Object Shape, Object Function, and Object Name

Object Shape, Object Function, and Object Name

JOURNAL OF MEMORY AND LANGUAGE 38, 1–27 (1998) ARTICLE NO. ML972533 Object Shape, Object Function, and Object Name Barbara Landau University of Delaware and Linda Smith and Susan Jones Indiana University We investigated the roles of shape and function in object naming. Two-, three-, and five-year- olds and adults heard novel or familiar objects named; some participants also were instructed about the objects’ functions. Then they were asked to generalize the names to new objects that preserved shape or functional capability; some participants also judged the objects’ potential for carrying out the designated function. Children generalized the name by object shape regardless of instruction, but adults did so only in the absence of instruction or for familiar objects. Knowledge of function independent of naming became increasingly stronger and diverse over age. The strong developmental changes in the role of function bear on mechanisms of object naming. q 1998 Academic Press Common sense tells us that if we know function. As Miller and Johnson-Laird (1976) argued, function is a critical aspect of catego- what an object is we often know what it does. If asked ‘‘What is a chair?’’, one might re- rizing most human artifacts, so much so that spond ‘‘Something you sit on’’; if asked ‘‘function—at least for artifacts—is more ba- ‘‘What is a knife?’’, a plausible answer might sic to the definition than form’’ (p. 229). begin ‘‘Something you cut with.’’ Indeed, the In this paper, we consider the role of object importance of function in our knowledge of form and function in the early development named artifact categories is so deeply in- of object naming—specifically, the naming of grained that it often serves as a starting as- artifacts. Interest in the relative roles of object sumption in discussions of the ontogeny and appearance and function has a long history in nature of naming: Assuming that artifact both the developmental and adult literatures names are cover terms for artifact categories, on object naming and concept representation and that function is a critical component of (Bloom, 1996; Gentner, 1978; Malt & John- many such categories, it follows that artifact son, 1992), partly because these properties names should be generalized on the basis of tend to be viewed as major criteria for mem- bership in artifact categories. In our view, however, the contrast is an especially interest- This research was supported by NICHD Grant PHS RO1 HD-28675, NIMH Grant PHS RO1 MH-55240, and ing one because sensitivity to the properties Social and Behavioral Sciences Research Grant 12-FY93- themselves stems from different sources, their 0723 from the March of Dimes. We thank C. E. Wright relationship is complex, and there may be de- for advice on statistical matters, the University Montes- velopmental changes between them that yield sori, Irvine Child Development Center, and the University insight into the development and mechanisms of Delaware Preschool for cooperating with us, and Diane Beck, Jamie Chosak, Jennifer Nolan, and Melissa of object naming. Although function might be Schweisguth for help in conducting the studies. more important than form in adults’ lexical Address reprint requests and correspondence to Barbara categorization of artifacts, it may not be in Landau, Department of Psychology, Wolf Hall, Univer- children’s. Further, tracking possible develop- sity of Delaware, Newark, Delaware 19716. E-mail: blandau@udel.edu. mental changes in form and function in nam- 1 0749-596X/98 $25.00 Copyright q 1998 by Academic Press All rights of reproduction in any form reserved. AID JML 2533 / a010h$$$81 12-17-97 08:40:26 jmla AP: JML

2 LANDAU, SMITH, AND JONES ing may yield new insights into ontogenetic Landau, Smith, & Jones, 1992; Smith, Jones, & Landau, 1992). In these studies, adults show process. Information about form originates principally through the visual system, and an extreme bias: They reject objects that vary even a small amount in shape while accepting function through an understanding of the physical principles (such as gravity or force) objects that are radically different from the standard in either texture or size.

involved in the interactions of people with ob- jects and objects with each other. The existence of a shape bias in no way implies that it is the only mechanism at work One hypothesis about the relationship be- tween these sources of information is that the during object naming. On the contrary, the bias is highly context dependent, occuring in early development of object naming princi- pally engages the perceptual systems, and only the specific context of object naming, but not in nonnaming contexts that also require judg- secondarily the systems of general world- knowledge about objects. Because of this, ments of similarity (see Jones & Smith, 1993; Smith, 1994, for reviews). Furthermore, in early object naming may be relatively ‘‘im- mune’’ to the influences of young children’s contexts where similarity of shape is pitted directly against taxonomic category member- knowledge about objects, including for arti- facts an object’s functions (Smith, Jones, & ship (an unusual situation in the real world), the importance of shape declines with age (be- Landau, 1996). We ask whether this early im- munity occurs only in naming tasks, whether tween three and five) and with familiarity of category (Baldwin, 1992; Imai, Gentner, & it occurs over a variety of object types, and whether and how lexical categorization comes Uchida, 1994). Thus, while shape is not the only information that children use to establish to incorporate information about function. In the following sections, we review evi- lexical membership, it does seem to enjoy a special status during children’s first encoun- dence supporting the importance of shape in early object naming, the importance of func- ters with newly named objects. The contextual dependence of the shape tion in mature object naming, and ways of evaluating the relative importance of these bias and its decline in the context of familiar objects suggests that an emphasis on shape is over development.

modifiable when alternative bases for general- The Importance of Shape in Early Object ization become known. Object function pres- Naming ents itself as an obvious source of information which might critically influence lexical cate- In a variety of studies, we have shown that young children and adults tend to generalize gory formation. a novel artifact’s name to other objects that The Importance of Function in Mature are similar to the exemplar object in shape Object Naming rather than texture, substance, or size. The findings of preference for same-shape objects There is considerable evidence consistent with the idea that functional information is a are consistent with the findings on the taxo- nomic basis for categorization in young chil- critical, even core, aspect of our mature named object categories. Rosch, Mervis, Gray, and dren and infants (Markman & Hutchinson, 1984; Waxman, 1995), as many objects in the Boyes-Braem (1976) found that basic level objects share a high degree of overlap in func- same taxonomic category do share overall shape (Imai, Gentner, & Uchida, 1994; Rosch tion. Malt and Johnson (1992) showed that object function—while not sufficient—can et al., 1976) and part structure (Tversky, 1989). The preference for same shape in ob- play an important role in adults’ decisions about category membership for novel arti- ject naming appears in fragile form by the age of 2, becomes stronger by the age of 3, and facts, for example, their judgments of when an object can legitimately be called a ‘‘boat.’’ is very strong in 5-year-olds (Jones, Smith, & Landau, 1991; Landau, Smith, & Jones, 1988; Finally, Barsalou (1989) argued that adults AID JML 2533 / a010h$$$82 12-17-97 08:40:26 jmla AP: JML

3 OBJECT SHAPE, OBJECT FUNCTION readily create novel ‘‘ad hoc’’ categories ‘‘hat’’ to other objects—such as keys—as he places them on his head. Nelson suggested based on function, e.g., ‘‘things to take on a picnic.’’ that once such categories are formed on the basis of action, the corresponding category la- Evidence also shows that school-aged chil- dren tend to rely on an object’s function in bels may be generalized on the basis of per- ceptual properties such as form. Thus function making lexical category assignments (Keil, 1989; Merriman, Scott, & Marazita, 1993; would serve as the core of the infant’s con- cept, while perceptual similarity would follow Richards, Goldfarb, Richards, & Hassen, 1989). Keil found that such older children as the basis for generalizing the object’s name. Knowledge of object function is indeed ac- would select as a ‘‘hammer’’ an object that was heavy enough to pound objects rather than quired before or during the earliest object naming, making plausible the idea that func- one that had the overall appearance of a ham- mer but could not carry out the standard flat- tion might be the core for object naming. In habituation tasks, Kolstad and Baillargeon tening function due to a hole placed strategi- cally in the hammer’s head. Richards et al. (1991) found that 10- and 12-month-old in- fants who were given experience with a func- (1989) found that fourth to sixth graders and adults judged object category membership on tional property (bottoms that serve to contain a substance) then generalized on the basis of the basis of function rather than form. For example, they were unlikely to accept an ob- that property rather than overall similarity of appearance. Madole and Cohen (1992) found ject that was ‘‘just like a fork but had no tines’’ as ‘‘still a fork.’’ that 14-month-olds were sensitive to form– function correlations: After habituating to ob- Might object function also serve as a critical basis for naming during the early years of jects exhibiting a given form together with a given function (carried out by particular object word learning? One framework, which we will call ‘‘action-based,’’ sees the foundation for parts), they dishabituated to objects pos- sessing novel form–function combinations.

categories as the product of sensory and motor schemas that develop as the infant grasps, ma- In nonhabituation tasks, there are similar findings. Brown (1990) reported that as early nipulates, and otherwise discovers an object’s properties through action. According to Piaget as 18 months, children will select an object to perform a function on the basis of its function- (1954), the infant’s sensori-motor activities become organized over the first year of life ally relevant properties rather than other sa- lient features. In one experiment, children as the infant discovers enduring properties of objects such as their shape, size, and mallea- were enticed to retrieve a toy from some dis- tance away using a long rigid cane. Then they bility. Discovering the physical effects of ob- jects on each other constitutes some of the were given a choice of several objects to use as a tool. The children chose objects that pos- infant’s earliest knowledge, and could thus serve as a first step in the acquisition of names sessed both sufficient length and rigidity for the task in preference to objects that looked for objects.

