Infants Prefer Tunes Previously Introduced by Speakers of Their Native Language

Infants show attentional biases for certain individuals over others based on various cues. However, the role of these biases in shaping infants' preferences and learning is not clear. This study asked whether infants' preference for native speakers (Kinzler, Dupoux, & Spelke, 2007) would modulate their preferences for tunes. After getting equal exposure to two different tunes introduced by two speakers, 7‐month‐olds (N = 32) listened longer to the tune that was introduced by a native speaker compared to the tune that was introduced by a foreign speaker. This suggests that the social‐emotional context in which exposure to stimuli occurs influences auditory preferences, and that the early emerging attentional biases might have important ramifications regarding social learning in early infancy.     

Infants Learn Baby Signs From Video

There is little evidence that infants learn from infant‐oriented educational videos and television programming. This 4‐week longitudinal experiment investigated 15‐month‐olds' (N = 92) ability to learn American Sign Language signs (e.g., patting head for hat) from at‐home viewing of instructional video, either with or without parent support, compared to traditional parent instruction and a no‐exposure control condition. Forced‐choice, elicited production, and parent report measures indicate learning across all three exposure conditions, with a trend toward more robust learning in the parent support conditions, regardless of medium. There were no differences between experimental and control conditions in the acquisition of corresponding verbal labels. This constitutes the first experimental evidence of infants' ability to learn expressive communication from commercially available educational videos.     

Learning From Their Own Actions: The Unique Effect of Producing Actions on Infants' Action Understanding

Prior research suggests that infants' action production affects their action understanding, but little is known about the aspects of motor experience that render these effects. In Study 1, the relative contributions of self‐produced (n = 30) and observational (n = 30) action experience on 3‐month‐old infants' action understanding was assessed using a visual habituation paradigm. In Study 2, generalization of training to a new context was examined (n = 30). Results revealed a unique effect of active over observational experience. Furthermore, findings suggest that benefits of trained actions do not generalize broadly, at least following brief training.     

From Flexibility to Constraint: The Contrastive Use of Lexical Tone in Early Word Learning

Infants must develop both flexibility and constraint in their interpretation of acceptable word forms. The current experiments examined the development of infants' lexical interpretation of non‐native variations in pitch contour. Fourteen‐, 17‐, and 19‐month‐olds (Experiments 1 and 2, N = 72) heard labels for two novel objects; labels contained the same syllable produced with distinct pitch contours (Mandarin lexical tones). The youngest infants learned the label–object mappings, but the older groups did not, despite being able to discriminate pitch differences in an object‐free task (Experiment 3, N = 14). Results indicate that 14‐month‐olds remain flexible regarding what sounds make meaningful distinctions between words. By 17–19 months, experience with a nontonal native language constrains infants' interpretation of lexical tone.     

Mental Spatial Transformations in 14‐ and 16‐Month‐Old Infants: Effects of Action and Observational Experience

Infants' ability to mentally track the orientation of an object during a hidden rotation was investigated (N = 28 in each experiment). A toy on a turntable was fully covered and then rotated 90°. When revealed, the toy had turned with the turntable (probable event), remained at its starting orientation (improbable event in Experiment 1), or turned to the opposite side (improbable event in Experiment 2). Results demonstrated a developmental progression between 14 and 16 months of age in infants' sensitivity to spatial object relations and their ability to track the orientation of an object during hidden rotation. Experiment 3 showed that 14‐month‐olds' performance improved with hands‐on training, highlighting the role of action experience in cognitive development.     

Red to Green or Fast to Slow? Infants' Visual Working Memory for “Just Salient Differences”

In this study, 6‐month‐old infants' visual working memory for a static feature (color) and a dynamic feature (rotational motion) was compared. Comparing infants' use of different features can only be done properly if experimental manipulations to those features are equally salient (Kaldy & Blaser, 2009; Kaldy, Blaser, & Leslie, 2006). The interdimensional salience mapping method was used to find two objects that each were one Just Salient Difference from a common baseline object (N = 16). These calibrated stimuli were then used in a subsequent two‐alternative forced‐choice preferential looking memory test (N = 28). Results showed that infants noted the color change, but not the equally salient change in rotation speed.     

Learning to Match Auditory and Visual Speech Cues: Social Influences on Acquisition of Phonological Categories

Infants' language exposure largely involves face‐to‐face interactions providing acoustic and visual speech cues but also social cues that might foster language learning. Yet, both audiovisual speech information and social information have so far received little attention in research on infants' early language development. Using a preferential looking paradigm, 44 German 6‐month olds' ability to detect mismatches between concurrently presented auditory and visual native vowels was tested. Outcomes were related to mothers' speech style and interactive behavior assessed during free play with their infant, and to infant‐specific factors assessed through a questionnaire. Results show that mothers' and infants' social behavior modulated infants' preference for matching audiovisual speech. Moreover, infants' audiovisual speech perception correlated with later vocabulary size, suggesting a lasting effect on language development.     

