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Manual skills slowly develop throughout infancy and have been shown to create clear views of objects that provide better support for visually sustained attention, recognition, memory, and learning. These clear views may coincide with the development of manual skills, or that social scaffolding supports clear viewing experiences like those generated by toddlers during active object exploration. This study used a head-mounted eye tracker to record 5- to 24-month-olds' object views during repeated mother-infant play sessions (Ns = 18). Results show an early beginning of scaffolding in which parents generate views similar to those of older infants and toddlers, resulting in increased fixations to objects. The finding implicates parents as early scaffolders of object attention and learning. [ABSTRACT FROM AUTHOR]

Both human and nonhuman primate adults use infant-directed facial and vocal expressions across many contexts when interacting with infants (e.g., feeding, playing). This infant-oriented style of communication, known as infant-directed speech (IDS), seems to benefit human infants in numerous ways, including facilitating language acquisition. Given the variety of contexts in which adults use IDS, we hypothesized that IDS supports learning beyond the linguistic domain and that these benefits may extend to nonhuman primates. We exposed 2.5-month- old rhesus macaque infants (N = 15) to IDS, adult-directed speech (ADS), and a non-social control (CTR) during a video presentation of unrelated stimuli. After a 5-or 60-minute delay, infants were shown the familiar video side-by- side with a novel video. Infants exhibited a novelty preference after the 5-minute delay, but not after the 60-minute delay, in the ADS and CTR conditions, and a novelty preference in the IDS condition only after the 60-minute delay. These results are the first to suggest that exposure to IDS affects infants’ long-term memory, even in non-linguistic animals. [ABSTRACT FROM AUTHOR]

Eye movements were recorded as 12-month-olds (n = 15), 4-year-olds (n = 17), and adults (n = 19) watched a 15-min video with sequences of shots conveying continuous motion. The central question was whether, and at what age, viewers anticipate the reappearance of objects following cuts to new shots. Adults were more likely than younger viewers to make anticipatory eye movements. Four-year-olds responded to transitions more slowly and tended to fixate the center of the screen. Infants' eye movement patterns reflected a tendency to react rather than anticipate. Findings are consistent with the hypothesis that adults integrate content across shots and understand how space is represented in edited video. Results are interpreted with respect to a developing understanding of film editing due to experience and cognitive maturation. [ABSTRACT FROM AUTHOR]

This paper examines an experimental technique that uses visual narrative methodology and dialogue commentary to create an effective research methodology for a pilot project studying babies and toddlers in long day care centres and family contexts. Researchers from different cultural backgrounds using video technology, formed the team of chief investigators. One video clip was chosen to make independent descriptions, comments and interpretations of what was noticed. Later, initial visual narrative descriptions were shared and extended after reading one another's responses. This process created a dialogue commentary that enabled data overview, interpretative analyses and synthesis supported by snapshot moments taken from video clip. One aim of the project was to visually capture the cultural worlds and transitory relationships of babies and toddlers. Researchers showed the selected video clip separately to babies' room educator, centre director, and parents recording their responses. Using visual narrative methodology, dialogue commentary, and a shared cultural historical theoretical framework, revealed useful contradictions that raised social and cultural questions such as: How do educators recognize cultural worlds and transitory relationships of babies and toddlers? How are transitory moments related to pedagogically by educators? Integrating researchers' personal, cultural and affective responses, affords new critical cultural perspectives. This paper draws on screen capture snapshot moments from one video clip, taken from babies' pilot project data. These offer small windows into methodological approaches used to research the cultural world and transitory moments of three infants and their educator, located in the babies' room of an Australian long day care (LDC) site. [ABSTRACT FROM AUTHOR]

