Attention to Multiple Cues During Spontaneous Object Labeling

It is well established that 2‐year‐olds attribute a novel label to an object’s global shape rather than local features (i.e., parts). Although recent studies have found that younger infants also attend to global rather than local features when given a label, the test stimuli in these experiments confounded parts and shape by varying both or neither. With infants (16‐ and 24‐month‐olds) and adults, this experiment disentangled shape and parts with appropriate test objects. Results showed a clear development of a strategy incorporating multiple cues. Across three age groups, there was an increase in generalizing labels to objects matching the exemplar’s local and global features (parts, base, and shape), and a decrease to objects matching in only one local feature. We discuss these results in terms of a learned flexibility in using multiple cues to predict lexical categories.     

Young Infants' Perception of Object Unity in Rotation Displays

Much research has been devoted to questions regarding how infants begin to perceive the unity of partly occluded objects, and it is clear that object motion plays a central role. Little is known, however, about how infants' motion processing skills are used in such tasks. One important kinetic cue for object shape is structure from motion, but its role in unity perception remains unknown. To address this issue, we presented 2‐ and 4‐month‐old infants with displays in which object unity was specified by vertical rotation. After habituation to this display, infants viewed broken and complete versions of the object to test their preference for the broken object, an indication of perception of unity in the occlusion display. Positive evidence for the perception of unity was provided by both age groups. Concomitant edge translation available in 1 condition did not appear to contribute above and beyond simple rotation. These results suggest that structure from motion, and perhaps contour deformation and shading cues, can contribute important information for veridical object percepts in very young infants.     

Four‐Month‐Olds' Discrimination of Voice Changes in Multimodal Displays as a Function of Discrimination Protocol

Past studies have found equivocal support for the ability of young infants to discriminate infant‐directed (ID) speech information in the presence of auditory‐only versus auditory + visual displays (faces + voices). Generally, younger infants appear to have more difficulty discriminating a change in the vocal properties of ID speech when they are accompanied by faces. Forty 4‐month‐old infants were tested using either an infant‐controlled habituation procedure (Experiment 1) or a fixed‐trial habituation procedure (Experiment 2). The prediction was that the infant‐controlled habituation procedure would be a more sensitive measure of infant attention to complex displays. The results indicated that 4‐month‐old infants discriminated voice changes in dynamic face + voice displays depending on the order in which they were viewed during the infant‐controlled habituation procedure. In contrast, no evidence of discrimination was found in the fixed‐trial procedure. The findings suggest that the selection of experimental methodology plays a significant role in the empirical observations of infant perceptual abilities.     

Where Infants Look Determines How They See: Eye Movements and Object Perception Performance in 3‐Month‐Olds

A fundamental question of perceptual development concerns how infants come to perceive partly hidden objects as unified across a spatial gap imposed by an occluder. Much is known about the time course of development of perceptual completion during the first several months after birth, as well as some of the visual information that supports unity perception in infants. The goal of this investigation was to examine the inputs to this process. We recorded eye movements in 3‐month‐old infants as they participated in a standard object unity task and found systematic differences in scanning patterns between those infants whose post‐habituation preferences were indicative of unity perception versus those infants who did not perceive unity. Perceivers, relative to nonperceivers, scanned more reliably in the vicinity of the visible rod parts and scanned more frequently across the range of rod motion. These results suggest that emerging object concepts are tied closely to available visual information in the environment, and the process of information pickup.     

Oculomotor Exploration of Impossible Figures in Early Infancy

Previous studies have revealed that young infants can distinguish between displays of possible or impossible figures, which may require detection of inconsistent depth relations among local line junctions that disrupt global object configurations. Here, we used an eye‐tracking paradigm to record eye movements in young infants during an object discrimination task with matched pairs of possible and impossible figures. Our goal was to identify differential patterns of oculomotor activity as infants viewed pictures of possible and impossible objects. We predicted that infants would actively attend to specific pictorial depth cues that denote shape (e.g., T‐junctions), and in the context of an impossible figure that they would fixate to a greater extent in anomalous regions of the display relative to other parts. By the age of 4 months, infants fixated reliably longer overall on displays of impossible versus possible cubes, specifically within the critical region where the incompatible lines and irreconcilable depth relations were located, implying an early capacity for selective attention to critical line junction information and integration of local depth cues necessary to perceive object coherence.     

