Developmental psychology focuses on how psychological constructs change with age. In cognitive development research, however, the specifics of this emergence is often underspecified. Researchers often provisionally assume linear growth by including chronological age as a predictor in regression models. In this work, we aim to evaluate this…

Learning to walk allows infants to travel faster and farther and explore more of their environments. In turn, walking may have a cascading effect on infants' communication and subsequent responses from caregivers. We tested for an "inflection point"--a dramatic shift in the developmental progression--in infant communication and caregiver…

Fourteen-month-olds selectively imitated a sub-efficient means (illuminating a lightbox by a head-touch) when this was modeled by linguistic ingroup members in video-demonstrations. A follow-up study with slightly older infants, however, could replicate this effect only in a video-demonstration context. Hence it still remains unclear whether…

Purpose: The aim of this study is to analyze the changes in temporal synchrony between gesture and speech of multimodal communicative behaviors in the transition from babbling to two-word productions. Method: Ten Spanish-speaking children were observed at 9, 12, 15, and 18 months of age in a semistructured play situation. We longitudinally…

The infant brain may be predisposed to identify perceptually salient cues that are common to both signed and spoken languages. Recent theory based on spoken languages has advanced sonority as one of these potential language acquisition cues. Using a preferential looking paradigm with an infrared eye tracker, we explored visual attention of hearing…

Fragmented sleep is common in infancy. Although night awakening is known to decrease with age, in some infants night awakening is more persistent and continues into older ages. However, the influence of fragmented sleep on development is poorly known. In the present study, the longitudinal relationship between fragmented sleep and psychomotor…

An extensive literature links language problems with behavioral difficulties and academic underachievement. Although less extensive, emerging literature suggests that temperament, Positive Affectivity (PA) in particular, contributes to language development. Thus, the present study was focused on PA related temperament dimensions in infancy as…

We investigated longitudinal relations among gaze following and face scanning in infancy and later language development. At 12 months, infants watched videos of a woman describing an object while their passive viewing was measured with an eye-tracker. We examined the relation between infants' face scanning behavior and their tendency to follow the…

Halberda (2003) demonstrated that 17-month-old infants, but not 14- or 16-month-olds, use a strategy known as mutual exclusivity (ME) to identify the meanings of new words. When 17-month-olds were presented with a novel word in an intermodal preferential looking task, they preferentially fixated a novel object over an object for which they already…

Four experiments investigated infants' preferences for age-appropriate and age-inappropriate infant-directed speech (IDS) over adult-directed speech (ADS). Two initial experiments showed that 6-, 10-, and 14-month-olds preferred IDS directed toward younger infants, and 4-, 8-, 10-, and 14-month-olds, but not 6-month-olds, preferred IDS directed…

Although vocalization and mouthing are behaviors frequently performed by infants, little is known about the characteristics of vocalizations that occur with objects, hands, or fingers in infants' mouths. The purpose of this research was to investigate characteristics of vocalizations associated with mouthing in 6 to 9-month-old infants during play…

In 4 experiments, we examined 16- and 20-month-old infants' understanding of proper names and count nouns. In each experiment, infants were taught a novel word modeled linguistically as either a proper name (e.g., "DAXY") or a count noun (e.g., "a DAXY") for a stuffed animal shown on a puppet stage. This animal was moved to a new location on the…

Results indicated that the more frequently the children studied expressed emotion, the older the age of language achievements; and the more time spent in neutral affect, the younger the age of language achievements. (PCB)

Three experiments examined the relation between language acquisition and other symbolic abilities in 18- and 26-month-olds. Found that 18-month-olds spontaneously interpreted gestures, like words, as names for object categories. At 26 months, they spontaneously interpreted words as names and novel gestures as names only when given additional…

Two studies examined whether 1-year olds' name learning during joint attention was guided by expectation that names will be in the form of spoken words. Results showed that 13-month olds, but not 20-month olds, learned a new sound/object correspondence, as evidenced by their choosing targets reliably in responses to hearing the word or sound on…