Background: Lead is a pervasive neurotoxicant that has been associated with poorer cognitive, behavioral, and motor outcomes in children. The effects of lead on sensory function have not been well characterized. The aim of this study was to assess the effects of prenatal lead exposure on infant sensory function, as measured by auditory brainstem response (ABR) and grating visual acuity (VA).Methods: Lead was measured in maternal blood in mid- and late-pregnancy (mean gestational age = 15.5 and 39.0 weeks, respectively) and umbilical cord blood in a cohort of full-term infants in rural northeastern China. ABR latencies (peaks I, III, V) were measured in newborns during unsedated sleep (n = 315). The ABR central-to-peripheral (C-P) ratio was calculated as the ratio between the III-V and I-III interpeak intervals. VA was measured in 6-week-olds using Teller Acuity Cards (n = 1019) and assigned as the narrowest grid the infant fixated on. Multivariate linear regression was used to evaluate relationships between tertiles of mid-pregnancy, late-pregnancy, or cord lead and newborn ABR or 6-week VA.Results: Higher late-pregnancy lead levels were associated with higher ABR C-P ratios and lower VA. In covariate-adjusted analyses, mean C-P ratios were 4.6 and 3.2 % higher in infants whose mothers had lead > 3.8 μg/dL and lead = 2-3.8 μg/dL, respectively, than for infants whose mothers had lead < 2 μg/dL (p-trend =0.002). In adjusted analyses for VA, mean scores were 8.5 and 7.2 % lower for maternal lead > 3.8 μg/dL and lead = 2-3.8 μg/dL, respectively, compared to lead < 2 μg/dL (p-trend =0.009).Conclusion: Auditory and visual systems maturation appears delayed in infants with higher prenatal lead exposure during late-pregnancy, even at relatively low levels. Both systems start myelinating in late gestation and mature rapidly in infancy. Higher ABR C-P ratio and lower grating VA scores suggest effects of low-level lead exposure on sensory system myelination. [ABSTRACT FROM AUTHOR]

Visual exploration in infants and adults has been studied using two very different paradigms: free viewing of flat screen displays in desk-mounted eye-tracking studies and real-world visual guidance of action in head-mounted eye-tracking studies. To test whether classic findings from screen-based studies generalize to real-world visual exploration and to compare natural visual exploration in infants and adults, we tested observers in a new paradigm that combines critical aspects of both previous techniques: free viewing during real-world visual exploration. Mothers and their 9-month-old infants wore head-mounted eye trackers while mothers carried their infants in a forward-facing infant carrier through a series of indoor hallways. Demands for visual guidance of action were minimal in mothers and absent for infants, so both engaged in free viewing while moving through the environment. Similar to screen-based studies, during free viewing in the real world low-level saliency was related to gaze direction. In contrast to screen-based studies, only infants - not adults - were biased to look at people, participants of both ages did not show a classic center bias, and mothers and infants did not display high levels of inter-observer consistency. Results indicate that several aspects of visual exploration of a flat screen display do not generalize to visual exploration in the real world. [ABSTRACT FROM AUTHOR]

Infants' understanding of how their actions affect the visibility of hidden objects may be a crucial aspect of the development of search behaviour. To investigate this possibility, 7-month-old infants took part in a two-day training study. At the start of the first session, and at the end of the second, all infants performed a search task with a hiding-well. On both days, infants had an additional training experience. The 'Agency group' learnt to spin a turntable to reveal a hidden toy, whilst the 'Means-End' group learnt the same means-end motor action, but the toy was always visible. The Agency group showed greater improvement on the hiding-well search task following their training experience. We suggest that the Agency group's turntable experience was effective because it provided the experience of bringing objects back into visibility by one's actions. Further, the performance of the Agency group demonstrates generalized transfer of learning across situations with both different motor actions and stimuli in infants as young as 7 months. [ABSTRACT FROM AUTHOR]

The goal of the current study is to assess the temporal dynamics of vision and action to evaluate the underlying word representations that guide infants' responses. Sixteen-month-old infants participated in a two-alternative forced-choice word-picture matching task. We conducted a moment-by-moment analysis of looking and reaching behaviors as they occurred in tandem to assess the speed with which a prompted word was processed (visual reaction time) as a function of the type of haptic response: Target, Distractor, or No Touch. Visual reaction times (visual RTs) were significantly slower during No Touches compared to Distractor and Target Touches, which were statistically indistinguishable. The finding that visual RTs were significantly faster during Distractor Touches compared to No Touches suggests that incorrect and absent haptic responses appear to index distinct knowledge states: incorrect responses are associated with partial knowledge whereas absent responses appear to reflect a true failure to map lexical items to their target referents. Further, we found that those children who were faster at processing words were also those children who exhibited better haptic performance. This research provides a methodological clarification on knowledge measured by the visual and haptic modalities and new evidence for a continuum of word knowledge in the second year of life. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the long-term results of simultaneous bilateral external dacryocystorhinostomy (EX-DCR) in cases with bilateral dacryostenosis. Methods: Thirty-four eyes of 17 consecutive patients with a history of bilateral epiphora were included in the study between 2007 and 2011. Demographic information, etiology of the obstruction, history of lacrimal surgery, type of anesthesia, duration of surgery, incidence of postoperative nasal bleeding and infection, surgical outcomes, and duration of follow-up were recorded. During the lacrimal irrigation, there was not any passage noticed in the patients' eyes. The post-operative follow-up was 13 to 44 months (mean 33.6 months). Results: Of 17 patients undergoing simultaneous bilateral EX-DCR with a mean age of 42.8 years, one of the patients had a history of bilateral unsuccessful DCR performed in a different center. One patient had previously failed bilateral probing before undergoing bilateral EX-DCR. This latter patient was a four-month-old baby with bilateral dacryoceles. Bicanalicular silicone intubation was performed in 15 eyes of 10 patients that had a canalicular problem or fibrotic lacrimal sac. It has been discerned that complaints about epiphora disappeared in 33 of the eyes (97%) and that the passage was open during the lacrimal irrigation. One eye with a history of unsuccessful dacryocystorhinostomy failed to respond positively to our operation. Conclusions: In our study, high success rates of simultaneous bilateral EX-DCR were found in both children and adult patients with bilateral dacryostenosis during a long-term follow-up. We believe that simultaneous bilateral dacryocystorhinostomy has medical, social, and economic advantages. [ABSTRACT FROM AUTHOR]

