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In press: Developmental Science

DO YOU SEE WHAT I SEE?

INFANTS’ REASONING ABOUT OTHERS’ INCOMPLETE PERCEPTIONS

Yuyan Luo

and

Whitney Beck

University of Missouri

Address correspondence to Yuyan Luo, Department of Psychological Sciences, University of Missouri,

Columbia, MO 65211, USA; phone: (573) 882-0429; fax: (573) 882-7710; email: luoy@missouri.edu.

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Abstract

Twelve-month-olds realize that when an agent cannot see an object, her incomplete perceptions

still guide her goal-directed actions. What if the agent had incomplete perceptions because she could only

see one part of the object, e.g., one side of a screen? In the present research, 16-month-olds were first

shown an agent who always pointed to red objects, as opposed to a black or a yellow object, suggesting

that she preferred red over the other colors. Next, two screens were introduced while the agent was absent.

The screens were (1) red or green on both sides; (2) red on the front (infants’ side) but green on the back

(the agent’s side) or vice versa; or (3) only colored red or green on the front. During test, the agent, who

could only see the back of the screens, pointed to one of the two screens. The results revealed that while

infants expected the agent to continue acting on her color preference and point to the red rather than the

green screen during test, they did so in accord with the agent’s perceptions of the screens, rather than their

own perceptions: they expected the agent to point to the red screen in (1), but to the green-front screen in

(2), and they had no prediction of which screen the agent should point to in (3). The implications of the

present findings for early psychological reasoning research are discussed.

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We know that infants possess some understanding about the psychology of agents (i.e., objects

that can act and react to their environment) (e.g., Gergely & Csibra, 2003; Leslie, 1995; Premack &

Premack, 1995). From a young age, infants interpret the actions of agents in terms of goals and dispositions

(e.g., Bíró & Leslie, 2007; Gergely, Nádasdy, Csibra, & Bíró, 1995; Kuhlmeier, Wynn, & Bloom, 2003; Luo &

Baillargeon, 2005; Phillips & Wellman, 2005; Sommerville, Woodward, & Needham, 2005; Woodward, 1998;

Woodward & Guajardo, 2002). Recent research suggests that at least by the second year, infants also

appear to consider an agent’s perceptions and beliefs to make sense of the agent’s goals and dispositions,

even when those perceptions and beliefs are incomplete or false (e.g., Allard & Onishi, 2008; Luo &

Baillargeon, 2007; Luo & Johnson, in press; Onishi & Baillargeon, 2005; Sodian, Thoermer, & Metz, 2007;

Song & Baillargeon, in press; Southgate, Senju, & Csibra, 2007; Surian, Caldi, & Sperber, 2007). In the

present research, we focused on how infants considered an agent’s incomplete perceptions to interpret her

disposition-guided behavior.

In her ground-breaking study, Woodward (1998) demonstrated that infants at 5 to 6 months of age

encode a human agent’s repeated actions of grasping an object as goal-directed. In one experiment, infants

were first habituated to an event in which they saw the human agent’s arm and hand reach for and grasp

object-A, as opposed to object-B. Following habituation, the objects’ positions were reversed. During test,

infants saw the agent’s arm and hand reach for and grasp object-A in its new location (old-goal event) or

object-B in the position previously occupied by object-A (new-goal event). Infants looked reliably longer at

the new- than at the old-goal event. These and control results suggested that infants interpreted the agent’s

actions during habituation as directed toward the goal of approaching object-A, and that they expected the

agent to continue acting on this goal during test and hence responded with increased attention when the

agent’s arm and hand reached for and grasped object-B instead in the new-goal event.

A few recent studies (e.g., Luo, 2008; Luo & Baillargeon, 2005; Song, Baillargeon, & Fisher, 2005b)

showed that in the Woodward-type task, infants also interpret agents’ goal-directed actions as stemming

from particular dispositions. A disposition is defined as a tendency or state that helps us interpret and

predict an agent’s goal-directed behavior. In these studies, infants were assigned to a two-object or a one-

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object condition. The two-object condition was essentially similar to the Woodward (1998) study described

above. The one-object condition was identical to the two-object condition except that when the agent

approached object-A, object-B was absent. During test, infants again looked reliably longer at the new- than

at the old-goal event in the two-object condition. However, they looked about equally at the two events in the

one-object condition. These results suggested that in the two-object condition, infants attributed to the agent

a goal of approaching object-A as well as a particular disposition, a preference for object-A over object-B.