The Influence of Labels,Non‐Labeling Sounds,and Source of Auditory Input on 9‐ and 15‐Month‐Olds' Object Categorization

This experiment examines the joint influence of auditory and social cues on infants' basic‐level and global categorization. Nine‐ and fifteen‐month‐olds were familiarized to a series of category exemplars in an object‐examining task. Objects were introduced with a labeling phrase, a non‐labeling sound, or no sound, and auditory input was presented orally by the experimenter or played on a hidden voice recorder. Novel objects from the familiarized category and a contrasting category were then presented. Results of analyses performed on novelty preference scores indicated that infants demonstrated basic‐level categorization in all conditions. However, infants at both age levels only demonstrated global categorization when labeling phrases were introduced. In addition, labels led to global categorization in 9‐month‐olds regardless of the source of those labels; however, labels only led to global categorization in 15‐month‐olds when the labels were presented orally by the experimenter.     

Within‐rhythm Class Native Language Discrimination Abilities of Basque‐Spanish Monolingual and Bilingual Infants at 3.5 Months of Age

Language rhythm determines young infants' language discrimination abilities. However, it is unclear whether young bilingual infants exposed to rhythmically similar languages develop sensitivities to cross‐linguistic rhythm cues to discriminate their dual language input. To address this question, 3.5‐month‐old monolingual Basque, monolingual Spanish and bilingual Basque‐Spanish infants' language discrimination abilities (across low‐pass filtered speech samples of Basque and Spanish) have been tested using the visual habituation procedure. Although falling within the same rhythmic class, Basque and Spanish exhibit significant differences in their distributions of vocalic intervals (within‐rhythmic class variation). All infant groups in our study successfully discriminated between the languages, although each group exhibited a different pattern. Monolingual Spanish infants succeeded only when they heard Basque during habituation, suggesting that they were influenced by native language recognition. The bilingual and the Basque monolingual infants showed no such asymmetries and succeeded irrespective of the language of habituation. Additionally, bilingual infants exhibited longer looking times in the test phase as compared with monolinguals, reflecting that bilingual infants attend to their native languages differently than monolinguals. Overall, results suggest that bilingual infants are sensitive to within‐rhythm acoustic regularities of their native language(s) facilitating language discrimination and hence supporting early bilingual acquisition.     

Evidence of the Face Inversion Effect in 4‐Month‐Old Infants

This study tested the presence of the face inversion effect in 4‐month‐old infants using habituation to criterion followed by a novelty preference paradigm. Results of Experiment 1 confirmed previous findings, showing that when 1 single photograph of a face is presented in the habituation phase and when infants are required to recognize the same photograph, no differences in recognition performance with upright and inverted faces are found. However, Experiment 2 showed that, when infants are habituated to a face shown in a variety of poses and are required to recognize a new pose of the same face, infants' recognition performances were higher for upright than for inverted faces. Overall, results indicate that, under some experimental conditions, 4‐month‐olds process faces differently according to whether faces are presented upright or inverted.     

Mental Rotation of Dynamic,Three‐Dimensional Stimuli by 3‐Month‐Old Infants

Mental rotation involves transforming a mental image of an object so as to accurately predict how the object would look if it were rotated in space. This study examined mental rotation in male and female 3‐month‐olds, using the stimuli and paradigm developed by Moore and Johnson (2008) . Infants were habituated to a video of a three‐dimensional object rotating back and forth through a 240° angle around the vertical axis. After habituation, infants were tested both with videos of the same object rotating through the previously unseen 120° angle, and with the mirror image of that display. Unlike females, who fixated the test displays for approximately equal durations, males spent significantly more time fixating the familiar object than the mirror‐image object. Because familiarity preferences like this emerge when infants are relatively slow to process a habituation stimulus, the data support the interpretation that mental rotation of dynamic three‐dimensional stimuli is relatively difficult—but possible—for 3‐month‐old males. Interpretation of the sex differences observed in 3‐ and 5‐month‐olds’ performances is discussed.     