In this vein, Nelson (1974) argued that ob- more like the standard that had previously been shown to work. Brown argued that chil- ject categories underlying early words are ini- tially formed on the basis of action—what the dren bring to this problem-solving task an un- derstanding of what is relevantly ‘‘similar’’ infant does with an object (see also Werner & Kaplan, 1963). These functional categories are to the standard: here, length and rigidity, not surface texture or overall shape.

the prelinguistic categories that serve as the basis for first words, which are often words These ideas about the early importance of function are also consistent with current ‘‘the- for moveable and manipulable objects. Nelson gave the example of the child who first utters ory-driven’’ views of word learning, which show that even young children appreciate the the word ‘‘hat’’ in the context of placing it on his head. Subsequently, he might generalize deeper properties underlying an object’s AID JML 2533 / a010h$$$82 12-17-97 08:40:26 jmla AP: JML

4 LANDAU, SMITH, AND JONES named category and that this understanding shape-based generalization among 2- to 5- year-olds and adults (see Jones & Smith, allows them to bypass superficial (often ap- pearance-based) similarities (e.g., Gelman, 1993; Landau, 1994, for review). In Gentner’s study, the only indication of function-based 1988). Of particular relevance is a study by McCarrell and Callanan (1995) which showed responses in adults was their spontaneous ten- dency to call the hybrid a ‘‘jiggy-zimbo’’ that 2- and 4-year-olds were sensitive to corre- spondences between an animal’s form and upon first seeing it. Their use of the function- based ‘‘zimbo’’ as the head noun suggests that its ‘‘function’’ (here, a behavior such as ‘‘stretches tall to eat cherries’’). This sensitiv- they thought the object was a member of the ‘‘zimbo’’ category, but one with ‘‘jiggy’’ ity was sufficient to promote inductive infer- ences about the behavior of new category properties (Lyons, 1977). Other studies also have found a dominance members, suggesting that knowledge of func- tion may play a critical role in tasks of catego- for an object’s overall appearance compared to its function among young children and have rization other than naming. For artifacts, func- tion may be the key conceptual property (see suggested a developmental increase in the im- portance of function. Tomikawa and Dodd Keil, 1989) and thus within this general view of word learning, an emphasis on function (1982) found that 2- and 3-year-olds more readily learned names for perceptually similar over shape might be expected in naming as well as other kinds of categorization. objects (that had different functions) than for objects sharing a common function (but hav- ing different shapes). Merriman (1993) found Evaluating the Importance of Shape and an increase between ages 3 and 6 in the ten- Function in Early Object Naming dency to generalize a novel name on the basis of function (as opposed to appearance), but Previous studies on naming suggest that the two different kinds of information may inter- even in 6-year-olds function was weighted only slightly more strongly than appearance.

act differently at different points in develop- ment. In one of the earliest studies pitting ap- Although there are no comparable studies of novel object naming among older children and pearance against function, Gentner (1978) in- troduced children and adults to two different adults, related findings suggest that at these ages function may often prevail in the naming complex novel objects each possessing a very salient function (a lever dispensed jellybeans of familiar objects (Richards et al., 1989; Rosch et al., 1976).

for the ‘‘jiggy’’; an identical lever moved parts of a face for the ‘‘zimbo’’). Participants These findings suggest that overall appear- ance, primarily similarity of shape, dominates were encouraged to manipulate each object repeatedly, viewing the function; during this, function in early object naming. However, there is an alternative interpretation. It is pos- each object was labeled. Later, participants were shown a hybrid object which possessed sible that, given the particular stimuli used, the appearances (shapes) of the objects were the form of the zimbo but produced jellybeans like the jiggy. They were asked whether it much more salient overall than the properties supporting the functions. If so, children might should be called a ‘‘jiggy’’ (following the ob- ject’s overall appearance) or a ‘‘zimbo’’ (fol- have generalized on the basis of object shape no matter what kind of task they were given.

lowing its function). Gentner found a U-shaped function: 2- to To argue that similarity of shape not only dominates object function, but specifically 5-year-olds and adults chose strongly on the basis of appearance, but 5- to 15-year-olds does so in the context of object naming, one would need a test that discovers whether chil- chose more than half the time on the basis of function. The strong reliance on appearance dren are sensitive to the objects’ functional properties and then a measure of whether this among 2- to 5-year-olds and adults is consis- tent with our previous findings showing robust sensitivity enters into the object naming task. AID JML 2533 / a010h$$$82 12-17-97 08:40:26 jmla AP: JML

5 OBJECT SHAPE, OBJECT FUNCTION A recent set of experiments assessed this knowledge of the objects’ functions. We did this using simple novel artifacts with simple possibility. Smith, Jones, and Landau (1996) showed 3-year-olds and adults highly complex novel functions (Experiment 1). Keeping in mind that the findings may vary widely with novel artifacts built of a distinctive base object with salient appended parts. In a Name task, object and function type, we then proceeded to ask the same questions using functions participants were asked whether test objects had the same name as the exemplar. In a Simi- which are known to be accessible to very young children (Experiment 2). Finally, be- larity task, participants were asked whether test objects were ‘‘the same as’’ the exemplar. cause the form and function relationship in naming may be different for familiar than for Half of the participants were also shown a function for either the base object or the sa- novel objects (Merriman, 1993), we investi- gated these roles in children’s and adults’ lient parts. Note that both tasks—Name and Similarity—required participants to make knowledge of familiar everyday objects (Ex- periment 3).

judgments on the basis of some kind of simi- larity. The question was whether the basis EXPERIMENT 1 would be the same for both tasks. Results showed that adults’ judgments in We tested children’s and adults’ attention to shape over material in object naming (Name the Name and Similarity tasks were influenced by the functional information. Three-year- task), where the object’s function could be carried out by virtue of its material. All parti- olds’ judgments in the Similarity task were also influenced by the functions. However, cipants heard a novel object named. Half of them were explicitly shown a material-based children’s judgments in the Name task were immune to influence from information about function and half were not, and then all were asked to extend the standard object’s name function. Instead, their judgments were influ- enced by changes in the relative perceptual to new objects. Those who were shown the function were also directly asked whether salience of the base vs the parts. These results led Smith et al. to suggest that early object each object could be used to carry out the designated function (Function task). Our ques- naming may in some way be so tightly tied to certain aspects of perception that it is cut tion was whether the instructions about object function could influence participants’ atten- off from other influences of world knowledge that the child has. tion to shape vs material, and whether the pat- tern of responses in the Name task would dif- These results suggest a strong hypothesis for the development of object naming. Spe- fer from those of the Function task. cifically, knowledge of function—while criti- Method cal for the formation and use of mature object representations that underlie naming—may Participants. Seventy-two participants were tested, including twenty-four 3- and 5-year- play a quite minor role in early object naming. Further, the results suggest that immunity to olds and adults, with each age group balanced for gender. Mean ages of the children were 3; functional knowledge should be seen earlier than age 3, but may begin to change with 5 and 5; 4 (Ranges Å 3; 0–3; 10, 4; 11–5; 11). Children were drawn from preschools in development after this point.

The purpose of the present experiments was the area around Irvine, California, and adults were undergraduates at the University of Cali- to begin to test this account, using a wider developmental window and a broader range fornia, Irvine, who participated for class credit. Half of each age group was randomly of objects and functions than those used by Smith et al. (1996). We began by challenging assigned to each of the two experimental con- ditions described below. children’s and adults’ attention to object shape in a naming task and comparing it to their Design and materials. In the No-Function condition, participants were shown the stan- responses in a task that directly assessed their AID JML 2533 / a010h$$$83 12-17-97 08:40:26 jmla AP: JML

6 LANDAU, SMITH, AND JONES and therefore provide a comparison point to previous findings of a shape bias in the context of naming. However, the materials were novel and designed specifically to support clear functions. The test set for each standard included nine objects: two subsets of four plus a replica of the standard. Each subset contained two Same-shape and two Same-material objects. The Same-material objects were the same ma- terial as the standard but different shapes; and the Same-shape objects were the same shape as the standard but were made of different materials—ones that could not support the standard’s function. In the Rif set, the novel materials were nonporous, either styrofoam or a tightly woven, glossy fabric covering a thick soft pad. In the Dax set, these materials were hard and impenetrable, either brick-shaped Lego parts assembled into the U shape or plas- ter painted to a high gloss. In both the Rif and Dax sets, each Same-shape object was matched in color to one Same-material object. Procedure. Participants in the No-Function FIG. 1. Objects used in Experiment 1. The ‘‘standard’’ condition were shown one of the standards Rif and Dax are shown at the left. Test objects included and told, ‘‘See this? This is a dax.’’ Then the two Same-shape (different material) and two Same-mate- standard was placed to the side, still in full rial (different shape) objects (see text for full description). view, and each of the nine test objects was removed from a box one at a time and shown to the participant, who was asked ‘‘Is this a dard object and heard it labeled, but no in- formation about function was provided. In rif/dax?’’ (Name question). After he or she answered yes or no to each object, it was put the Function condition, participants saw the standard and heard it labeled, but they were back in the box and the next object was brought out. Each object was queried twice, also told and shown what the standard was used for. followed by the second standard and test set, for a total of 18 test trials per set and 36 in Two sets of objects were constructed (see Fig. 1). The standard for the Rif set was a total. Participants in the Function condition un- roughly 2’’ 1 2’’ roundish object made of pale yellow sponge used in standard sink derwent the same procedure, with the follow- ing exception. They were shown the standard sponges. The Rif’s function was to wipe up water. The standard for the Dax set was a 2’’ and told, ‘‘See this? This is a rif. Rifs are made by a special company so they can do 1 2’’ squarish U-shaped object made of dark brown cork, similar to that used for bulletin this (demonstrate function). See? So rifs are made so you can mop up water with them.’’ boards. The Dax’s function was to support stick pins of the type used to hold messages Exactly parallel instructions were given for the Dax standard. To demonstrate the function on cork boards. The shapes of these objects were the same as those used in previous stud- for the Rif set, the experimenter took a small bottle of water, spilled some on the table, and ies of the shape bias (e.g., Jones, Smith, & Landau, 1991; Landau, Smith, & Jones, 1988), mopped up the puddle with the object, saying AID JML 2533 / a010h$$$83 12-17-97 08:40:26 jmla AP: JML