These attributions led infants to expect the agent to maintain the preference and form the same goal of

approaching object-A as before. They thus responded with increased attention when the agent approached

object-B instead during test. The results of the one-object condition suggested that although infants

attributed to the agent the goal of approaching object-A, since the agent did so repeatedly, this goal

attribution was insufficient for infants to predict what the agent should do when a new object, object-B, was

introduced during test. They thus accepted that the agent could approach either object. Therefore, in some

cases at least, a disposition may be a more powerful predictor of agents’ actions than a goal – it can help

predict what an agent will do to pursue her goal in a relatively different context. Knowing that an agent

prefers one object over another can lead to predictions that the agent will still approach its preferred object

when the positions of the two objects change. However, only knowing the agent’s goal directed towards one

object provides no information as to the agent’s actions when a new object is added.

Luo and Baillargeon (2007) found that 12.5-month-olds also consider what an agent perceives and

remembers when interpreting the agent’s preference-guided actions. In their study, infants watched an agent

repeatedly reach for and grasp object-A, which was visible to the agent through a transparent screen, as

opposed to object-B. Object-B was either visible to the agent through another transparent screen; hidden

from the agent (but not the infants) by an opaque screen; or placed by the agent herself behind the opaque

screen, so that even though she could no longer see object-B, she knew of its presence there. The results

showed that infants responded based on the agent’s perceptions: they interpreted the agent’s repeated

actions toward object-A as revealing her preference for object-A over object-B only when she could see

object-B or when she was aware of its presence, but not when object-B was hidden from her. Recent

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investigations suggest that when the agent holds false perceptions or beliefs, rather than incomplete

perceptions as in Luo and Baillargeon (2007), 13- to 15-month-old infants also use the agent’s perceptions

and beliefs to interpret her actions (Onishi & Baillargeon, 2005; Song & Baillargeon, in press; Surian et al.,

2007).

The present research sought new evidence indicating that infants consider an agent’s incomplete

perceptions to make sense of her disposition-guided actions. In Luo and Baillargeon (2007), the agent held

incomplete perceptions because she could not see an entire object. We designed situations in which the

agent could only see one part of the object. We reasoned that these situations might be more sophisticated

and hence tested older, 16-month-old infants. In addition, we asked whether infants could make inferences

about an agent’s color preference, a new type of dispositions. As discussed above, infants can interpret

agents’ goal-directed actions as stemming from a particular disposition. Infants have been found to attribute

to agents several simple dispositions: a positive disposition towards an agent (e.g., Hamlin, Wynn, & Bloom,

2007; Kuhlmeier et al., 2003; Premack & Premack, 1997) or an object (e.g., Luo & Baillargeon, 2005, 2007;

Luo & Johnson, in press; Repacholi & Gopnik, 1997; Song & Baillargeon, in press), or an inclination to

perform certain actions (e.g., Song & Baillargeon, 2007; Song, Baillargeon, & Fisher, 2005a). In these cases,

after seeing an agent’s behavior in one context, infants use disposition attributions to make predictions of

the agent’s actions in a relatively different context. Specifically, after seeing how a helper or a hinderer

interact with an agent going up a hill, infants form expectations as to whether the agent should later

approach the helper or the hinder (e.g., Hamlin et al., 2007; Kuhlmeier & Wynn, 2003; Kuhlmeier et al.,

2003); after seeing an agent repeatedly choose one object over another, infants expect the agent to

approach the same object when the positions of the two objects change (e.g., Luo & Baillargeon, 2005,

2007; Luo & Johnson, in press; Song et al., 2005b); after seeing an agent slide different objects, infants

expect the agent to later pick a new object that is also slideable (e.g., Song & Baillargeon, 2007; Song et al.,

2005a). We examined whether infants could ascribe to agents yet another type of simple disposition

involving features of objects: a preference for a certain color. In particular, after seeing an agent point to red

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objects as opposed to black and yellow objects, would infants then generalize this to a relatively new

context and expect the agent to also point to a red but not a green screen?

Experiment

Sixteen-month-olds were assigned to one of three conditions, a congruent, an incongruent, or an

ignorance condition (see Fig. 1). In the congruent condition, infants first watched two familiarization displays.

