Cortical Indexes of Saccade Planning Following Covert Orienting in 20‐Week‐Old Infants

This study examined scalp‐recorded, event‐related potential (ERP) indexes of saccade planning in 20‐week‐old infants. A spatial cuing procedure was used in which the infants were presented with a central fixation stimulus and a peripheral cue. A peripheral target followed the cue on the ipsilateral or contralateral side of the cue. The procedure resulted in covert orienting of attention in these participants, reflected in behavioral (e.g., response facilitation or inhibition of return depending on cue‐target stimulus‐onset asynchrony) and ERP (P1 facilitation to ipsilateral target) indexes of covert orienting of attention. A presaccadic ERP that occurred over the frontal cortex about 50 msec before the saccade onset was largest when the saccade was to a target in a cued location. A presaccadic ERP potential that occurred about 300 msec before the saccade onset was largest for the saccades toward the cued location whether the target was present or not. These results suggest that saccade planning occurs in infants at this age and that infant saccade planning is controlled by cortical systems.     

Infants in Foster Care

Abstract

This article highlights the importance of attachment issues for infants placed in foster care. We offer a framework for understanding how early separation and maltreatment may affect infants' ability to securely rely on a foster parent. We argue that disruptions in foster infants' primary attachment relationships, combined with a history of maltreatment, place these infants at risk for developing predominantly insecure or disorganized attachments to foster parents, regardless of foster parent characteristics. We argue that foster infants' successful passage through the foster care system requires a high level of foster parent sensitivity to their unique attachment needs. We also argue that this level of sensitivity is likely to require specialized training for foster parents.     

Young Infants Match Facial and Vocal Emotional Expressions of Other Infants

Research has demonstrated that infants recognize emotional expressions of adults in the first half year of life. We extended this research to a new domain, infant perception of the expressions of other infants. In an intermodal matching procedure, 3.5‐ and 5‐month‐old infants heard a series of infant vocal expressions (positive and negative affect) along with side‐by‐side dynamic videos in which one infant conveyed positive facial affect and another infant conveyed negative facial affect. Results demonstrated that 5‐month‐olds matched the vocal expressions with the affectively congruent facial expressions, whereas 3.5‐month‐olds showed no evidence of matching. These findings indicate that by 5 months of age, infants detect, discriminate, and match the facial and vocal affective displays of other infants. Further, because the facial and vocal expressions were portrayed by different infants and shared no face–voice synchrony, temporal, or intensity patterning, matching was likely based on detection of a more general affective valence common to the face and voice.     

Prelinguistic Vocal Development in Infants with Typical Hearing and Infants with Severe-to-Profound Hearing Loss

Delays in the onset of canonical babbling with hearing loss are extensively documented. Relatively little is known about other aspects of prelinguistic vocal development and hearing loss. Eight infants with typical hearing and eight with severe-to-profound hearing loss were matched with regard to a significant vocal development milestone, the onset of canonical babbling, and were examined at three points in time: before, at, and after the onset of canonical babbling. No differences in volubility were noted between the two infant groups. Growth in canonical babbling appeared to be slower for infants with hearing loss than infants with typical hearing. Glottal and glide production was similar in both groups. The results add to a body of information delineating aspects of prelinguistic vocal development that seem to differ or to be similar in infants with hearing loss compared to infants with typical hearing.     

The Onset of Working Memory in Infants

We used an optimized configuration of the delayed‐response task to explore the ability of young infants to remember which of 2 locations was correct across 12 trials after a 1‐ to 2‐sec delay. Performance improved with age, particularly after 5.5 months. These findings suggest an onset of appreciable working memory for many infants in the middle of their 6th month.     