7 OBJECT SHAPE, OBJECT FUNCTION ‘‘I can mop up water with it.’’ The Rif was The reliability of these findings was con- firmed by a mixed analysis of variance con- then set next to the bottle of water, where it remained during the test trials. To demonstrate ducted on the numbers of ‘‘yes’’ responses, with age and condition as between-subjects the function for the Dax set, the experimenter took a push pin and stuck it into the surface factors and property (Same shape/Same mate- rial) the within-subjects factor. This analysis of the object, saying ‘‘I can stick pins into it and they’ll hold.’’ The object with the embed- revealed a main effect of property, F(1,66) Å 35.04, p õ .01, and interactions between age ded pin was left visible during the test trials. After the entire naming procedure was com- and property, F(2,66) Å 18.52, p õ .01, and condition and property, F(1,66) Å 58.15, p plete, participants in the Function condition were asked directly whether they thought each õ .01, which were subsumed by a three-way interaction among age, condition, and prop- of the test objects could support the designated function of the relevant standard (Function erty, F(2,66) Å 11.86, p õ .01. Planned com- parisons within age showed reliable prefer- question). Participants were directed to look at the standard and were asked ‘‘Do you re- ences for Same-shape over Same-material ob- jects for the 3’s in both the No-Function and member what I did with this one?’’ If they did not respond promptly, the experimenter Function conditions, t’s (66) Å 5.91, 4.04, re- spectively, p’s õ .05, and for the 5’s and reminded them, saying ‘‘I mopped up water with it (stuck a pin in it so it would hold).’’ adults in the No Function condition, t’s (66) Å 5.78, 4.79, respectively, p’s õ .05. The Then they were asked either ‘‘Could you mop up water with this one?’’ (for the Rif set) or adults in the Function condition showed a reli- able preference for material over shape, t(66) ‘‘Could you stick a pin in this one so it would hold?’’ (for the Dax set). In this part of the Å 06.66, p õ .05. Planned comparisons were also carried out within age to compare shape procedure, each test object was queried just once. The test items were presented in one of and material responses across No-Function and Function conditions. Only the adults two randomized orders, and the presentation order of object sets was counterbalanced over showed a reliable difference between the two conditions, although the fives approached sig- participants.

nificance, t’s (66) Å .66, 1.86, 4.06 for the Results and Discussion 3’s, 5’s, and adults, critical t Å 1.99, p õ .05. An examination of individual performances Table 1 shows the mean proportions of ‘‘yes’’ responses to the Name question for provides greater insight into the develop- mental trend. Figure 2 shows the scatterplots Same-shape and Same-material objects over age and condition (No Function and Func- of individual performances—the number of ‘‘yes’’ responses to Same-shape vs Same-ma- tion). The table also shows the results for the Function question (Function condition only). terial responses for each individual over age and condition. The left panel shows the data Preliminary analyses revealed no differences between object sets, so the results for both for the Name question. Each dot represents one child’s performance. Individuals who said questions were collapsed across object set (Dax vs Rif). ‘‘yes’’ to more Same-shape than Same-mate- rial objects fall in the lower half of the figure, Name question. As is apparent, 3-year-olds generalized the name strongly on the basis whereas those who did the reverse fall in the upper half. Individuals who accepted an equal of shape in both No-Function and Function conditions. Adults, in contrast, generalized on number of the two object types fall along the diagonal.

the basis of shape in the No-Function condi- tion but material in the Function condition. Three-year-olds in both conditions and 5- year-olds and adults in the No Function condi- Five-year-olds generalized strongly on the ba- sis of shape in No-Function condition and tion accepted more Same-shape than Same- material objects. The dominance of shape over weakly in the Function condition. AID JML 2533 / a010h$$$83 12-17-97 08:40:26 jmla AP: JML

8 LANDAU, SMITH, AND JONES TABLE 1 Mean Proportions (SE) of ‘‘Yes’’ Responses to Same-Shape and Same Material Objects (Experiment 1) No function Function Name question Name question Function question Condition,a question, Same Same Same Same Same Same and age shape material shape material shape material 3 yr .92 (.04) .18 (.06) .76 (.07) .25 (.08) .38 (.11) .58 (.12) 5 yr .82 (.08) .09 (.05) .41 (.10) .34 (.08) .04 (.04) .78 (.10) Adults .69 (.09) .09 (.05) .06 (.03) .89 (.06) .06 (.03) .93 (.05) a n Å 12 in each age group and condition. Participants in the No-Function condition answered only the Name question; participants in the Function condition answered both the Name and Function questions. material among 3’s was reliable in both condi- whether the test objects could carry out the designated functions. Results from this ques- tions, n Å 12 vs 0 and 10 vs 0, as it was among 5’s and adults in the No-Function condition, n tion are also shown in Table 1. The first issue was whether the Function question elicited the Å 10 vs 0 and 9 vs 1, respectively, p’s õ .05, Binomial tests (assuming a random probabil- same generalization pattern as the Name ques- tion. We answered this by directly comparing ity of .50 in this and all further Binomials). Adults also showed a reliable dominance of responses to the Name and Function questions among participants who had been instructed material over shape in the Function condition, n Å 11 vs 0, p õ .05, Binomial test, and the about function (the Function condition). Pre- liminary analyses revealed no effects of object 5’s showed no preference in that condition, n Å 4 shape, 4 material, 4 equivocal. The set, so the data were collapsed over this factor. The mean proportions of ‘‘yes’’ responses to preference for Same-shape objects differed re- liably across the two conditions for the 5-year- Same-shape and Same-material objects were submitted to a mixed analysis of variance with olds and adults, p’s õ .05, Fisher Exact tests. Thus, the analysis of individuals was consis- age the between-subjects factor and property and question type (Name vs Function) as tent with the group analysis. To summarize the results of the Name ques- within-subjects factors. The results showed a main effect of property, F(1,33) Å 49.10, p tion, when a novel object was introduced and named with no further information, young õ .01, and interactions between age and prop- erty, F(2,33) Å 34.93, p õ .01, and question children and adults relied on shape as the basis for generalizing the name. When competing type and property, F(1,33) Å 38.57, p õ .01, both subsumed by a three-way interaction information about the functional importance of material was provided, adults switched among age, question type, and property, F(2,33) Å 8.46, p õ .01. Planned comparisons from naming by shape to naming by material. The 5-year-olds were affected by instructional revealed several reliable differences across question type: The 3- and 5-year-olds pre- condition, with a different pattern of prefer- ences when given functional instruction. Un- ferred shape when asked the Name question but not when asked the Function question; the like adults, however, the 5-year-olds did not reliably shift to material when told the objects’ adults showed no such difference, as they pre- ferred material when asked either question, t’s functions.

Name vs function question. Participants (33) Å 2.5, 2.86, .14, p’s õ .05. Thus the two questions elicited different responses in 3- and who were given instructions about the objects’ functions were also queried directly about 5-year-olds, but not adults. AID JML 2533 / a010h$$$83 12-17-97 08:40:26 jmla AP: JML

9 OBJECT SHAPE, OBJECT FUNCTION FIG. 2. Individual participants’ choices of Same-shape vs Same-material objects for the Name Question and the Function question in Experiment 1. Closed circles represent individuals who were not instructed about function (No-Function condition) and were asked the Name question only. Open circles represent individuals who were instructed about function and were asked both the Name and Function questions (Function condition). Individuals who chose on the basis of shape fall into the lower half of the plot whereas those who chose on the basis of material fall into the upper half.