Purpose To provide population-based normative visual acuity ( VA) by age, in children participating in the Sydney Paediatric Eye Disease Study aged 6 to <72 months. Methods Monocular VA was measured using the Amblyopia Treatment Study ( ATS HOTV) protocol (24 to <72 months). Some children were also tested using linear ETDRS or HOTV log MAR VA charts (30 to <72 months). If unable to perform recognition acuity, the Teller Acuity Cards II ( TAC II) was performed (6 to <42 months). Children with significant refractive error or ocular disease were excluded. Results Improvement in VA with age was shown on all three vision tests (all p < 0.0001). Mean VA using ATS HOTV ( n = 836) was 0.13 log MAR (6/8) at <36 months, which improved to −0.01 (6/6) at 66 to <72 months. Mean ETDRS/ HOTV ( n = 399) VA was 0.26 log MAR (6/11) at <36 months, which improved to 0.1 (6/7.5) at 66 to <72 months. Mean monocular TAC II ( n = 442) was 5.7 cycles/degree (0.72 log MAR) at 6 to <9 months and improved to 12.4 cycles/degree (0.38 log MAR) at age 30 to <33 months. Associations with ATS HOTV VA included prematurity (p = 0.027) and socio economic status ( SES) factors such as home ownership (p = 0.039) and employment of one (p = 0.019) or both parents (p = 0.003). Conclusions VA norms in children improved with age and were different according to the VA test used. Low SES was associated with poorer VA, supporting the need for test specific VA norms to be established for different populations. The ATS HOTV appears to be the best test to use for vision screening due to its lower false positive referral rate. [ABSTRACT FROM AUTHOR]

In a series of preferential-looking experiments, infants 5 to 6 months of age were tested for their responsiveness to crossed and uncrossed horizontal disparity. In Experiments 1 and 2, infants were presented with dynamic random dot stereograms displaying a square target defined by either a 0.5° crossed or a 0.5° uncrossed horizontal disparity and a square control target defined by a 0.5° vertical disparity. In Experiment 3, infants were presented with the crossed and the uncrossed horizontal disparity targets used in Experiments 1 and 2. According to the results, the participants looked more often at the crossed (Experiment 1), as well as the uncrossed (Experiment 2), horizontal disparity targets than at the vertical disparity target. These results suggest that the infants were sensitive to both crossed and uncrossed horizontal disparity information. Moreover, the participants exhibited a natural visual preference for the crossed over the uncrossed horizontal disparity (Experiment 3). Since prior research established natural looking and reaching preferences for the (apparently) nearer of two objects, this finding is consistent with the hypothesis that the infants were able to extract the depth relations specified by crossed (near) and uncrossed (far) horizontal disparity. [ABSTRACT FROM AUTHOR]

