Prenatal Alcohol Exposure and Infant Information Processing Ability

403 black, inner-city infants born to women recruited prenatally on the basis of their alcohol consumption during pregnancy were assessed on a battery focusing on information processing and complexity of play. Prenatal alcohol exposure was not related to visual recognition memory or cross-modal transfer of information but was associated with longer fixation duration, a measure indicative of slower, less efficient information processing; lower scores on elicited play; and longer periods of toy exploration, possibly also due to slower cognitive processing. The effects on processing speed and elicited play were dose-dependent and not attributable to maternal depression, parental intellectual stimulation, other prenatal drug exposure, or postpartum maternal drinking. The processing speed deficit is consistent with deficits in older children prenatally exposed to alcohol; the present study is the first to identify slower cognitive processing in infancy and in tasks not dependent on motoric proficiency.     

Back to Basics: A Bilingual Advantage in Infant Visual Habituation

Comparisons of cognitive processing in monolinguals and bilinguals have revealed a bilingual advantage in inhibitory control. Recent studies have demonstrated advantages associated with exposure to two languages in infancy. However, the domain specificity and scope of the infant bilingual advantage in infancy remains unclear. In the present study, 114 monolingual and bilingual infants were compared in a very basic task of information processing—visual habituation—at 6 months of age. Bilingual infants demonstrated greater efficiency in stimulus encoding as well as in improved recognition memory for familiar stimuli as compared to monolinguals. Findings reveal a generalized cognitive advantage in bilingual infants that is broad in scope, early to emerge, and not specific to language.     

Prenatal substance exposure diagnosed at birth and infant involvement with child protective services

Infants have the highest rates of maltreatment reporting and entries to foster care. Prenatal substance exposure is thought to contribute to early involvement with child protective services (CPS), yet there have been limited data with which to examine this relationship or variations by substance type. Using linked birth, hospital discharge, and CPS records from California, we estimated the population prevalence of medically diagnosed substance exposure and neonatal withdrawal disorders at birth. We then explored the corresponding rates of CPS involvement during the first year of life by substance type after adjusting for sociodemographic and health factors. Among 551,232 infants born alive in 2006, 1.45% (n = 7994) were diagnosed with prenatal substance exposure at birth; 61.2% of those diagnosed were reported to CPS before age 1 and nearly one third (29.9%) were placed in foster care. Medically diagnosed prenatal substance exposure was strongly associated with an infant’s likelihood of being reported to CPS, yet significant variation in the likelihood and level of CPS involvement was observed by substance type. Although these data undoubtedly understate the prevalence of prenatal illicit drug and alcohol use, this study provides a population-based characterization of a common pathway to CPS involvement during infancy. Future research is needed to explicate the longer-term trajectories of infants diagnosed with prenatal substance exposure, including the role of CPS.     

Differential rates of visual information processing in full-term and preterm infants

This study investigated the effect of increasing familiarization time on the visual recognition memory of 6- and 12-month-old full-term and preterm infants. Infants were given trials in which they viewed a shape for either 10-, 15-, 20-, or 30-sec familiarization and were then tested for visual recognition memory using the paired comparison technique. While the older infants showed evidence of recognition memory after less familiarization time than the younger ones, at both ages preterms required considerably longer familiarization than full-terms. The pattern of performance replicates our earlier finding of developmental lags in the visual information processing of 6-month-old preterms and extends these findings to 12-month-olds. These results suggest that there are persistent differences between preterm and full-term infants throughout at least the first year of life in this very fundamental aspect of cognition.     

Infants' cross-modal transfer from solid objects to their graphic representations

12-month-old infants were familiarized either tactually or visually with objects and then tested for visual recognition memory using either (1) the familiar and a novel object, (2) colored pictures of the objects, or (3) outline drawings of them. In Study 1, infants showed recognition memory on all 3 visual intramodal problems but showed cross-modal transfer only when objects were used as test stimuli. With increased familiarization times in Study 2, transfer from tactually presented samples to both pictorial displays was achieved, indicating that after feeling an object the infants were able to recognize it visually solely on the basis of its contour. With reduced familiarization times in Study 3, there was no evidence for transfer from visually presented samples to the 2 pictorial displays, replicating the pattern of results observed cross-modally in Study 1 and suggesting that, at least in certain respects, cross-modal and intramodal perception follow similar principles.     