Early Segmentation Abilities in Preterm Infants

Infants born preterm have higher risks of developing linguistic deficits. Considering that the ability to segment words from fluent speech is crucial for lexical acquisition, Experiment 1 tested the ability of healthy extremely‐to‐late preterm infants to segment monosyllabic words at 6 months of postnatal age. Results establish basic segmentation skills in these infants. While we failed to find an effect of the degree of prematurity, this issue will need further exploration. Future studies will also have to specify the scope of these early segmentation skills, both in terms of the types of words segmented, the cues used to do so, and in terms of possible differences in performance between subgroups of preterm infants (e.g., based on gestational age or medical risks). Lastly, given that the preterm infants tested had a mean maturational age of 4 months, Experiment 2 explored monosyllabic segmentation in full‐term 4‐month olds. Infants succeeded at the task, providing the earliest developmental evidence of word segmentation in full‐term infants. These findings better specify the early trajectory of segmentation abilities in both full‐term and healthy, low‐risk preterm infants and support the proposal that prematurity might have a differential effect on the early acquisition of various linguistic levels.     

Assessing Speech Discrimination in Individual Infants

Assessing speech discrimination skills in individual infants from clinical populations (e.g., infants with hearing impairment) has important diagnostic value. However, most infant speech discrimination paradigms have been designed to test group effects rather than individual differences. Other procedures suffer from high attrition rates. In this study, we developed 4 variants of the Visual Habituation Procedure (VHP) and assessed their robustness in detecting individual 9‐month‐old infants' ability to discriminate highly contrastive nonwords. In each variant, infants were first habituated to audiovisual repetitions of a nonword (seepug) before entering the test phase. The test phase in Experiment 1 (extended variant) consisted of 7 old trials (seepug) and 7 novel trials (boodup) in alternating order. In Experiment 2, we tested 3 novel variants that incorporated methodological features of other behavioral paradigms. For the oddity variant, only 4 novel trials and 10 old trials were used. The stimulus alternation variant was identical to the extended variant except that novel trials were replaced with “alternating” trials—trials that contained repetitions of both the old and novel nonwords. The hybrid variant incorporated elements from both the oddity and the stimulus alternation variants. The hybrid variant proved to be the most successful in detecting statistically significant discrimination in individual infants (8 out of 10), suggesting that both the oddity and the stimulus alternation features contribute to providing a robust methodology for assessing discrimination in individual infants. In Experiment 3, we found that the hybrid variant had good test‐retest reliability. Implications of these results for future infant speech perception work with clinical populations are discussed.     

Development of Pre-Word-Learning Skills in Infants with Cochlear Implants

Families of infants who are congenitally deaf now have the option of cochlear implantation at a very young age. In order to assess the effectiveness of early cochlear implantation, however, new behavioral procedures are needed to measure speech perception and language skills during infancy. One important component of language development is word learning-a complex skill that involves learning arbitrary relations between words and their referents. A precursor to word learning is the ability to perceive and encode intersensory relations between co-occurring auditory and visual events. Recent studies in infants with normal hearing have shown that intersensory redundancies, such as temporal synchrony, can facilitate the ability to learn arbitrary pairings between speech sounds and objects (Gogate & Bahrick, 1998). To investigate the early stages of learning arbitrary pairings of sounds and objects after cochlear implantation, we used the Preferential Looking Paradigm (PLP) to assess infants' ability to associate speech sounds to objects that moved in temporal synchrony with the onset and offsets of the signals. Children with normal hearing ranging in age from 6, 9, 18, and 30 months served as controls and demonstrated the ability to learn arbitrary pairings between temporally synchronous speech sounds and dynamic visual events. Infants who received their cochlear implants (CIs) at earlier ages (7-15 months of age) performed similarly to the infants with normal hearing after about 2-6 months of CI experience. In contrast, infants who received their implants at later ages (16-25 months of age) did not demonstrate learning of the associations within the context of this experiment. Possible implications of these findings are discussed.     