Pointing, like eye gaze, is a deictic gesture that can be used to orient the attention of another person towards an object or an event. Previous research suggests that infants first begin to follow a pointing gesture between 10 and 13 months of age. We investigated whether sensitivity to pointing could be seen at younger ages employing a technique recently used to show early sensitivity to perceived eye gaze. Three experiments were conducted with 4.5- and 6.5-month-old infants. Our first goal was to examine whether these infants could show a systematic response to pointing by shifting their visual attention in the direction of a pointing gesture when we eliminated the difficulty of disengaging fixation from a pointing hand. The results from Experiments 1 and 2 suggest that a dynamic, but not a static, pointing gesture triggers shifts of visual attention in infants as young as 4.5 months of age. Our second goal was to clarify whether this response was based on sensitivity to the directional posture of the pointing hand, the motion of the pointing hand, or both. The results from Experiment 3 suggest that the direction of motion is necessary but not sufficient to orient infants' attention toward a distal target. Infants shifted their attention in the direction of the pointing finger, but only when the hand was moving in the same direction. These results suggest that infants are prepared to orient to the distal referent of a pointing gesture which likely contributes to their learning the communicative function of pointing. [ABSTRACT FROM AUTHOR]

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Abstract: The docosahexaenoic acid (DHA, C22:6n-3) status of infants at birth and maternal DHA intake during pregnancy are interconnected and associated with infants’ developmental performance. High-dosage supplementation of long-chain polyunsaturated fatty acids (LCPUFAs; particularly DHA) in mothers, started at mid-pregnancy, has been associated with long-term positive effects on intelligence quotient scores of neurodevelopment. Poor maternal and infant DHA status could partly contribute to the observed association between certain conditions and impaired developmental outcome. The dietary DHA enrichment of human milk seems to be functionally effective in breastfed infants only when lactating mothers start supplementation during pregnancy. Results from trials in artificially fed infants are dissimilar and could be related in part to uninvestigated covariates such as infant DHA status at birth and the individual genetic background. Nevertheless, DHA supplementation during the complementary feeding period seems to be effective in improving neurofunctional and visual performance. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The authors aimed to investigate the association between the distance at which infants fixate their own reflections and visual acuity card testing, and to determine whether this could form the basis of a new clinical test of visual function in infants. METHODS: 78 healthy infants under 9 months of age (range 1–266 days, mean 56.5±64SD) were recruited and held close to a mirror such that they attended their own reflections. The distance from the mirror was increased until they no longer held fixation. Binocular acuities were tested with the Teller acuity card procedure. RESULTS: Reliability was rated ‘good’ in 58 and 60 infants respectively, for mirror distances and for the acuity cards. Data were also included for moderate reliability (n=20 and 14 respectively). The mean mirror distance was 54.9 cm (range 13.5–178, SD=42.8). The mean Teller acuity was 2.19 cycles per degree (range 0.2–14.5, SD=2.8). (Snellen equivalent 6/82, range 6/900–6/12). Mirror distance showed linear correlation with both Teller acuity (R2=0.69, p<0.0005) and with age (R2=0.73, p<0.0005) by univariate analysis. Using multivariate analysis, only age retained significance. Using logarithmic scales and a logistic growth function for age, correlations were stronger (log mirror distance vs log Teller acuity, R2=0.86, p<0.0005; logistic regression of log mirror distance vs log age, R2=0.88, p<0.0005), and both retained independent significance in a multivariate model. CONCLUSION: Mirror fixation distance increases with age in infants and has a good correlation with acuity card results. The portability and ease of use would make it a useful additional tool for detecting impaired visual function in infants. [ABSTRACT FROM AUTHOR]

Abstract: Motion cues provide a rich source of information about translations of the observer through the environment as well as the movements of objects and surfaces. While the direction of motion can be extracted locally these local measurements are, in general, insufficient for determining object and surface motions. To study the development of local and global motion processing mechanisms, we recorded Visual Evoked Potentials (VEPs) in response to dynamic random dot displays that alternated between coherent rotational motion and random motion at 0.8Hz. We compared the spatio-temporal tuning of the evoked response in 4–6months old infants to that of adults by recording over a range of dot displacements and temporal update rates. Responses recorded at the frequency of the coherent motion modulation were tuned for displacement at the occipital midline in both adults in infants. Responses at lateral electrodes were tuned for speed in adults, but not in infants. Infant responses were maximal at a larger range of spatial displacement than that of adults. In contrast, responses recorded at the dot-update rate showed a more similar parametric displacement tuning and scalp topography in infants and adults. Taken together, our results suggest that while local motion processing is relatively mature at 4–6months, global integration mechanisms exhibit significant immaturities at this age. [Copyright &y& Elsevier]