Vagal Regulation in Breastfeeding Infants and Their Mothers

Consistent with the gustatory–vagal hypothesis, vagal stimulation during breastfeeding may contribute to infants' physiological regulatory development independent of caregiving effects. This study examined whether breastfeeding predicted 6‐month‐old infants' (N = 151) and their mothers' vagal regulation during the face‐to‐face still‐face (FFSF). Although breastfed and nonbreastfed infants showed expected vagal withdrawal during the Still‐Face episode, only breastfed infants showed continued withdrawal during the reunion episode, suggesting greater physiological mobilization to repair the interaction. Breastfeeding mothers showed higher vagal tone than nonbreastfeeding mothers at baseline, suggesting greater capacity for regulation, and throughout the FFSF, suggesting calmer states. Breastfeeding effects were independent of maternal sensitivity. Findings suggest that infants' and mothers' physiological regulation may be shaped by breastfeeding independently of associated social factors.     

Accent,Language, and Race: 4–6‐Year‐Old Children's Inferences Differ by Speaker Cue

Three experiments examined 4‐ to 6‐year‐olds' use of potential cues to geographic background. In Experiment 1 (N = 72), 4‐ to 5‐year‐olds used a speaker's foreign accent to infer that they currently live far away, but 6‐year‐olds did not. In Experiment 2 (N = 72), children at all ages used accent to infer where a speaker was born. In both experiments, race played some role in children's geographic inferences. Finally, in Experiment 3 (N = 48), 6‐year‐olds used language to infer both where a speaker was born and where they currently live. These findings reveal critical differences across development in the ways that speaker characteristics are used as inferential cues to a speaker's geographic location and history.     

Being Mimicked Increases Prosocial Behavior in 18‐Month‐Old Infants

Most previous research on imitation in infancy has focused on infants' learning of instrumental actions on objects. This study focused instead on the more social side of imitation, testing whether being mimicked increases prosocial behavior in infants, as it does in adults (van Baaren, Holland, Kawakami, & van Knippenberg, 2004). Eighteen‐month‐old infants (N = 48) were either mimicked or not by an experimenter; then either that experimenter or a different adult needed help. Infants who had previously been mimicked were significantly more likely to help both adults than infants who had not been mimicked. Thus, even in infancy, mimicry has positive social consequences: It promotes a general prosocial orientation toward others.     

What Will I Like Best When I'm All Grown Up? Preschoolers' Understanding of Future Preferences

Three experiments investigated 3‐, 4‐, and 5‐year‐olds' (N = 240) understanding that their future or “grown‐up” preferences may differ from their current ones (self‐future condition). This understanding was compared to children's understanding of the preferences of a grown‐up (adult‐now condition) or the grown‐up preferences of a same‐aged peer (peer‐future condition). Children's performance across all three conditions improved significantly with age. Moreover, children found it significantly more difficult to reason about their own future preferences than they did to reason either about an adult's preferences or the future preferences of a peer. These results have important implications for theories about future thinking and perspective‐taking abilities, more broadly.     

Visual Short‐Term Memory for Complex Objects in 6‐ and 8‐Month‐Old Infants

Infants' visual short‐term memory (VSTM) for simple objects undergoes dramatic development: Six‐month‐old infants can store in VSTM information about only a simple object presented in isolation, whereas 8‐month‐old infants can store information about simple objects presented in multiple‐item arrays. This study extended this work to examine the development of infants' VSTM for complex objects during this same period (N = 105). Using the simultaneous streams change detection paradigm, Experiment 1 confirmed the previous developmental trajectory between 6 and 8 months. Experiment 2 showed that doubling the exposure time did not enhance 6‐month‐old infants' change detection, demonstrating that the developmental change is not due to encoding speed. Thus, VSTM for simple and complex objects appears to follow the same developmental trajectory.     

Differences in the Nonverbal Requests of Great Apes and Human Infants

This study investigated how great apes and human infants use imperative pointing to request objects. In a series of three experiments (infants, N = 44; apes, N = 12), subjects were given the opportunity to either point to a desired object from a distance or else to approach closer and request it proximally. The apes always approached close to the object, signaling their request through instrumental actions. In contrast, the infants quite often stayed at a distance, directing the experimenters' attention to the desired object through index‐finger pointing, even when the object was in the open and they could obtain it by themselves. Findings distinguish 12‐month‐olds' imperative pointing from ontogenetic and phylogenetic earlier forms of ritualized reaching.     

Infants’ and Young Children's Imitation of Linguistic In‐Group and Out‐Group Informants

Although children can use social categories to intelligently select informants, children's preference for in‐group informants has not been consistently demonstrated across age and context. This research clarifies the extent to which children use social categories to guide learning by presenting participants with a live or video‐recorded action demonstration by a linguistic in‐group and/or out‐group model. Participants’ (N = 104) propensity to imitate these actions was assessed. Nineteen‐month‐olds did not selectively imitate the actions of the in‐group model in live contexts, though in‐group preferences were found after watching the demonstration on video. Three‐year‐olds selectively imitated the actions demonstrated by the in‐group member regardless of context. These results indicate that in‐group preferences have a more nuanced effect on social learning than previous research has indicated.     