Deficits in visual recognition in low birth weight infant pigtailed monkeys (Macaca nemestrina)

15 low birth weight and 15 normal birth weight pigtailed monkey infants were administered an adaptation of a standardized test of visual recognition memory, originally developed for human infants. Animals were given a series of problems in which 2 identical black-and-white patterns were presented for a familiarization period. The previously exposed pattern was then paired with a novel one, and looking time to each pattern was recorded. The normal birth weight animals directed a significant amount of their visual attention to the novel stimuli, thus demonstrating recognition abilities. As a group, the performance of the low birth weight infants remained at chance. These findings have important implications for an animal model to examine factors contributing to poor cognitive outcome in low birth weight human infants.     

Information processing in seven-month-old infants as a function of risk status

7-month-old full-terms and high-risk preterms (less than 1,500 grams at birth) were compared on problems of visual recognition memory and tactual-to-visual cross-modal transfer. On the visual problems, preterm infants showed significantly less differential attentiveness to novelty than full-terms. They also required longer exposure times during visual familiarization, primarily because of longer pauses between fixations. Preterms and full-terms exhibited different patterns of looking, as indicated by the duration of fixation and the frequency in shifts of gaze. On the cross-modal problems, preterms and full-terms both exhibited similar and significant preferences for familiar rather than novel stimuli, a direction of preference which suggests that these problems were relatively difficult for both groups. For the preterms, novelty and exposure-time scores were found to be related to several medical risk factors. Novelty preferences were compromised in preterms who had suffered RDS postnatally, particularly those who had required prolonged mechanical ventilation. In general, high-risk preterms exhibited deficits in visual recognition memory and in the ability to recruit, sustain, and shift attention.     

The effect of low-level prenatal methylmercury exposure on visual recognition memory in infant crab-eating macaques

Infant crab-eating macaques exposed in utero to maternal subclinical levels of methylmercury (MeHg) and their nonexposed controls were administered an adaptation of a standardized test of visual recognition memory. Exposed animals showed recognition deficits in that they directed significantly less visual attention to novel stimuli than did controls. These results parallel those obtained by other investigators with high-risk and teratogen-exposed human infants.     

Prenatal testosterone,visual-spatial memory,and numerical skills in young children

Lateralization of the brain is strongly influenced by prenatal androgens, with differential exposure thought to account for cognitive sex differences. This study investigated sex and individual differences and relationships between 2D:4D (the ratio of the 2nd to 4th digit [digit ratio] as a proxy indicator of prenatal testosterone exposure), visual-spatial memory, and numerical skills in 5-year-old children. No sex differences were found in any of the numerical or visual-spatial tasks. Visual-spatial memory was positively correlated with arithmetic score. Girls with a lower (more masculinised) 2D:4D had better number sense and visual-spatial skills, whilst boys with lower 2D:4D had better arithmetic skills. This suggests that prenatal testosterone exposure may have differential effects on the visual-spatial and numerical skills of girls and boys.     

Age‐Related Changes in Spreading Activation During Infancy

The concept of spreading activation describes how retrieval of one memory cues retrieval of other memories that are associated with it. This study explored spreading activation in 6‐, 12‐, and 18‐month‐old infants. Infants (n = 144) learned two tasks within the same experimental session; one task, deferred imitation (DI), is typically remembered longer than the other task, visual recognition memory (VRM). At all ages, retrieval of the DI memory facilitated retrieval of the VRM memory, but the conditions under which this spreading activation occurred changed as a function of age. The implications of these findings are discussed in relation to the development of mnemonic networks during infancy and the value of studying infants for our understanding of memory more generally.     

Infant Visual Attention and Stimulus Repetition Effects on Object Recognition

This study examined behavioral, heart rate (HR), and event-related potential (ERP) correlates of attention and recognition memory for 4.5-, 6-, and 7.5-month-old infants (N = 45) during stimulus encoding. Attention was utilized as an independent variable using HR measures. The Nc ERP component associated with attention and the late slow wave (LSW) associated with recognition memory were analyzed. The 7.5-month-olds demonstrated a significant reduction in Nc amplitude with stimulus repetition. This reduction in Nc was not found for younger infants. Additionally, infants only demonstrated differential LSW amplitude based on stimulus type on attentive trials as defined by HR changes. These findings indicate that from 4.5 to 7.5 months, infants’ attentional engagement is influenced by an increasingly broader range of stimulus characteristics.     