A Cross‐Linguistic Study of Word‐Mapping in 18‐ to 20‐Month‐Old Infants

This study was designed to examine whether infants acquiring languages that place a differential emphasis on nouns and verbs, focus their attention on motions or objects in the presence of a novel word. An infant‐controlled habituation paradigm was used to teach 18‐ to 20‐month‐old English‐, French‐, and Japanese‐speaking infants’ novel words for events. Infants were habituated to two word‐event pairings and then presented with new combinations that involved a familiar word with a new object or motion, or both. Children could map the novel word to both the object and the motion, despite the differential salience of object and motion words in their native language. A control experiment with no label confirmed that both object and motion changes were detectable.     

Infants' First Words are not Phonetically Specified: Own Name Recognition in British English‐Learning 5‐Month‐Olds

By the end of their first year of life, infants’ representations of familiar words contain phonetic detail; yet little is known about the nature of these representations at the very beginning of word learning. Bouchon et al. ( 2015 ) showed that French‐learning 5‐month‐olds could detect a vowel change in their own name and not a consonant change, but also that infants reacted to the acoustic distance between vowels. Here, we tested British English‐learning 5‐month‐olds in a similar study to examine whether the acoustic/phonological characteristics of the native language shape the nature of the acoustic/phonetic cues that infants pay attention to. In the first experiment, British English‐learning infants failed to recognize their own name compared to a mispronunciation of initial consonant (e.g., Molly versus Nolly) or vowel (e.g., April versus Ipril). Yet in the second experiment, they did so when the contrasted name was phonetically dissimilar (e.g., Sophie versus Amber). Differences in phoneme category (stops versus continuants) between the correct consonant versus the incorrect one significantly predicted infants’ own name recognition in the first experiment. Altogether, these data suggest that infants might enter into a phonetic mode of processing through different paths depending on the acoustic characteristics of their native language.     

Temporal Sequence of Global‐Local Processing in 3‐Month‐Old Infants

In 3 experiments, the temporal processing sequence of local and global visual properties was investigated with 3‐month‐old infants. Across the experiments, a global pattern was discriminated under conditions of less familiarization than was necessary for local elements to be discriminated, thus indicating a global precedence in the sequence of visual processing at 3 months of age. Patterns of discrimination were also observed to vary as a function of individual differences in infants' look duration. Furthermore, the pattern of novelty and familiarity preferences for short‐looking infants varied in complex ways as a function of familiarization time: Preferences for novel global properties were supplanted by familiarity preferences at the point in familiarization at which infants first became sensitive to local properties.     

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 Relationship Between Processing Facial Identity and Emotional Expression in 8‐Month‐Old Infants

In Experiment 1, it was investigated whether infants process facial identity and emotional expression independently or in conjunction with one another. Eight‐month‐old infants were habituated to two upright or two inverted faces varying in facial identity and emotional expression. Infants were tested with a habituation face, a switch face, and a novel face. In the switch faces, a new combination of identity and emotional expression was presented. The results show that infants differentiated between switch and habituation faces only in the upright condition but not in the inverted condition. Experiment 2 provides evidence that infants’ nonresponse in the inverted condition can be attributed to their independent processing of facial identity and emotional expression. This suggests that infants in the upright condition processed facial identity and emotional expression in conjunction with one another.     

Infants' Evolving Representations of Object Motion During Occlusion: A Longitudinal Study of 6‐ to 12‐Month‐Old Infants

Infants' ability to track temporarily occluded objects that moved on circular trajectories was investigated in 20 infants using a longitudinal design. They were first seen at 6 months and then every 2nd month until the end of their 1st year. Infants were presented with occlusion events covering 20% of the target's trajectory (effective occlusion interval ranged from 500–4,000 msec). Gaze was measured using an ASL 504 infrared eye‐tracking system. Results effectively demonstrate that infants from 6 months of age can represent the spatiotemporal dynamics of occluded objects. Infants at all ages tested were able to predict, under certain conditions, when and where the object would reappear after occlusion. They moved gaze accurately to the position where the object was going to reappear and scaled their timing to the current occlusion duration. The average rate of predictive gaze crossings increased with occlusion duration. These results are discussed as a 2‐factor process. Successful predictions are dependent on strong representations, themselves dependent on the richness of information available during encoding and graded representations.     