In each, a female human agent sat at a window behind and between two distinct objects, a red object on the

right (from the infant’s perspective) and an object of a different color on the left; she pointed to the red object.

A red toy pepper and a black cup, a red cardboard pyramid and a yellow toy house, were used in the first

and second familiarization displays, respectively. Next, the window was closed and infants watched an

orientation event in which two screens, the left one red and the right one green, were introduced. The

screens were mounted on a handle, which extended outside the apparatus, so that a hidden experimenter

could use the handle to rotate the screens. The screens first stood upright. The experimenter lowered the

screens to lay them flat on the floor and infants could see that the back of each screen was of the same

color as the front; she then rotated the screens 900 upward. This sequence was repeated once, after which

the screens were kept upright. The window was then opened and the agent sat at the window, as in

familiarization, behind and between the two upright screens. Infants saw a test event in which the agent

pointed to the red-front (red-front event) or the green-front screen (green-front event).

The incongruent condition was identical to the congruent condition except that the screens were of

different colors on the two sides: the left screen was green on the front and red on the back (green-front

screen), while the right screen was red on the front and green on the back (red-front screen).

If infants in the congruent condition realized that the agent’s actions during familiarization revealed

her preference for the color red over other colors, and expected her to maintain this color preference during

test when she saw the screens, then infants who saw the green-front event should look reliably longer than

those who saw the red-front event. In contrast, if infants in the incongruent condition again attributed to the

agent a preference for red over other colors, and recognized that the agent could only see the back but not

the front of the screens (since she was absent when the screens were introduced and hence should be

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unaware of the fact that the screens were also red or green on the front), then they should expect the agent

to point to the green-front screen to act on her color preference because it was red on the back. Infants who

saw the red-front event should therefore look reliably longer than those who saw the green-front event.

Note that according to our predictions, infants should find the green-front event in the congruent

condition and the red-front event in the incongruent condition unexpected. Both screens were positioned on

the right. Therefore, infants might simply respond to which direction, left or right, the agent pointed during

test, ignoring the colors of the screens: they might find it more interesting when the agent pointed at the right

than at the left screen. The ignorance condition was thus designed to rule out this alternative interpretation.

This condition was identical to the congruent condition except that the screens were only colored on the

front: the left screen was red (red-front screen) and the right green (green-front screen); the back of the

screens were covered with the same light-brown contact paper that covered the apparatus floor. If infants

simply responded to which direction the agent pointed at during test, those in the ignorance condition should

respond like those in the congruent condition and look reliably longer at the green-front than at the red-front

screen. However, if infants responded by taking the agent’s perspectives, infants in the ignorance condition

should behave differently. They should realize that although the agent had a preference for the color red

over other colors, as revealed during familiarization, she should be ignorant of the colors on the front of the

screens since she was absent when the screens were introduced. Therefore, infants should have no

expectation as to which of the two screens the agent would point to during test, for both screens appeared

identical to her and neither was red. Infants who saw the red-front event and those who saw the green-front

event should thus look about equally.

Method

Participants

Participants were 42 healthy term infants, 21 male and 21 female (range: 15 months, 5 days to 17

months, 29 days, M = 16 months, 6 days). Seven infants were assigned to each of the six experimental

groups formed by crossing the three conditions (congruent, incongruent, or ignorance) and the two test

events (red- or green-front). Another 8 infants were tested but eliminated, because of fussiness (2),

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distraction (2), observer difficulties (1), procedural problems (1), or test looking times that were more than 3

SDs from the mean (2).

Apparatus

The apparatus consisted of a wooden display box (114 cm high x 104 cm wide x 47.5 cm deep)

mounted 76 cm above the room floor. The infant sat on a parent's lap and faced an opening (53 cm x 102

cm) in the front of the apparatus. Between trials, a curtain consisting of a muslin-covered frame (61 cm x

104 cm) was lowered in front of the opening. The side walls of the apparatus were painted white, and the

floor was covered with light-brown contact paper. The back wall of the apparatus was made of a white foam

board. A rectangular window (35 cm x 45 cm) was created in its midsection. During familiarization and test,

the window was opened and a human agent, wearing a white shirt, sat centered on the apparatus and

behind the window. During orientation, the window was closed.