Maternal alcohol use and neonatal habituation assessed with the Brazelton scale

Newborn behavioral effects of intrauterine alcohol exposure were examined in 417 infants given the Brazelton Neonatal Assessment Scale. In this longitudinal prospective study, maternal alcohol use was obtained by self-report during the fifth month of pregnancy. Factor analysis of the Brazelton scale yielded 6 factors that were entered into a multiple regression analysis as dependent variables. Maternal alcohol use in mid-pregnancy was significantly related to poorer habituation and increased low arousal in newborn infants, even after adjusting for smoking and caffeine use by mothers, maternal age and nutrition during pregnancy, sex and age of the infant, and obstetric medication. This study lends further support to recognition of maternal alcohol use during pregnancy as a risk factor for alterations in newborn behavior.     

Disposition and health outcomes among infants born to mothers with no prenatal care

ObjectiveThis study assessed infant disposition and health outcomes among offspring born to mothers without prenatal care, based on maternal characteristics and the reason for lack of prenatal care (i.e., denial of pregnancy, concealment of pregnancy, primary substance use, financial barriers and multiparity).MethodsA retrospective record review was completed at an urban academic medical center. Subjects were women who presented at delivery or immediately postpartum with no history of prenatal care (N = 211), and their infants.ResultsInfants of mothers with substance use problems had the highest rates of referral to child protective services and out-of-home placement at discharge, though mothers with other reasons for no prenatal care also experienced both referral and placement. Infants born to mothers using substances experienced the highest rates of neonatal intensive care unit admission, and the lowest mean birth weight.ConclusionsThough those without prenatal care experienced a variety of adverse outcomes, substance use problems were most frequently correlated with adverse infant outcomes. Mothers who either had lost custody of other children or with substance use problems were at highest risk of losing custody of their infants. Those who denied or concealed their pregnancy still frequently retained custody.Practice implicationsAmong mothers without prenatal care, those with substance use problems were least likely to retain custody of their infant at hospital discharge. Custody status of the mother's other children was also independently associated with infant custody. Mothers who denied or concealed their pregnancy still often retained custody. Referrals of mothers with no prenatal care for psychiatric evaluation were rare, though referrals to social work were frequent. Child protective services occasionally did not investigate referrals in the denial and concealment groups. Healthcare providers should be aware of the medical and psychological needs of this vulnerable population of infants and mothers.     

Prenatal Cocaine Exposure and Infant Cortisol Reactivity

This study examined the effects of prenatal cocaine exposure on infant hypothalamic–pituitary–adrenal axis activity and reactivity at 7 months of infant age. Participants were 168 caregiver–infant dyads (87 cocaine exposed, 81 not cocaine exposed; 47% boys). Maternal behavior, caregiving instability, and infant growth and behavior were assessed, and children's saliva was sampled before, during, and after standardized procedures designed to elicit emotional arousal. Results revealed cocaine-exposed infants had a high amplitude trajectory of cortisol reactivity compared to non-cocaine-exposed infants. Infant gender and caregiving instability moderated this association. The findings support a dual hazard vulnerability model and have implications for evolutionary-developmental theories of individual differences in biological sensitivity to context.     

Adult word recognition and visual sequential memory

Two experiments were conducted investigating the role of visual sequential memory skill in the word recognition efficiency of undergraduate university students. Word recognition was assessed in a lexical decision task using regularly and strangely spelt words, and nonwords that were either standard orthographically legal strings or items made from words with internal transposed letters. Symbol memory was evaluated in a recognition procedure in which sequences of three to five unfamiliar complex symbols were presented, each followed by a subsequent array containing the symbols either in the same order or with an order transposition. In Experiment 1, there was no independent contribution of symbol memory to either word or nonword processing independently of the ability to discriminate the symbols from one another. In Experiment 2, although symbol memory made a significant contribution to word recognition independently of symbol discrimination and letter identification for two conditions??long strangely spelt words and short transposed-letter items, the effects were extremely small. It was concluded that non-verbal visual sequential memory skill does not play a central role in underpinning efficiency of word recognition in experienced adult readers.     

Preference for Infant-directed Speech in the First Month after Birth

2 experiments examined behavioral preferences for infant-directed (ID) speech over adult-directed (AD) speech in young infants. Using a modification of the visual-fixation-based auditory-preference procedure, Experiments 1 and 2 examined whether 12 1-month-old and 16 2-day-old infants looked longer at a visual stimulus when looking produced ID as opposed to AD speech. The results showed that both 1-month-olds and newborns preferred ID over AD speech. Although the absolute magnitude of the ID speech preference was significantly greater, with the older infants showing longer looking durations than the younger infants, subsequent analyses showed no significant difference in the relative magnitude of this effect. Differences in overall looking times between the 2 groups apparently reflect task variables rather than differences in speech processing. These results suggest that infants' preference for the exaggerated prosodic features of ID speech is present from birth and may not depend on any specific postnatal experience. However, the possible role of prenatal auditory experience with speech is considered.     

