The key to understanding core knowledge resides in the fetus.

What Babies Know outlines a compelling case for why infancy research is fundamental for conceptualizing what it is to be human. There is another period in human development that is relatively inaccessible, yet is more important. In order to truly understand the nature of core knowledge, perception, and cognition, we must start not with the infant, but with the fetus.

Should I follow your virtual gaze? Infants' gaze following over video call.

From 10 months of age, human infants start to understand the function of the eyes in the looking behavior of others to the point where they preferentially orient toward an object if the social partner has open eyes rather than closed eyes. Thus far, gaze following has been investigated in controlled laboratory paradigms. The current study investigated this early ability using a remote live testing procedure, testing infants in their everyday environment while manipulating whether the experimenter could or could not see some target objects. A total of 32 11- and 12-month-old infants' looking behavior was assessed, varying the experimenter's eye status condition (open eyes vs closed eyes) in a between-participant design. Results showed that infants followed the gaze of a virtual social partner and that they preferentially followed open eyes rather than closed eyes. These data generalize past laboratory findings to a noisier home environment and demonstrate gaze processing capacities of infants to a virtual partner interacting with the participants in a live setup.

Offline Calibration for Infant Gaze and Head Tracking across a Wide Horizontal Visual Field.

Most well-established eye-tracking research paradigms adopt remote systems, which typically feature regular flat screens of limited width. Limitations of current eye-tracking methods over a wide area include calibration, the significant loss of data due to head movements, and the reduction of data quality over the course of an experimental session. Here, we introduced a novel method of tracking gaze and head movements that combines the possibility of investigating a wide field of view and an offline calibration procedure to enhance the accuracy of measurements. A 4-camera Smart Eye Pro system was adapted for infant research to detect gaze movements across 126° of the horizontal meridian. To accurately track this visual area, an online system calibration was combined with a new offline gaze calibration procedure. Results revealed that the proposed system successfully tracked infants' head and gaze beyond the average screen size. The implementation of an offline calibration procedure improved the validity and spatial accuracy of measures by correcting a systematic top-right error (1.38° mean horizontal error and 1.46° mean vertical error). This approach could be critical for deriving accurate physiological measures from the eye and represents a substantial methodological advance for tracking looking behaviour across both central and peripheral regions. The offline calibration is particularly useful for work with developing populations, such as infants, and for people who may have difficulties in following instructions.

Identifying the limits of peripheral visual processing in 9-month-old infants.

Most fundamental aspects of information processing in infancy have been primarily investigated using simplified images centrally presented on computer displays. This approach lacks ecological validity as in reality the majority of visual information is presented across the visual field, over a range of eccentricities. Limited studies are present, however, about the extent and the characteristics of infant peripheral vision after 7 months of age. The present work investigates the limits of infant (9-month-olds) and adult visual fields using a detection task. Gabor patches were presented at one of six eccentricities per hemifield, from 35° up to 60° in the left and right mid-peripheral visual fields. Detection rates at different eccentricities were measured from video recordings (infant sample) or key press responses (adult sample). Infant performance declined below chance level beyond 50°, whereas adults performed at ceiling level across all eccentricities. The performance of 9-month-olds was unequal even within 50°, suggesting regions of differential sensitivity to low-level visual information in the infant's periphery. These findings are key to understanding the limits of visual fields in the infant and, in turn, will inform the design of future infant studies.

Understanding the causes and consequences of variability in infant ERP editing practices.

The current study examined the effects of variability on infant event-related potential (ERP) data editing methods. A widespread approach for analyzing infant ERPs is through a trial-by-trial editing process. Researchers identify electroencephalogram (EEG) channels containing artifacts and reject trials that are judged to contain excessive noise. This process can be performed manually by experienced researchers, partially automated by specialized software, or completely automated using an artifact-detection algorithm. Here, we compared the editing process from four different editors-three human experts and an automated algorithm-on the final ERP from an existing infant EEG dataset. Findings reveal that agreement between editors was low, for both the numbers of included trials and of interpolated channels. Critically, variability resulted in differences in the final ERP morphology and in the statistical results of the target ERP that each editor obtained. We also analyzed sources of disagreement by estimating the EEG characteristics that each human editor considered for accepting an ERP trial. In sum, our study reveals significant variability in ERP data editing pipelines, which has important consequences for the final ERP results. These findings represent an important step toward developing best practices for ERP editing methods in infancy research.

Is schizotypic maternal personality linked to sensory gating abilities during infancy?