Postural Position Constrains Multimodal Object Exploration in Infants

Recent research has revealed the important role of multimodal object exploration in infants' cognitive and social development. Yet, the real‐time effects of postural position on infants' object exploration have been largely ignored. In the current study, 5‐ to 7‐month‐old infants (N = 29) handled objects while placed in supported sitting, supine, and prone postures, and their spontaneous exploratory behaviors were observed. Infants produced more manual, oral, and visual exploration in sitting compared to lying supine and prone. Moreover, while sitting, infants more often coupled manual exploration with mouthing and visual examination. Infants' opportunities for learning from object exploration are embedded within a real‐time postural context that constrains the quantity and quality of exploratory behavior.     

Looking Behavior and Smiling in Down Syndrome Infants

We studied the relation between direction of gaze and smiling in 15 typically developing infants and 15 infants with Down syndrome. All of them were videotaped during face-to-face interaction with their mothers at home, and while having access to their familiar toys. Results showed that mothers in the two groups behaved in a similar way; that Down syndrome infants looked at their mother's face for longer than typically developing children; and that the relationship between looking and smiling was similar in the two cases and reflected as an increase in the time the infant looked at its mother's face and a decrease in the time the infant looked at toys. It was deduced that Down syndrome infants are capable of distinguishing the differential significance of faces and toys, so that, in the same way as typically developing infants, they direct their affective behavior fundamentally towards the social element, which leads us to consider the affiliative function implied by this expression.     

Free Viewing Gaze Behavior in Infants and Adults

The current study investigated age differences in free viewing gaze behavior. Adults and 6‐, 9‐, 12‐, and 24‐month‐old infants watched a 60‐sec Sesame Street video clip while their eye movements were recorded. Adults displayed high intersubject consistency in eye movements; they tended to fixate the same places at the same. Infants showed weaker consistency between observers and intersubject consistency increased with age. Across age groups, the influence of both bottom‐up features (fixating visually salient areas) and top‐down features (looking at faces) increased. Moreover, individual differences in fixating bottom‐up and top‐down features predicted whether infants’ eye movements were consistent with those of adults, even when controlling for age. However, this relation was moderated by the number of faces available in the scene, suggesting that the development of adult‐like viewing involves learning when to prioritize looking at bottom‐up and top‐down features.     

Syntactic Categorization in French‐Learning Infants

Recent work showed that infants recognize and store function words starting from the age of 6–8 months. Using a visual fixation procedure, the present study tested whether French‐learning 14‐month‐olds have the knowledge of syntactic categories of determiners and pronouns, respectively, and whether they can use these function words for categorizing novel words to nouns and verbs. The prosodic characteristics of novel words stimuli for noun versus verb uses were balanced. The only distinguishing cue was the preceding determiners versus subject pronouns, the former being the most common for nouns and the latter the most common for verbs, i.e., Det + Noun, Pron + Verb. We expected that noun categorization may be easier than verb categorization because the co‐occurrence of determiners with nouns is more consistent than that of subject pronouns with verbs in French. The results showed that infants grouped the individual determiners as one common class, and that they appeared to use the determiners to categorize novel words into nouns. However, we found no evidence of verb categorization. Unlike determiners, pronouns were not perceived as a common syntactic class.     

Acoustic Packaging of Action Sequences by Infants

This study investigated whether acoustic input, in the form of infant‐directed speech, influenced infants' segmenting of action sequences. Thirty‐two 7.5‐ to 11.5‐month‐old infants were familiarized with video sequences made up of short action clips. Narration coincided with portions of the action stream to package certain pairs of clips together. At test, packaged and nonpackaged pairs of actions were presented side by side in silence. Narration heard during familiarization influenced how infants viewed the action units, such that at test, infants older than 9.5 months (but not younger) looked longer at the nonpackaged than the packaged action sequences. The role of infant‐directed speech as well as other types of acoustic input in assisting infants' processing of action is discussed.     