The second issue was whether children un- and adults reliably preferred material, t’s (33) Å 05.3, 06.2, respectively, p’s õ .05. Thus, derstood the standard objects’ functions, whether they generalized correctly in the although both the 3’s and 5’s showed different response patterns in the Name vs Function Function question (i.e., on the basis of mate- rial), and most important, whether this under- questions, only the 5’s and adults reliably re- sponded reliably ‘‘correctly’’ to the Function standing affected their generalizations in the Name question. Planned comparisons for the question—that is, on the basis of material. Comparisons for the Name question showed Function question showed that 5-year-olds AID JML 2533 / a010h$$$84 12-17-97 08:40:26 jmla AP: JML

10 LANDAU, SMITH, AND JONES that 3-year-olds reliably preferred shape and quadrant of the right panels in Fig. 2). This that adults reliably preferred material, t’s (33) group included four 3-year-olds and nine 5- Å 3.6, 05.9, respectively, p’s õ .05, just as year-olds. The second group included the re- in the previous analysis of the Name question. maining 11 children. Given this division, we Individual participants’ pattern of shape vs analyzed the number of shape vs material- material responses for the two questions con- based responses in the Name question, using firmed these patterns (see Fig. 2, left and right an analysis of variance with age and group panels). Three-year-olds reliably preferred as the between-subjects factors and property shape when asked the Name question, n Å 10 (shape, material) as the within-subjects factor. shape, 0 material preference, p õ .01, Bino- There was a main effect of property only, with mial test, but showed no reliable preference responses by shape reliably greater than by when asked the Function question, n Å 7 ma- material, M’s Å .58, .29, respectively, F(1,20) terial, 3 shape preference, p Å .17, Binomial Å 5.5, p õ .05. There were no interactions. test. Seven of the 3-year-olds switched from These results suggest that object function a shape preference when asked the Name may not enter into object naming early in de- question to a material preference when asked velopment, even when children understand the the Function question; one did the reverse, object properties related to function. First, confirming a reliable difference in their re- there were no reliable effects of instructional sponses across the two questions, p Å .03, condition on the 3-year-olds’ responses to the Binomial test. Five-year-olds showed no pref- Name question and weak effects on the 5- erence when asked the Name question, n Å 4 year-olds’ responses; only adults were reliably shape, 4 material, but reliably preferred mate- and strongly affected, generalizing names dif- rial when asked the Function question, n Å ferently when given instruction about func- 11 material, 0 shape, p õ .01, Binomial test. tion. Second, even children who generalized Three of the 5-year-olds switched from a on the basis of material in the Function ques- shape preference in the Name question to a tion still generalized by shape in the Name material preference in the Function question; question. Thus, although some children under- none did the reverse. Adults reliably preferred stood that material was critical to carrying out material for both questions, n Å 11 material, the function, this knowledge did not enter into 0 shape for the Name question, n Å 12 mate- their naming responses.

rial, 0 shape for the Function question, p’s õ It is possible, however, that functional .01, Binomial test. Thus, although there were knowledge did not affect naming because the reliable differences across question type for objects and functions used in Experiment 1 both the 3- and 5-year-olds, the nature of the were quite novel and perhaps not part of natu- change was different. Three-year-olds showed ral, early developing systems of knowledge. shape-based responses when asked the Name Only the adults may have truly understood the question, and diffuse responses when asked functions, which were surely familiar to them. the Function question. Five-year-olds showed Accordingly, in Experiment 2 we asked the divided responses when asked the Name ques- Name and Function questions using objects tion and material-based responses when asked whose functions should be understood by age the Function question.

2: retrieval of one object by another (Brown, Did the children’s varying understanding of 1990) and containment (Kolstad & Baillar- the objects’ functions affect their responses to geon, 1991). If the results of Experiment 1 the Name question? To address this, we di- were due to the unusual or complex nature of vided the children into two groups. One group the functions we devised, then more familiar responded correctly to the Function question, functions might be more likely to enter into specifically, accepting greater than 50% of the naming for 3- and 5-year-olds and perhaps time on material and less than 50% of the time on shape (locating them in the upper left-hand even for younger children. To test this possi- AID JML 2533 / a010h$$$84 12-17-97 08:40:26 jmla AP: JML

11 OBJECT SHAPE, OBJECT FUNCTION bility, we extended our study downward function: One had a large hole in the bottom, in age. a second was perforated with holes throughout the surface, and the third was made of flimsy EXPERIMENT 2 tissue paper. The object with the hole in the bottom violated the containment function in a Method way similar to the containers used by Kolstad Participants. Ninety-six participants were and Baillargeon (1991). Each of the Same- tested, 24 each of 2-year-olds (M age 2;6, function objects was a different shape from range 24–35 months), 3-year-olds (M age 3;7, the standard. In each set, each Same-shape range 3; –3;11), 5-year-olds (M age 5;5, range object was matched in color to one Same- 5;1–5;11), and adults. Participants were function object.

drawn from the same populations as in Experi- Procedures were identical to those of Ex- ment 1 and age groups were balanced for periment 1, except for appropriate modifica- gender. tion of the Function condition instructions for Design, materials, and procedure. The the new object sets. In addition, the instruc- overall design was identical to Experiment 1, tions were simplified a bit to ensure that even with half of the participants in each age group the youngest children would understand them. randomly assigned to the No-Function condi- For the Cane set, participants were told ‘‘See tion and half to the Function condition. How- this? This is a dax (rif). And this is what I ever, all participants were asked both the can do with it. I can pull toys with it.’’ The Name question and the Function question. experimenter took a small toy and placed it at There were two sets of objects (see Fig. 3).

the far end of a table, several feet away, then The standard for the Cane set was a 6’’ long hooked it with the head of the cane and pulled blue cane made of hardened clay. The function it toward herself. For the Container set, the of this standard was to retrieve small toys from experimenter introduced the object in the several feet away by hooking and pulling same way, then poured a small amount of wa- them. The test items included a replica of the ter into the standard and lifted the container, standard plus six additional items. Three of moving it along a path and saying ‘‘I can carry these were the Same-shape as the standard, water with it.’’ but could not support the designated function: Following this introduction, participants One was too short (2’’) and the remaining were tested as in Experiment 1 on the Name two were made of either lightweight fabric or question (‘‘Is this a dax?’’) with two trials for beads strung on a cotton thread, each too each of six objects per set, a total of 24 trials. flimsy to secure and pull small toys. These After all items in both sets were queried, parti- objects violated the relevant function in ways cipants were asked the Function question. similar to those in Brown’s (1990) study. The They were shown the standard once more. remaining three test items could support the Those hearing Function instructions were Same-function as the standard, being the same asked ‘‘Do you remember what I did with this length and material. However, their handle one?’’ In most cases, participants answered pieces and heads were shaped differently. correctly. If they did not respond spontane- The standard for the Container set was a ously, the experimenter prompted by saying 2’’ 1 2’’ 1 2’’ trapezoidal-type container ‘‘I pulled the toy (carried water) with it.’’ All made of hardened clay. It stood on short legs participants then were asked for each test item, and was completely open at the top. Its desig- ‘‘Could you pull a toy from over there with nated function was to carry water. The test this?’’ or ‘‘Could you carry water with this?’’ items included a replica of the standard plus Note that although the No-Function partici- three Same-shape and three Same-function ob- pants were not given information about the jects. The Same-shape objects were identical in shape but could not support the designated standard’s function, they could plausibly AID JML 2533 / a010h$$$84 12-17-97 08:40:26 jmla AP: JML

12 LANDAU, SMITH, AND JONES FIG. 3. Objects used in Experiment 2. The ‘‘standard’’ for each set is shown at the left. Test objects included three Same-shape (different function) and three Same-function (different shape) objects. The specified function for the Cane set was to pull toys from across a table. The function for the Container set was to carry water. The Same-shape objects for the Cane set violated the specified function by being too short or too flimsy; those for the Container set violated function by possessing holes in the surface or being composed of thin paper.

AID JML 2533 / a010h$2533 12-17-97 08:40:26 jmla AP: JML

13 OBJECT SHAPE, OBJECT FUNCTION judge whether or not each of the test items tions preferred Same-function over Same- shape objects, Bonferroni critical d Å .24, could carry out the specified function. All test items were presented in one of two p Å .05. The adult pattern in the Name ques- tion was responsible for the only reliable pair- randomized orders, and the presentation order of the Cane or Container set was counterbal- wise effects of condition: They preferred Same-shape objects in the No-Function condi- anced.

tion, and Same-function objects in the Func- Results and Discussion tion condition, Bonferroni critical d Å .24, p Å .05. In Table 2 are shown the mean proportions of ‘‘yes’’ responses to Same-shape and Same- To assess the differential effects of question type among children, we conducted a separate function objects over age and condition for the Name question (‘‘Is this a dax?’’) and the four-way analysis of variance (age, condition, question type, and property) on the children’s Function question (‘‘Could you pull a toy/ carry water with this . When asked the data only. The relevant means, shown in Table 2, indicate differences between the two ques- Name question, participants of all ages pre- ferred the Same-shape objects, except for the tions among 3- and 5-year-olds. This was re- flected in the principal result from the analy- adults in the Function condition, who general- ized on the basis of function. When asked sis, a three-way interaction among age, ques- tion type, and property, F(2,66) Å 9.56, p õ the Function question, 3- and 5-year-olds and adults preferred the Same-function objects .05. This interaction subsumed all other ef- fects, which included main effects of age, whereas 2-year-olds showed a slight prefer- ence for Same-shape objects. Thus there were F(2,66) Å 7.3, p õ .01, question type, F(1,66) Å 12.39, p õ .01, and property, F(1,66) Å qualitatively different patterns of response for the two questions, and within each question, 10.35, p õ .01, two-way interactions between age and question type, F(2,66) Å 4.28, p õ the developmental pattern was different. Preliminary analyses suggested that there .05, age and property, F(2,66) Å 3.74, p õ .05, and question type and property, F(1,66) were different interactions involving object set for the Name and the Function questions. Å 119.83, p õ .01. There was no effect of or interactions with condition.

