Infants' Sensitivity to the Causal Features of Means‐End Support Sequences in Action and Perception

Current work has yielded differential findings regarding infants' ability to perceptually detect the causal structure of a means‐end support sequence. Resolving this debate has important implications for perception‐action dissociations in this domain of object knowledge. In Study 1, 12‐month‐old infants' ability to perceive the causal structure of a cloth‐pulling sequence was assessed via a habituation paradigm. After seeing an event in which a supported toy was moved by pulling a cloth that it sat on, 12‐month‐old infants demonstrated longer looking to events that violated the causal structure of this sequence than to events that preserved the causal structure but varied other perceptual features of the event. Studies 2 and 3 investigated 10‐month‐olds' interpretations of means‐end support sequences using both a habituation paradigm and a task that assessed infants' own means‐end actions. Whereas 10‐month‐olds failed to demonstrate an understanding of the causal structure when tested using a flat cloth as the support (Study 2), sensitivity to this structure was apparent when a rectangular box was the support. These patterns were evident in both action and perception (Study 3). Moreover, individual variation in action task performance was related to visual habituation performance. The results are discussed with respect to the relation between action and perception in infancy.     

Means‐End Behavior in Young Infants: The Interplay of Action Perception and Action Production

In 2 experiments, the interplay of action perception and action production was investigated in 6‐month‐old infants. In Experiment 1, infants received 2 versions of a means‐end task in counterbalanced order. In the action perception version, a preferential looking paradigm in which infants were shown an actor performing means‐end behavior with an expected and an unexpected outcome was used. In the action production version, infants had to pull a cloth to receive a toy. In Experiment 2, infants' ability to perform the action production task with a cloth was compared to their ability to perform the action production task with a less flexible board. Finally, Experiment 3 was designed to control for alternative low‐level explanations of the differences in the looking times toward the final states presented in Experiment 1 by only presenting the final states of the action perception task without showing the initial action sequence. Results obtained in Experiment 1 showed that in the action perception task, infants discriminated between the expected and the unexpected outcome. This perceptual ability was independent of their actual competence in executing means‐ end behavior in the action production task. Experiment 2 showed no difference in 6‐month‐olds' performance in the action production task depending on the properties of the support under the toy. Similarly, in Experiment 3, no differences in looking times between the 2 final states were found. The findings are discussed in light of theories on the development of action perception and action production.     

Common Coding of Observation and Execution of Action in 9‐Month‐Old Infants

Do 9‐month‐old infants motorically simulate actions they perceive others perform? Two experiments tested whether action observation, like overt reaching, is sufficient to elicit the Piagetian A‐not‐B error. Infants recovered a toy hidden at location A or observed an experimenter recover the toy. After the toy was hidden at location B, infants in both conditions perseverated in reaching to A, demonstrating that active search by the infant is not necessary for the A‐not‐B error. Consistent with prior research, infants displayed an ipsilateral bias when reaching, the so‐called mysterious midline barrier. A similar ipsilateral bias was also observed depending on the manner in which the experimenter reached; infants perseverated following observation of ipsi‐ but not contralateral reaches by the experimenter. Thus, infants perseverated only following observation of actions they themselves were able to perform, suggesting that they coded others' actions in terms of motor simulation.     

Detecting Transparent Barriers: Clear Evidence Against the Means‐End Deficit Account of Search Failures

The standard explanation of infants' search failures with hidden objects, despite an apparent sensitivity to them, is a deficit in the means‐end skill for retrieving objects from occluders. Studies equating means‐end demands for retrieving toys from transparent and opaque barriers challenge this account by showing that infants succeed more with visible objects. However, they suffer from a critical limitation: Infants may retrieve visible objects without noticing the transparent barriers in front of them. We addressed this concern by requiring infants to notice a barrier to retrieve a toy and specifically to pull down a rotating screen to retrieve a toy from behind it. Seven‐month‐olds used this means‐end skill more often with a transparent barrier than an opaque one. Thus, neither a means‐end deficit nor an ability to ignore transparent barriers fully accounts for search failures. Relations to other findings challenging the means‐end deficit account and implications for approaches to studying cognitive development are discussed.     