Poverty and the Daily Lives of Infants

It has been amply demonstrated that poor children suffer disadvantages as compared to their more advantaged peers. This paper examines important aspects of infants’ daily experiences in a southeastern city in the United States in order to illustrate differences between poor and non-poor infants. “Poor” infants were compared to their “non-poor” counterparts on the quality of parenting they received; quality of their home environments; relative health and safety; stability, structure, and predictability of their daily lives; and exposure to diverse experiences in the community. Findings reveal that poor infants are at a consistent disadvantage across all domains when compared to their more affluent counterparts. These daily deficiencies might be conceptualized as the mechanisms through which poverty exerts its negative effects. This paper shifts the focus from macro-level variables such as larger economic and social factors to the cumulative effect of deficiencies at the micro-level. Intervening to ameliorate the micro-level deficits that are most modifiable may lessen the cumulative risk and provide some small avenues toward resilience for the most disadvantaged and at-risk infants.     

Complex Interrelations of Trait Vulnerabilities in Mothers and their Infants

Despite the developmental and clinical relevance of this area of inquiry, no studies have examined the interrelations of trait vulnerabilities in the affective, behavioral, and interpersonal domains between mothers and their infants. Thus, this study examined the interrelations of three trait vulnerabilities (i.e., negative affective intensity, impulsivity, and insecure attachment) between mothers and their 12‐ to 23‐month‐old infants, focusing in particular on the unique and interactive influence of these maternal trait vulnerabilities on the expression of and precursors to these traits in their infants. Mother–infant dyads (N = 101) completed several laboratory procedures, and mothers reported on their own and their infants' expressions of the trait vulnerabilities of interest. Findings from this study provide preliminary evidence for intergenerational relations between these traits and suggest that it is the confluence of trait vulnerabilities in mothers that relates to the early expression of some of these traits in infants.     

Behavioral and Cortical Measures of Infants' Visual Expectations

Features of the habituation paradigm were combined with the visual expectation paradigm to examine behavioral and cortical indexes of infants' visual expectations. Eight 3‐month‐old infants watched an alternating picture sequence while their eye movements were videotaped and their cortical electrophysiological activity (event‐related potential [ERP]) was recorded. Two ERP epochs were examined: a 3,000‐msec stimulus‐locked epoch included 1,000 msec before stimulus onset through 1,000 msec after stimulus offset; and a 1,200‐msec response‐locked epoch included 700 msec before saccade onset through 500 msec after the saccade. All infants anticipated upcoming pictures, and eye movement latencies for pictures that were not anticipated were comparable to saccade latencies reported in other visual expectation studies of infants at this age. Three components were identified in the stimulus‐locked ERP waveform: a slowly developing negativity prior to picture onset, a postonset negative slow wave, and a late negative deflection that peaked about 750 msec after picture onset. All stimulus‐locked components were larger for familiar than for unfamiliar pictures; prestimulus negativity was also greater before anticipated pictures. The response‐locked waveform contained 2 prominent features: a slowly increasing negative shift (NS) that began about 500 msec before saccade onset and a positive presaccadic potential that occurred about 30 to 90 msec before the saccade. Response‐locked components were larger for anticipatory saccades at the frontal scalp site; for reactive saccades, response‐locked components were larger at the vertex. Results are informative about ERPs in infants, cortical control of eye movements, and the development of visual expectations.     

Avoidance of Heights on the Visual Cliff in Newly Walking Infants

Work with infants on the “visual cliff” links avoidance of drop‐offs to experience with self‐produced locomotion. Adolph's (2002) research on infants' perception of slope and gap traversability suggests that learning to avoid falling down is highly specific to the postural context in which it occurs. Infants, for example, who have learned to avoid crossing risky slopes while crawling must learn anew such avoidance when they start walking. Do newly walking infants avoid crossing the drop‐off of the visual cliff? Twenty prewalking but experienced crawling infants were compared with 20 similarly aged newly walking infants on their reactions to the visual cliff. Newly walking infants avoided moving onto the cliff's deep side even more consistently than did the prewalking crawlers. Thus, in the context of drop‐offs in visual texture, our results show that once avoidance of drop‐offs is established under conditions of crawling, it is developmentally maintained once infants begin walking.