During familiarization, two pairs of colored toys were used. One pair consisted of a red toy pepper

(7.6 cm x 12.7 cm x 7.6 cm) and a black cup (10 cm high and 8 cm in diameter), the other consisted of a red

cardboard pyramid (13 cm high and 9.5 cm x 9.5 cm at the bottom) and a yellow toy house (19 cm x 12.5

cm x 12.5 cm).

During orientation and test, two foam board screens (20.5 cm x 20.5 cm, 0.5 cm thick and 24 cm

apart) mounted on a foam board handle (5 cm high, 102 cm long, and 0.7 cm thick) were used. The handle

was fastened to the apparatus floor by Velcro; its right end extended outside the apparatus through a slit in

a muslin-covered window (31 cm x 30.5 cm) in the right side wall. An experimenter rotated this end to raise

and lower the screens. In the congruent condition, the left screen was covered with red tape and the right

green on both sides. In the incongruent condition, the left screen was covered with green tape on the front

and red tape on the back, and vice versa for the right screen. In the ignorance condition, the left and right

screens were covered with red and green tape, respectively, only on the front; the back of the screens were

covered with the same light-brown contact paper as the floor.

Procedure

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Two naïve observers monitored each infant's looking behavior through peepholes in large cloth-

covered frames on either side of the apparatus. The primary observer's looking times were used to

determine the endings of the trials (see below). Interobserver agreement was measured for 38 of the 42

infants and averaged 92% per trial per infant.

All infants first received four familiarization trials; they saw the familiarization display 1 on the first

and third trials in which the agent pointed at the red toy pepper and the familiarization display 2 on the

second and fourth trials in which the agent pointed at the red cardboard pyramid. The agent remained in this

position until the trial ended when infants (1) looked away for 2 consecutive seconds after having looked for

at least 2 cumulative seconds, or (2) looked for 30 cumulative seconds.

Next, infants received two orientation trials in which the two screens appropriate for their condition

were introduced. The screens remained upright until the trial ended by the same criteria as in familiarization.

Finally, all infants received one test trial in which the agent pointed to the red- (red-front event) or

the green-front screen (green-front event), remaining in this position until the trial ended. Half of infants in

each condition saw the red-front event; the other saw the green-front event. Each test trial ended when

infant (1) looked away for 2 consecutive seconds after having looked for at least 5 cumulative seconds, or (2)

looked for 60 cumulative seconds.

At the start of each familiarization and test trial, the agent sat at the window in the back wall of the

apparatus, with her eyes focused on a neutral mark between the two objects. While pointing to an object,

the agent kept her gaze on the object. Thus, the agent did not make eye contact with the infant during the

experiment.

Infants attended well to the 2-s pre-trials in both familiarization and test (means range: 1.9-s to 2.0-

s) and to the 12-s pre-trials in orientation (means range: 11.1-s to 11.9-s). Preliminary analyses of the test

main-trial data revealed no significant interaction among condition, event, and sex, F(2, 30) = 0.41; the data

were therefore collapsed across sex in subsequent analyses.

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Results

The analysis of infants’ familiarization and orientation main-trial looking times (see Fig. 2) revealed

that infants in the six experimental groups did not differ in their looking behavior during these two phases.

The only significant effect was that of familiarization display, suggesting that across conditions, infants

looked reliably longer at display 1 on the first and third trials than at display 2 on the second and fourth trials.

Infants' test main-trial looking times (see Fig. 2) were analyzed by a 3 x 2 ANOVA with condition

(congruent, incongruent, or ignorance) and event (red- or green-front) as between-subjects factors. The

analysis yielded a significant condition x event interaction, F(2, 36) = 6.74, p < .005. Planned comparisons

revealed that (1) in the congruent condition, infants who saw the green-front event (M = 24.0, SD = 7.2)

looked reliably longer than those who saw the red-front event (M = 13.3, SD = 7.0), F(1, 36) = 8.71, p < .01,

Cohen’s d = 1.5, (2) in the incongruent condition, infants who saw the red-front event (M = 18.3, SD = 8.3)

looked reliably longer than those who saw the green-front event (M = 10.6, SD = 2.5), F(1, 36) = 4.52, p

