Active sleep is associated with the face preference in the newborns who familiarized with a responsive face

Aim of this study was to investigate the preferential looking behaviour, subsequent to a familiarization task (8-min) with a previously responsive or motionless face, before and after a sleep cycle. Moreover, the role of the active sleep in memory consolidation of the responsive or motionless faces was explored. Hypotheses were that the newborns undergoing a motionless familiarization will exhibit a novelty effect (preference for the novel face) whereas the newborns undergoing a responsive familiarization will show a familiarity effect (preference for the known face) before and after the sleep cycle; moreover, the amount of active sleep will be associated with the looking time at the known face after a sleep cycle.Forty-five healthy full-term newborns were randomly assigned to two groups (group 1: motionless-familiarization and group 2: responsive-familiarization); in both groups newborns were video-recorded during four post-familiarization face-preference tasks, two of them performed before and two after a sleep cycle.During the pre-sleep-trials, there was not a significant preference for one face in both groups. During the post-sleep trials, the newborns showed a clear preference for the novel face. This effect was more evident in group 1. Only in group 2 there was a significant positive correlation between the active sleep duration and the looking duration at the known-face during the post-sleep trials (r = 0.41; p = 0.040). Multiple regression confirmed that only in the group 2 the total duration of the active sleep was associated with the looking duration at the known-face during the post-sleep trials (Adjusted R² = 0.13; β = 0.41; t = 2.2; p = 0.040).Findings showed that in newborns the face representation can be recalled after a sleep cycle. Moreover, the amount of the active sleep predicted the post-sleep looking toward the known-face only in the newborns who interactively familiarized with the face.     

Newborns' face recognition is based on spatial frequencies below 0.5 cycles per degree

A critical question in Cognitive Science concerns how knowledge of specific domains emerges during development. Here we examined how limitations of the visual system during the first days of life may shape subsequent development of face processing abilities. By manipulating the bands of spatial frequencies of face images, we investigated what is the nature of the visual information that newborn infants rely on to perform face recognition. Newborns were able to extract from a face the visual information lying from 0 to 1 cpd (Experiment 1), but only a narrower 0-0.5 cpd spatial frequency range was successful to accomplish face recognition (Experiment 2). These results provide the first empirical support of a low spatial frequency advantage in individual face recognition at birth and suggest that early in life low-level, non-specific perceptual constraints affect the development of the face processing system.     

The interaction between gaze direction and facial expressions in newborns

The ability to decode facial expressions is an important component of social interaction and functioning. This ability is even more fundamental early in life, prior to the development of verbal communication. However, it is still unclear whether newborns can detect, discriminate and process facial expressions, and, if so, what the mechanisms underlying this ability are. In this study, we extend the investigation of perceived emotional expression by manipulating gaze direction with different facial expressions. Specifically, newborns were presented with faces displaying neutral, fearful, or happy facial expressions accompanied with direct or averted gaze, and tested in a visual preference paradigm. Four experiments were conducted in which different combinations of expression and gaze were used. However, only in the fourth experiment did newborns show a visual preference for a specific emotional display; they looked significantly longer at a happy face than a neutral one only when both were accompanied with direct gaze. These results provide support for the advantage of happy facial expressions in the development of a face processing system and suggest that this preference reflects experience acquired during the first few days after birth.     

Visual statistical learning in the newborn infant

Statistical learning – implicit learning of statistical regularities within sensory input – is a way of acquiring structure within continuous sensory environments. Statistics computation, initially shown to be involved in word segmentation, has been demonstrated to be a general mechanism that operates across domains, across time and space, and across species. Recently, statistical leaning has been reported to be present even at birth when newborns were tested with a speech stream. The aim of the present study was to extend this finding, by investigating whether newborns’ ability to extract statistics operates in multiple modalities, as found for older infants and adults. Using the habituation procedure, two experiments were carried out in which visual sequences were presented. Results demonstrate that statistical learning is a general mechanism that extracts statistics across domain since the onset of sensory experience. Intriguingly, present data reveal that newborn learner’s limited cognitive resources constrain the functioning of statistical learning, narrowing the range of what can be learned.     