We examined each of these interactions and found that none of them was relevant to or Planned comparisons evaluated the three- way interaction by assessing the children’s mitigated the results relevant to the principal hypotheses. Therefore, we collapsed over ob- preferences across question type. The 3- and 5-year-olds both accepted more Same-shape ject set for further analyses. Preliminary anal- yses also indicated a four-way interaction objects when asked the Name question than the Function question, t’s (66) Å 3.62, 3.0, among age, question type, condition, and property, F(3,88) Å 4.03, p õ .01, reflecting p’s õ .05, and more Same-function objects when asked the Function question than the the qualitatively different patterns of re- sponse for the two questions. Name question, t’s (66) Å 03.25, 06.75, p’s õ.05. Two-year-olds did not accept same- Planned comparisons were conducted to as- sess these patterns, specifically examining the shape objects differentially over the two ques- tions, but did accept more Same-function ob- different effects of condition and property over age, separately for the two questions. jects when asked the Function question than the Name question, t’s (66) Å 0.75, 03.87, When asked the Name question, participants in all age groups and in both conditions pre- p õ .05. Individual participant plots for the two ferred Same-shape over Same-function ob- jects, except for the adults in the Function questions are shown in Fig. 4. The overall pattern supports the group analysis: When condition, who reliably preferred Same-func- tion to Same-shape. When asked the Function asked the Name question, 2-, 3-, and 5-year- olds in both conditions showed a reliable pref- question, 5-year-olds and adults in both condi- AID JML 2533 / a010h$$$84 12-17-97 08:40:26 jmla AP: JML

14 LANDAU, SMITH, AND JONES TABLE 2 Mean Proportions (SE) of ‘‘Yes’’ Responses to Same-Shape and Same-Function Objects (Experiment 2) No function Function M Conditiona Same Same Same Same Same Same and age shape function shape function shape function Name question 2 yr .73 (.08) .41 (.12) .76 (.08) .41 (.12) .74 .41 3 yr .72 (.11) .25 (.13) .73 (.07) .32 (.13) .72 .28 5 yr .49 (.11) .08 (.08) .52 (.11) .19 (.08) .51 .14 Adults .69 (.09) .33 (.10) .26 (.06) .78 (.06) Function question 2 yr .73 (.08) .62 (.10) .86 (.05) .82 (.10) .80 .72 3 yr .40 (.10) .59 (.11) .46 (.09) .50 (.10) .43 .55 5 yr .22 (.05) .68 (.07) .33 (.08) .69 (.08) .27 .68 Adults .39 (.06) .94 (.04) .19 (.03) .92 (.04) .29 .93 a n Å 12 in each age group and condition (No Function, Function). All participants answered both the Name and Function questions.

erence for Same-shape objects, n Å 19 vs 0, the analysis. In the group that accepted Same- function objects greater than 50% of the time 18 vs 1, 19 vs 1 over the three age groups, p’s õ .05, Binomial test. Adults showed a and Same-shape objects less than 50% of the time, there were eight 3-year-olds and four- reliable preference for Same-shape objects in the No-Function condition, n Å 10 of 12, but teen 5-year-olds; these were divided evenly between the No-Function and Function condi- for Same-function objects in the Function con- dition, n Å 11 of 12, x2 (1) Å 13.59, p õ .05. tions. In the second group (who did not meet the criterion) were the remainder of the chil- When asked the Function question, 2-year- olds did not show any distinct preference for dren, including sixteen 3-year-olds and ten 5- year-olds. Again, these were divided evenly Same-shape vs Same-function objects, n Å 8 vs 7, respectively, whereas 3’s, 5’s, and adults between the conditions. Given this division, we analyzed the responses to the Name ques- preferred Same-function objects. n Å 12 vs 6, 19 vs 2, 24 vs 0 for each age group, p’s õ tion, using an analysis of variance with age and group as between-subjects factors and .05, for the 5’s and adults, p Å .07 for the 3’s, Binomial tests. The only difference from the property (Same-shape, Same-function) as the within-subjects factor. The results showed a overall analysis is the addition that 3-year- olds reliably preferred Same-function objects main effect of property only, with children accepting Same-shape objects more often than when asked the Function question. As in Experiment 1, we asked whether chil- Same-function objects, M proportions Å .62, .19, respectively, F(1,44) Å 49.45, p õ .01.

dren’s varying understanding of the functions affected their responses to the Name question. To summarize, the results of this experi- ment were consistent with those of Experi- We again divided children into two groups in accord with their performance on the Function ment 1. As in that experiment, the Name ques- tion (‘‘Is this an X?’’)elicited a preference for question (using the same criterion as in Exper- iment 1). There were no 2-year-olds who an- Same-shape objects among both children and adults when no functional instruction about swered the Function question correctly by this criterion, so these children were dropped from the objects was provided. When functional in- AID JML 2533 / a010h$$$84 12-17-97 08:40:26 jmla AP: JML

15 OBJECT SHAPE, OBJECT FUNCTION FIG. 4. Individual participants’ choices of Same-shape vs Same-function objects for the Name question and the Function question in Experiment 2. Closed circles represent individuals who had not been instructed about function (No-Function condition); open circles those who were instructed about function (Function condition). All participants were asked the Name question and the Function question. formation was provided, adults showed a their relationship to the Name question also confirmed and extended the results of Experi- strong bias for objects that could support the same function. These functions depended on ment 1. As in Experiment 1, adults in the Name question were strongly affected by in- material in Experiment 1 and material, length, and global object structure in the present ex- struction about function, whereas they an- swered the Function question correctly periment.

The results of the Function question and whether instructed or not. Clearly, the adults AID JML 2533 / a010h$$$85 12-17-97 08:40:26 jmla AP: JML

16 LANDAU, SMITH, AND JONES could determine by inspection whether the ob- of a novel object name. This is consistent with two possibilities. One is that functional jects could carry out a given function. Also as in Experiment 1, 3- and 5-year-olds responded knowledge must be extremely robust to be incorporated into object naming generaliza- differently to the Function question than they had to the Name question, and there was an tions. The second is that the initial links be- tween perception and naming are so strong increase between age 3 and 5 in the strength and accuracy of responses to the Function that even extremely robust functional knowl- edge is excluded from naming judgments.

question. Two-year-olds showed no evidence of being able to correctly judge whether the These two possibilities can be tested using common objects whose functions are well un- objects could carry out their functions. Cru- cially, the developmental changes in the 3- derstood. and 5-year-olds’ responses to the Function question did not appear to affect their re- EXPERIMENT 3 sponses to the Name question: There was an Method overall preference for Same-shape objects among children who did respond correctly to Participants. Ninety-two participants were tested, twenty-four 2-year-olds (M age 2;6, the Function question as well as those who did not. range 29–31 months), twenty-two 3-year-olds (M age 3;4, range 36–46 months), twenty-two Although there was no effect of being in- structed about function among 5-year-olds in 5-year-olds (M age 5;3, range 60–70 months), and twenty-four adults. They were drawn from the present experiment, these children were rather conservative in their generalization of the same populations as in previous experi- ments, as well as from preschools in the area the name (compared to levels of generaliza- tion in Experiment 1). Why didn’t they gener- around Bloomington, Indiana and Newark, Delaware. All age groups were balanced for alize strongly to all Same-shape objects? Spontaneous comments suggest that their gender. Design. The overall design and procedure knowledge about named objects might have played a role. For example, in the No-Function were similar to the previous experiments, ex- cept that question type was a between-subjects condition, the cloth and bead canes were sometimes rejected with comments such as variable, with roughly half of the participants in each age group asked the Name question ‘‘it’s a piece of towel’’ or ‘‘it’s like a neck- lace’’ and the pyramid container with ‘‘looks and half the Function question. Participants who were asked the Name question were like a volcano.’’ In the Function condition, the perforated and paper containers were shown a standard, heard it labeled with its real name, and heard its function described. Then sometimes rejected with comments such as ‘‘has holes in it ‘ ‘ it’s too soft to pull,’’ or they were shown a series of test objects and were asked whether each had the same name ‘‘it’s not hard.’’ Although these comments were not frequent enough to analyze, they sug- as the standard. Participants who were asked the Function question observed as the experi- gest that the 5-year-olds’ decisions to reject some of the Same-shape objects were based menter showed them how the standard carried out its function and then were asked whether either on their similarity to other known ob- jects or, in the Function condition, the inabil- the test objects could be used for that function. However, they never heard any of the objects ity of the object to support the designated function. named.