< .05, d = 1.3, and (3) in the ignorance condition, infants who saw the green-front (M = 14.2, SD = 7.6) and

red-front (M = 16.1, SD = 6.7) events looked about equally, F (1, 36) = 0.26, d = -0.3. The main effects of

condition, F(2, 36) = 1.53, p > .20, and event, F(1, 36) = 0.03, were not significant. Examinations of

individual infants’ looking times confirmed these results (congruent condition: Wilcoxon rank-sum W = 34, p

< .025; incongruent condition: W = 36, p = .05; ignorance condition: W = 48, n.s.).1

Infants’ pointing behavior

In reviewing videotaped records of the testing sessions, it became evident that infants sometimes

pointed during the experiment. We therefore examined their pointing behavior. A pointing action was defined

as when “infants extended their arm (either fully or slightly bent) and index finger or hand” (p. F3) in the

direction of the apparatus (Liszkowski, Carpenter, & Tomasello, 2007). Two coders blind to infant’s condition

coded 41 of the 42 infants’ videotapes. Inter-coder agreement on whether pointing happened on each trial

was 93%. The judgments by the more experienced coder were used.

During familiarization, pointing happened on 11 of the 56 trials in the congruent and in the

incongruent condition (56 was the product of 14 times 4 as the 14 infants each received 4 familiarization

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trials), and on 12 of the 52 trials in the ignorance condition (52 was the product of 13 times 4 because only

13 infants could be coded from the videotape). During orientation, pointing happened on 2 of the 28 trials in

the congruent condition (28 was the product of 14 times 2 as the 14 infants each received 2 orientation

trials), on 7 of the 28 trials in the incongruent condition, and on 3 of the 26 trials in the ignorance condition.

During test, pointing happened on 3 of the 14 trials in the congruent condition (the 14 infants each received

one test trial), on 4 of the 14 trials in the incongruent condition, and on 6 of the 13 trials in the ignorance

condition. A loglinear model (Agresti, 1996) with condition (congruent, incongruent, or ignorance), trial type

(familiarization, orientation, or test), and outcome (pointing or no-pointing) as factors and count (number of

trials) as the dependent variable best fit these data (χ212 = 10.75, p > .50). The model revealed that infants’

pointing pattern among the three conditions during orientation (χ21 = 26.26, p < .0001) and test (χ21 = 63.04,

p <.0001) differed significantly from that of familiarization. In other words, infants in the three conditions

pointed about the same amount during familiarization, but their pointing differed among conditions during

orientation and test.

Discussion

Infants in the congruent condition who saw the green-front event looked reliably longer than those

who saw the red-front event during test, suggesting that they (1) attributed to the agent a preference for the

color red over other colors after watching her point to a red toy as opposed to a black or a yellow one during

familiarization, (2) expected her to continue acting on this color preference and point at the red but not the

green screen during test, and (3) responded with increased attention when she failed to do so in the green-

front event. Infants in the incongruent condition who saw the red-front event looked reliably longer than

those who saw the green-front event, indicating that although infants attributed to the agent a color

preference based on her actions during familiarization, they (1) also realized that the agent was absent

when the screens with different colored front and back were introduced during orientation, (2) expected the

agent, who could only see the back of the screens during test, to point to the green-front screen which was

red to her, and therefore (3) responded with prolonged looking when this expectation was violated in the

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red-front event. Infants in the ignorance condition who saw the green- and red-front events looked about

equally, suggesting that they recognized that the agent could not act on her color preference during test,

since she could only see the uncolored back of the screens, and hence accepted that the agent could point

at either screen. Together, these results revealed that infants learned and remembered the colors on both

sides of the screens during orientation but used the agent’s perceptions, which only included the back of the

screens, to predict and interpret her actions during test, even when the agents’ perceptions differed from

their own.

Infants also pointed during the experiment. Prior research on infant pointing suggests that in the

second year of life, infants point to show their attention to objects or to “communicate” with others, e.g., to

share mutual interests or to inform others of things they do not know about (e.g., Ganea, 2005; Legerstee &

Barillas, 2003; Liszkowski, Carpenter, Henning, Striano, & Tomasello, 2004; Liszkowski et al., 2007; Moore

