containers, they go on supporting surfaces. Extension: Assume greater extension takes priority over less extension for amount, volume, height, length, width, and choose the more extended amount, length, etc. Event order: Assume clause order mirrors actual event order, such that clause-1 describes event-1, clause-2 describes event-2, and follow instructions or act-out events accordingly. Agent identification: Assume usual or canonical relations hold among participants in an event, and interpret utterances accordingly (e.g., cups go on saucers, dogs chase cats, mothers feed babies, etc.).

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neither a passive (e.g., The mother was fed by the baby) nor an active (e.g., The baby fed the mother), two-year-olds act out such sentences incorrectly (e.g., Strohner and Nelson, 1974). So what have been called non-linguistic strategies generally reflect reliance on a mixture of information drawn from physical and linguistic co-presence on particular occasions. This mix, combined with whatever else young children already know about the usual relations among objects (e.g., shoes go on feet; people sleep in beds; birds have feathers) and the actions that can be performed on or with them (e.g., eating/spoon; drying/towel; shutting/lid) provides them with an initial basis for construing adult instructions and requests even when they do not yet have adultlike command of the language. Children make use of all the information available in making inferences about the meanings of unfamiliar words. But in the absence of adequate pragmatic directions, they may still be unable to set up any relation between an unfamiliar and a familiar term, or between two unfamiliar terms. This in turn would account for their failure to adopt the alternate perspective licensed by the new term. In short, since even very young children are attuned to the pragmatics of the conversational context, pragmatic directions appear to play a critical role in helping children acquire new meanings and in helping them relate new meanings to old ones.

8. Conclusion Children make use of multiple perspectives from age one on. They show this in their uses of spatial perspective, when they take into account someone else’s physical point of view, and in their pretend play. As soon as they have the words, they use them to mark different conceptual perspectives, as when they use two different terms to characterise the same referent, as a basket and as a hat, say, or as a horse (a pull-toy) and as a chair. When they reject the term an adult offers, they reject that conceptual perspective. They also reveal their ability to use two or more terms for the same referent when they construct novel terms for subkinds, innovative compounds of the type poodle-dog for a subkind of dog. They construct such compounds in their spontaneous speech before age two, and on demand from age two on. Also, from two on, they can shift perspective when asked, from cat to animal, or the reverse, and from sailor to dog, or the reverse. That is, even two-year-olds can shift conceptual perspective from one level to another, and from one domain to another. The limiting factor would appear to be their vocabulary, not their ability to shift perspective per se: this ability appears in many non-linguistic tasks too, again from the age of one to one-and-a-half on. Older children, aged three and up, show equal ease in going from one level to another when asked questions that require a shift in perspective, and they too readily apply multiple terms to the same referent. In short, the evidence supports the view that children adopt multiple perspectives from the start. To talk about alternate perspectives, children need to understand how terms are related. For example, nothing in the forms of the words animal and cat would allow

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the inference that a cat could be talked about either as the cat or that animal. But if children are offered pragmatic directions like ‘A cat is a kind of animal’, or ‘That cat is Jan’s pet,’ they readily adopt the alternate perspectives required. If such directions are absent, they may ignore a new term or refuse to use it: They lack the information needed to infer that it too refers to the target object type. In word learning tasks, it is the presence or absence of the relevant pragmatic directions that accounts for whether children will or won’t accept more than one term for a particular object. In summary, children readily adopt alternate conceptual perspectives on the same entity. They both accept and make use of multiple terms for referring to the same entities, and they do so from as early as 18 months. The emergence of perspectivetaking marked by lexical choices appears to coincide with the emergence of spatial perspective-taking and with the onset of pretend-play, both of which presuppose the ability to take alternate perspectives on the same entity. Speakers mark the perspective they have chosen on an event, an action, or an object in their choice of words. Realising that this is the case and making use of multiple perspectives from the start is an integral part of acquiring a language.

Acknowledgements This research was supported in part by the Center for the Study of Language and Information, Stanford University. I thank Gedeon Dea´k, Samuel Fraidin, Yukiko Morimoto, Emanuel Schegloff, Michael F. Schober, Michael Tomasello, Barbara Tversky, and two anonymous reviewers, for their helpful comments. I owe a special debt to Herbert H. Clark for many conversations about perspective as well as for discussion of earlier versions of this paper.

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