Materials. There were two sets of objects, The findings thus support the notion that there are strong developmental changes in one with a well-known standard and the other with a less well-known standard. The standard children’s knowledge of objects’ functions, and that this knowledge is only slowly incor- for the Comb set was a 4’’ 1 3’’ blue plastic 10-prong comb with no handle. The test set porated into children’s initial generalizations AID JML 2533 / a010h$$$85 12-17-97 08:40:26 jmla AP: JML

17 OBJECT SHAPE, OBJECT FUNCTION included four Same-shape and four Same- tic clip by 8% of these children. Correct re- sponses for the clamps included ‘‘clamp,’’ function objects. The Same-shape objects were all identical to the standard in shape and ‘‘clip ‘ ‘ paper clip,’’ and ‘‘to hold paper.’’ The test objects in both sets varied in color size, but each was made from a material that would not support combing hair. These in- from the standard. All Same-function objects could successfully be used to hang doll clothes cluded soft modeling clay, flimsy packaging material, lightweight foam rubber, and writing on the line. Procedures. Participants who were asked paper. The Same-function objects were made of rigid materials, and were real objects, in- the Name question were first shown the stan- dard and asked ‘‘Do you know what this is?’’ cluding a plastic fork, a toy plastic rake, a plastic spaghetti spoon with ‘‘teeth,’’ and a The standard for the Comb set was introduced next to a realistic life-sized model of a female plastic and metal potato masher with wave- like prongs at the mashing end. We chose the head with long blond hair. Most answered cor- rectly, but if they did not, they were told ‘‘This first two of these objects to be familiar and the latter two to be unfamiliar to children; is a comb.’’ Then they were asked ‘‘Do you know what we do with this?’’ Again, most consistent with this, the fork was correctly named during the procedures by all of the chil- participants answered correctly, or took the comb and proceeded to demonstrate on the dren who said it was not ‘‘a comb,’’ the rake by 50%, the spaghetti spoon by 12%, and the model. If they did not, the experimenter said ‘‘We use it to comb our hair’’ and proceeded potato masher by 3% of these children. The plastic fork was approximately the same size to demonstrate on the model. The comb and model head were then moved aside but left in as the comb, the spaghetti spoon and potato masher were approximately 12’’ long, and the full view, and participants were shown each of the eight test objects for the Comb set, one toy rake was approximately 24’’ long. Infor- mal trials confirmed that these objects could at a time, and asked ‘‘Is this a comb?’’ The procedure for the Clothespin set was identical, indeed be used to comb one’s hair. The standard for the Clothespin set was a except that the standard was introduced next to a 6’’ 1 8’’ clothesline setup made of tinker standard wooden clothespin with a metal hinge. The Same-shape objects were identical toys and a piece of heavy string, and the dem- onstration was conducted using doll-sized to the standard in shape and size, and were constructed with a hinge identical to that of items. Although not all children initially knew the name ‘‘clothespin,’’ all easily understood the standard. However, these objects were made of materials that could not support hang- its function and many commented that it ‘‘held up’’ clothes, or was to ‘‘put them up’’ (on the ing even doll clothes on the model clothesline we used: These included soft modeling clay, clothesline). Pilot data showed that children would often spontaneously name rejected ob- packaging material, foam rubber, and felt. The Same-function objects were real objects, all jects when asked this question. Hence after the entire procedure was completed, participants approximately the same size as the clothespin and made of rigid material. These included a were queried on those they had rejected by asking ‘‘You said this is not a comb/clothes- girl’s plastic hair clip, a metal clamp, a heavy ‘‘Bulldog’’ paper clamp, and a plastic-cov- pin. What is it?’’ Participants who were asked the Function ered paper clamp (the three clamps were of different shapes). The first two were expected question were shown the setup for each stan- dard and heard a brief introduction which led to be familiar to children, the latter two unfa- miliar. In fact, none were highly familiar. The into the set of test questions. For the Comb standard, they heard ‘‘Barbie (the doll) just hair clip was named correctly during the pro- cedures by 28% of the children who said it woke up and needs to fix her hair because she needs to go to work. She looked all over and was not ‘‘a clothespin,’’ the metal clamp by 22%, the Bulldog clamp by 22%, and the plas- all she could find was this (standard).’’ The AID JML 2533 / a010h$$$85 12-17-97 08:40:26 jmla AP: JML

18 LANDAU, SMITH, AND JONES experimenter then combed the doll’s hair, and actions between question type and property, F(1,60) Å 80.72, p õ .01, and between prop- proceeded to ask for each test object, ‘‘Could she use this to fix her hair?’’ For the Clothes- erty and object set, F(1,60) Å 27.31, p õ .01. The source of the first interaction is clear pin standard, participants heard ‘‘Binky just washed his blanket because it was dirty. Now from Table 3. When asked the Name question, participants accepted Same-shape objects reli- he needs to hang it up to dry. Binky looked all over and all he could find was this (stan- ably more often than Same-function objects, whereas the reverse was true for the Function dard).’’ The experimenter hung the blanket on the line using the standard, and proceeded to question, Tukey’s HSD Å .18, p õ .05. The interaction between object set and property ask for each test object, ‘‘Could Binky use this to hang up his blanket?’’ During this pro- was due to reliably greater acceptance of Same-shape objects for the Comb set, but no cedure, most 2-year-olds (but none of the older children) insisted on trying out the dif- overall difference between the Same-shape and Same-function objects for the Clothespin ferent test objects before or while answering. Therefore, their results were analyzed sepa- set, Tukey’s HSD Å .11, p õ .05. A separate analysis of variance was carried rately from those of the other participants. All test objects were presented in one of out for the 2-year-olds, with question type the between-subjects factor and property and ob- two randomized orders, and the order of object set was counterbalanced over participants. ject set the within-subjects factors. There was an interaction between question type and Results and Discussion property, F(1,22) Å 22.02, p õ .01, and one between property and object set, F(1,22) Å In Table 3 are shown the mean proportions of ‘‘yes’’ responses to Same-shape and Same- 12.08, p õ .01. The source of the first interac- tion is the same as in the other age groups, function objects over age and question type. These results show a preference for Same- evident from Table 3. When asked the Name question, participants accepted Same-shape shape objects across all ages for the Name question, and a preference for Same-function objects reliably more often than Same-func- tion objects, whereas the reverse was true objects across age for the Function question. The results of the Name question replicated when they were asked the Function question, Tukey’s HSD Å .21, p õ .05. The second those of previous experiments among chil- dren, but did not for adults: When functional interaction reflected the same differences be- tween the Comb and Clothespin set as de- information was provided for novel objects in Experiments 1 and 2, adults generalized on scribed above, Tukey’s HSD Å .18, p õ .05. Individual participant plots confirmed and the basis of function. Here, when the objects were known, and despite adults’ functional amplified these overall patterns (see Fig. 5). For the Name question, there was a preference knowledge, they generalized on the basis of shape. among all age groups for Same-shape over Same-function objects, n Å 9 vs 2, 11 vs 0, The mean numbers of ‘‘yes’’ responses to the two questions were entered into a mixed 10 vs 1, and 8 vs 3 for 2’s, 3’s, 5’s, and adults, respectively. This preference was reliable analysis of variance with age (3’s, 5’s, and adults) and question type as the between-sub- among children, p’s õ .05, Binomial tests. For the Function question, there was a reliable jects factors and property and object set as the within-subjects factors. There were main preference for Same-function over Same- shape objects among all ages, n Å 9 vs 1, 8 effects of age, F(2,60) Å 7.38, p õ .01, and object set, F(1,60) Å 31.28, p õ .01, with 3- vs 1, 9 vs 1, 10 vs 0 for 2-, 3-, and 5-year- olds and adults, p’s õ .05, Binomial tests.

year-olds saying ‘‘yes’’ more frequently than both 5-year-olds and adults, and the Clothes- Names for objects. When participants judged an object not to be a comb/clothespin, pin set eliciting more ‘‘yes’’ responses than the Comb set. There were also two-way inter- they were asked ‘‘What is it?’’ In addition, AID JML 2533 / a010h$$$85 12-17-97 08:40:26 jmla AP: JML

19 OBJECT SHAPE, OBJECT FUNCTION TABLE 3 Mean Proportions (SE) of ‘‘Yes’’ Responses to Same-Shape and Same-Function Objects (Experiment 3) Name questiona Function questionb Same Same Same Same Age shape function shape function 2 yr .67 (.08) .38 (.08) .51 (.07) .74 (.07) 3 yr .88 (.05) .32 (.08) .32 (.08) .63 (.07) 5 yr .54 (.08) .21 (.07) .15 (.06) .45 (.07) Adults .58 (.08) .14 (.06) .06 (.02) .74 (.08) a n Å 12 in each age group. b n Å 12 each in the 2-year-old and adult groups, n Å 10 each in the 3-year-old and 5-year-old groups. they sometimes spontaneously named these or ‘‘it’s a sponge comb.’’ These comments occurred primarily among young children rejected objects. Given this, different individ- uals were queried for different items (de- (proportions Å .33, .20, .12 of the comments among 3’s, 5’s, and adults, respectively). Thus pending on their responses to the principal yes/no questions), not all individuals an- these people specified the comb/clothespin’s sub-kind by mentioning its material with an swered all those questions, and those who did so offered different names for the different adjective. In contrast, those who rejected the objects test objects. Nevertheless, the names provide insight into children’s and adults’ generaliza- used the material term as head noun, e.g., ‘‘it’s a piece of paper ‘ ‘ it’s thin packaging tions.