Schizotypy is a personality dimension within the general population elevated among schizophrenia-spectrum patients and their first-degree relatives. Sensory gating is the pre-attentional habituation of responses distinguishing between important and irrelevant information. This is measured by event-related potentials, which have been found to display abnormalities in schizophrenic disorders. The current study investigated whether 6-month-old infants of mothers with schizotypic traits display sensory gating abnormalities. The paired-tone paradigm: two identical auditory tones (stimulus 1 and stimulus 2) played 500 ms apart, was used to probe the selective activation of the brain during 15-minutes of sleep. Their mothers completed the Oxford and Liverpool Inventory of Feelings and Experiences-Short Form as an index of schizotypy dimensionality, categorized into: infants of control, and infants of schizotypic, mothers. The findings revealed that although the infants' P50 components displayed significant differences between stimulus 1 and stimulus 2 in the paired-tone paradigm, there was no clear difference between infants of schizotypic and infants of control mothers. In contrast, all mothers displayed significant differences between stimulus 1 and stimulus 2, as observed in the infants, but also significant differences between their sensory gating ability correlated with schizotypy dimensionality. These findings are consistent with sensory processes, such as sensory gating, evidencing impairment in schizophrenia-spectrum disorders. The present research supports the idea that first-degree relatives of individuals who identify on this spectrum, within the sub-clinical category, do not display the same deficit at 6 postnatal months of age.

Semantic processing of actions at 9months is linked to language proficiency at 9 and 18months.

The current study uses event-related potential methodologies to investigate how social-cognitive processes in preverbal infants relate to language performance. We assessed 9-month-olds' understanding of the semantic structure of actions via an N400 event-related potential (ERP) response to action sequences that contained expected and unexpected outcomes. At 9 and 18months of age, infants' language abilities were measured using the Swedish Early Communicative Development Inventory (SECDI). Here we show that 9-month-olds' understanding of the semantic structure of actions, evidenced in an N400 ERP response to action sequences with unexpected outcomes, is related to language comprehension scores at 9months and is related to language production scores at 18months of age. Infants who showed a selective N400 response to unexpected action outcomes are those who are classed as above mean in their language proficiency. The results provide evidence that language performance is related to the ability to detect and interpret human actions at 9months of age. This study suggests that some basic cognitive mechanisms are involved in the processing of sequential events that are shared between two conceptually different cognitive domains and that pre-linguistic social understanding skills and language proficiency are linked to one another.

Theta- and alpha-band EEG activity in response to eye gaze cues in early infancy.

In order to elucidate the development of how infants use eye gaze as a referential cue, we investigated theta and alpha oscillations in response to object-directed and object-averted eye gaze in infants aged 2, 4, 5, and 9months. At 2months of age, no difference between conditions was found. In 4- and 9-month-olds, alpha-band activity desynchronized more in response to faces looking at objects compared to faces looking away from objects. Theta activity in 5-month-old infants differed between conditions with more theta synchronization for object-averted eye gaze. Whereas alpha desynchronization might reflect mechanisms of early social object learning, theta is proposed to imply activity in the executive attention network. The interplay between alpha and theta activity represents developmental changes in both kinds of processes during early infancy.

The Detection of Face-like Stimuli at the Edge of the Infant Visual Field.

Human infants are highly sensitive to social information in their visual world. In laboratory settings, researchers have mainly studied the development of social information processing using faces presented on standard computer displays, in paradigms exploring face-to-face, direct eye contact social interactions. This is a simplification of a richer visual environment in which social information derives from the wider visual field and detection involves navigating the world with eyes, head and body movements. The present study measured 9-month-old infants' sensitivities to face-like configurations across mid-peripheral visual areas using a detection task. Upright and inverted face-like stimuli appeared at one of three eccentricities (50°, 55° or 60°) in the left and right hemifields. Detection rates at different eccentricities were measured from video recordings. Results indicated that infant performance was heterogeneous and dropped beyond 55°, with a marginal advantage for targets appearing in the left hemifield. Infants' orienting behaviour was not influenced by the orientation of the target stimulus. These findings are key to understanding how face stimuli are perceived outside foveal regions and are informative for the design of infant paradigms involving stimulus presentation across a wider field of view, in more naturalistic visual environments.

Infants Oscillatory Frequencies change during Free-Play.