& D'Entremont, 2001; Saylor, 2004; Tomasello, Carpenter, & Liszkowski, 2007). The pointing behavior

observed in the present research seemed to be consistent with these findings. During familiarization, infants

in the three conditions pointed about the same amount: they might simply do so to imitate the agent, or to

express or share their interests in the situation. During orientation, the condition-appropriate screens were

introduced with the agent absent. Infants’ pointing in this phase might indicate their recognition of the

novelty of the screens: they pointed the most in the incongruent condition, less so in the ignorance condition,

and least in the congruent condition. During test, infants’ pointing might suggest that they attempted to “tell”

the agent something: they pointed the most in the ignorance condition when the agent could not see the

colors on the screens, least in the congruent condition when the agent’s perceptions of the screens were

identical to theirs; whereas in the incongruent condition, infants might be pointing to inform the agent of the

fact that the screens were of different colors on the two sides, while accepting that the agent acted

according to what colors she saw. Therefore, these post-hoc patterns of infant pointing might provide

converging evidence that infants considered the agent’s incomplete perceptions, but not their own more

complete perceptions, to make sense of the agent’s actions. However, the present research was not

specifically designed to elicit infant pointing. Pointing only happened on a small portion of the trials. A

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proportion of infants did not point at all, and it was difficult to determine whether infants were pointing at the

screens or the agent when they did point. Future research could use situations more conducive to infants’

pointing and/or other behavior in looking-time tasks to provide various measures of infants’ knowledge.2

The present results have implications for two lines of research. First, these results extend prior

findings that infants consider agents’ incomplete or false perceptions and beliefs to make sense of agents’

behavior (e.g., Allard & Onishi, 2008; Luo & Baillargeon, 2007; Onishi & Baillargeon, 2005; Sodian et al.,

2007; Song & Baillargeon, in press) to new situations in which the agent holds incomplete perceptions not

because the whole object is hidden from her, but because only one part of an object is visible to her.

Together with reports that infants also non-egocentrically take into account agents’ knowledge-states to

guide their own behavior or to interact with agents (e.g., Moll & Tomasello, 2004, 2006; O'Neill, 1996;

Tomasello & Haberl, 2003), these findings lend support to the claim that at least by the second year, infants

possess rudimentary perspective-taking abilities.

Flavell and his colleagues introduced an important distinction between two levels in the

development of children’s understanding of others’ perspectives (e.g., Flavell, 1978, 2004; Lempers, Flavell,

& Flavell, 1977; Masangkay et al., 1974). Level-1 involves understanding what objects agents can see;

children at this level realize, for example, that they may be able to see an object that another agent cannot

see or vice versa. Level-2 involves understanding how objects appear to agents; children at this level

recognize, for example, that the same object or scene may appear differently when viewed from different

perspectives or by agents with different perceptual experiences. When cast in these terms, the present

results revealed infants’ level-1 understanding that the agent could only see the back of the screens while

they themselves saw the front of the screens during test. The present findings could also be relevant to

infants’ level-2 understanding: infants, who saw both sides of the screens during orientation, realized that

the agent’s absence during orientation and her perspectives during test determined her knowledge about

the screens, which differed from their own.

Second, the present research reveals another type of simple dispositions infants ascribe to agents:

a color preference. In the present experiment, seeing four instances of two color pairings, red-black and red-

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yellow, enabled 16-month-olds to attribute to the agent a preference for the color red, which they

generalized to the test event in a relatively new context, predicting that the agent should prefer red over a

new color, green. In Song et al. (2005a), 13.5-month-olds watched an agent slide three different objects and

realized that the agent had an inclination to slide things, which they also generalized to a relatively new

context, expecting the agent to slide a new object. Although it remains unclear whether 13.5-month-olds

could succeed with only two exemplars, as in the present study, Song and Baillargeon (2007) later found

that 9.5-month-olds in a similar study needed six exemplars. It thus seems reasonable that younger infants

need more exemplars to learn about an agent’s dispositions from her actions. These findings, together with

those showing that infants attribute to agents a positive disposition towards certain objects or agents (e.g.,

Hamlin et al., 2007; Kuhlmeier et al., 2003; Luo & Baillargeon, 2007; Repacholi & Gopnik, 1997), pose

exciting research questions. For instance, do dispositions differ in terms of how well a disposition predicts

agents’ goal-directed actions? In the present experiment, infants expect the agent to always point to a red

object. In Song et al. (2005a), infants expect the agent to always slide an object. However, in a Woodward

(1998) type of task, given the one-object condition results described in the Introduction, it seems unlikely

that infants expect an agent who prefers object-A over object-B to always approach object-A as opposed to

other objects. Therefore, it remains to be seen what evidence enables infants to attribute to an agent an

object-specific disposition, which predicts that the agent will always choose the particular object. In addition,

can infants distinguish dispositions specific to a certain person and those shared by a group (e.g., Buresh &

Woodward, 2007)? Future studies addressing these questions will shed light on the nature and development

of early psychological understanding.