Interacting Socially With Human Hands at 24 Months of Age

This experiment explored whether or not 2‐year‐olds would engage in synchronic imitation with human hands. Sixty‐four 24‐month‐old infants participated. In a test of synchronic imitation, infants were given a toy while a model simultaneously performed novel actions on an identical toy. Infants were randomly assigned to 1 of 4 model conditions: a familiar person, an unfamiliar person, disembodied human hands, and disembodied robotic pincers. Infants were as likely to synchronically imitate disembodied hands as a person. Imitation of the pincers was significantly lower. This pattern suggests that 2‐year‐olds will engage socially with human hands in the absence of the rest of the body.     

The Development of Gaze Following in a Third‐Party Context

Infants follow the gaze of an individual with whom they are directly interacting by the end of the first year. By 18 months infants are capable of learning novel words in observational (or third‐party) contexts (Floor & Akhtar, 2006). To examine third‐party gaze following in 12‐ and 18‐month‐olds, the parent and experimenter engaged in a conversation while the infant was present. For 8 trials approximately every 30 sec the experimenter would turn her head to the right or left to fixate on a toy placed on either side of the room with the parent following suit. In the first experiment, the parent was seated next to the infant and the experimenter opposite, whereas in the second experiment the positions of the adults were switched. In Experiment 1, 18‐month‐olds but not 12‐month‐olds followed gaze. In Experiment 2, 12‐month‐olds acquired a tendency to follow gaze during the experimental session. These results suggest that an incipient ability to follow third‐party gaze is present by 12 months and that infants acquire a more reliable and general ability to follow the gaze of noninteractive others between 12 and 18 months.     

It Is Not Just About Location: Infants Perseverate to Container Shape During Object Search

In searching for a toy hidden at a new location, infants will err by searching at the previously correct location. This study investigated the possibility that 8.5‐month‐old infants would perseverate on the basis of other visual features by which covers could be individuated. Infants saw a toy hidden under 1 of 2 distinctly shaped covers. Following successful retrievals from the Shape A cover, infants saw the toy hidden under the Shape B cover. On this B trial, the covers were at locations that had not been baited on the preceding trials, precluding location perseveration. The infants erred by choosing the unbaited Shape A cover more often than control infants presented with 1 type of cover throughout. The findings suggest that infants perseverate to cover shape and are form biases biased toward cover shape even when location information is sufficient to support retrieval.     

Rational Imitation in 12‐Month‐Old Infants Christiane Schwier,Catharine van Maanen,Malinda Carpenter

Gergely, Bekkering, and Király (2002) demonstrated that 14‐month‐old infants engage in “rational imitation.” To investigate the development and flexibility of this skill, we tested 12‐month‐olds on a different but analogous task. Infants watched as an adult made a toy animal use a particular action to get to an endpoint. In 1 condition there was a barrier that prevented a more straightforward action and so gave the actor no choice but to use the demonstrated action. In the other condition there was no barrier, so the actor had a free choice to use the demonstrated action or not. Twelve‐month‐olds showed the same pattern of results as in Gergely and colleagues' study: They copied the particular action demonstrated more often when the adult freely chose to use the action than when she was forced to use it. Twelve‐month‐olds, too, thus show an understanding of others' intentions as rational choices and can use this understanding in cultural learning contexts.     

Onset of Voluntary Communication: Smiling Looks to Mother

Playing infants often direct smiling looks toward social partners. In some cases the smile begins before the look, so it cannot be a response to the sight or behavior of the social partner. In this study we asked whether smiles that anticipate social contact are used by 8‐ to 12‐month‐old infants as voluntary social signals. Eighty infants—20 at each of 8, 9, 10, and 12 months of age—completed 5 tasks. The tasks assessed anticipatory smiling during toy play, means‐end understanding (2 tasks), intentional communication via gesture and vocalizations, and memory for mother's location. Across all ages, anticipatory smiling was strongly predicted by intentional gestural and vocal communication and by means‐end understanding. The findings are discussed in terms of the nature and origins of infants' voluntary communications.     

Six‐Month‐Old Infants Predict Agents’ Goal‐Directed Actions on Occluded Objects

Infants can infer agents’ goals after observing agents’ goal‐directed actions on objects and can subsequently make predictions about how agents will act on objects in the future. We investigated the representations supporting these predictions. We familiarized 6‐month‐old infants to an agent who preferentially reached for one of two featurally distinct objects following a cue. At test, the objects were sequentially occluded from the infant in the agent's presence. We asked whether infants could generate action predictions without visual access to the relevant objects by measuring whether infants shifted their gaze to the location of the agent's hidden goal object following the cue. We also examined what infants represented about the hidden objects by removing one of the occluders to reveal either the original hidden object or the unexpected other object and measuring infants’ looking time. We found that, even without visual access to the objects, infants made predictive gazes to the location of the agent's occluded goal object, but failed to represent the features of either hidden object. These results suggest that infants make goal‐based action predictions when the relevant objects in the scene are occluded, but doing so may come at the expense of maintaining representations of the objects.     