Background: Studies of infant siblings of children diagnosed with autism have allowed for a prospective approach to study the emergence of autism in infancy and revealed early behavioral characteristics of the broader autism phenotype. In view of previous findings of atypical eye gaze processing in children and adults with autism, the aim of this study was to examine the early autism phenotype in infant siblings of children diagnosed with autism spectrum disorder (sib-ASD), focusing on the neural correlates of direct compared with averted gaze. Methods: A group of 19 sib-ASD was compared with 17 control infants with no family history of ASD (mean age = 10 months) on their response to direct versus averted gaze in static stimuli. Results: Relative to the control group, the sib-ASD group showed prolonged latency of the occipital P400 event-related potentials component in response to direct gaze, but they did not differ in earlier components. Similarly, time-frequency analysis of high-frequency oscillatory activity in the gamma band showed group differences in response to direct gaze, where induced gamma activity was late and less persistent over the right temporal region in the sib-ASD group. Conclusion: This study suggests that a broader autism phenotype, which includes an atypical response to direct gaze, is manifest early in infancy. [Copyright &y& Elsevier]

Abstract: The present study investigated the role that comprehending words for objects plays in 10- and 11-month-old infants'' ability to individuate those objects in a spatiotemporally ambiguous event. To do this, we employed an object individuation task in which infants were familiarized to two objects coming in and out from behind a screen in alternation, and then the screen was removed to reveal either both or only one of the objects. Results show that only when 10- and 11-month-olds comprehend words for both objects seen do they exhibit looking behavior that is consistent with object individuation (i.e., looking longer when one of the objects is surreptitiously removed). Neither level of object permanence reasoning nor overall receptive vocabulary had an effect on performance in the object individuation task, indicating that the effect was specific to the immediate parameters of the situation, and not a function of overall precocity on the part of the succeeding infants. These results suggest that comprehending the words for occluded/disoccluded objects provides a kind of “glue” which allows infants to bind the mental index of an object with its perceptual features (thus precipitating the formation of two mental indexes, rather than one). They further suggest that a shift from object indexing driven by the where (dorsal) system to one which is driven by integration of the ventral and dorsal neural systems, usually not observed until 12 months of age, can be facilitated by word comprehension in 10- and 11-month-old infants. [Copyright &y& Elsevier]

This paper reviews the general stages of infant vision development with specific emphasis on the environmental factors affecting the emergence of the basic vision functions (visual acuity, pursuits, saccades, binocularity, and visual perception). Vision guidance and optometric vision therapy activities are explained and demonstrated to educate and guide parents in playful interactions with their child. The activities are suited for the infant from birth to age three. The aim is to prevent vision abnormalities from developing by providing a comprehensive program of movement oriented vision stimulation. [ABSTRACT FROM AUTHOR]

The optometric literature has begun to emphasize pediatric vision and vision development with the advent and prominence of the InfantSEE™ program and recently published research articles on amblyopia, strabismus, emmetropization and the development of refractive errors. There are three conditions with which clinicians should be familiar. These three conditions include: esotropia, high refractive error/anisometropia and amblyopia. They are serious health and vision threats for the infant. It is fitting that this trinity of early visual developmental conditions be addressed by optometric physicians specializing in vision development. The treatment of these conditions is improving, but still leaves many children handicapped throughout life. The healing arts should always consider alternatives and improvements to what is presently considered the customary treatment for these conditions. This is especially true since the current treatment leaves room for improvement. This paper considers research that suggests and/or promotes an alternative treatment strategy that addresses these three conditions. [ABSTRACT FROM AUTHOR]

The developmental visual assessment of infants should include both qualitative and quantitative aspects. The quantitative components are based on static findings that can be compared to normative data and various developmental changes that occur over time. The qualitative aspects are not easily measured. These dynamic aspects should be observed as an ongoing process. This information can provide insights into how the infant is performing the particular task and what strategies they employ. These insights can be valuable when determining the unmet visual needs of the infant and to help in the development of therapy programs. While examining infants we should keep in mind the goal of the evaluation. Beyond doing a health evaluation, we should evaluate what can be done to provide the most appropriate plan to help the infant to develop to their potential. We should also be mindful that the experiences and world of an infant are much different than an adult. Their world begins at near and extends outward after birth. Early growth and development should allow the infant to go beyond their physical world of prehension and provide an opportunity to extend their visual world outward into the environment. [ABSTRACT FROM AUTHOR]