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Acknowledgments

This research was supported by research funds from the University of Missouri to the first author.

We thank Renée Baillargeon, Shawn Christ, Frieder Kohn, Lexin Li, Kris Onishi, Doug Steinley, and Kristy

vanMarle for helpful suggestions. We are also grateful to the University of Missouri Infant Cognition

Laboratory for their help with data collection, and the parents and infants who participated in the research.

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Footnotes

1. The test data were subjected to an analysis of covariance (ANCOVA); the factors were as in the ANOVA,

and the covariates were the infants’ mean looking times at the display 1 and display 2 during the

familiarization trials and their mean looking times during the orientation trials. The results replicated those of

the ANOVA: the condition x event interaction was significant, F(2, 33) = 4.84, p < .025; and planned

comparisons yielded similar results to those of the ANOVA (congruent condition: F(1, 33) = 6.97, p < .025;

incongruent condition: F(1, 33) = 4.55, p < .05; ignorance condition: F(1, 33) = 0.20).

2. The pointing data suggest that infants might construe the present situation as communicative (e.g.,

Southgate, van Maane, & Csibra, 2007; Tomasello et al., 2007). Although the agent did not establish eye

contact or have verbal communication with the infant, the fact that she pointed might indicate her intention to

communicate. Infants might thus point to “respond” to her. However, infants even pointed during orientation

in which the agent was absent from the apparatus. It is thus also possible that infants pointed to

communicate with their parents, who held them sitting in front of the apparatus. Our data were simply

insufficient to determine which of these possibilities was at play.

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Figure Captions

Figure 1. Schematic drawing of the events shown in the congruent, incongruent, and ignorance conditions.

Congruent condition. (a) Familiarization display 1. Each familiarization trial consisted of a 2-s pre-trial and a

main-trial. At the start of the pre-trial, the agent sat behind the back window between the toy pepper and the

cup, looking at a neutral mark between them; the two toys were 34 cm apart and each about 13 cm from the

back wall. When the computer signaled that the infant had looked for 2 cumulative seconds, the 2-s pre-trial

began in which the agent used her right index finger to point to the red toy pepper while turning to look at it;

she then paused, with her eyes focused on the pepper. In the main-trial, the infants watched this paused

scene until the trial ended. When this occurred, an experimenter hidden behind the apparatus lowered the

curtain in front of the apparatus. (b) Familiarization display 2. This display was similar to the familiarization

display 1 except that the toy pepper and the cup were replaced with the cardboard pyramid and the toy

house. The two toys were 27 cm apart; the backmost tip of the pyramid was 5.5 cm from the back wall and

the house was 13 cm from it. (c) Orientation event. Each orientation trial consisted of a 12-s pre-trial and a

main-trial. At the start of the pre-trial, the screens stood upright, 13 cm from the back wall. When the

computer signaled that the infant had looked for 2 cumulative seconds, the 12-s pre-trial began. After a 1-s

pause, the experimenter lowered the screens so that they lay flat on the floor (2 s). After another 1-s pause,

the experimenter rotated the screens 90 degrees upward (2 s). This sequence was repeated once;

afterwards, the screens were kept upright. In the main-trial, the infants watched this paused scene until the

trial ended. (d) Test events. Green-front event. This event was similar to the familiarization display 1 except

that the toys were replaced with the two upright screens and the agent pointed at the green-front screen.

Red-front event. This event was identical to the green-front event except that the agent pointed to the red-

front screen. Incongruent and Ignorance conditions. (a-d). The events shown in the two conditions were

identical to those of the congruent condition except that the screens appropriate for the condition were used

during orientation and test.

22

Figure 2. Mean looking times during the familiarization, orientation, and test trials of the infants in the six

experimental groups formed by crossing the congruent, incongruent, and ignorance conditions and the

green-front and red-front test events. Error bars represent standard errors. An asterisk (*) denotes p < .05.