The effect of modality on long-term recognition memory

Two experiments examined the effects of visual and auditory modes of input on long-term memory. In Experiment 1, 40 subjects learned a 40-word list presented in a blocked or random fashion. In the blocked conditions learners were presented half the nouns in one modality followed by the remaining 20 words in the other modality (See-Hear or Hear-See). Subjects in random conditions also received half the list in each modality, but the presentation was random (Mixed or Mixed Reverse). Following a 6-min delay, subjects completed an 80-item visual recognition test. Analysis of these data showed significantly (p < .05) greater recognition of words presented visually than those presented auditorily. Experiment 2 was designed to test the hypothesis that learners may visualize a “literal copy” of the stimulus item by controlling for the extent to which the recognition measure offered a visual cue. Two groups of 40 subjects were examined using the same procedure used in Experiment 1, with the exception that one group received a visual recognition test while the other was tested auditorily. These data showed that the lack of a visual cue hindered the recognition of visually presented words, while it had little effect on stimuli presented auditorily. The results of these experiments were interpreted as support for the hypothesis that physical characteristics of a stimulus may persist in memory well beyond immediate memory intervals. Subjects were seen to make modality-specific decisions by testing long-term memory for the presence or absence of a visual memory trace.     

Moderate level alcohol during pregnancy, prenatal stress, or both and limbic-hypothalamic-pituitary-adrenocortical axis response to stress in rhesus monkeys

This study examined the relationship between moderate-level prenatal alcohol exposure, prenatal stress, and postnatal response to a challenging event in 6-month-old rhesus monkeys. Forty-one rhesus monkey (Macaca mulatta) infants were exposed prenatally to moderate level alcohol, maternal stress, or both. Offspring plasma cortisol and adrenocorticotrophic hormone (ACTH) were determined from blood samples before maternal separation and after separation. Behavioral observations were made repeatedly across separation. Moderate-level prenatal alcohol exposure was associated with significantly higher plasma ACTH response to maternal separation. Offspring exposed to prenatal alcohol, prenatal stress, and prenatal alcohol and stress showed reduced behavioral adaptation to stress compared with controls. Baseline, 2-hr, and 26-hr plasma ACTH levels were intercorrelated and predicted behavior during separation.     

Orthographic processing and visual sequential memory in unexpectedly poor spellers

Does unexpectedly poor spelling in adults result from inferior visual sequential memory? In one experiment, unexpectedly poor spellers performed significantly worse than better spellers in the immediate reproduction of sequences of visual symbols, but in a second experiment, the effect was not replicated. Poor spellers were also no worse at the immediate recognition of symbol sequences. Overall, the results indicate that inferior visual memory is not characteristic of unexpectedly poor spellers. However, they do have less efficient orthographic processing skill: they were significantly slower and more error prone than better spellers at classifying both regularly and strangely spelt words, as well as at detecting letter transpositions in long words. They can thus be considered as subtly worse word readers than better spellers. While the findings question the notion of unexpectedly poor spelling in relation to normal adults, they provide confirmation of the intimate relationship between reading and spelling processes.     

Attention and memory for faces and actions in infancy: the salience of actions over faces in dynamic events

Discrimination and memory for video films of women performing different activities was investigated in 5.5 month-old infants. In Experiment 1, infants (N = 24) were familiarized to the faces of one of three women performing one of three repetitive activities (blowing bubbles, brushing hair, and brushing teeth). Overall, results indicated discrimination and memory for the actions but not the faces after both a 1-min and a 7-week delay. Memory was demonstrated by a visual preference for the novel actions after the 1-min delay and for the familiar actions after the 7-week delay, replicating prior findings that preferences shift as a function of retention time. Experiment 2 (N = 12) demonstrated discrimination and memory for the faces when infants were presented in static poses at the 1-min delay, but not the 7-week delay. In Experiment 3 (N = 18), discrimination of the actions was replicated, but no discrimination among the objects embedded in the actions (hairbrush, bubble wand, toothbrush) was found. These findings demonstrate the attentional salience of actions over faces in dynamic events to 5.5 month-olds. They highlight the disparity between results generated from moving versus static displays in infancy research and emphasize the importance of using dynamic events as a basis for generalizing about perception and memory for events in the real world.