You go this way and I'll go that way: developmental changes in infants' detection of correlations among static and dynamic features in motion events

Four experiments utilizing the habituation procedure examined 10- to 18-month-olds' ability to detect and encode correlations among features in a motion event (N = 136). Infants were habituated to two events in which objects-with distinct parts and a distinct body-moved across a screen along a rectilinear or curvilinear motion path. Infants were then tested with one familiar event and three events in which one feature of the object (parts, body, or motion path) was presented in a novel combination with the other features. The results of the experiments revealed that 10-month-olds process independently static features in an event, but do not process correlations among dynamic features; whereas 14-month-olds detect the correlation between an object's parts and its motion trajectory, but only when the movement of parts is correlated with the motion of the object. Further, the data show that 18-month-olds detect correlations between all three features when the parts of the object move, but they detect only the relation between parts and motion path when the parts do not move. It is proposed that infants develop representations for the static and dynamic properties of objects through a sensitive perceptual system that detects individual features, whole objects, and movement properties, and a domain-general associative learning mechanism that encodes independent features and correlations among features.     

The birth of words: ten-month-olds learn words through perceptual salience

A core task in language acquisition is mapping words onto objects, actions, and events. Two studies investigated how children learn to map novel labels onto novel objects. Study 1 investigated whether 10-month-olds use both perceptual and social cues to learn a word. Study 2, a control study, tested whether infants paired the label with a particular spatial location rather than to an object. Results show that 10-month-olds can learn new labels and do so by relying on the perceptual salience of an object instead of social cues provided by a speaker. This is in direct contrast to the way in which older children (12-, 18-, and 24-month-olds) learn and extend new object names.     

Two- to eight-month-old infants' perception of dynamic auditory-visual spatial colocation

From birth, infants detect associations between the locations of static visual objects and sounds they emit, but there is limited evidence regarding their sensitivity to the dynamic equivalent when a sound-emitting object moves. In 4 experiments involving thirty-six 2-month-olds, forty-eight 5-month-olds, and forty-eight 8-month-olds, we investigated infants' ability to process this form of spatial colocation. Whereas there was no evidence of spontaneous sensitivity, all age groups detected a dynamic colocation during habituation and looked longer at test trials in which sound and sight were dislocated. Only 2-month-olds showed clear sensitivity to the dislocation relation, although 8-month-olds did so following additional habituation. These results are discussed relative to the intersensory redundancy hypothesis and work suggesting increasing specificity in processing with age.     

Perception of dynamic and static audiovisual sequences in 3- and 4-month-old infants

This study investigated perception of audiovisual sequences in 3- and 4-month-old infants. Infants were habituated to sequences consisting of moving/sounding or looming/sounding objects and then tested for their ability to detect changes in the order of the objects, sounds, or both. Results showed that 3-month-olds perceived the order of 3-element sequences and that 4-month-olds perceived the order of 3- and 4-element sequences. In addition, results indicated that perception of moving sequences was more robust than of looming ones and that detection of order differences was not based on primacy cues. The current results show that perception of multisensory sequences and their structure emerges early in development, and a preliminary model of the development of sequence perception is offered.     

Changes in Cooperation and Self-Other Differentiation during the Second Year

Cooperation in peer interaction emerges during the second half of the second year. A consideration of the skills and knowledge entailed in these early forms of cooperation suggests that young children's emerging ability to differentiate self from other as causal agents may relate to their ability to coordinate behavior with age mates toward a common goal. Children at 12, 18, 24, and 30 months were observed in same-age, same-sex dyads (8 dyads per age) while attempting to solve a simple cooperation problem. They were also individually administered an elicited imitation task used to index decentration, or self-other differentiation. No 12-month-old dyad could cooperate, 18-month-olds did so infrequently and apparently accidentally, whereas 24- and 30-month-olds were able to coordinate behavior with one another quickly and effectively. Children who were better able to accommodate their behavior to one another during cooperation also represented the agency of others at a more advanced, decentered level.     

The evolutionary significance of pretend play: Two-year-olds’ interpretation of behavioral cues

Pretend play begins very early in human life. A key question is why, when figuring out reality is young children’s major developmental task, they engage in its deliberate falsification. A second key question is how children know that pretend events are not real. Here we report three experiments addressing the latter question and providing indirect evidence for speculation on the first question. Children (N = 96) were shown actors eating or pretending to eat from covered bowls, and they had to indicate, on the basis of the actors’ behavioral signs, which actor was pretending to eat or had the real food. Even 24-month-olds could do so when the contents of the bowls were shown before the actions, and even when substitute objects were shown. However, when one of the bowls contained imaginary objects (i.e., was empty), even 30-month-olds could not indicate which actor was pretending. These studies show how the ability to interpret pretending from behavioral cues develops gradually as children’s representational abilities become more free of contextual support. We propose that, from an evolutionary and ontogenetic standpoint, pretend play might serve to heighten children’s sensitivity to social signs. This sensitivity could assist the development of theory of mind, with which social pretend play is associated. In this way, pretend play in humans might serve a similar purpose to play fighting in other species: In both cases, play might sensitize the organism to social signs that will allow for sophisticated coordination of social behavior later in life.     