Collapsing spontaneous comments to the foam,’’ or ‘‘it’s a comb sponge.’’ This oc- curred primarily among older children and question ‘‘Is it a comb/clothespin?’’ and re- sponses to the question ‘‘What is it?’’ (if not adults (proportions Å .09, .38, .43 for the 3’s, 5’s, adults, respectively). In these construc- a comb or clothespin), participants offered a total of 472 responses (164 to the Same-shape tions, individuals directly named the Same- shape objects as portions of material, sug- objects, 308 to the Same-function objects). For the Same-shape objects, the most frequent gesting that they thought of the Same-shape objects as hunks of material that happened to comment concerned the objects’ material, e.g., ‘‘It’s made out of play-dough ‘ ‘ It’s a soft look like a comb or clothespin. Comments for the Same-function objects comb ‘ ‘ made out of carpet,’’ or ‘‘It’s plas- tic’’ (M proportion Å .53 overall; .15, .48, were quite different. Not surprisingly, when these items were rejected as a ‘‘comb’’ or .75, and .59 for 2’s, 3’s, 5’s, and adults). The second most common response among chil- ‘‘clothespin,’’ individuals tended to provide the object’s known label or some functionally- dren was either ‘‘don’t know’’ or no response (proportions Å .62, .29, .11 for 2’s, 3’s, 5’s). related expression, e.g., ‘‘It’s a fork ‘ ‘ a thing for spaghetti,’’ or ‘‘for making zucchini Adults’ second most common response con- cerned the objects’ shape (proportion Å .23), soup’’ (M proportion Å .59 overall; .32, .47, .58, and .90 for 2’s, 3’s, 5’s, and adults). The e.g., ‘‘It’s the shape of a comb.’’ Analyzing the material comments further, second most common response among chil- dren was ‘‘don’t know’’ or no response (pro- participants differed in their names, depending on whether they had accepted or rejected the portions Å .47, .32, and .36 for 2’s, 3’s, and 5’s).

objects. Those who accepted the objects used ‘‘comb’’ or ‘‘clothespin’’ as head noun, e.g., Thus, the Same-shape objects elicited com- ments about their material and the Same-func- ‘‘it’s a paper comb ‘ ‘ it’s a bath comb,’’ AID JML 2533 / a010h$$$85 12-17-97 08:40:26 jmla AP: JML

20 LANDAU, SMITH, AND JONES FIG. 5. Individual participants’ choices of Same-shape vs Same-function objects in Experiment 3, collapsed over comb and clothespin. Individuals were asked either the Name question or the Function question. tion objects elicited comments about their to have the shape of a comb/clothespin. On the other hand, older participants did not think known object kind. The change in the material comments over age, however, suggests that 3- that function alone was sufficient to make something a comb/clothespin. Just because the year-olds accepted the Same-shape objects as instances of a comb/clothespin made of an spaghetti scoop, rake, or potato masher could be used to comb the hair did not make it a unusual material, but that 5-year-olds and adults viewed the Same-shape objects as comb. Putting together these two predominant response patterns, 5-year-olds and adults were hunks of plastic or play-dough that happened AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

21 OBJECT SHAPE, OBJECT FUNCTION apparently loathe to accept either the Same- jects, and their understanding of these objects’ functional properties outside of the naming shape or the Same-function objects as in- stances of a comb or clothespin. context. We found that young children generalized To summarize, the basic pattern of results among children replicated those of the previ- novel and familiar object names on the basis of shape, even when functional information ous experiments, although with certain intrigu- ing differences. For real, everyday familiar was provided. However, with development, and especially in adulthood, explicit func- objects, children tended to extend the object’s name to objects of the same shape. This pat- tional information came to guide the naming of novel objects. For familiar objects—at tern also was shown by adults in this experi- ment, despite the fact that the object’s func- least those at the basic level—older children and adults rejected function as the basis for tions were explicitly mentioned (and, obvi- ously, were well-known). Although rejection generalizing the objects’ names, but they also generalized rather conservatively on the basis of certain Same-function objects could have been increased by some participants’ knowl- of shape alone. Miller and Johnson-Laird’s (1976) observation on the importance of ob- edge of their actual names (e.g., a ‘‘rake’’ cannot be a ‘‘comb,’’ Principle of Mutual Ex- ject function for adults is thus partially sup- ported, but shown to be false for young chil- clusivity, Markman & Wachtel, 1988), this would not explain why these participants also dren, at least in the current context. The reliance on shape was not found for accepted Same-shape objects that could not fulfill the designated functions. However, direct questions about the objects’ functions. Across the three experiments there were modulating this tendency to generalize on shape, older children and adults were gener- strong developmental trends in participants’ understanding of function as well as its role ally less likely than 3-year-olds to accept test objects at all. This developmentally increas- in naming. Differences in responses to the Name vs Function questions occurred among ing conservatism is consistent with Malt and Johnson’s (1992) findings among adults and 3- and 5-year-olds and adults in all experi- ments and by 2-year-olds when they tested the suggests that neither shape nor function by itself is ultimately sufficient for naming well- objects for themselves (Experiment 3). How- ever, only 5-year-olds and adults showed known objects—at least, those at the basic level such as a comb or clothespin. strong and systematically correct responding to the Function question. One might infer that As in previous experiments, responses to the Function question were different from the children relied on shape in the Name ques- tion because they did not understand the dem- those of the Name question, and in this experi- ment, the responses were systematically cor- onstrated functions. However, there were no differences in naming generalizations among rect across all ages.

children who clearly understood the functions GENERAL DISCUSSION relative to those who did not. The consistency of the results over the three The present studies sought to determine whether early object naming primarily en- experiments was striking in view of the range of objects used and the increasingly familiar gages the perceptual systems and is immune to influences from general world-knowledge, functions tapped. In Experiment 1, the results of the No-Function condition were consistent and if so, how this might change developmen- tally. Specifically, we asked whether young with those of other experiments in which a novel artifact is named and children are asked children’s and adults’ tendency to generalize object names on the basis of shape could be to generalize its name to new objects. In these cases, the objects are truly novel and there is overturned if functional information about the objects was provided. We tested children’s little that a person can infer about their cate- gory beyond, possibly, that they are artifacts.

and adults’ naming of novel and familiar ob- AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

22 LANDAU, SMITH, AND JONES Instruction about these objects’ functions had with shape dominating when one must choose between the two—at least for objects at the little impact among the younger children, though it did among adults. In Experiment 2, basic level. The pattern among adults suggests that if an object does not look like a comb or the objects were novel, yet their functions were similar to familiar objects and were a clothespin, then no matter how effectively it can be used to comb the hair or hang clothes, known to be within infants’ and toddler’s un- derstanding (Brown, 1990; Kolstad & Baillar- it is unlikely that it will be called by that name (see Malt, 1993, for similar findings).

geon, 1991). Instruction about these objects’ functions still had no impact on their naming, The Importance of Shape in the though again, it did among adults. Development of Object Naming The picture for familiar objects was differ- The early dominance of shape and its in- ent. All children recognized the comb, and creasingly complex modulation is consistent some also recognized the clothespin. Adults with other findings in the literature on object knew both and what they were used for. In naming. Gentner (1978) pitted form and func- this context, explicitly mentioning the objects’ tion against each other and found the same functions had no effect on any age group: Indi- overall reliance on shape among children as viduals at all ages generalized comb and we did. However, Gentner also found a strong clothespin on the basis of shape, not function. shape bias among adults, consistent only with This fact rules out the possibility that explic- the results of our No-Function conditions (Ex- itly mentioning the objects’ functions in Ex- periments 1 and 2), and with those of Experi- periments 1 and 2 created some obvious task ment 3, using familiar objects. It is difficult demands that caused adults to generalize the to assess the meaning of this difference, al- names by function in those settings. However, though it is possible that Gentner’s older chil- even though they did not generalize comb and dren and adults were actually split on form vs clothespin on the basis of function, older chil- function: They often called the hybrid a dren and adults were rather conservative in ‘‘jiggy-zimbo,’’ which would suggest that generalizing to any of the test objects, and function was more important for inclusion in often remarked that the Same-shape objects the object category. When forced to choose were hunks of material, rather than soft/plas- between ‘‘jiggy’’ and ‘‘zimbo,’’ however, tic/paper ‘‘combs’’ or ‘‘clothespins.’’ adults went with form (the ‘‘jiggy’’), perhaps Recall that the test set for the comb and because the objects were similar to familiar clothespin included real objects, some of objects (the zimbo was a modified gum-ball which were familiar and named correctly, e.g., machine). This would be consistent with our the fork and the rake. People might have re- findings that adults consider appearance to be jected these objects because they already had important for familiar objects.

another basic name, using the Principle of Mu- Our results are also consistent with those tual Exclusivity (Markman & Wachtel, 1988). of Merriman et al. (1993), who found a devel- However, this would not explain why partici- opmental increase in children’s reliance on pants also accepted Same-shape objects that function for both novel and familiar objects. could not fulfill the designated function. Merriman et al.’s data suggest a similar devel- Thus shape survived competition with func- opmental course to ours: Three and a half to 4- tion most dramatically among children and year-olds showed an average of 37% function least dramatically among adults who heard in- choices (and by inference, 63% shape structions about the functions of novel objects choices); 4-1 2- to 5-year-olds showed 46% or who judged familiar common objects. This suggests that for novel objects, children will function choices (54% shape), and 6-year-olds showed 62% function choices. Thus, it was go with shape and adults with function. Once these objects have become familiar, however, only by 6 years of age that Merriman et al.’s children were generalizing object names on both shape and function will co-articulate, AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

23 OBJECT SHAPE, OBJECT FUNCTION the basis of function at a greater than change dren’s explanations were strongly based on relevant parts and that children even appealed level (see also Keil, 1989; Prawat & Wild- fong; Subrahmanyam, 1997). to these parts in cases where their function had been disabled (e.g., by positioning the Our results would appear to be inconsistent, however, with recent findings by Kemler-Nel- bristles to make them inaccessible). Shipley (1997) has suggested that such effects of fa- son (1995). In that study, 3-, 4-, and 5-year- olds were shown complex novel artifacts miliarity could reflect ‘‘entrenchment,’’ whereby certain functions take on a special which were named repeatedly as their func- tions were demonstrated. Children then were importance because of their centrality in a cul- ture.