When observing infant retinoscopic responses, it may be advisable to regard near retinoscopy as an infant's relaxed state because of the order of visual development. The infant sustains a meaningful visual contact first at near and then moves outward. This essay is based on Gesell's utilization of an ordered organization of development from the skeletal, to the visceral, and finally to the cortical stage. He compared these functions in vision to visual reaching, grasping and manipulation. This is the history of how infant retinoscopy developed as an extension of dynamic retinoscopy. This paper introduces a model for defining the differences in retinoscopy reflexes as they relate to Gesell's three developmental categories. In so doing, it helps the retinoseopist focus on the different aspects of the reflex as a way to help understand an individual's visual performance. These retinoscopy observations raise a question about what with and against motion indicate when examining infants. This is based on the recognition that relative convergence and relative accommodation are not equal to the related changes in physical optics. Relative accommodation and convergence are evident whenever an individual visually localizes a perceived distance which is different than the physical distance. As an example, when an individual attends to a base-out (closer) or base-in (farther) projection of a stereopsis view, the perceived distance different than the physical presentation. Relative accommodation and accommodation yield different qualities and motion of the reflex. [ABSTRACT FROM AUTHOR]

In 3 experiments, the author investigated 16- to 20-month-old infants' attention to dynamic and static parts in learning about self-propelled objects. In Experiment 1, infants were habituated to simple noncausal events in which a geometric figure with a single moving part started to move without physical contact from an identical geometric figure that possessed a single static part. Infants were then tested with an event in which the parts of the objects were switched. In Experiments 2 and 3, infants were habituated and tested with identical events except that the part possessed by each object during habitation was switched relative to the first experiment. Results of the experiments revealed that 16-month-olds failed to encode the relation between an object's part and its onset of motion, 18-month-olds were unconstrained in the relations involving self-propulsion that they would encode, and 20-month-olds were constrained in the relations they would encode. The results are discussed with regard to the developmental trajectory of learning about motion properties and the mechanism involved in early concept acquisition. [ABSTRACT FROM AUTHOR]

Discusses the factors to consider in achieving surgical timing for infantile esotropia. Prevalence of the disease among neonates; Development of stereopsis in infants; Scientific evidences of binocularity loss in infantile esotropia.

Discusses the implantation of intraocular lenses in infancy which resulted to the rapid growth of the eye during the stage and its long-term visual outcomes. Causes and prevalence of cataract among infants; Background on the ocular growth and visual development of babies; Challenges in implanting intraocular lenses.

Focuses on a study which compared the exploratory behaviors used by infants who were congenitally blind and infants with normal vision. Background of the study population; List of exploratory behaviors used by infants; Similarities and differences between blind and sighted infants.

We monitored changes in looking that emerged when 3- to 6-month-old infants were presented with 48 trials pairing familiar and novel faces. Graphic displays were used to identify changes in looking throughout the task. Many infants exhibited strong side biases produced by infants looking repeatedly in the same direction. Although an overall novelty preference was found for the group, individual infants exhibited brief novelty runs. Few infants began with a familiarity preference. We argue that variable looking patterns emerged during the task from competition between the infants' preference to look to something novel versus their tendency to look back to previous locations. Our data suggest that looking during paired-comparison tasks is a dynamic process dependent on perceptual-motor events happening during the task itself. [ABSTRACT FROM AUTHOR]

The importance of the tear film for the integrity of the ocular surface is well established. Full-term neonates produce tears normally, but low spontaneous blink rates during early life raises important questions regarding tear dynamics and stability. Although an afferent neural pathway that could potentially detect tear break-up is in place at birth, there is indirect evidence that the neonatal tear film is adapted to resist evaporation-mediated tear thinning. This adaptation presumably prevents drying of the ocular surface during long inter-blink periods. However, low rates of tear turnover may have important implications for the defence of the eye against potential pathogens. [Copyright &y& Elsevier]

Four experiments assessed visual short-term memory capacity in 4- to 13-month-old infants by comparing their looking to changing and nonchanging stimulus streams presented side by side. In each stream, 1 to 6 colored squares repeatedly appeared and disappeared. In changing streams, the color of a different randomly chosen square changed each time the display reappeared; the colors remained the same in nonchanging streams. Infants should look longer at changing streams, but only if they can remember the colors of the squares. The youngest infants preferred changing streams only when the displays contained one object, whereas older infants preferred changing streams when the displays contained up to 4 objects. Thus, visual short-term memory capacity increases significantly across the first year of life. [ABSTRACT FROM AUTHOR]