Individual and Developmental Differences in Disengagement of Fixation in Early Infancy

The current study investigated whether individual and developmental differences in look duration are correlated with the latency for infants to disengage fixation from a visual stimulus. Ninety-four infants (52 3-month-olds, 42 4-month-olds) were tested in a procedure that measured ocular reaction time to shift fixation from a central target to a peripheral target under conditions in which the central-target either remained present ("competition" condition) or was removed from the display ("noncompetition" condition). Look duration was correlated with disengagement latency; longer-looking infants were slower than shorter-looking infants to shift fixation to the peripheral target on competition trials, but not noncompetition trials. Results were similar for 3- and 4-month-olds, although 3-month-olds showed slower latencies on all trials. Furthermore, long-looking infants were not consistently slower, but rather showed greater variability in their response latencies under conditions that required disengagement of fixation. The results support the position that developmental and individual differences in look duration are linked to the development of the neural attentional systems that control the ability to disengage, or inhibit, visual fixation.     

Counting the nouns: simple structural cues to verb meaning

Two-year-olds use the sentence structures verbs appear in--subcategorization frames--to guide verb learning. This is syntactic bootstrapping. This study probed the developmental origins of this ability. The structure-mapping account proposes that children begin with a bias toward one-to-one mapping between nouns in sentences and participant roles in events. This account predicts that subcategorization frames should guide very early verb learning, if the number of nouns in the sentences is informative. In 3 experiments, one hundred and thirty-six 21- and 19-month-olds assigned appropriately different interpretations to novel verbs in transitive ("He's gorping him!") versus intransitive sentences ("He's gorping!") differing in their number of nouns. Thus, subcategorization frames guide verb interpretation in very young children. These findings constrain theoretical proposals about mechanisms for syntactic bootstrapping.     

Two-year-olds use the generic/nongeneric distinction to guide their inferences about novel kinds

These studies investigated two hundred and forty-four 24- and 30-month-olds' sensitivity to generic versus nongeneric language when acquiring knowledge about novel kinds. Toddlers were administered an inductive inference task, during which they heard a generic noun phrase (e.g., "Blicks drink milk") or a nongeneric noun phrase (e.g., "This blick drinks milk") paired with an action (e.g., drinking) modeled on an object. They were then provided with the model and a nonmodel exemplar and asked to imitate the action. After hearing nongeneric phrases, 30-month-olds, but not 24-month-olds, imitated more often with the model than with the nonmodel exemplar. In contrast, after hearing generic phrases, 30-month-olds imitated equally often with both exemplars. These results suggest that 30-month-olds use the generic/nongeneric distinction to guide their inferences about novel kinds.     

Children's knowledge of thematic and taxonomic relations at two years of age

An interesting conflict exists in the developmental literature concerning the strength of thematic versus taxonomic associations. "Dog-doghouse" is a thematic match, while "dog-horse" is a taxonomic match. This study compared the ability of children to identify both types of associations at 2 points during the third year of life: 26 months (N = 15) and 34 months (N = 24). A reinforced match-to-sample technique was used in which half of the matches were thematic and the other half were taxonomic. Both age groups were able to identify thematic matches, although children near 3 years of age were able to recognize a wider range of thematic associations than children near 2 years of age. The 26-month-olds were unable to identify taxonomic matches that had no perceptual basis, but the 34-month-olds were successful at this task; the 34-month-olds appeared to have a more general understanding of categories that was less tied to perceptual features.     

Developmental Changes in Imitation from Television during Infancy

Infants' (N = 276) ability to learn from television under seminaturalistic conditions was examined in five experiments with 12-, 15-, and 18-month-olds. In all experiments, an adult performed a series of specific actions with novel stimuli. Some infants watched the demonstration live, and some infants watched the same demonstration on television from prerecorded videotape. Infants' ability to reproduce the target actions was then assessed either immediately or after a 24-hour delay. Infants of all ages exhibited imitation when the actions were modeled live. There were age-related and task-related differences, however, in infants' ability to imitate the same actions modeled on television. The role of perceptual, attentional, and cognitive development in the ability to learn from television is discussed.     

Pointing at objects in other rooms: young children's sensitivity to perspective after walking with and without vision

Locomotion alters the spatial structure of an observer's perspective, that is, the network of observer to environment distances and directions. The purpose of the present 6 experiments was to investigate the sensitivity of 12-48-month-olds to changes in perspective that are occluded from view by walls and by darkness. To assess sensitivity, children were shown a target object in one room, walked into an adjacent room and asked to point in the straight-line direction at the target. In Experiment 1, 42 12-48-month-olds were tested and results indicated that children older than 36 months responded by pointing straight at the occluded target, whereas younger children tended to point in the direction of their route away from the target. In Experiments 2-4, 24- and 48-month-olds were tested and results demonstrated that 48-month-olds were sensitive to the proprioceptive and to the visual-environmental cues for the changes in perspective structure. The 24-month-olds, however, responded by pointing straight toward the target when visual-environmental cues were absent, whereas they pointed in the direction of their route when they were present. In Experiments 5 and 6 additional 24-month-olds were tested to assess the effects of short-term training and of a continuous view of the target on responding in the presence of visual-environmental cues. The results indicated relatively early sensitivity to proprioceptive cues for changes in perspective and somewhat later sensitivity to appropriate visual-environmental cues under these conditions.     