Relating 7‐Month‐Olds Visuo‐Spatial Working Memory to Other Basic Mental Skills Assessed With Two Different Versions of the Habituation–Dishabituation Paradigm

This study examines the relationship between various basic mental processing abilities in infancy. Two groups of 7‐month‐olds received the same delayed‐response task to assess visuo‐spatial working memory, but two different habituation–dishabituation tasks to assess processing speed and recognition memory. The single‐stimulus group (N = 32) was familiarized with only one abstract stimulus, whereas the categorization group (N = 32) received varying exemplars of the same kind. In the categorization group, infants high on working memory showed stronger habituation and dishabituation responses than infants scoring low in working memory. No corresponding relations were found for the single‐stimulus group. This suggests that working memory performance is systematically linked to other basic mental skills in 7‐month‐olds, but that corresponding relations may not get evident in any kind of habituation–dishabituation procedure. Implications for understanding the complex interplay of basic mental abilities in infancy will be discussed.     

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.     

Twelve‐Month‐Olds Understand Social Intentions Based on Prosody and Gesture Shape

Infants infer social and pragmatic intentions underlying attention‐directing gestures, but the basis on which infants make these inferences is not well understood. Previous studies suggest that infants rely on information from preceding shared action contexts and joint perceptual scenes. Here, we tested whether 12‐month‐olds use information from act‐accompanying cues, in particular prosody and hand shape, to guide their pragmatic understanding. In Experiment 1, caregivers directed infants’ attention to an object to request it, share interest in it, or inform them about a hidden aspect. Caregivers used distinct prosodic and gestural patterns to express each pragmatic intention. Experiment 2 was identical except that experimenters provided identical lexical information across conditions and used three sets of trained prosodic and gestural patterns. In all conditions, the joint perceptual scenes and preceding shared action contexts were identical. In both experiments, infants reacted appropriately to the adults’ intentions by attending to the object mostly in the sharing interest condition, offering the object mostly in the imperative condition, and searching for the referent mostly in the informing condition. Infants’ ability to comprehend pragmatic intentions based on prosody and gesture shape expands infants’ communicative understanding from common activities to novel situations for which shared background knowledge is missing.     

12‐Month‐Old Infants Represent Probable Endings of Motion Events

This experiment investigated 12‐month‐old infants' ability to link an event's beginning to its probable ending. Following Csibra, Biro, Koos, and Gergely (2003), infants were habituated to a simple chasing event involving animated balls, and at test saw 2 possible endings: either 1 ball caught the other or failed to do so. Two controls were added to the previous work. First, the total amount of motion was controlled in the test endings; second, the endings were paired with a nonchasing beginning to ensure that behavior at test reflected representation of the event beginning itself. The results replicated Csibra et al.'s finding that infants look longer at the noncatching ending following the chasing beginning; moreover, infants showed no preference for either ending following the no‐chasing beginning. This study supports the claim that infants can calculate the rational ending of a goal‐directed motion event.     

A Global‐to‐Basic Trend in Early Categorization: Evidence From a Dual‐Category Habituation Task

A series of 3 experiments are reviewed in which infants between 4 and 10 months of age were familiarized with members of 2 basic‐level object categories. The degree of distinctiveness between categories was varied. Preference tests were intended to determine whether infants formed a single category representation (at a more global level) or 2 basic‐level representations. Across 3 experiments, 10‐month‐old infants appeared to have formed multiple basic‐level categories, whereas younger infants tended to form broader, more inclusive representations. The tendency to form multiple categories was influenced to some extent by category distinctiveness. Whereas 10‐month‐olds formed separate categories for all contrasts, 7‐month‐olds did so only when the 2 familiarized categories were from separate global domains. A perceptual account of the global‐to‐basic shift in early categorization is offered. Task dependencies in early categorization are also discussed.