The Superposition Hypothesis states that the binocular vision of newborn infants blends together the monocular visual responses of the two eyes, even when the visual stimulus evokes binocular rivalry in adults. According to the Superposition Hypothesis, this blending is replaced by binocular rivalry after the emergence of stereopsis [Neonate Cognition: Beyond the Blooming, Buzzing Confusion, Erlbaum, Hillsdale, NJ, 1985, p. 37; Early Visual Development Normal and Abnormal, Oxford University Press, New York, 1993, p. 201]. The main evidence for the Superposition Hypothesis is a preferential looking experiment [Vision Res., 26 (3) (1986) 501], in which 8–12-week-old infants fixated a rivalrous (for adults) dichoptic plaid, in preference over a fusible grating of parallel lines. This report describes our attempt to repeat that important experiment. Infant stereopsis emerged at 8.6 weeks under our conditions, but infants did not preferentially fixate the dichoptic plaid at any age between age 5 and 16 weeks. Control experiments showed that our result was not due to technical differences between their experiment and ours (red/green vs. polarizing glasses, the use of a fixation point, or the infant observation apparatus). Therefore, blending of the visual responses to rivalrous (for adults) stimuli is not a general feature of the pre-stereoptic infant visual system. [Copyright &y& Elsevier]

The present paper aims at studying the relationships between posture, muscle tone and visual attention in 5 month-old infants. To this end, a specially designed seating arrangement made it possible to vary posture while keeping constant the spatial relationship between eyes and stimuli. Five month-olds were placed in the reclining position (30°) or in a more erect position (60°). The more erect the posture, the more difficult it should be for the infant to maintain a straight body axis. Muscle tone was evaluated, and infants distinguished in terms of whether they were hypertonic or hypotonic. It was hypothesised that in a more erect position hypotonic children, who experience more difficulties in maintaining posture, should organise their visual exploration in ways different from those considered to be hypertonic. To test it, pairs of three-dimensional stimuli were presented in the distal visual field for one group (N =48) and in the proximal visual field in another group (N =32) for 2 min in each posture. The dynamical organisation of attention was evaluated through the number and duration of fixations on each target, the number of shifts from one target to the other (alternations) and the number of repetitions (back to the previous target). Results showed that visual behaviour was significantly affected by the distance at which stimuli were presented. Infants spent more time in visual exploration when the object was within reach than when it was out of reach. Although posture was shown to play a role in the organisation of visual exploration, no link with muscle tone was found, a surprising result which is discussed. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The present study was aimed at investigating whether, because of a differential sensitivity between the upper and the lower visual fields, in a visual preference task newborns would orient more frequently and look longer at patterns with a great number of high–contrast areas in the upper or lower visual field. Newborns were presented with three pairs of geometrical stimuli, each composed of a pattern with a greater number of elements in the upper part or a pattern with more elements in the lower part. The results showed a reliable preference for the stimuli that had more elements in the upper than in the lower part. The evidence obtained suggests the possibility that, at birth, the visibility of a stimulus depends not only on its sensory properties, but also on its structural characteristics. [ABSTRACT FROM AUTHOR]

Why do infants have difficulty searching for objects hidden by occluders before 8 months when other evidence has indicated they are sensitive to hidden objects months earlier? One explanation suggests that infants know hidden objects exist but lack the means-end skill to retrieve them from occluders. However, this experiment explores the unique contribution of object visibility by presenting 6- and 10-month-old infants with visible and hidden objects that could be retrieved with little to no means-end skill. Results indicate that 6-month-old infants searched significantly less for hidden objects than visible objects, although both conditions were equated for means-end demands. In contrast, there were no differences among 10-month-old infants. These results highlight the effect of object visibility on search and indicate that a means-end deficit cannot be the only cause of search problems. Explanations for the effect of object visibility are discussed. [ABSTRACT FROM AUTHOR]

Several models of the development of infant visual attention have used information about neural development. Most of these models have been based on nonhuman animal studies and have relied on indirect measures of neural development in human infants. This article discusses methods for studying a “neurodevelopmental” model of infant visual attention using indirect and direct measures of cortical activity. We concentrate on the effect of attention on eye movement control and show how animal-based models, indirect measurement in human infants, and direct measurement of brain activity inform this model. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 226–236, 2002. DOI 10.1002/dev.10029 [ABSTRACT FROM AUTHOR]