The role of rigid motion in newborns' face recognition

The study investigated whether dynamic information promotes newborns' ability to recognize a face. After being habituated to a face undergoing an ordered sequential head rigid motion (Exp. 1), 1- to 3-day-old newborns fully recognized the familiar face shown in the profile pose, as documented by a preference for the profile pose of a novel face. When familiarized to an ordered sequence of different viewpoint static images of a face (Exp. 2), newborns failed to recognize the profile pose of the familiar face, their visual exploration of the familiar and novel faces being at chance. Habituation to a random head rigid motion (Exp. 3) allowed only a partial recognition of face identity, as newborns preferred the profile pose of the familiar, rather than the novel, face. Rigid head motion is an important source of information for newborns' face recognition, probably aiding the derivation of a three-dimensional face structure.     

Newborn preference for a new face vs. a previously seen communicative or motionless face

Newborn infants prefer to look at a new face compared to a known face (still-face). This effect does not happen with the mother-face. The newborns could be attracted by the mother-face because, unlike the still-face, it confirms an expectation of communication.Fifty newborns were video-recorded. Sixteen of them were recruited in the final sample: nine were exposed to a communicative face and seven to a still-face. All the 16 newborns were successively exposed to two preference-tasks where a new face was compared with the known face.Only newborns previously exposed to a still-face preferred to look at a new face instead of the known face. The results suggest that the newborns are able to build a dynamic representation of faces.     

Factors influencing newborns' preference for faces with eye contact

We investigated newborns' sensitivity to the direction of gaze of another's face by using a preferential looking technique. This study extends earlier work on a preference for faces with direct gaze in newborns. In Experiment 1, we replicate the basic finding of Farroni and colleagues that newborns prefer to look at faces with direct gaze. In Experiments 2 and 3, we establish that a preference for faces with direct gaze in newborns is present only within the context of an upright face and a straight head, suggesting that relatively primitive configuration-sensitive mechanisms may be operating. Overall, these results further the view that relatively simple perceptual biases in newborns may be an essential foundation for later social-cognitive development.     

Newborns' recognition of changing and unchanging aspects of schematic faces

The present study investigated newborns' ability to discriminate, recognize, and learn visual information embedded in the schematic face-like patterns preferred at birth. Four experiments were carried out using the visual-paired comparison paradigm. Results indicated that newborns discriminated face-like stimuli relying on their internal features (Experiments 1 and 4) and recognized a perceptual invariance between face-like configurations in conditions of low (Experiment 2) and high-perceptual variability (Experiment 3) of their inner elements. Altogether, data show that the presence of the preferred structure that schematically defines a face, displaying a triplet of elements in the correct locations for eyes and mouth, does not constitute a limit that constrains newborns' face learning processes.     

Neonatal finger and arm movements as determined by a social and an object context

What kind of hand and finger movements are newborn infants preoccupied with, and how are these movements organized and controlled? These questions were studied in two experiments under three conditions: a social condition, in which the mother (in expt 1) or the experimenter (in expt 2) sat face to face with the infant; an object condition, in which a ball moving slowly and irregularly was presented to the infant; and a baseline condition (in expt 1) without ball or mother present. The size of the ball and the distance to it was chosen so that it approximately corresponded to the visual angle of the head of the model. Twenty-six neonates participated in the study ranging from 2 to 6 days of age at the time of observation. All infants were in an alert, optimal awake state during the experiments. The infants' finger movements were scored from video recordings. The result revealed a large variety of relatively independent finger movements. It was found that finger movements differed both in quantity and quality between the three conditions. There were many more finger movements in the social condition than in the object and baseline conditions. In addition, there were relatively more transitional finger movements and flexions of the hand in the social condition, and relatively more thumb-index finger activity and extensions of the hand in the object condition. Finally, the arms were more often forward extended in the object condition than in the social condition. The results support the notion that neonates show different modes of functioning towards people and objects.     

Suprasegmental information affects processing of talking faces at birth

From birth, newborns show a preference for faces talking a native language compared to silent faces. The present study addresses two questions that remained unanswered by previous research: (a) Does the familiarity with the language play a role in this process and (b) Are all the linguistic and paralinguistic cues necessary in this case? Experiment 1 extended newborns’ preference for native speakers to non-native ones. Given that fetuses and newborns are sensitive to the prosodic characteristics of speech, Experiments 2 and 3 presented faces talking native and nonnative languages with the speech stream being low-pass filtered. Results showed that newborns preferred looking at a person who talked to them even when only the prosodic cues were provided for both languages. Nonetheless, a familiarity preference for the previously talking face is observed in the “normal speech” condition (i.e., Experiment 1) and a novelty preference in the “filtered speech” condition (Experiments 2 and 3). This asymmetry reveals that newborns process these two types of stimuli differently and that they may already be sensitive to a mismatch between the articulatory movements of the face and the corresponding speech sounds.