Developmental and Temperamental Differences in Emotion Regulation in Infancy

One of the major adaptations during the infancy period is the development of the ability to cope with arousing or uncertain events. The following study was designed to examine emotion regulation strategy use between 6 and 18 months. 75 infants (25 each of 6-, 12-, and 18-month-olds) were videotaped interacting with 3 female strangers. Coping strategies were coded using a portable computer with a continuous sampling program, enabling coders to record both frequencies and durations of behaviors. Results indicated that 6-month-olds were more likely than 12- or 18-month-olds to use gaze aversion and fussing as their primary emotion regulation strategies, and were less likely than the older infants to use self-soothing and self-distraction. 18-month-olds were more likely than the younger infants to attempt to direct their interactions with the strangers. Infants' strategy use also differed as a function of their wariness of strangers, particularly at 12 months of age.     

Infants' use of shared linguistic information to clarify ambiguous requests

Do infants use past linguistic information to interpret an ambiguous request for an object? When infants in this research were shown 2 objects, and asked for 1 with an indefinite request (e.g., "Can you get it for me?"), both 15- and 18-month-olds used the speaker's previous reference to an absent object to interpret the request. The 18-month-olds did so even when the request was made after a 2.5-min delay. When the request was made by a person who did not participate in the conversation, the infants did not use the previous verbal information. These results demonstrate infants' ability to use language as a source of information in ambiguous contexts and indicate an early appreciation of the shared nature of conversation.     

Emotional eavesdropping: infants selectively respond to indirect emotional signals

Two experiments examined whether 18-month-olds learn from emotions directed to a third party. Infants watched an adult perform actions on objects, and an Emoter expressed Anger or Neutral affect toward the adult in response to her actions. The Emoter then became neutral and infants were given access to the objects. Infants' actions were influenced by their memory of the Emoter's affect. Moreover, infants' actions varied as a function of whether they were currently in the Emoter's visual field. If the previously angry Emoter was absent (Experiment 1) or turned her back (Experiment 2), infants did not use the prior emotion to regulate their behavior. Infants learn from emotional eavesdropping, and their subsequent behavior depends on the Emoter's orientation toward them.     

Sensitivity to Visual-Tactile Colocation on the Body Prior to Skilled Reaching in Early Infancy

Two experiments examined perceptual colocation of visual and tactile stimuli in young infants. Experiment 1 compared 4- (n = 15) and 6-month-old (n = 12) infants’ visual preferences for visual-tactile stimulus pairs presented across the same or different feet. The 4- and 6-month-olds showed, respectively, preferences for colocated and noncolocated conditions, demonstrating sensitivity to visual-tactile colocation on their feet. This extends previous findings of visual-tactile perceptual colocation on the hands in older infants. Control conditions excluded the possibility that both 6- (Experiment 1), and 4-month-olds (Experiment 2, n = 12) perceived colocation on the basis of an undifferentiated supramodal coding of spatial distance between stimuli. Bimodal perception of visual-tactile colocation is available by 4 months of age, that is, prior to the development of skilled reaching.     

When less is more: how infants learn to form an abstract categorical representation of support

Two experiments explored how infants learn to form an abstract categorical representation of support (i.e., on) when habituated to few (i.e., 2) or many (i.e., 6) examples of the relation. When habituated to 2 pairs of objects in a support relation, 14-month-olds, but not 10-month-olds, formed the abstract spatial category (i.e., generalized the relation to novel objects). When habituated to 6 object pairs in a support relation, infants did not attend to the relation. The results indicate that infants learn to form an abstract spatial category of support between 10 and 14 months and that having fewer object pairs depicting this relation facilitates their acquisition of the abstract categorical representation.     

Visual Constancies Amidst Changes in Handled Objects for 5- to 24-Month-Old Infants

Manual skills slowly develop throughout infancy and have been shown to create clear views of objects that provide better support for visually sustained attention, recognition, memory, and learning. These clear views may coincide with the development of manual skills, or that social scaffolding supports clear viewing experiences like those generated by toddlers during active object exploration. This study used a head-mounted eye tracker to record 5- to 24-month-olds’ object views during repeated mother-infant play sessions (Ns = 18). Results show an early beginning of scaffolding in which parents generate views similar to those of older infants and toddlers, resulting in increased fixations to objects. The finding implicates parents as early scaffolders of object attention and learning.     

Maternal language to prelinguistic infants: syntactic aspects

Maternal speech to children has been shown to vary by age and language ability of the children. Previous studies have usually involved children over 1 year of age. In this study maternal speech to male and female 4-, 6-, and 8-month-old infants was recorded in the laboratory. Mothers used shorter utterances to 8-month-olds than to 4- or 6-month-olds, presumably in response to the infant's changing level of comprehension. Mothers used more sentences with subjects, verbs, or objects deleted to 8-month-olds and more complex sentences to 4-month-olds.