Social interactions are known to be an essential component of infant development. For this reason, exploring functional neural activity while infants are engaged in social interactions will enable a better understanding of the infant social brain. This in turn, will enable the beginning of disentangling the neural basis of social and non-social interactions as well as the influence that maternal engagement has on infant brain function. Maternal sensitivity serves as a model for socio-emotional development during infancy, which poses the question: do interactions between parents and their offspring present altered electrophysiological responses in comparison to the general population if said parents are at risk of mental health disorders? The current research aimed to observe the oscillatory activity of 6-month-old infants during spontaneous free-play interactions with their mother. A 5-minute unconstrained free-play session was recorded between infant-mother dyads with EEG recordings taken from the 6-month-old infants (n = 64). During the recording, social and non-social behaviours were coded and EEG assessed with these epochs. Results showed an increase in oscillatory activity both when an infant played independently or interacted with their mother and oscillatory power was greatest in the alpha and theta bands. In the present 6-month-old cohort, no hemispheric power differences were observed as oscillatory power in the corresponding neural regions (i.e. left and right temporal regions) appeared to mirror each other. Instead, temporal estimates were larger and different from all other regions, whilst the frontal and parietal regions bihemispherically displayed similar estimates, which were larger than those observed centrally, but smaller than those displayed in the temporal locations. The interactions observed between the behavioural events and frequency bands demonstrated a significant reduction in power comparative to the power observed in the gamma band during the baseline event. The present research sought to explore the obstacle of artificial play paradigms for neuroscience research, whereby researchers question how much these paradigms relate to reality. The present manuscript will discuss the strengths and limitations of taking an unconstrained free-play approach.

Fetal eye movements in response to a visual stimulus.

INTRODUCTION: In 2D ultrasound, the lens of the fetal eye can be distinguished as white circles within the hypoechoic eyeball, and eye movements can be visualized from about 15 weeks' gestation. It has been shown that from 31 weeks gestational age the fetal sensory system is capable of directed vision if enough light is available. METHODS: We have developed a light source for delivering visual stimuli to be seen by the fetal eye, using laser dot diodes emitting at 650 nm. The 2D component of 94 fetal ultrasound scans (mean gestational age 240 days), where the light stimulus was presented, was coded to determine whether the eyes moved in response to the stimuli independent of any head movement. RESULTS: The light stimulus significantly provoked head and eye movements, but after the light was withdrawn the head stopped moving, yet the eyes continued to move. CONCLUSION: This provides evidence for visual attention mechanisms that can be controlled through eye movements that are independent of head movements prior to birth.

Looking at eye gaze processing and its neural correlates in infancy-implications for social development and autism spectrum disorder.

The importance of eye gaze as a means of communication is indisputable. However, there is debate about whether there is a dedicated neural module, which functions as an eye gaze detector and when infants are able to use eye gaze cues in a referential way. The application of neuroscience methodologies to developmental psychology has provided new insights into early social cognitive development. This review integrates findings on the development of eye gaze processing with research on the neural mechanisms underlying infant and adult social cognition. This research shows how a cognitive neuroscience approach can improve our understanding of social development and autism spectrum disorder.

The neural correlates of infant and adult goal prediction: evidence for semantic processing systems.

The sequential nature of action ensures that an individual can anticipate the conclusion of an observed action via the use of semantic rules. The semantic processing of language and action has been linked to the N400 component of the event-related potential (ERP). The authors developed an ERP paradigm in which infants and adults observed simple sequences of actions. In one condition the conclusion of the sequence was anticipated, whereas in the other condition the conclusion was not anticipated. Adults and infants at 9 months and 7 months were assessed via the same neural mechanisms-the N400 component and analysis of the theta frequency. Results indicated that adults and infants at 9 months produced N400-like responses when anticipating action conclusions. The infants at 7 months displayed no N400 component. Analysis of the theta frequency provided support for the relation between the N400 and semantic processing. This study suggests that infants at 9 months anticipate goals and use similar cognitive mechanisms to adults in this task. In addition, this result suggests that language processing may derive from understanding action in early development.

Links between action perception and action production in 10-week-old infants.

In order to understand how experience of an action alters functional brain responses to visual information, we examined the effects of reflex walking on how 10-week-old infants processed biological motion. We gave experience of the reflex walk to half the participants, and did not give this experience to the other half of the sample. The participant's electrical brain activity in response to viewing upright and inverted walking and crawling movements indicated the detection of biological motion only for that group which experience the reflex walk, as evidenced by parietal electrode greater positivity for the upright than the inverted condition. This effect was observed only for the walking stimuli. This study suggests that parietal regions are associated with the perception of biological motion even at 9-11 weeks. Further, this result strongly suggests that experience refines the perception of biological motion and that at 10 weeks of age, the link between action perception and action production is tightly woven.

N400 involvement in the processing of action sequences.