Infants' Perception of Emotion From Body Movements

Adults recognize emotions conveyed by bodies with comparable accuracy to facial emotions. However, no prior study has explored infants' perception of body emotions. In Experiment 1, 6.5‐month‐olds (n = 32) preferred happy over neutral actions of actors with covered faces in upright but not inverted silent videos. In Experiment 2, infants (n = 32) matched happy and angry videos to corresponding vocalizations when the videos were upright but not when they were inverted. Experiment 3 (n = 16) demonstrated that infants' performance in Experiment 2 was not driven by information from the covered face and head. Thus, young infants are sensitive to emotions conveyed by bodies and match them to affective vocalizations, indicating sophisticated emotion processing capabilities early in life.     

Selective Imitation of In‐Group Over Out‐Group Members in 14‐Month‐Old Infants

Recent research has shown that infants are more likely to engage with in‐group over out‐group members. However, it is not known whether infants' learning is influenced by a model's group membership. This study investigated whether 14‐month‐olds (N = 66) selectively imitate and adopt the preferences of in‐group versus out‐group members. Infants watched an adult tell a story either in their native language (in‐group) or a foreign language (out‐group). The adult then demonstrated a novel action (imitation task) and chose 1 of 2 objects (preference task). Infants did not show selectivity in the preference task, but they imitated the in‐group model more faithfully than the out‐group model. This suggests that cultural learning is beginning to be truly cultural by 14 months of age.     

Verbal Positional Memory in 7‐Month‐Olds

Verbal memory is a fundamental prerequisite for language learning. This study investigated 7‐month‐olds' (N = 62) ability to remember the identity and order of elements in a multisyllabic word. The results indicate that infants detect changes in the order of edge syllables, or the identity of the middle syllables, but fail to encode the order of middle syllables. This suggests that the representational format of multisyllabic words is determined by core mnemonic biases, which favor accurate encoding of edges and limits the encoding of temporal order for internal segments. The studies support accounts proposing that content and order are encoded separately; in addition, the data show that this dissociation occurs early in development.     

Getting to No: Pragmatic and Semantic Factors in Two‐ and Three‐Year‐Olds' Understanding of Negation

Although infants say “no” early, older children have difficulty understanding its truth‐functional meaning. Two experiments investigate whether this difficulty stems from the infelicity of negative sentences out of the blue. In Experiment 1, given supportive discourse, 3‐year‐olds (N = 16) understood both affirmative and negative sentences. However, with sentence types randomized, 2‐year‐olds (N = 28) still failed. In Experiment 2, affirmative and negative sentences were blocked. Two‐year‐olds (N = 28) now succeeded, but only when affirmatives were presented first. Thus, although discourse felicity seems the primary bottleneck for 3‐year‐olds' understanding of negation, 2‐year‐olds struggle with its semantic processing. Contrary to accounts where negatives are understood via affirmatives, both sentence types were processed equally quickly, suggesting previously reported asymmetries are due to pragmatic accommodation, not semantic processing.     

Toddlers Default to Canonical Surface‐to‐Meaning Mapping When Learning Verbs

Previous work has shown that toddlers readily encode each noun in the sentence as a distinct argument of the verb. However, languages allow multiple mappings between form and meaning that do not fit this canonical format. Two experiments examined French 28‐month‐olds' interpretation of right‐dislocated sentences (noun_i‐verb, noun_i) where the presence of clear, language‐specific cues should block such a canonical mapping. Toddlers (N = 96) interpreted novel verbs embedded in these sentences as transitive, disregarding prosodic cues to dislocation (Experiment 1) but correctly interpreted right‐dislocated sentences containing well‐known verbs (Experiment 2). These results suggest that toddlers can integrate multiple cues in ideal conditions, but default to canonical surface‐to‐meaning mapping when extracting structural information about novel verbs in semantically impoverished conditions.     

Infants Prefer Infant‐Directed Song Over Speech

In their everyday communication, parents do not only speak but also sing with their infants. However, it remains unclear whether infants' can discriminate speech from song or prefer one over the other. The present study examined the ability of 6‐ to 10‐month‐old infants (N = 66) from English‐speaking households in London, Ontario, Canada to discriminate between auditory stimuli of native Russian‐speaking and native English‐speaking mothers speaking or singing to their infants. Infants listened significantly longer to the sung stimuli compared to the spoken stimuli. This is the first study to demonstrate that, even in the absence of other multimodal cues, infant listeners are able to discriminate between sung and spoken stimuli, and furthermore, prefer to listen to sung stimuli over spoken stimuli.