Many studies have demonstrated that newborns prefer upright faces over upside-down faces. Based on this evidence, some have suggested that faces represent a special class of stimuli for newborns and there is a qualitative difference between the processes involved in perception of facelike and non-facelike patterns (i.e. structural hypothesis). Others suggest that there is no reason to suppose that faces are different from other patterns, because faces, like any other class of visual stimuli, are subject to filtering by the properties of the visual system (i.e. sensory hypothesis). The core question that will be addressed in the present paper is whether, to manifest itself, face preference requires the unique structure of the face, represented by the relative spatial location of its internal features, or rather some more general properties that other stimuli may also possess. Evidence will be presented supporting the idea that newborns do not respond to facelike stimuli by ‘facedness’ but, rather, by some general structural characteristics that best satisfy the constraints of the immature visual system. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Colour and facial configuration are both very salient aspects of the visual environment for infants, but may both be selectively processed by the right hemisphere (RHS) and under some conditions may compete for RHS resources. The present investigation assessed the relative potency of facial configuration and colour in the two halves of the visual field for 32 infants (with a mean age of 24 weeks). The infants were familiarized to triads of facial figures presented for 250 ms in the left or right visual field. The faces were all different in colour and facial pattern (expression), but one of them (the target) was shown in an upright orientation while the others (distractors) were inverted. The results of paired-comparison recognition tests indicated that the displays had been initially parsed in terms of configurational category (upright faces versus inverted non-faces) in both visual fields, attesting to the primacy of this categorical distinction in both hemispheres. However, the focus for subsequent encoding reflected marked hemispheric discrepancies, with a left visual field (RHS) bias to target colour (comprising the first evidence of this for infants) and a contrary right visual field [left hemisphere (LHS)] advantage for distractor pattern. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This experiment investigates neonatal intersensory functioning between touch and vision for texture density. The experiment compared manual activity (holding time and hand pressure frequency) recorded on objects in the presence (test period) or absence of visual information (pre-test and post-test periods). Thirty-two babies were assigned to four experimental conditions according to texture density of the objects held and seen during the test period: Objects had either the same (matching conditions) or different (mismatching conditions) texture density information. The results clearly showed that in matching conditions, holding times were systematically increased during the test period. However, hand pressure frequency remained unchanged over the three test periods. In the mismatching conditions, holding times remained unchanged over the three test periods. However, hand pressure frequency systematically changed during the test period according to the texture density of the visual object. These results indicate newborns' capability to compare texture density information across modalities. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 38: 123–132, 2001 [ABSTRACT FROM AUTHOR]

Provides an overview on the development of visual attention in infancy. Relationship between attention and infant cognition; Ascending brainstem pathways and functions related to alertness; Components of spatial orienting and their neutral substrates; Development of spatial orienting; Development of attention to object features; Substrates of endogenous visual attention.

Examines the effects of auditory and other communicative experience on development of visual attention in infants. Development of visual attention by deaf and hearing infants; Association between infants' hearing status and patterns of visual attention; Differences in time in various attention states of infants; Relation of early visual attention on maturation, communicative experiences and other developing skills.

Testes newborns, six-week-olds and 12-week-olds with three pairs of face and nonface stimuli modified from previous studies. Use of a standardized method based on the Teller acuity card procedure; Influence of the visibility of the stimuli and by the resemblance to a human face on newborns' preferences; Mechanism predisposing newborns to look toward faces.

Focuses on five- and eight-month-old infants' sensitivity to line junctions in curved objects. Infant vision; Pictorial depth cues; Statis-monocular depth information; Perception of line junctions; Visual and depth perception.

Focuses on a study which investigated the influence of the essential fatty acid status and some potentially confounding factors on the visual acuity acuity at 7 months of age, in children born at term. Materials and methods; Results and discussion; Conclusion.

Evaluates the role of visual input during reaching and grasping in infants. Behavioral and kinematic measures; Completion of reach and grasp to a darkened object; Use of vision when object is visible; Increased infant contact with illuminated object.

Examines the preference for orienting to novel locations and novel objects in infants. Development of preference for novel locations; Relation of development to the ability to program eye movements; Comparison of inhibition of return of six- and three-month old infants.

Studies the effect of self-produced locomotion in the visual control of posture in infants and the use of optic flow for postural control. Analysis of infant postural response as a function of age; Interaction of optic flow with age and condition of wall motion; Visual experience as a factor in the use of optic flow.

Studies the importance of vision in early reaching of infants by presenting infants with moving objects at two lighting conditions. Studies demonstrating the ability of infants to reach objects without vision; Success rate for contacting the target object; Tendency of infants to reach for a moving object using their contralateral hand; Ability of infants to anticipate the object's movement.

Presents the results of a study in which visual fixation in infants from three to six months of age was examined for its fit to the theory of `attentional inertia.' How the study was conducted; Discussion on the theory of `attentional inertia; Findings of the study.