Understanding others' sequences of action is a fundamental aspect of human movement and is the key to detecting goal directed behavior and intentional actions. Human action contains semantic information whereby logical chains of events are entirely dependent on the sequence in which they are performed. The sequential nature of action ensures that an observing individual anticipates the conclusion of a viewed action. This experiment reports on the results of 15 participants who viewed videos of an actress performing actions. Half the stimuli contained an anticipated conclusion to the action whereas half did not. Results from the passive viewing of stimuli depicting eating actions indicated an increased N400 response over frontal, central and parietal regions when viewing the unanticipated conclusions of the actions as compared with the amplitude for the anticipated condition. These results show that (1) neural systems exist to rapidly discern semantic information in actions, and (2) the N400 component, which predicts semantic information in language, also anticipates information within goal directed action.

Social cognition in the first year.

Although the study of infancy has answered many important questions about the human capacity for social cognition, the relatively young field of developmental social cognition is far from reaching its adulthood. With the merging of developmental, behavioral and neurocognitive sciences, some growing pains are in store. New work demonstrates that research into early social cognitive development must integrate various research fields and methods in order to achieve a more robust understanding of the nature and parameters of human social cognition.

Neural correlates of the perception of goal-directed action in infants.

We investigated the neural correlates of the perception of human goal-directed action by 8-month-old infants. Infants viewed video loops of complete and incomplete actions, which they could discriminate according to our pilot study, while we recorded their electrophysiological brain activity. Analysis of bursts of gamma-band oscillations resulting from passive viewing of these stimuli indicated increased gamma-band activity over left frontal regions when viewing incomplete actions as compared with complete actions. These results suggest that by 8 months infants are sensitive to the disruption of perceived goal-directed actions.

Event-related potentials discriminate familiar and unusual goal outcomes in 5-month-olds and adults.

Previous event-related potential (ERP) work has indicated that the neural processing of action sequences develops with age. Although adults and 9-month-olds use a semantic processing system, perceiving actions activates attentional processes in 7-month-olds. However, presenting a sequence of action context, action execution and action conclusion could challenge infants' developing working memory capacities. A shortened stimulus presentation of a highly familiar action, presenting only the action conclusion of an eating action, may therefore enable semantic processing in even younger infants. The present study examined neural correlates of the processing of expected and unexpected action conclusions in adults and infants at 5 months of age. We analyzed ERP components reflecting semantic processing (N400), attentional processes (negative central in infants; P1, N2 in adults) and the infant positive slow wave (PSW), a marker of familiarity. In infants, the PSW was enhanced on left frontal channels in response to unexpected as compared to the expected outcomes. We did not find differences between conditions in ERP waves reflecting semantic processing or overt attentional mechanisms. In adults, in addition to differences in attentional processes on the P1 and the N2, an N400 occurred only in response to the unexpected action outcome, suggesting semantic processing taking place even without a complete action sequence being present. Results indicate that infants are already sensitive to differences in action outcomes, although the underlying mechanism which is based on familiarity is relatively rudimentary when contrasted with adults. This finding points toward different cognitive mechanisms being involved in action processing during development. (PsycINFO Database Record

The Human Fetus Preferentially Engages with Face-like Visual Stimuli.

In the third trimester of pregnancy, the human fetus has the capacity to process perceptual information [1-3]. With advances in 4D ultrasound technology, detailed assessment of fetal behavior [4] is now possible. Furthermore, modeling of intrauterine conditions has indicated a substantially greater luminance within the uterus than previously thought [5]. Consequently, light conveying perceptual content could be projected through the uterine wall and perceived by the fetus, dependent on how light interfaces with maternal tissue. We do know that human infants at birth show a preference to engage with a top-heavy, face-like stimulus when contrasted with all other forms of stimuli [6, 7]. However, the viability of performing such an experiment based on visual stimuli projected through the uterine wall with fetal participants is not currently known. We examined fetal head turns to visually presented upright and inverted face-like stimuli. Here we show that the fetus in the third trimester of pregnancy is more likely to engage with upright configural stimuli when contrasted to inverted visual stimuli, in a manner similar to results with newborn participants. The current study suggests that postnatal experience is not required for this preference. In addition, we describe a new method whereby it is possible to deliver specific visual stimuli to the fetus. This new technique provides an important new pathway for the assessment of prenatal visual perceptual capacities.

The perception of biological motion by infants: an event-related potential study.

The current study investigates how human infants process and interpret human movement. Neural correlates to the perception of biological motion by 8-month-old infants were assessed. Analysis of event-related potentials (ERPs) resulting from the passive viewing of upright and inverted point-light displays (PLDs) depicting human movement indicated a larger positive amplitude in right parietal regions between 200 and 300 ms for observing upright PLDs when compared with observing inverted PLDs. These results show that infants at 8 months of age process upright and inverted PLDs differently from each other. The implications for our understanding of infant visual perception are discussed.