The Effect of Simulated Self Versus Object Movement in a Nonsearch Task

This study examined 6‐month‐old infants' abilities to use the visual information provided by simulated self‐movement through the world, and movement of an object through the world, for spatial orientation. Infants were habituated to a visual display in which they saw a toy hidden, followed by either rotation of the point of observation through the world (simulated self‐movement) or movement of the object itself through the world (object movement). Following habituation, infants saw test displays in which the hidden toy reappeared at the correct or incorrect location, relative to the earlier movements. Infants habituated to simulated self‐movement looked longer at the recovery of the toy from an incorrect, relative to correct location. In contrast, infants habituated to object movement showed no differential looking to either correct or incorrect test displays. These findings are discussed within a theoretical framework of spatial orientation emphasizing the availability and use of spatial information.     

Effects of Exogenous and Endogenous Distracters on Immediate and Long‐Term Recall in Toddlers

We explored the role that exogenous and endogenous competitors for attention play in infants’ abilities to encode and retain information over a 6‐month period. Sixty‐six children visited the laboratory at 15 months, and 32 returned for a second visit at 21 months. Children observed models of conventional‐ relation and enabling‐relation action sequences. Half the children were distracted by a “Mister Monkey” mechanical toy during the conventional‐relation sequence, while the other half was distracted during the enabling‐relation sequence. The Early Childhood Behavior Questionnaire indexed endogenous factors at both ages. Immediate postmodel production of target actions indexed encoding efficiency, and 6‐month production of target actions indexed long‐term recall. The exogenous distracter impacted encoding efficiency (i.e., immediate recall), but not long‐term recall. Endogenous factors (i.e., temperament) were primarily associated with long‐term recall. Of special interest was our finding that endogenous factors, especially surgency, moderated the effect of the exogenous distracter. It appears that when learning conventional‐relation sequences in the presence of exogenous distracters, surgency mobilizes attentional resources toward the learning objective; however, when learning enabling‐relation sequences under the same conditions, surgency either boosts the saliency of the distracters or boosts children’s susceptibility to them.     

Twelve‐Month‐Old Infants’ Sensitivity to Others’ Emotions Following Positive and Negative Events

This study investigated infants’ sensitivity to others’ congruent and incongruent emotional reactions to positive and negative events. Thirty‐six 12‐month‐old infants viewed three distinct interpersonal events (give a toy, break a toy, fight over a toy) followed by an emotional expression (happiness, sadness, anger) that was either congruent or incongruent with the preceding event outcome. The duration of infants' looking toward each emotional reaction was examined. Infants demonstrated sensitivity to incongruent emotional reactions for the give and fight events, representing the earliest evidence to date of emotional sensitivity to negative events.     

Intention or Attention Before Pointing: Do Infants’ Early Holdout Gestures Reflect Evidence of a Declarative Motive?

Gestures are the first signs of intentional communication within prelinguistic infants and can reflect various motives, including a declarative motive to share attention and interest. The ability to use gestures declaratively has been linked to later language development; therefore, it is important to understand the origins of this motive. Previous research has focused on the use of declarative pointing at around 12 months; however, other potential forms of declarative communication, such as holdout gestures, are yet to be studied in detail. The purpose of this study was to examine whether from 10 months, infants use holdouts declaratively. We elicited holdouts from 36 infants and then reacted to these gestures in four different conditions: (1) joint attention: shared interest; (2) infant attention: attended to infant; (3) toy attention: attended to toy; (4) ignore: gesture was not attended to. Infants’ behavioral responses were recorded. When the experimenter engaged in joint attention, infants were significantly more likely to display a positive attitude and produced fewer re‐engagement attempts. In contrast, the three non‐joint attention conditions displayed significantly higher negative attitudes and attempts to re‐engage the experimenter. We conclude that infants display declarative communication prior to 12 months, resetting the age at which these more complex skills emerge.     

Do 8‐Month‐Old Infants Consider Situational Constraints When Interpreting Others’ Gaze as Goal‐Directed Action?