asked to generalize the object’s name to novel objects that were either globally similar or dis- If so, then Kemler-Nelson’s results would concur with a pattern that has emerged in a similar to the standard and that either could or could not carry out the demonstrated function. number of studies of naming, whereby shape is enriched by other knowledge over age. As Children generalized on the basis of both function and similarity, with function having one example, Jones, Smith, and Landau (1991) showed 2- and 3-year-olds wooden ob- a very large effect at all age levels. One obvious possibility is that Kemler-Nel- jects decorated with ‘‘eyes’’ to suggest anim- acy. Jones et al. found that 2-year-olds in- son’s children named on the basis of function because of their repeated hands-on experience creased their reliance on shape for the ‘‘eyes’’ objects, but 3-year-olds generalized to objects of carrying out the function and hearing the object’s name, compared to our method, sharing shape or texture, as if the surface properties of animate-type objects was im- which provided more limited exposure to the objects’ functions. It is possible that additional portant as well as shape. Jones et al. proposed that children increasingly come to recognize sustained experience with our novel objects might drive children’s attention to function for the correlations among the different sets of properties that distinguish animate from inani- naming. However, even increased experience with objects’ functions would not explain why mate objects, for example, that named objects with eyes will also share shape, texture, and children in our experiments generalized famil- iar objects’ names on the basis of shape rather substance. This increased understanding then drives attention differentially to either shape than function.

A second possibility is that children in alone (in the case of artifact-type objects) or to shape and texture (for animates). This in- Kemler-Nelson’s study were actually general- izing on the basis of familiar object parts and creasingly articulated basis for generalization (from shape alone to shape plus other proper- their functions, rather than the novel objects as a whole. The standard in her studies had ties) is consistent with our findings on familiar objects, as well as findings from other investi- two possible functions: One was to paint lines across paper (the parts were four small paint- gators (Baldwin, 1992; Imai, Uchida, & Gent- ner, 1994).

brushes at one end) and the other was to make music (the parts were several tightly drawn The Development of Naming and Knowledge wire strings that could be plucked). Children’s of Function reliance on function in these cases may have been due in part to their familiarity with the Although children answered the Name question on the basis of shape in every experi- functions of these or similar object parts, re- sulting in generalization on the basis of spe- ment, they did not show this pattern when asked the Function question. From the age of cific parts that typically carry out specific functions, just as they might generalize the 2, in at least some cases, children knew that objects with the same shape as the standard term ‘‘comb’’ to a novel object that has a comb as one prominent sub-part. Consistent would not necessarily support these functions, and they also knew that objects with different with this idea, Kemler-Nelson found that chil- AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

24 LANDAU, SMITH, AND JONES shapes could do so. These results are consis- between object naming and knowledge of ob- ject function argues against theories that em- tent with evidence that young children’s basis for judging one object’s similarity to another phasize an action-based foundation. The pres- ent results are, however, compatible with the- is task dependent (see Medin, Goldstone, & Gentner, 1993; Smith & Heise, 1992). For ex- ories that emphasize perceptual similarity in young children’s generalization of object ample, Smith et al. (1996) found that children who judged which objects were ‘‘like’’ a stan- names (Clark, 1973; Landau et al., 1988; Smith et al., 1996) and in particular, a hypoth- dard were strongly affected by variations in object function, whereas those who judged esis proposed by Gentner (1978); Salient ob- ject functions may draw the young child’s at- which objects had the same name as the stan- dard were affected by variations in perceptual tention to objects, but the child who hears an object named may switch her attention to the similarity.

In addition to these differences across ques- object’s shape, storing information about what it looks like for later generalization. tion type, there were strong developmental changes in the children’s ability to answer the An Early and Later Role for Object Shape Function question correctly at all. Only 5- in the Development of Object Naming year-olds and adults responded strongly and systematically correctly about function. An early reliance on shape in object naming would make sense for learning, as would en- Three-year-olds’ responses to the Function question were relatively weak in Experiment richment later on. First, the human visual sys- tem is exquisitely sensitive to the perception 1 and 2, and 2-year-olds’ responses were very weak in Experiment 2 and strong only in Ex- of 3-dimensional object shape, and object rec- ognition is accomplished largely by analysis periment 3, where they actually tried out the test objects. Based on the results of other stud- of shape. Although we do not fully understand what constitutes perceived ‘‘same shape,’’ ies (e.g., Brown, 1990; Kolstad & Baillargeon, 1989), we expected stronger demonstrated most recent theories rely on a 3-dimensional recovery of part-based structure which is in- competence among the youngest children— especially for the functions of ‘‘pulling a toy’’ variant across viewpoints (Biederman, 1987; Hoffman & Richards, 1982; Marr, 1982; and ‘‘carrying water.’’ Why didn’t these chil- dren do better? Marr & Vaina, 1984). Even infants are likely to detect similarity and differences among ob- We speculate that making explicit judg- ments of object functions is actually quite dif- jects in their 3-D shape. Further, detection of object shape does not ficult, requiring some explicit understanding of the physical principles involved in success- depend on specific experiences and hence is not subject to large variability in experience: fully carrying out functions such as absorp- tion, adhesion, and attachment. Preschooler’s As long as infants spontaneously explore their environment, they are likely to pick up infor- knowledge of object function is far from per- fect (Kelemen, 1995; Matan, 1996), and their mation about shape. Although some object functions will be discovered by spontaneous explicit judgments of how function can be car- ried out may be quite different from that of exploration, many others must await specific instruction. The child who must wait for such adults (Kemler-Nelson, 1995). Thus, it would not be surprising if the full explicit under- instruction will be at a marked disadvantage for acquiring vocabulary, whereas evidence standing of many object functions only slowly comes to enrich object naming, as we found suggests that early vocabulary growth follows a similar rapid course across wide differences here.

Although the children’s explicit knowledge in social and cultural conditions. Finally, object shape is highly reliable for of function clearly grew over development, they never generalized object names solely on predicting object kind: Although it is not fail- safe for correctly generalizing to other mem- the basis of function. This early distinction AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

25 OBJECT SHAPE, OBJECT FUNCTION bers of a named category, it is an excellent ferent named categories. Things called combs start. Objects of the same kind are usually may require certain critical shape elements; named by the same name; objects of the same rocks may not (Keil, 1994). In between these shape also often share the same kind. Thus the cases might be objects such as clocks (Bloom, child who relies on shape has a good chance 1996). It is an empirical question whether such of correctly generalizing object names to new variations in the importance of shape occurs instances. When he or she errs, correction can for all ages or just among older children and be made, and the child can suitably modify her adults. Our theory would predict the latter. critieria for naming objects in that particular A second reason is that there are different category. developmental timetables for acquiring knowl- By these arguments, we do not wish to sug- edge about different objects. Children (and gest that extending an object name to same- adults) undoubtedly acquire knowledge about shape objects is always the same as extending object functions at different times for different the name to objects that are truly in the same objects, and the interpretation of many object ‘‘category.’’ Criteria for category membership properties depends on specific object knowl- are no doubt quite complex and abstract. For edge (e.g., Keil & Carroll, 1980). Excepting artifacts, the most serious criterion for mem- very simple ones such as containment or sup- bership may be something quite beyond visi- port, functions can vary enormously in their ble shape—for example, knowledge of the complexity: Although the function of a chair creator’s intention (Bloom, 1996) or knowl- might be accessible to a very young child, edge of the historical connection between ob- the function of a plumber’s helper is probably jects (Malt, 1993). What we do wish to argue known only to adults, and is acquired under is that shape seems to bear a special meaning very specific circumstances. for objects, and as such is a candidate for preferred status in early development. For Conclusions young children in particular, looking like a comb licenses calling it a comb; looking like Common sense tells us that if we know a clothespin licenses calling it a clothespin. what an object is we often know what it does. Sameness of shape licenses sameness of name. Our experiments have shown that even very How, then, might this preference for shape young children know what familiar objects do, interact with deeper beliefs about object cate- can learn what some novel objects do, and can gories, and how might enrichment over devel- generalize this knowledge on occasion, if not opment occur? Imai, Gentner, and Uchida perfectly. However, the experiments also have (1994) have recently suggested that children’s shown that, although object function is im- attention to shape when naming objects is it- portant in naming for adults, it is not for young self theory-based, reflecting children’s beliefs children.

about the importance of shape in word exten- Our studies have focused on simple objects sion. Further, shape similarity may motivate with simple functions, and we have attempted or support changes in beliefs about other prop- to dissociate shape from function in order to erties of a named object (McCarrell & Cal- determine the circumstances under which lanan, 1995; Medin & Ortony, 1989), consis- shape as a basis for name extension can with- tent with developmental change toward en- stand challenge from other properties. We richment, not replacement by functional fully recognize that shape, function, and name knowledge.

are most likely intertwined in a more complex Even when function does begin to enter into manner for many real objects, and we expect naming, however, piecemeal development is that sorting these out may provide a real likely. One reason is that individuals may vary challenge for psychologists as well as young in their conceptions of just how important shape and function are to membership in dif- learners. AID JML 2533 / a010h$$$86 12-17-97 08:40:26 jmla AP: JML

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