Some actions of agents are ambiguous in terms of goal‐directedness to young infants. If given reasons why an agent performed these ambiguous actions, would infants then be able to perceive the actions as goal‐directed? Prior results show that infants younger than 12 months can not encode the relationship between a human agent’s looking behavior and the target of her gaze as goal‐directed. In the present experiments, 8‐month‐olds responded in ways suggesting that they interpreted an agent’s action of looking at object‐A as opposed to object‐B as evidence for her goal directed toward object‐A, if her looking action was rational given certain situational constraints: a barrier separated her from the objects or her hands were occupied. Therefore, the infants seem to consider situational constraints when attributing goals to agents’ otherwise ambiguous actions; they seem to realize that within such constraints, these actions are efficient ways for agents to achieve goals.     

The Effects of Graded Occlusion on Manual Search and Visual Attention in 5‐ to 8‐Month‐Old Infants

Young infants may be limited in searching for hidden objects because they lack the means‐end motor skill to lift occluders from objects. This account was investigated by presenting 5‐ to 8‐month‐old infants with objects hidden behind transparent, semitransparent, and opaque curtains. If a means—end deficit explains search limitations, then infants should search no more for an object behind a transparent curtain than for objects behind semitransparent or opaque curtains. However, level of occlusion had a significant effect on manual search and visual attention. Infants retrieved and contacted the object more, contacted the curtain more, and looked away less with the transparent curtain than with the semi transparent or opaque curtains. Adding a time delay before allowing search and presenting a distraction after occlusion further depressed infants' behavior. The findings fail to support the means—end deficit hypothesis, but are consistent with the account that young infants lack object permanence.     

Decalage in Infants' Search for Mothers Versus Toys Demonstrated With a Delayed Response Task

Thirty‐one infants, 7 to 14 months of age, were tested on object and mother permanence using a delayed response task (Diamond, 1985), in which a delay period is enforced before infants are allowed to search for hidden objects. Infants were tested in 2 separate conditions in which they searched for their mothers and a large toy, both of which were hidden under curtained tables. The delay period before search was allowed was incremented after each successful trial until infants either failed to search or searched in the wrong location. Infants were scored for the maximum delay preceding a successful search. The results from 17 infants showed that infants were able to withstand significantly longer delays before successful search for the mother than for the toy. These results support previous studies showing that mother permanence precedes object permanence in infants older than 8 months.     

Is Agency Skin Deep? Surface Attributes Influence Infants' Sensitivity to Goal‐Directed Action

Three studies investigated the role of surface attributes in infants' identification of agents, using a habituation paradigm designed to tap infants' interpretation of grasping as goal directed (Woodward, 1998). When they viewed a bare human hand grasping objects, 7‐ and 12‐month‐old infants focused on the relation between the hand and its goal. When the surface properties of the hand were obscured by a glove, however, neither 7‐ nor 12‐month‐old infants represented its actions as goal directed (Study 1). Next, infants were shown that the gloved hands were part of a person either prior to (Study 2) or during (Study 3) the habituation procedure. Infants who actively monitored the gloved person in Study 2 and older infants in Study 3 interpreted the gloved reaches as goal directed. Thus, varying the extent to which an entity is identifiable as a person impacts infants' interpretation of the entity as an agent.     

How Manual Object Exploration is Associated with 7‐ to 8‐Month‐Old Infants’ Visual Prediction Abilities in Spatial Object Processing

The present experiment examined whether infants’ visual prediction performance of the appearance of objects moving in space is related to their manual object exploration ability. Fifty‐five 7‐ to 8‐month‐old infants were tested. A visual object prediction paradigm was developed during which a three‐dimensional object was presented in a live eye‐tracking setting. During familiarization, the object rotated back and forth along the vertical axis. While the object was moving, two target parts of it were briefly occluded from view and uncovered again as the object changed its direction of motion. In the test phase, the entire object was rotated around 90° and now rotated along the horizontal axis. We recorded infants’ eye movements directed at the target locations and analyzed the prediction rates. All of the infants also participated in a manual object exploration task, in which they freely explored five toy blocks. Infants with a higher level of object exploration skill had higher prediction rates during test trials as compared to infants with less proficient object exploratory actions. The results support the interpretation that advanced manual object exploration experience is associated with infants’ advanced visual prediction ability of the appearance of objects moving in space.